From: John De Armond
X-Source: The Hotrod Mailing list
Date: Apr 1992
Subject: Re: copper head gaskets

>  Thanks for the terrific info on head sealing. I will definitely try it.
>Now what about this Datsun?!! Street car, strip car, road course..?

Street sleeper.  Looks stock except for the 3.5" exhaust out the back.
I estimate from acceleration calculations about 400 hp.

>How fast is it?

Well it's not right now.  Broke a piston.  I was out on the interstate
with the radar gun mounted on the dash.  I had 10 psi of boost dialed
in, was wide open, had 155 on the radar gun, reached down to start running
the boost up and... A fleck of scale stopped the water injection nozzle
up.  Instant detonation and piston kit.  *Sob*.  New pistons are on the
way.

>Are you intercooled?

I will be this time.  I'd relied on heavy water injection before.  Aside
from the reliability problem, it uses WAY too much water to be a
practical street car.   That loud pedal just screams to be mashed.
You can  almost hear the water flow when you do.

It's a riot.  The engine makes enough torque that you can see the hood
line distort when the boost hits.  God, have I had fun with the
string back glove crowd :-)

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: Apr 1992
Subject: RE: COPPER HEAD GASKETS

> What type of water injection are you running?  Two stage pump, or just
>pressurized feed from the water bottle?

I have a ~3 gallon tank I fabricated to tuck in below the battery in
the Z engine compartment.  this is pressureized from the manifold.
Water flows from this through an adjustable holdoff valve set to 5 psi,
through a holly carb jet and into the intake right in front of the
turbine inlet.  This provides flow proportional to boost pressure and
is lots simpler than the electronic ones.  I've considered a
block arrangement whereby the flow is blocked until the knock sensor
detects detonation.  If I still need water injection after the addition
of the intercooler, I might do that.

> My Yamaha is extremely sensitive to ambient air temperature, enough

It would work on the bike but I'm not sure where you'd put the water.

> At 15psi on the Yamaha, it's like a giant Foot out of Heaven, booting
>you right in the arse.

I can just imagine.

>-> God, have I had fun with the string back glove crowd :-)
>
> You mean those cretins who drive *stock* cars?  <sniff>

Particularly the portch/corvette/infiniti/lexus/bmw/benz crowd.
Funniest look I ever got was from this dood in a (what's that high
buck porche that looks like a turd on wheels?  929?) complete with
the little hat, the gloves, the glasses and all that stuff that
I blasted onto the emergency lane :-)

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: Apr 1992
Subject: Re: Stringback crowd

>	You should have seen the look on the Mustang driver's face when our
>beat up old Datsun 510 with four people piled in it showed him our tailights
>right after he smirked at the car and said "You guys wouldn't have a chance!"
>        If only we could control the flame shooting abilities of the rotary,
>a little puff of flame would have really topped it off.

I gotta tell you about one of the funniest runs I ever did.  I had
just broken the piston in the turbo motor.  Still ran fine but
laid a mosquito cloud like nothing you've ever seen :-)  I was backing
out of my drive when the door popped open, snagged the dirt bank and
ripped the door off.  Hmm, time to do all that body work I'd been
planning on.  So I throw the door in the truck and take it along
with all my new parts over to the body shop.  Then I go to get the Z.

Now imagine this.  Faded red paint, dented right side front quarter
thanks to a hit'n'run parking lot altercation, door missing and
smoking like a freight train.

So I'm sitting at this traffic light, the last one on the way out of
town.  The road beyond is mostly downhill, about half a mile of
divided 4 lane.  This BRAND NEW 300zx turbo pulls up beside me.  Now I'm sitting
there with no door so I could hear them laughing.  Bunch of kids.
I ask 'em if they want to go for it?  More laughs.  I call 'em chicken.
Laughing stops.  I get the christmas tree, er green light :-)  The
ZX lights the tires.  Just to make it fair, I wait until they actually
start moving before I nail it.  By the time I got to the other end of
the 4 lane, I could see only white smoke.  I pulled over to wait on 'em.
Smoke clears.  They're about 3/4 down the road and are attempting to
turn around across the median  :-)  They would NOT come down
and face their victor.  What a riot.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: May 1992
Subject: Re: turbocharger scavenge pump

> Okay, now for the question:  what about an electric scavenge pump?
>I'm pretty sure a Mallory pump like I'm using in the fuel system will
>work, but I'm concerned about what would happen if the pump quit.  I'm
>guessing the mechanical pressure pump (the turbo's oil taps off the main
>pump) would push oil out into the compressor and exhaust housings, since
>the Hitachi turbo has no seals.  Best as I can figure, the turbo would
>still get oil, but the bike would fog mosquitoes for a few miles until
>it quit from oil fouling.  I could handle that; I just don't want to
>have to hunt down another turbo if the electric pump dies.

I don't know if the pump will work or not but an easy way to mitigate
the risk of loss of return flow is simply to tee the return line and
run the tee'd line to the top of the cylinder head somewhere.  Normally
the pump will handle the flow and the head pressure will keep the
oil where it belongs.  If the pump quits, there will be enough pressure
to push the oil up the tube to the cam cover.  There may be some smoking
from the exit line head pressure but the flow won't stop.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: May 1992
Subject: Re: turbocharger scavenge pump

>emory!chaos.lrk.ar.us!dave.williams (Dave Williams)

>-> I don't know if the pump will work or not but an easy way to mitigate
>-> the risk of loss of return flow is simply to tee the return line and
>-> run the tee'd line to the top of the cylinder head somewhere.
>-> Normally the pump will handle the flow and the head pressure will
>-> keep the oil where it belongs.  If the pump quits, there will be
>-> enough pressure to push the oil up the tube to the cam cover.
>
> CAM COVER?  The turbo is *underneath* the engine; I was planning to run
>the return line to the top of the transmission housing.

I know.  Read what I said.  The line to the cam cover would normally do
nothing other than vent the turbo.  Only if the pump failed would
oil flow up and over the turbo.  Like I said, it will probably smoke
but it won't fail the turbo.  I'd go to the transmission vent only
with extreme caution.  Obstructing this vent can cause the engine to
start oiling.

> If I tee the line, the scavenge pump would just suck air, right?  Most
>electric pumps have warnings about not doing that.

You've almost got to have an air vent in the exhaust line.  All the literature
warns you about allowing the oil exhaust line from going solid with oil.
Among the other problems, the excess oil in the bearing capsule can cause it
to overheat or at the least reduce the performance of the blower from
the extra drag.  I can't imagine the oily froth that normally emits from
a turbo being harmful to a scavenging pump but it's something to check on.

From: John De Armond
X-Source: The Hotrod Mailing list
Date: Jun 1992
Subject: Re: turbocharger scavenge pump

In wiz.hotrod you write:

> The service manual for the XJ has about fifty pages of exploded views,
>assembly drawings, drawings of every single part, and flow charts.
>There's nothing that looks like a vent in the scavenge line - the
>scavenge pump (which is below the crankcase oil level) pulls through a
>port on the left side of the motor, which has a flex hose running back
>to the turbo's oil outlet.

> We're not talking about a drainback line - the setup is designed to
>work with a scavenge pump.  Unless I've missed your point again?  It's
>been one of those weekends.

I'm reluctant to try to address this particular engine because I've
never worked on one but I've never seen a turbo designed to have a solid
(ie, no air return path) oil exhaust.  Not saying it can't be done.
Just that I've never seen it.  If the turbo is designed for a solid
return, more the better.  Unless you can come up with some kind of bypass
mechanism that probably won't work when you need it, a vent will still be
the safest bypass to accomidate scavenge pump failure.  If the scavenge
pump really cannot tolerate air, a check valve (brake booster checkvalve,
for instance) would keep air out but let oil overflow if the pump
fails.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: Jun 1992
Subject: Re: Intercoolers (was Re: Water injection)

>My plan is to place it directly between the turbo and the manifold on
>top of the engine and cut a hole in the hood over top of it. This keeps
>the runner short for better "throttle" response. Cooling air would be
>supplied by a duct from the chin spoiler (yes it has one). I would do
>and after checks for exhaust gas temp. under load and then fiddle with
>maximum fuel delivery and boost pressure until I get close to the
>original exhaust gas temp.

As long as the engine is port fuel  injected, the manifold volume and
length has virtually no effect on throttle response.  I used to
think it did too and experience with carburated engines will lead
you to that conclusion.  Then I was talking to someone at Ford Research
who knows about this stuff and mentioned the problem.  He said not
to worry about it and suggested I do the math on pneumatic time constants
to confirm it.  I did and did some experiments involving adding a lot
of volume to the intake (a pony keg, actually :-) of a FI turbo car.
He was right.  What happens in a carburated car is the long manifold
upsets the mixture and the lag results from this bad mixture having to
flow out.  Getting rid of the airflow meter if you have one and
replacing it with a MAP system will remove any residual mixture upset.

Don't worry about intake length.  Worry about placement.  The single
most important ingredient to getting an intercooler to work right is
getting enough air across it.  Buy the current edition of Hugh
MacInnes' book "Turbochargers" and read the chapter on the subject.
His opinion is if you have to make a tradeoff, sacrifice radiator cooling
for intercooling.  The thermal mass of the block and coolant cushions
sudden heat loads.  The intercooler's needs are instantaneous when
you hit the throttle.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Date: Jul 1992
Subject: re: MacInnes book on turbos

>->relatively small engines.  Nowadays you can drop by the junkyard and
>->pick up turbos for practically nothing - I have a couple of AiResearch
>->jobs in the shed I paid $75 each for.
>
>This never occurred to me - you can get a semi-decent turbo from
>a junk yard?  What are the indicators of wear/goodness?

Good clean and straight impellers with no significant divots from debris
(there will almost always be some dust erosion), no oil deposits on
the turbine impeller, no coked oil in the oil passages and a free
turning shaft.  Beyond that, the best indicator is whether the junque
yard has more than one so you can swap it if it is bad.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Subject: Re: Turbos and towing
Date: Wednesday, Jul 22 1992 03:35:23
X-Sequence: 1693

>Judging solely by my Cummins-powered W350 (Dodge one-ton, 4x4, turbocharged
>Diesel), *exhaust* temperature may be the limiting consideration.  I don't
>have a 'feel' for exhaust temperature in a gasoline turbocharged engine,
>but there is a specified maximum for my Diesel (1290 F).  Above this
>temperature, damage to exhaust valves may occur?  Combustion temp, cylinder
>pressure, exhaust temp and (probably) catalytic converter temp will all
>rise...

Almost on the money.  The main concern is overheating turbo housing and
wheel.  The combination of high turbine speed and high temperature
can cause the wheel to explode.  I'd consider the 1290 spec to be
right for gas turbos too.  The correct way to limit the stress while
towing is to install an EGT.  These things are cheap and easy to
install.  Just keep the exhaust temp below 1290 and don't worry about
what the boost is.

John

From: John De Armond
X-Source: The Hotrod Mailing list
Subject: Re: BBB (Big Block Buick) Turbos
Date: Wednesday, Jul 29 1992 02:36:32
X-Sequence: 1748

>It's good to see someone else has a curious streak that parallels my own
>admittedly twisted one!  I've thought that a BBB with twin turbos would be
>easier to control if you used a Holley Pro-Jection injector setup to deliver
>fuel.

You don't want to do that.  Aside from the problems specific to the Pro-
jection I mentioned previously, TBI, at least in a suck-through configuration
is impossible to tune.  There is vastly too much manifold surface to wet
to ever get enough acceleration enrichment with a reasonably sized injector
system.  Intercoolers make it worse.  Unless you change the fuel pump,
blow-through with the pro-jection will not work either.  The cheezy
little pump included in the kit does not have enough spare head to
compensate 10-15 psi of boost.  I found it interesting that this
tiny little pump pulls almost 8 amps under normal conditions while a
Bosch pump installed in exactly the same conditions only pulled 2 amps
and made a LOT less noise.

>The biggest problem I see is the EXPENSE!  I wonder if any GN technology
>could be borrowed and/or adapted to make this work?  Just idle wonderings ...

I ran into an interesting fellow this weekend at the 5th annual Datsun
Z-car Convention in Knoxville, TN.  He had the fastest Zcar I'd ever
driven.  acceleration/coast down estimates of road horsepower is around
600 at 20 psi of boost from his homemade turbo system from a 2800 cc
engine on 110 octane racing gas.  I'm going to write his work up
for the list and for the Z-car list as soon as I get time and I'm going
to do a very detailed article for the magazine because of his nifty
work.  He reminds me of me but without the electronics knowledge.

He used the stock 280 FI manifold, suitably ported, with the injectors
mounted in the stock location right above the valves.  The throttle valve
is in the stock position.  An intercooler is used.

The interesting thing is he had someone build him a very simple analog
fuel injection controller that works from a custom made hot wire airflow
meter.  He used a Bosch hot wire mounted in a 5" diameter pipe.  What is
VERY interesting is the system does NO acceleration enrichment (no
manifold surface is wetted), takes no throttle position input and has
no cold start enrichment to speak of.  All of this flies in the face
of most conventional wisdom.  There are simply idle and WOT mixture
pots that represent the zero and span adjustments of the pulse width
controller.

The throttle response is instantaneous - much faster than I thought
possible with the size turbo used.  On the autocross course there was
a straight coming from a >90 degree turn that was about the length of
the width of 10 parking places in the school parking lot.  I stood behind
the turn and radar gunned the contestants.  Most hotrodded Zs (triple
webers, etc) hit about 45 on the straight.  The built-up small block
conversions (I WANT one) ran in the 55 range.  This turbo car,
despite the large amount of tire spin, hit 65.  This in spite of him
babying the tranny to keep from breaking 1st gear.  This same engine
idled  quietly at 900 rpm (spec) and slogged around in traffic just
like a stocker.

A couple of lessons here.  First, getting the plumbing and the injector
placement right is vital.  Secondly, electronics are really the Godsend of
the 90s for us hotrodders even if we are not electronics experts.

john

Newsgroups: wiz.hotrod
Subject: Re:::  Diesel turbocharger comments
Date: Monday, Jul 27 1992 02:29:33
From: John De Armond

>The only thing that keeps 'nagging' at me is that there are, other than the 
>Roots blower on GMCs, no mechanically-driven supercharged Diesels (that I
>have ever been made aware of).  That fact bothers me...  It seems either
>there is some fundamental reason I'm missing, or it just has never been
>deemed worthwhile...

Two factors.  First, the turbo uses mostly wasted energy.  Big win.
Secondly, a properly matched turbo will run in its 65-70% island
on the compressor map.  A roots supercharger is lucky to be 20% 
efficient.  The added intake air heating causes soot and reduces 
power.  An aftercooler is a partial but expensive solution.
Much cheaper just to hang a turbo on the thing.

John


------
 
Newsgroups: wiz.hotrod
Subject: re: :  Diesel turbocharger comments
Date: Monday, Jul 27 1992 02:41:49
From: jgd (John De Armond)

>On the subject of exhaust manifolding, you need the output from all four
>cylinders to go into the turbo on each side of the engine; supposedly, the
>best setup is the cast iron manifolds, since these will maintain the heat and 
>pressure and will not warp; an adaptor for the manifold to the turbo base
>should work ok - if necessary, you can have a flange welded.

One caution.  These setups invariably keep the exhaust pretty hot and 
welded tube setups almost always bend and leak if there is any
tension on them.  Like holding up a turbo for instance.  I've
had a LOT of trouble with this problem on a wide variety of engines.

>There are a few other things to consider, such as timing, fuel pressure,
>turbo sizing, intake manifolding, etc.  A good place to start is to get 
>Hugh MacInnes' book, "How to Select and Install Turbochargers" from HP books, 
>which gives a lot of good practical information, and is well worth the 
>money, IMHO (about $15).

Yup.

>
>You just need to ask yourself, "do I reeaally need 900HP?"

Well.. Only slightly less than I need a thousand :-)  

John

Newsgroups: wiz.hotrod
Subject: Re:  BBB (Big Block Buick) Turbos
Date: Wednesday, Jul 29 1992 21:23:40
From: John De Armond

>I've been wanting to do a dual turbo number on my 302 Ford for about a year
>now. my problem lies in my EFI unit, it has a 4" MAS and this only allows for
>about 475Hp and the 4-40# injectors will only flow enough for about 440Hp.
>I called the engineer that is responsible for this EFI unit and talked to him
>about my problem. He said that the parent company had killed the gasoline line
>of EFI and only work with "alternative fuels". 

Which company is this?  Is this an EFI brand system or a Ford EEC?

>He was restrained from giving me
>any information on the workings of the MAS or the program on the EEPROM.

What a prick.  

>Somewhere around 500-600 Hp would be enough fun for even me. :)
>I've ordered the Mcinnes book on turbos from the local bookery and am trying 
>find someone to analyse the MAS. I should have the assembly code disassembled
>someday, doing it manually. :(

I can probably help you on the MAS.  You gotta write me an article on
the disassembly if you get it finished :-)

>I want to put two MAS's in front of two turbos blowing into the manifold
>with an injector into each port.
>the DECU is fully adjustable and should be easy to reprogram.
>if i get it all figured out it should power upto ~900Hp.
>This could be made at home, seeings how i am.
>should be fun.

I'd give very serious consideration to going with a speed-density scheme.
The range of flow involved with heavily turbocharged engines is 
pretty rough for a MAS to handle and still have a bit of accuracy and 
more importantly, repeatability, at low flow.  GM has MAPs good to
2 BAR (30 psi boost.)  Despite gasping at the thought of creating a 
half-breed :-), this might be your best bet.  

My new friend from South Carolina with the turbo Z is having the same
turndown problems I predict you will have.  He has had to do some extreme
stuff to his bosch MAF to temperature stabilize it so the idle mix
will repeat.  This includes potting the electronics in aerosol insulating
foam.

If you do go with the MAF, you can still use only one as long as the 
ratios of flow remain the same.  An alternative is to pipe the 
inlets of the turbos together and use a sampling arrangement.  
Placing a small MAF inside a larger diameter pipe is a perfectly legit
solution.  Indeed my wife's toyota uses this scheme, with the MAF 
being only about a half inch in diameter but placed to sample 
the main flow.  As long as you can scale the output, you'll be fine.

John

Date: Fri Oct 9 00:49:44 1992   
Subject: Turbo question...

Well, my Z doesn't have a turbo, but I was wondering about a device I've seen
over the past few years.

It's an electronic system which installs an electric oil pump in the oil
system.  The computer will then pressurize the system before the car is
started (ie. the starter is in-operative for the first few seconds), and
continually circulate the oil after the car is turned off.

I understand why this would be beneficial...but _how_ beneficial?  Just
looking for speculation.
-- 

[This topic is subject to hot debate.  My *opinion* as an engine builder is
there is no need for an oil pressurization system IFF you a) let the 
engine idle a bit before shutting down after hard running and b) don't
race the engine until the oil pressure comes up.  There is more than enough
oil retained in the engine bearings by capillary action to generate the 
initial oil wedge.  This oil film will hang around for years.  Cylinder
walls, particularly those washed down by unburned gas during shutdown
and startup, would benefit BUT no aux oil source feeding the stock oiling
system can reach the cylinder walls.  The crank must be turning
for slung oil to reach the cylinders. If you want to spend some money
to do something nice for your engine, get an oil cooler.  Big win
for turbocharged engines.  JGD]

From: John De Armond
Date: Fri Oct 9 16:56:41 1992   
Subject: Re: Turbo/Super Chargers

> I'm currently driving a '74 260Z 2+2 with a slightly modified engine which is
>giving me approx 175 horses.
> What I'd love to do is get some sort of Turbo or Supercharger hooked up to
>my car. What I'm looking for is something that won't involve major engine
>surgery, and won't clean out my bank acct.

After years of work and dozens of turbo motors, I can distill it down
to this.  $5000.  That will get you an intercooled, turbocharged engine
built to handle the stress and that will make oh, maybe 450 hp at 15-20 psi
of boost.  It will include the fuel injection and ignition controls necessary 
to make it work and to encourage the engine to keep its pistons in the holes 
where they belong and in one piece.

If you're not willing to do that then frankly, aftermarket turbocharging
is not worth the money.  The same money will buy more power from 
conventional techniques.  For low boost, you'd be better off buying a complete
turbo ZX engine from a wreck.  

> I figure that the cheapest way to ram more air into the Intake would be to
>get a scoop on the hood, but I'm a little wary about cutting into a Z that
>(except for the Engine) is 100% Stock.

If you designed a proper NACA duct (no trivial task) and positioned it
properly, you might get a few inches of water boost at high speed.
About all it would do is complicate your carburation.  Ducting cool
air in from in front of the radiator is a much larger win for a lot 
less trouble.  Letting hot air OUT of the engine compartment helps too.
Louvered battery cover doors are available on the aftermarket.  I've 
added additional ventillation in the form of a series of 1/2" holes
bored through the firewall into the windshield wiper motor compartment
(under the louvers below the windshield.)   This lets hot air flow
out and over the car.  Manometer testing has demonstrated that area
to be a fairly low pressure area.

John

Newsgroups: alt.hotrod,wiz.hotrod
Subject: Re: Yunick article
Date: Saturday, Oct 10 1992 22:36:05
From: John De Armond

>        "When you have an engine making 1000 horsepower, you need
>         to deliver 1000 pounds of fuel an hour.  I never got it
>         done.  Frankly, looking back now, I don't believe it can
>         be done.  This was moving the fuel mechanically, of course.
>         Using a contemporary electric system, is an entirely
>         different story."
>
> It's nice to see Yunick bite the big one every now and then.  Not out
>of meanness - it's just that his stature in the racing world is so great
>it's easy to get discouraged just thinking about trying to get where he
>is.  Unless some editor got in there and munged the article, of course.

Yeah.  Smokey's the kind of guy you just love to hate and hate to love
or something like that.  I've met him a couple of times briefly.
I don't think we'd get along very well.  Reminds me of Perot.

> From the fragmentary descriptions given in the article, it sounds like
>Yunick was running into the compressor-surge problem you get with two
>turbos sharing a common plenum, or he never figured the right correction
>factor for upping the fuel flow with boost.  Twenty years after the
>fact, it's hard to tell.

That sounds about right.  1 BSFC would be about right for an alky engine.
1000 lbs/hr works out to 125 lb/hr per cylinder on an 8 cylinder engine.
That's certainly within the capability of modern EFI, perhaps with two
injectors per cylinder.  Consider the enrichment problem with an engine
running 30 psi of boost or 2 atmospheres.  I use the rule of thumb to
add 1 to the volumetric efficiency for each atmosphere.  The motor is
probably doing .7 VE or so off boost and suddenly the turbos hit and
the VE jumps to 2.7 or so.  That's almost three times the fuel requirement
with no change in throttle position or RPM.  Pretty difficult to handle
mechanically, surely not with a Hilborn.  From Smokey's other writings,
I figure he hates/fears electronics enough to not even consider anything
but a mechanical solution.  Interesting thought experiment in any 
case.

John

Date: Sat Oct 10 23:57:50 1992   
Subject: Re: Turbo question...
To: z-car@uunet.UU.NET@Dixie.COM

> Re: turbo afterrun oilers/cool down-
> 
> Yes, a minute is a drag...BUT...if you start the cool down process
> by coasting a bit prior to being parked, you'll save yourself a bit
> of time. (But jeez folks, it's not like one minute out of your drive 
> time is going to kill you when weighing the possibility of slaving over
> your engine for several hours replacing the spent snail...not to mention
> the cost.)

	How about designing a simple circuit that when you turn 
	off the engine, it maintains the connection to keep the 
	engine running for 60 seconds while you jump out of the 
	car and lock it. (You would probably get lots of funny 
	looks like the old Cadillac owners that left their lights
	on!)
	
	Optional circuit sensing the engine temp off the internal
	sensor would only allow the extended time for high engine 
	temperatures. 

	An op-amp and possibly a 555, transistor and a relay wired 
	to the ignition should about do it. 

	Mikef


[ That would work, as would an industrial time delay realy.  I would like
to point out, however, that the cooling starts at the moment the engine
last comes out of boost.  So if you idle to your parking place or 
down your driveway or whatever, you've already put in a significant 
part of any cooling.  As a practical matter, I've never had any 
problems allowing enough time between my last boost and shutdown.  
JGD]

From: Brandon Dixon <emory!Princeton.EDU!bdd>
X-Source: The Hotrod Mailing list
Date: Feb 1993

Howdy!

Now that I'm a turbo car owner, I've been thinking about some
issues relating normally aspirated cars and turbo cars.
The reason that a turbo car of a given displacement can make more
power than an equally sized n.a. car is clear: decrease compression
ratio, but increase manifild pressure so that more air and fuel go in.
But, if I look at some numbers on turbo cars, I have some questions:
Suppose that you drop the C.R. to 8:1, but you put 2 bar pressure at
the intake manifold.  How does this motor stay together?  I mean we
can't build a 16:1 n.a. motor....  Obviously there must be a bit more
inefficiency in filling the cylinders in the turbo car, but how much?

[Quite nicely, actually.  A bit tricky but doable.  The turbo Z engines
I build will run at 25-30 psi manifold pressure. It requires racing
gas and fairly heavy water injection but it DOES make a LOT of power.
I have never had the opportunity to balance off boost vs compression
but I do know that a low compression, high boost motor is very doggy
off-boost.  JGD]

How much less efficient do the cylinders get filled with 2 bar of pressure?
Where is the largest inefficiency?

[The problem is the exhaust also has an above atmospheric pressure in it
which limits filling.  I typically see 10-12 psi of pressure between the
exhaust port and turbo inlet on the above described motor.  This is IMHO
kinda high and could be improved by juggling turbine wheel size and A/R
housing size but again we're talking about a lot of bux to do so.  One
thing the higher restriction turbine does is give a bit better throttle
response because it spools up faster.  JGD]

I have gotten the impression (wrongly???) that efficeincy of the intake
tract and valve timing etc. were less critical on a turbo car.  This
could just be that most are designed to help low end response????

[to make a given amount of power, that is true.  To achieve the best power
or to achieve the best efficiency, tuning matters just as much as with
normally aspirated engines.  JGD]

Any ideas?

Brandon

From: Brandon Dixon <emory!Princeton.EDU!bdd>
X-Source: The Hotrod Mailing list
Date: Feb 1993

[To continue our discussion of turbo stuff:]

>How much less efficient do the cylinders get filled with 2 bar of pressure?
>Where is the largest inefficiency?

>[The problem is the exhaust also has an above atmospheric pressure in it
>which limits filling.  I typically see 10-12 psi of pressure between the
>exhaust port and turbo inlet on the above described motor.  This is IMHO
>kinda high and could be improved by juggling turbine wheel size and A/R
>housing size but again we're talking about a lot of bux to do so.  One
>thing the higher restriction turbine does is give a bit better throttle
>response because it spools up faster.  JGD]

>I have gotten the impression (wrongly???) that efficeincy of the intake
>tract and valve timing etc. were less critical on a turbo car.  This
>could just be that most are designed to help low end response????

>[to make a given amount of power, that is true.  To achieve the best power
>or to achieve the best efficiency, tuning matters just as much as with
>normally aspirated engines.  JGD]

My current car (944T) with an aftermarket chip falls into the category
that we were describing: 8:1 c.r. and 2bar of boost.  I runs great on
93 octane without any water injection or other detonation prevention
methods.  I guess that I'm trying to figure out where to go from here.
I may not have much room without water injection or other detonation
prevention techniques (or GOOD gas of course).
I would be interested in measuring the backpressure prior to the
'charger.  How did you instrument this?  Things are pretty hot there.

[Just weld on a socket and attach a steel tube fitting to the header.
or drill and tap the cast iron exhaust manifold.  Run steel tubing
for a foot or so.  Hot gasses won't go any farther than that.
Then use the pressure indicator of your choice.  I generally use a
pressure transmitter and stripchart recorder but an ordinary pressure
gauge works fine.  BTW, an ordinary oil pressure transmitter works
fine if you drive it with a constant current, use kelvin sensing (separate
wires for excitation and measurement) and calibrate it against a gauge.
Being cheap, or more accurately, not caring to drive across atlanta to
buy the things, I make my sockets out of short lengths of rod stock or
thick walled tubing, depending on what I have on hand.  Just weld it on,
drill the hole into the exhaust and tap appropriate pipe threads.
Because I have a bunch left over from my nuking days, I use Swagelock
stainless steel compression fittings but ordinary steel will work.  JGD]

The exhaust side of the plumbing seems to be about as free flowing as
I can get: the headers are nice and the pipe is large enough.  I'll
assume that the cat flows well enough (unless someone tells me otherwise).

The intake side of things looks like it could be improved by porting the
manifold, but this could turn out to be a marginal improvement if the
exhaust side of things is the real bottleneck.

[The problem you run into with many OEM turbos is they are sized for good
throttle response which means a small turbine and a small A/R housing
with lots of wastegate bypass.  This works but the turbine represents a
lot of restriction.  Add a new PROM or otherwise muck with the wastegate
so that a lot more exhaust flow goes through the housing and the
exhaust pressure rises.  This pressure effectively subtracts from the
intake pressure.  You suffer the additional heating from compressing
atmospheric pressure air but you get only a fraction of the power the
gauge manifold pressure would indicate.  A more realistic pressure indication
is the differential across the engine.  That is, the manifold pressure minus
the exhaust pressure.  You can easily measure this even without a DP cell.
Simply mount a common pressure gauge in a small, heavy glass jar and pipe
the jar to the low pressure side.  Pipe the gauge to the high pressure side
and the gauge will read the difference.  JGD]

My turbo has 72k on it, so I guess that it's day will come.  There was
an S model unit with a slightly larger exhaust housing, so it may be worth
the trouble then.

While I have your attention, there seems to be a lot of net knowledge
about domestic engine management boxes, but are there folks out there
that know the insides of a bosch motoronic box?  Got any ideas about how
to obtain description of the data format on the eproms?

Thanks!
Brandon Dixon
bdd@cs.princeton.edu

From: emory!uunet.UU.NET!contex!marvin.contex.com!frank (Frank Perdicaro)
X-Source: The Hotrod Mailing list
Date: Feb 1993
Subject: Re: Intercooling a supercharged engine

If you are interested in cooling with liquid gases, check out liquid
hydrogen.  Its heat capacity is off the scale ( if memory serves correctly )
compared to nearly everything else.

Yeah, it can be made to explode, and its cold.  My thought is to make a
low pressue liquid tank, and just vent the stuff.  I do not think I'd want
to try to burn it in the engine in a drag environment.  Just use it as
a cooling fluid, and vent it vertically.

The trick would be to keep the hydrogen exhaust at a non-explosive
concentration.  I'm not sure how to do that.

GE makes a series of moderate sized generators that use hydrogen gas
as the cooling medium.  It was chosen because it has the highest heat
capacity and resulted in low drag.

	 Frank Evan Perdicaro 				Xyvision Color Systems
      Legalize guns, drugs and cash...today.		101 Edgewater Drive
   inhouse: frank@marvin, x5572				Wakefield MA
outhouse: frank@contex.com, 617-245-4100x5572		018801285

[GE and Westinghouse makes big 'uns with hydrogen cooling, if 1200 MWE is
big :-)  Pressurized to 75 psi too.  I still have a snapshot memory (like
the memory of where you were when Kennedy was killed) from when I was
attending the TVA College of Nuk'lar Knowledge and the instructor stood
us before the generator at Sequoyah NP in Chattanooga told us that whole
structure, almost as long as a football field, had 75 psi of hydrogen in
it.  Wow.

Back to hotrodding, this discussion is, I think, shortchanging good old
fashioned water.  None of these gases has anywhere near the specific heat
of water.  Handling some of these cryrogenic liquids, avoiding hydrogen
enbrittlement, avoiding vibration stress fracture in the metal that would
be below the Nil Ductility Transition temperature would be major tasks
and carrying enough for a day of competition would be interesting.  Not
to mention expensive. The cooling requirements are not great.

Consider a 1000 cfm engine on an 8 second run.  It uses 133.3 cu feet of air.
Using my refrigeration handbook values of 0.075 lbs/cu ft at STP and
.24 btu/lb for air, that works out to 133.3 cu ft * .075 lbs/cu ft * .24 btu/lb
which equals 2.4 BTU.  Water has a specific heat of 1 btu/lb by definition
so 1 lb of water at, say 33 degrees could absorb this heat and only
rise 2.4 degrees. Double or triple this value to account for supercharging
energy input and cooling task is still trivial.

So for a heat exchanger large enough to fit under the blower, if you
simply fill it with freezing water, it will do a marvelous job of
cooling the intake charge.  The biggest problem would be to create
enough turbulence in the water to keep the heat transfer going.  JGD]

Date: Mon Mar 8 02:44:07 1993   
From: jg29005@de.deere.com (Jeff Giordano)
Subject: Re: timing chain replacement

>[Yes.  It's a tradeoff for top end.  I personally like the way it 
>drives with a little advance.  what it does depends on the amount
>of wear on the chain/sproket.  You need to try it to see.  Does 
>everyone know about making the wood wedge to drive between the chain
>guides to hold the chain and tensioner in place while mucking around
>with the sprocket?  JGD]

Any personal experiences on the effects of varying amounts of
cam advance?

[Not really.  I've experimented with the different holes and noted the 
results above but I've not done any extensive testing.

I'm also trying to decide on an appropriate amount of boost increase
for a stock turbo L28 ( running around 7.5 comp ratio). Is it 
possible to avoid an intercooler by using water injection, or should
I plan on both to go above 12 psi? Is 300 hp or so doable without
any internal modifications?

Thanks, Jeff

[300 hp is pretty easy.  10-12 psi should do it.  You'll probably
have to use water injection but it won't require a lot.  I'd 
do an intercooler if it were me.  No hassles and no maintenance.
You should be able to find a used one in a junk yard and not have to 
pay the rather stiff aftermarket prices.  You also might ask around
and find a radiator shop that caters to racers.  I know that 
replacement intercooler cores are stocked by these guys so you might
could get a custom one made for $150 or so.

At 10 psi, you'll need to O-ring the block. I'd also suggest
fabricating a bracket to support the turbo manifold assembly
from underneath so the stress of everything hanging off the side of
the head won't tend to wedge the opposite side up.  Every head gasket
I've ever blown was on the plug side and it "amazingly" stopped
when I started supporting all that mass.  JGD]

Date: Wed Apr 14 17:56:28 1993   
From: (Pete Paraska) <paraska@oasys.dt.navy.mil>
Subject: Re: V-8 Zcars

On Tue, 13 Apr 1993 17:28:04 -060,
  Bob_Wise writes:

>On Apr 13, 14:03, Thomas Miller wrote:
>> Subject: V-8 Zcars
>>
>> I recently sold my V-8 converted 72 240-Z.  I think this is the only REAL
>> way to compete with the big boys in a cost effective manner.  Sure you can
>> easily spend 5-10k on a six cylinder or rotary, but for around $2,000 you
>> can make the quickest car around.  My 240 had a 4 bolt main 350 Chevy with
>> a TH-350 3-speed automatic transmission putting out about 315HP. The stock
>
>Wouldn't a late model single or twin turbo 300ZX motor be a good bet
>as well?
>
>I expect the single turbo motor could be had reasonably cheaply,
>at least compared to a twin turbo.
>
>Also, why not a 280 turbo motor?

Bob,  this gets back to whether you like turbo's or not.  At least that's 
the issue for me.  I have a 73 240Z I'm doing structural mods and rust 
replacement on right now that I have a 327 Chevy V8 ready for.  I thought 
about a turboed Z motor and all of that and decided that I like low end 
torque a 300+ cube motor too much to settle on a turbo.  I guess a Grand 
National Turbo V6 would be alright though.  I was impressed with the 
torque the GN has - felt like the 60's again.  I haven't looked into it, 
but I'll bet a GN motor or 300ZX turbo motor would be more expensive than a 
normally aspirated V8.

I have a 92 Eclipse GSX, the AWD turbo model with 195 hp.  It's fun, but I 
hate waiting for that turbo to spool up.  Now, I guess if I had time and 
money for that car too, and I was willing to void the warranty, I'd do some 
power mods to it, but the turbo lag would still be there - if diminished, 
and the power would still be "up top".

Again, I think it comes down to where in the rpm band you like you torque.  
That will answer the question of "why not a turbo xxx motor instead of a 
heavier V8".  Everybody's different.

Pete Paraska (paraska@oasys.dt.navy.mil)                    Inter-Z#15

[I love turbo-motors (nothing like that hammer in the ars when the 
thing spools up) BUT.  Turbo horsepower is expensive.  I haven't broken
it down lately but 7 or 8 years ago, the last time I built a turbo Z motor,
350-400 hp costs around $10,000.  That much power requires forged 
pistons, an o-ringed block, head work, custom cam, the turbo kit,
an intercooler, water injection if you want to go above 15 psi boost
and for decent drivability, an aftermarket EFI.  Making 350 hp from
a small block V-8 is pretty trivial and not very expensive.  JGD]

Date: Fri Apr 16 00:58:33 1993   
From: Andrew Thayer <andrewt@coop.com>
Subject: V8 or Turbo?

It seems that many people have done V8's and turbos,
but has anybody seen any supercharged Z's?
Jim Cook Racing sells a supercharger setup for 70 to 78
Z's.  It consists of a new manifold, roots type blower,
and a programmable HOLLY projection TBI!  I think this
sells for about $3000.  This is a very cheap compared
to turbos and V8's.  10000 is quite a bit for a turbo
setup, but you can still do it (not as radical) for about
4000.  It's true that you can get a V8 for $2000, but 
I'll bet you'll need about another $1000 for radiator,
mounts, trans, headers, etc.  The blower seems like
a great way to go: fuel injection, no turbo lag,
and plenty of power.  Also it would be very easy to\
change the boost by changing the pully size.  I'd say
a good combination would be a ZXturbo block and head or
a 280Z block with a ZX head (around 7.5 to 1 comp.)
Another great advantage is you could install this all
in one day!  I think the whine of a blower in a z-car
is very tempting.  Maybe someday..

[They had one of those on display at the Z convention last year.  I looked
it over and talked to the people at the booth.  I was not impressed.
The blower itself looked nice and the installation looked to be clean.
But they had a 4 barrel Pro-jection on the thing, for christssake.
The 2 barrel throttle body flows more than enough air for any reasonable
amount of boost.  On my un-supercharged engine, all manifold vacuum is gone
by a little over 1/4 throttle.  I had to modify the ECU in order to
get the mixture anywhere near lean enough.  

Aside from the Pro-jection system, the major problem I have with this
kit is that it uses a Roots-type blower.  These things are terribly
inefficient as compared to screw types or the Vortech-type centrifugal
superchargers.  This translates directly into air temperature which
translates directly into diminished knock margin.  Avoiding knock
is the name of the game. 

As to installing the kit in a single day, don't believe it.  If they
tell you you can install the kit without O-ringing the block and run
any boost at all, they are blowing smoke.  I have some tricks up my
sleeve that allows up to about 10 lbs of boost without formal O-ringing
but they involve work on the head gasket mating surfaces and involve
using a Felpro racing head gasket with integral O-ringing.  In any event,
the head has to come off.

The last issue - something none of the kits address and which took me 
literally years to figure out - is that of supporting the mass of stuff
being hung off the side of the head.  All this mass hangs off one side 
of the head and its weight exerts force opposing the head bolt clamping
force on the opposite side, the sparkplug side.  The symptoms of this
problem are an engine that runs fine for an indefinite period of time
and then blows a  head gasket, always on the sparkplug side.  Careful
correlation of the facts over the years with failures finally
pointed out the problem.  While the forces involved are not of much
significance during normal conditions, if the car is involved in 
maneuvers such as hitting a curb or high speed over very rough roads,
the shock forces could relax the head enough to let the gasket blow.
The solution is to support this mass with a brace but none of the 
kit makers do it.  JGD]

Also:

the E31 head with 240 block :    9.5 to 1
    E88 head with 240 block :    8.8 to 1
    N42 head with 280 block :    8.3 to 1
    N42 head with 280ZX block :  aaround 10.5 to 1 -very nice!
    E31 head with 280ZX block :  around 11.2 to 1 -not on 90's gas

Im currently putting a motor together with N42 and ZXblock combo.
Two other people I know have done this and it works very well,
but you must run 93octane gas.  The compression is this high
because the N42 head is designed to work with dished pistons,
ZX blocks after 1/81 have flat top pistons.

Andrew T

From: emory!mlb.semi.harris.com!jws (James W. Swonger)
X-Source: The Hotrod Mailing list
Date: May 1993
Subject: Re:  Turbocharger oiling
X-Sequence: 5276

<the Keihin carb q>

I've had a couple of bikes with regular-ish Keihin carbs and they've all had
direct linkages to the slides, no springs inside except for one that holds
the mixture needle in place. Is this what you want to do, change the mixture?
If so there're a bunch of little grooves at the top of the needle and you
can set mixture by selecting which one the keeper clip is snapped into.

The carb racks I've rebuilt all have master spring providing the return force
for the whole set. The internal spring is not for return, just to hold the
needle in place. If you're using one off a rack, maybe the main return
spring is missing? Just a thought.

[He's using a CV-type carb which does have a spring that offsets air velocity
induced vacuum on a piston that operates the slide.  A butterfly throttle
is actually hooked to the throttle cable.

The first thought I had when I read the original post was "Are you blowing
or sucking through the carb?"  CV carbs don't work much at all when blown
through.  The piston slide arrangement is designed to maintain a pretty
constant air velocity thru the venturi.  When the air density changes markedly,
the mixture goes all to hell because more air mass for a given velocity
flows.  JGD]

From: emory!wal.hp.com!lupienj (John Lupien)
X-Source: The Hotrod Mailing list
Date: May 1993
Subject: Re: Turborcharged Two-Stroke
X-Sequence: 5290

> -> as this engine is a two stroke, it has no engine oil pump that can be
> -> used to supply oil to the turbocharger bearings, so I need to find a
> -> 12 voltelectric
>  How about driving a standard mechanical pump via the alternator shaft?
> The Kent 1600 used in the '70-'71 Pinto is designed for external
> mounting and would cost $30 or so, or you could use any Ford-style
> gerotor set and make up your own housing.

This suggestion suffers from the same problem as the blower idea below:
parasitic power loss. For a top-speed-record attempt, you want ALL the
power (or as much as you can arrange) going to the driveshaft. So run
a total-loss electrical system, maybe use a little bigger battery, and
yes, go with an electric oil pump for the turbo. The extra mass of the
battery won't affect top speed, just how long it takes to get there. And
it might even help hold the car down a bit...

>  I realize expansion chamber design is very weird, but I have doubts the
> chambers would function normally when restricted by the turbo.

This is a questionable area. The timing of the pressure waves may not
be affected significantly by the backpressure, but they would be affected
by increased exhaust temperature. However, the normal design of expansion
chambers supports two effects: creation of a supercharging effect by
impinging a positive pressure wave on the exhaust port after the intake
port has closed, forcing some expelled charge back into the cylinder,
and providing an assist to the purging of the cylinder while both ports
are open by impinging a negative pressure wave on the exhaust port at the
right point in the cycle.  The need for the first effect is eliminated
since you already have supercharging from the turbo. So the point of the
exhaust design becomes more of a question of effective purging of exhaust
gasses from the cylinder, which gets harder due to the backpressure from the
turbo. So an exhaust system design which maximizes the purging effect may
give significant gains.

[I think a series of chambers followed by a turbocharger has a good
possibility of working.  The stinger serves only to provide a pressure
bleed and thus establishes the average pressure in the chamber.  I
proved to myself many years ago that I could achieve the same result
with a long, large diameter stinger as I could with a short, small
diameter stinger.  Anybody remember that funky stinger-out-the-side-
of-the-chamber scheme Sachs or some such company did in the 70s?  If the
convergent cone terminates at the turbo inlet, it is coceivable that the
turbo could provide the backpressure.  The suction and plugging pulses
would function normally and would augment the forced induction.  I'd
expect the chamber dimentions to be different because more plugging than
suction would likely be needed because of the positive intake pressure.
On the other hand, it might be that a lower exhaust port, to make the
power stroke longer, offset by a stronger suction cycle, might also be a
win.

this sounds like a really interesting development project.  JGD]

--
---
John R. Lupien
lupienj@wal.hp.com

Date: Tue Jun 29 11:46:12 1993   
From: mikef@rosevax.rosemount.com (Michael Foerster)
Subject: Turbo Care

Subject: Re: Z-car for sale?
  text deleted...
  but...needs a new turbocharger

  This is very common with turbo chargers, however, not necessary.

  I learned long ago that turbo's don't like to run without oil.
  You can make your turbo run nearly indefinately if you NEVER allow
  it to run without oil, or run on old oil.  That means to change
  the oil every 2500 miles and when you change the oil, pull
  the coil wire and on fuel injected cars, open the fuel pump
  wiring (fuse??).

	Then, with the new oil and filter installed, crank the car
	over for about 40-50 seconds, or until the oil pressure
	gauge starts to show a little pressure (the filter fills up).

  This prevents the turbo from running dry at start up which is 
  extremely hard on them.  Turbos run at 10's of thousands of 
  RPM's and can take out the bearings in very short order.

  This is even a good idea for non-turbo engines.

  Mikef

[All that really isn't necessary.  5-6000 mile oil changes are fine for
normal service conditions.  That is what I use and I've put literally
hundreds of thousands of miles on high performance turbocharged engines.

About filling the filter by cranking, think about what you're saying,
Mike.  You're advocating using the starter to run the engine for
possibly an extended period when there is no oil pressure.  The bearing
loading in the engine is MUCH higher than it is with the turbocharger
bearing.   The engine bearings are at a much greater risk of damage
that is the turbo bearing.

It really doesn't matter which way you do it since the oil pump is a
positive displacement pump, and must turn the same number of turns to
fill the oil filter regardless of whether it is turned by the engine or
the starter.  As a practical matter, a Z engine fills the filter so fast
there is little to no risk to the engine.  One can cut that fill time by
simply pouring a half quart or so of oil in the filter before screwing
it on.  The only time I do anything special to the oiling system is
after having the oil pump off where there is a good chance it is not
primed.  I prime the pump using a vacuum pump connected through a special
fitting I made to screw in place of the filter.  After the pump is
primed, just crank crank the engine normally.

If you've ever run a turbocharged engine with the exhaust off the
turbine housing, you'll notice that at idle the turbine barely spins, if
at all.  Even a goodly shot of throttle doesn't spin it up much.  The
turbo bearing is very lightly loaded so any oil film is enough
protection during these conditions.  The turbocharger's two main enemies
are dirty oil (that is, containing abrasives) and heat.  Not letting
the turbo hot soak is the single biggest thing that can be done
to extend turbo life.  JGD]

From: Dan Hepner <emory!hposl03.cup.hp.com!dhepner>
X-Source: The Hotrod Mailing list
Date: Sep 1993
Subject: Hotrod diesel

>I'm surprised that no one's mentioned what can be done to
>hotrod a diesel. Multistage turbocharging can get the power
>up well past 1 HP/in3, even without increasing the RPM range.
>But I don't know much about the details. Are the injection pump
>and nozzles changed to handle the higher fuel flow and pressure?

The injection pump is changed to deliver more fuel.  This may well 
require a different pump.  The primary goal, in spades, when
increasing diesel power is to deliver both more O2 and more
fuel.

>Is the static compression dropped to keep the peak pressure
>under control?

Yes.  The Cummins 'B' for example:

18.5:1  normally aspirated
17.5:1  turbocharged
16.5:1  turbocharged, aftercooled

>Is the timing also retarded and the injection period
>lengthened to control peak pressure.

No (with minor exceptions).

The pressure curve is exceptionally steep in a diesel engine when
the fuel begins to burn some few ms after injection begins, and for
obvious reasons this near-vertical rise must not occur before TDC.  
The "few ms" varies based on engine design and cylinder pressure, 
not on the amount of fuel injected. The stock engine will be timed 
with it safely sufficiently retarded.  Since the injection of
fuel before burning begins indeed raises the pressure a little, 
there may be a need for some very slight retardation. 

The higher the pressure which exists during burning, the more
efficient the engine, the primary advantage a diesel has over
a gasoline engine (with many well known analogues in gasoline
engine variants).  Thus, one is motivated to burn the fuel as 
early after TDC as possible. A diesel engine will have completed 
combustion well before BDC, and one does not wish to get any
closer to BDC, as would happen if one extended the injection
period rather than flow.

Diesels have a well known "smoke point" which is important for
more than pollution reasons.  The smoke point is reached when
the combustion process is consuming  80-85% of the available
O2 (varies a bit with engine design).  One can indeed get more
(as much as 10% more) power by injecting more fuel, thus consuming 
more O2, but at the expense of radically increased fuel consumption, 
not to mention incredibly dense clouds of carbon and, as the O2
consumption goes over 90%, unburned diesel and carbon monoxide.
Running an engine near this point (which is where "tractor" pullers
seem to run them) one may find one's self injecting for a longer
period.

>Are oil cooled pistons mandatory? 

Are they ever not mandatory?  All of the designs I've seen derive
partial piston cooling from oil which one way or another makes it 
onto the underside of the piston.  The Cummins has an oil jet directed 
onto the piston as it descends.  Or did you have some other notion of 
oil cooling?

>I suspect that the biggest problem is the drivetrain. Where does 
>one find a transmission that can handle 800 ft-lb input torque?

On any 18 wheeler? (They can take about twice that).
Actually, one can get Allison automatics, and a whole selection of 
"normal" (with syncros) transmissions which can take 800 ft-lb.  Your
local garbage truck is probably running an 800 ft-lb engine using an
Allison.

>Norb Brotz                Cray Research Park    Internet: nbrotz@palm.cray.com

Dan Hepner

Date: Tue May 31 17:38:34 1994   
Subject:  Turbo boost increase
From: emory!aol.com!ZCARLOVER

You can also buy an alternate fueler. You can specify a "cut in" boost
presure and a rate of gain. Then you can add a 7th injector that cuts in at
say 8psi and fuels up to say 12-14psi. Watch out for detenation though.
Camden makes a basic unit for about $249 plus an injector plus an injector
holder. HKS also makes a unit BUT it is also about $700 plus injector plus
holder.

[Geezus!!!  I should be in that business!!!  Here's what I'd suggest.
Get an adjustable pressure switch and plumb it into the pressurized 
part of the intake.  Spearco sells a tiny switch for moderately
big bux (~$50) but a small industrial pressure switch (such as the 
Static-O-Ring brand) will work just fine.  Electrically wire the 
switch in series with an injector ballast resistor and an injector
that you mount ahead of the turbo somewhere in the intake so that 
when the pressure switch makes up, it energizes the injector.
Connect the injector fuel port to the main injection fuel rail through
an adjustable pressure regulator.  Northern Hydraulics is currently
selling some obviously surplus Parker-Hannefin miniature regulators for 
$12.  Attach a line from the pressurized intake to the reference port
of the regulator (just like the stock regulator).  Set the regulator
for whatever pressure is appropriate computed from the following
formula:

	new flow = old_flow * sqrt( new_pressure/old_pressure )

The "old_pressure" is that pressure where the injector flow was 
characterized and will normally be the normal fuel rail pressure.
I suggest getting a large injector and reducing the pressure to
10 psi or so.  The reason will be apparent in a moment.

Set the pressure switch to cut in at whatever boost the stock system 
starts to lean.  As the boost increases past the setpoint, the 
output pressure from the aux regulator you installed will increase
because you have it referenced to the intake manifold.  Thus the 
output of the aux injector will increase in proportion to the increased
manifold pressure (actually proportional to the square root of the 
increase but over the range we're interested in, consider it linear).
This works because the aux injector is UPSTREAM of the manifold and
thus not subject to boost pressure.   A little diddling with the 
cut-in setpoint and the starting fuel pressure will tailor this 
setup to the engine.  The total cost of this gizmo can be as little
as $50 including the injectors if you scrounge a bit.

Don't be afraid to use more than one injector if your additional fuel
requirement is more than one can handle.  Used stock injectors 
are cheap.  Low impedance injectors, such as the stock Z ones,
can be run in series.  High impedance ones, such as most GM injectors,
can be run in parallel.  Most injectors want to see about an amp of 
operating current.  Simply adjust the ballast resistor accordingly (high
impedance injectors don't use ballast resistors; they connect directly
across 12 volts)   JGD]

From: emory!prism.gatech.edu!gt0035b
X-Source: The Hotrod Mailing list
Date: Jun 1994
Subject: Re: Hotrod Mailing List Digest #226 (June 14, 1994)
X-Sequence: 8738

	A frenid and I have been talking about a supercharger driven by an
electric motor for a while now and the other day he ran across an add in a
late fifties Popular Mechanics for just that.  I was wondering if
anybody had seen such a thing before and whether it worked worth a darn.
My thinking is that for a car with a small engine that doesn't need a
big blower that it would be less of a drain on the engines power output to
install a good alternator. They're easy to find with all of the stereos
running around now days.  Let the battery make up any extra draw and power
something like a vortech blower or small compressor.  It would be real
easy to install and even easier to put variable boost on.  All it would
take is a pressure sender that would go open a certain persure and turn
the motor off for the second it would take the pressure to go back down.


Henry Sommer

[Run a few numbers.  Let's say a small engine supercharger could be
built to run on 25 hp (basing this on the power requirement of similar
industrial blowers I have some experience with).  There's 746 watts
in a HP.  Let's give the motor an efficiency of 90%.  That's about
820 watts/HP.  25 hp would be about 20,500 watts.  If you want to
be able to run it on a battery, it would need to be 12 or 24 volts.
Let's say 24 volts.  20,500/24 = 855 amps!  A 24 volt battery capable
of that kind of discharge rate for any length of time would be huge.
Not only that, the alternator would have to be sized to supply a
significant chunk of that amount of current if the supercharger is
to be available for use much of the time.  That would be one honking
alternator!!  To get an idea of how big, take a look at the generator
on a gas-powered welder.  These things supply about the same level
of power, though with vastly different electrical characteristics.
Wouldn't be much room in the engine compartment for the engine.

Never underestimate the power transmission capability of the common
V-belt.  JGD]

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Boosting Toyota RV Power.
Date: Mon, 16 May 2005 02:22:32 -0400
Message-ID: <eccg81tk4rp8gjd0f3843l2mdcs1ueume2@4ax.com>

On Sun, 15 May 2005 21:12:45 -0400, "Dan Listermann"
<dan@listermann.com> wrote:

>Our '84 Toyota Dolphin is a little pokey going uphill.  Frequently we find
>ourselves doing 55 in third with the flashers on.  A mechanic told me that
>we could soup the little thing up by getting a higher lifting cam, injectors
>and a header.  Or, he said, we could get a turbocharger and just "bolt it
>on."  Any drawbacks besides the money.  We would like to go out west, but
>there is no way I am going to climb I-70 west of Denver in third.
>
>Dan
>

Probably need to run the other way from that mechanic.  A turbocharger
adaptation is pretty much the opposite of "bolt it on".  Oh, the turbo
will just bolt on if you're lucky enough to find someone that still
sells the necessary manifolding but that's about 10% of the work.
Especially in a high torque application like yours.  I used to operate
a quite successful tuning shop specializing in turbocharging Datsun
and Toyota engines of that vintage and back so I have some experience
here.  Let's consider some additional things that must be done.  This
assumes you'd want to make enough boost to make the expense
worthwhile.

High torque loading means higher combustion chamber pressure than in a
pickup or car with the same engine.  Turbocharging makes it even
worse.  The engine must come out for some mods.  The combustion
chambers must be opened and dished forged pistons fitted to reduce the
pressure and withstand the inevitable knock under boost.  The block
must be O-ringed (a groove cut around each cylinder in which a ring of
wire is fitted to clamp the gasket against the added pressure).  I'd
probably also enlarge the head studs, given the load this engine would
be pulling.

A cam with less overlap would help economy a bit and improve the power
some but not essential.  An oil cooler is a must.  It needs to be one
with a thermostatic bypass so that the oil isn't undercooled in cool
weather.

A larger exhaust is necessary.  Exhaust pressure quickly chokes a
turbocharger.  If you live in an area where there are emissions
inspections, it might be tough to find a ready-built system with an EO
number that makes it acceptable to the inspectors.

A larger throttle body would help things immensely.  We like to
achieve as high a pressure in the turbine intake at WOT as possible to
minimize pumping losses.

That all leads up to the big problem.  Supplying enough fuel when
under boost and controlling detonation under boost.  No one that I
know of has hacked the older Toyota EFI controllers so a wrap-around
solution is necessary.  Several companies make boost fuelers but
they're expensive.  Couple grand for a complete system.  They're not
all that precise, making power being the primary objective, so the
economy is pretty poor under boost.

Next comes the ignition control.  Boost requires a retarded spark to
prevent knock.  There are two main method.  One is retard the spark a
specified number of degrees per psi of boost.  MSD makes a boost
retard unit that does that.  The problem is, the retard is fixed.  The
spark doesn't need as much retard at a given boost in cool conditions,
for instance, so power and economy is wasted.

The second method is a combination of knock sensor and mapped spark.
The spark is retarded according to the engine RPM and throttle
position.  The computer inches the spark up until the knock sensor
installed on the engine detects knock.  It then backs it down until
the knock is inaudible.  The better controllers control each cylinder
individually.  J&S Marine makes a nice little $500 box that does that.

I like to use both boxes.  The MSD unit to lever the spark back before
knock can commence and the knock controller to inch it back up for
best performance.  It takes a lot of work to get the combo right and
the cost of only one or two mistakes is collapsed piston lands (read:
new pistons and rings.)

An intercooler is a must for this kind of operation.  Spearco makes
'em to order.  Figure $800 for the cooler and plumbing.

Even if you do the work yourself you're looking at something in the
range of $5000.  Probably more like $8000 if you hire it done.  What
I've described is what it takes to make a moderately boosted engine
under heavy load operate reliably under extended wide open throttle.
I have a rogue's gallery of broken pistons and rods that document my
learning experience.

As to the "let's throw in a big cam" approach, I must point out that
this isn't a big V8 that is only producing maybe a quarter HP per cu
inch.  It is a small, high revving (compared to a V8) engine that is
already making a little less than 1 hp per cu inch.  It already has a
big cam by V8 standards.

Certainly more power is available but only at high RPM and at the
expense of low end torque, something that you dearly need.  Put a high
revving low torque engine up against a heavy vehicle and the clutch
becomes the fuse.

I started out in a Keystone motorhome on the Toy chassis so I can
sympathize with your need for more power.  Here are some things that
you can do to get a little more power for moderate money.

A better exhaust is first on the agenda.  Find a shop that can
mandrel-bend (not mash bend like regular muffler shops do) you a 2.5
to 3" exhaust with a Corvair type turbo muffler.  Several of the
aftermarket companies have scaled up the Corvair muffler to larger
sizes.  Another good muffler is the late 50s caddy muffler.  What GM
did with the turbo Corvair is cut the caddy muffler in half.  The
caddy muffler is huge but it flows as well as a straight pipe and is
very quiet.

Next look to open up the intake.  OEMs make restrictive air cleaners
to suppress noise.  I found that on many Japanese vehicles, a few
strategically placed holes in the air cleaner upstream of the element
does wonders.  So does getting cool air from in front of the radiator.
On the turbo 240z cars I built I'd run plumbing through the radiator
wall and place a large round custom fabricated air cleaner in front of
and off to the side of the radiator.  This would lower the intake air
temperature by as much as 80 deg on hot days.  Cool air == power.

If you're willing to remove the head then there are other things you
can do.  A different cam can help but its specs will have to be
carefully chosen for this application.  You need to find a cam grinder
who knows his way around jap engines.  I used to use Racer Brown but
he died and his company changed a lot.  You could buy a ricer hotrod
magazine at the newsstand and look to see what companies are
specializing in jap engines.

If you're willing to run mid-grade gas then one of the most direct
routes to more torque is increasing the compression.  You should be
able to go up a point and still be able to run mid-grade gas.
Increasing compression significantly improves the overall economy so
increased mileage would partially offset the additional cost.

Since I get the impression that you're not a DIY'er, you really need
to find a tuner familiar with that engine.  It'll take some work since
the engine is so old.  I would expect that $2,000 would buy you a
significant improvement over stock.  Whether it's worth it to you, you
have to decide.

John

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: Boosting Toyota RV Power.
Date: Mon, 16 May 2005 14:05:05 -0400
Message-ID: <ionh81d6u3bjnsil8gpk1ap83co5r2dbmo@4ax.com>

On Mon, 16 May 2005 09:03:41 -0400, "Dan Listermann"
<dan@listermann.com> wrote:

>Thanks John, I am going to print out you post and maybe consult my regular
>mechanic.

You're welcome.  One thing I forgot to mention.  Do not under any
circumstances add a K&N air filter, despite what your mechanic may
recommend.  You might as well just not have an air filter.  This is
very expensive and hard won advice.

The advice from others in this thread to look at engine swaps is also
certainly viable.  You might even find that a small block V8 would
fit.  That is a popular swap for Datsun 280Zs.  The V8 is smaller and
lighter than the stock engine.  The Ford is the better engines for
tight spaces because the distributor is in the front.  This allows the
engine to be tucked back under the cowl a little if necessary.  Even a
slightly warmed V8 in that lightweight rig would be a stroker! and
probably quite economical.

One other thought.  If a V8 won't fit you might scrounge around and
find a wrecked Buick Grand National.  This car has a little
turbocharged V6 (small block chebby with two cylinders sawn off) that
makes great buckets full of power.  Everything is already there.
Turbo, intercooler, tough engine, EFI computer with knock retard.

>
>Time savings is not the reason I would like to go faster up hill.  I fear
>being run over by things.  Anybody going 55 on the highway is taking their
>lives into their own hands anymore.  : )

No need to explain.  "I want to" is all the justification you need.

John