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From: Dave Baker
Subject: Re: Chips and things......
Date: 12 Jan 1999

>Subject: Re: Chips and things......
>From: Ian Thornton <>
>Date: 1/12/99  8:14PM  GMT
>Message-id: <>
> wrote:
>> I've got a Vauxhall Omega 2.0 CD 16v saloon with a manual gearbox.It's May
>> 1994 vintage with coming up 37,000 miles on the clock. Is there any one of
>> you tuning wizards out there that could advise me how to get a bit more
>> ooomph out of it? There are moments when driving the car when it seems to
>> distinctly underpowered and I was wondering whether a tuning specialist
>> improve the car's performance.I am aware that this kind of modification may
>> have insurance implications,but what I am really looking for is a modest
>> increase,not something that would make the car qualify for the Indy 500!I
>> have read in this NG about re-chipping to improve performance-it may well
>> that this particular model does not lend itself well to this kind of thing
>> and I will just have to live with the indifferent performance.
>Chipping a normally aspirated engine usually makes it more driveable
>(removing the some of the flat spots you just described) rather than
>increasing power/torque by a significant amount.  Remember that increasing
>torque significantly means increasing the capacity (very expensive) and
>significantly increasing power means increasing the amount of air that
>the engine can consume in a given time period which means either increasing
>the capacity (i.e. more air = more torque) or playing about with the cam
>profile (shifting the torque curve up the rev. range leading to more
>power).  Chipping a turbo engine does make it significantly faster because
>turbo boost is increased leading to more air/torque/power.
>I'm pretty sure that Superchips will do a chip for your car.  I have
>a Superchip in my car (3.8 M5) and even though the engine's already
>significantly tuned, it made it much more driveable and, even though
>I'm sure it can't be that much faster, it certainly feels it.
>Other cheap'ish options would be to fit a performance exhaust (prob.
>£200-£300 giving around 10bhp), a modified air filter or direct
>induction kit (£30-£60 giving around 2-7 bhp).  If you do have the
>car chipped, the chip can be 'retuned' to take advantage of any
>other modifications you do make to the engine.

Hmmmm - well if you halve the power estimates for exhaust and induction items
then maybe - modern cars are very well developed by the manufacturers to remain
competitive with other makes and large amounts of easy bolt on power are not
available like they used to be in the 70's and early 80's.

The only place where substantial amounts of power is available on almost every
vehicle is in the cylinder head because mass production techniques can't get
close to the flow possible with detailed flow development and porting work.

Dave Baker at Puma Race Engines (London - England)  - specialist flow
development and engine work. .

From: Dave Baker
Subject: Re: Chips and things......
Date: 13 Jan 1999

>From: (Chris Wilson)
>[This followup was posted to and a copy was e-
>mailed to]
>In article <77fuea$4g8$>, gulfstream@my-
> says...
>> I've got a Vauxhall Omega 2.0 CD 16v saloon with a manual gearbox.It's May
>> 1994 vintage with coming up 37,000 miles on the clock. Is there any one of
>> you tuning wizards out there that could advise me how to get a bit more
>> ooomph out of it? There are moments when driving the car when it seems
>> to be distinctly underpowered and I was wondering whether a tuning
>> specialist could improve the car's performance.I am aware that this
>> kind of modification may have insurance implications,but what I am
>> really looking for is a modest increase,not something that would make
>> the car qualify for the Indy 500!I have read in this NG about
>> re-chipping to improve performance-it may well be that this particular
>> model does not lend itself well to this kind of thing and I will just
>> have to live with the indifferent performance. I would just appreciate
>> some sensible responses to my enquiry.I live near
>> Stevenage,Hertfordshire,England and could do with pointing in the
>> direction of anyone doing this kind of work in the area. Many thanks in
>> advance,Vic Wildish.
>Hi Vic.Whilst not wanting to put a damper on your aspirations towards
>better performance,the following general stuff in regard to tuning
>late,fuel injected,electronically managed engines may help.
>Post the early eighties,more and more manufacturers went to electronic
>management of ignition and fuel,via fuel injection,and mapped ignition
>systems.Most fuel injection systems had one immediate impact.They no
>longer need a restrictive venturi (narrow throat) in the carburettor
>(s) to pull fuel out of the fuel bowl of the carb.Fuel injection
>*injected* the fuel under high or very high pressure.No restriction as
>such,and hence less of a power loss.Management of the ignition and
>fuel suddenly meant engines could get away with running camshafts with
>greater overlap,and higher lift,too.The old advance weight disi,and
>velocity sensitive carb limited what cam profile could remain
>driveable,without hesitations,poor low end performance and flat
>spots.To a large extent electronic management allowed much more
>freedom in valve sizes,port shapes,and cam timing,as well as running
>the engine at the best amount of ignition advance at all loads and
>RPM's without detonation,on differing fuel qualities,via knock sensor
>What I am slowly getting at is that it is *much* harder to get
>anything like a useful power gain from a modern,well designed,16 valve
>production engine on electronic management. The exhausts are free
>flowing,as are the intake systems.One needs to look at further
>performance optimisation of the cam profiles,and maybe bigger
>valves,stronger valve springs,moves away from hydraulic valve lifters
>and mechanical improvements to make higher revs safe,from a
>mechanical stress related point of view.Almost any change that has the
>potential for a marked improvement in power and torque,will require
>different fuel curves (the amount of fuel injected at any one set of
>parameters of air flow,temperature,engine RPM etcetera,etcetera),and
>different timing curves.One can fudge the fuel,*across the whole
>curve*,by increasing fuel pressure via an "up rated" fuel pressure
>regulator,but the the weeks of dyno testing to get the fuelling
>correct at every point,has then gone to pot ... :-(
>As for the ignition,there is very little indeed you can do to change
>the curve incrementally.Unfortunately,the *correct* answer is an
>aftermarket injection system,or at least an aftermarket ECU and
>wiring,that allows one to map the curves afresh,to suit your new power
>modifications.This is expensive,both in terms of hardware,(maybe over
>£1000 for the ECU and wiring loom),plus a lot of professional engine
>dyno time to get it all mapped correctly.
>Sometimes one can buy a complete package,say new cams,different
>throttle bodies and manifold,etcetera,that can come complete either
>with a modified EPROM for the existing ECU,or an aftermarket mappable
>ECU complete.If one limits mods to exactly those which the kit
>manufacturer intended,this should work well.If you change any
>parameter from the tuners package,the early comments about incorrect
>curves again apply..
>Changing the exhaust *system* or the air filter,on 90% of modern
>engines will do sod all.The mags claim this and that,but in reality a
>gain of 5 HP on a 120 HP engine is neither here nor there,for a road
>car.Humidity variations can see that much change.A rolling road is
>hard pressed to accurately repeat to 5 BHP on a figure of 120 HP
>total.To get greater gains,say 20 HP,you need to look at fairly
>dramatic alterations,both to the mechanical components,and their
>related fuelling and ignition curves.
>Turbo engines are a slightly different kettle of fish,as it is trivial
>to raise the boost,and usually to fudge some additional fuelling.
>Naturally aspirated remain tricky!
>The easiest/cheapest way to see increased performance is to reduce
>weight.Especially rotating weight,for improved acceleration.Do most
>people ask the most important question when buying new wheels,after
>ensuring the offset and sizing is correct? Do they *uggery :-) They
>should take a fishermans scales with them,and weigh the damned
>things.The first question a race car manufacturer asks his potential
>wheel suppliers is what do they weigh,and what is their rotational
>inertia.Simple questions,and the weight,if not rotational inertia,is
>easily self assessed.The performance differences can be
>surprising,and worthwhile.Given 3 different makes of tyre,with similar
>grip and handling characteristics,go for the lightest..Just weigh some
>of the cheap imported tyres against a decent performance make,like a
>Hoosier competition tyre that is road legal.The difference is
>amazing.As for remolds,they are incredibly heavy.
>If you are serious,and can live without goodies,buy a car with the
>minimum spec.Sun roofs,air con,PAS,electric windows and mirrors,power
>seats all can add hundreds of pounds.Lightweight front seats can add
>as much performance,in real terms,as a new exhaust and manifold.40
>pounds of fancy stereo gear does nothing for performance ;-)
>As cars become better,and more highly developed,the art of tuning
>their engines becomes more complex and expensive,unless one looks at
>the situation with a bit of lateral thinking.Instead of adding
>things,think in terms of removing them.Instead of buying a new set of
>wheels just for their looks,weigh them,and see if a gain can be had
>for free there.
>Just ideas,some may be practical for your situation,some not,but be
>aware it is all too easy to buy so called performance bits,and get the
>thing to go *slower* <g> At least the engine in your car starts off as
>one of the best basis for tuning available.

Right on Chris ! - everyone print this out and pin it up over the bed and read
it before going to sleep each night.

Most of the bolt on crap you buy these days to make modern cars go faster
actually ends up making them either slower or more thirsty or more
temperamental. Sadly, glossy adverts and glib sales talk sells more stuff than
properly developed and well thought out equipment. To make a modern engine
produce more power you nearly always have to start at the cylinder head and
improve port shape and/or valve size. Cams are getting hard to improve on
without sacrificing low end driveability and exhaust systems and induction
systems are pretty damn efficient these days.

Most people are only interested in bolt on stuff they can do overnight though
and if they spend enough money they can nearly always convince themselves that
the car is faster. What an impartial driver thinks about it (or an independant
rolling road) is another matter entirely.

A colleague had a Peugot 205 1.9 gti in the other day for a set up on the
rollers. It had been severely dicked about with in the air filter, chip and
exhaust department. The owner/prat (whatever) thought it was the dog's
danglies. The rolling road with no axe to grind said it was 20 bhp down on a
good standard one. The owner didn't even realise it was slower. The exhaust
made enough noise to make it seem quick. With all the standard bits back on it
the power came back up to normal levels.

Most of the "tuned" cars we see fall into the "well fucked up" category. Slow,
poor handling, poor fuel economy etc etc. I saw a gold the other day which the
owner had lowered right onto the bump stops. At 20 mph a minor dip in the road,
which I hadn't even realised existed in my own car, sent this heap of shite
straight across onto the other carriageway. I turned round and drove it back
and told the guy it was too dangerous to even test drive and I could give him
no opinion on the engine until he had made the suspension safe. Why was it
modified like this ?? - because he wanted it to look "cool" when he went to Gti

I must be getting old or something but please God - spare me any more of this.

Dave Baker at Puma Race Engines (London - England)  - specialist flow
development and engine work. .

From: Dave Baker
Subject: Re: Peugeot 205 1.9 GTi
Date: 16 Feb 1999

Seems to a popular thread this but apart from a few words of advice I'll just
hang on the sidelines. Of all the modified cars I see the 1.9 Pug is by far the
most disappointing in terms of how the actual power gains compare to what the
customer has been promised. Not that surprising really because Peugot worked
very hard to get 130 road tractable bhp from a 1.9 litre 2 valve engine. It's a
lot easier to mess up than to improve on.

Last year a so called 160 bhp conversion from a big name tuner came in that had
just less than standard power - checked on 2 rolling roads - crap on both. On
stripping it down the modified head turned out to be an exchange second hand
one with no new guides, no seats recut, valves not recut, guides not even
removed and refitted to enable the ports to be modified properly - just a quick
flash round with a flap wheel and a beadblast to make it look pretty on the
outside. The exhaust guides had 7 thou wear - best guess about 100,000 miles on
whatever engine it came off. The donor car was a 60,000 miler owned from new,
main dealer serviced. Would have been better off keeping the head it had on
originally. The "performance" cam measured up exactly the same as a standard
one. The suspension kit was fouling the arches and so hard I had to abandon the
test drive as it was actually physically painful going over bumps. £1,500 and
thank you very much sir.

The same firm did a full race engine for another customer which never finished
a race due to blow ups. Eventually it was independently stripped and found to
have been skimmed to over 13 to 1 compression ratio. I'm told the farthest it
went once was about 3 race laps before blowing the head gasket into the engine
bay. Usually it didn't manage to finish the practice laps.

Another full monty road car with twin webers, Magnex, Piper cam, ported head,
blueprinted bottom end turned out 118 bhp at the wheels (about 140 flywheel) -
about 10 up on standard - from a big Peugot name already mentioned in this
thread. They claim more but admit to me privately being in the trade so to
speak that about the most they see is low 140's. Still 10 up on standard on a
1.9 is a result compared to most of the ones you see and that firm does have a
good rep in the trade and don't do rip off jobs as far as I can tell.

I'm not going to post what we get from this engine in general, or how the ones
above finished up after we reworked them. To be honest I'm sick of jumping on
the bullshit bandwagen. When you've spent your money though there's a fighting
chance I'll catch you afterwards to put things right - thats how half my
customers turn up - sad thing is though that by then they are skint. Such is

I'll be interested to hear how you get on though. Especially in how much power
the tuners out there are promising these days. Plenty around who'll claim 160
to 170 from the 8 valver. Doubt you'll find one to even claim 190 though. 16
valver is a great engine - one of my favourites. Doing one for myself later
this year - nothing else around to touch it for power potential at that sort of
engine size. You'll need group A driveshafts though cos the standard ones twist
into spaghetti hoops when you get into the mid 200's bhp.

Have fun.

Dave Baker at Puma Race Engines (London - England)  - specialist flow
development and engine work. .

From: Dave Baker
Subject: Re: Peugeot 205 1.9 GTi
Date: 16 Feb 1999

I forgot the most important bit so here it is but I'm not going to go into
great detail and I don't really want to debate it - if anyone else thinks
things work differently thats fine. Normal transmission losses in a 2 wheel
drive road car are about 15% of the flywheel figure. So a 200 bhp engine will
show around 170 bhp at the wheels on a rolling road. Low powered cars usually
suffer slightly greater percentage losses so a 100 bhp engine will show around
80 bhp at the wheels. 15% will get you in the ballpark though.


No matter what the "dynoplot" printout or any other type of software says,
transmission losses are just a guesstimate. I'm not explaining further - take
it as read or believe someone else - I don't really mind. Any rolling road that
prints out an engine flywheel figure is a guess. If the losses come to much
more than 15% of the final flywheel figure then the guess was wrong - end of
story. (unless maybe the gearbox is full of sand)

This is how the power claim business works then. The firm will talk to you
about flywheel figures - in the main thats what the owner can compare to the
standard book figure anyway.

Come time to stump up the cash and you'll get a power plot measured at the
wheels on a rolling road but showing flywheel figures - the firm's own rolling
road of course. You probably won't even get to see the wheel figures but you
might if you kick up enough fuss. That flywheel figure will be anything they
want it to be depending on how they have the software set up and what they
promised you in the first place. Drive around for a few weeks and find you just
can't feel the car going much quicker than it did before. Take it to another
rolling road and get a wheel figure. "That's about a good figure for a standard
one" says the guy. Phone up the firm who did the work and say it only has X at
the wheels and thats about standard. "Oh no sir" they say - "a standard one
shows much less than that but yes it does have about X now on our rollers too
and thats a good gain on standard. Sorry though sir - but we only claim power
gains based on figures shown on our own rollers - so many other ones are so far
out of calibration we couldn't really do business on the basis of promising you
power figures that you could get independently checked - nice to hear from you
again though - click."

Think I'm kidding ? - well think again. Example 1 in the previous post - the
160 bhp claim car. That showed 108 at the wheels, after the work, on an
independent set of rollers. About exactly what a standard one shows for its
128-130 at the flywheel. When laddo phoned up the firm who did the work they
claimed that a standard one only showed low 90's at the wheels on their rollers
so 108 represented a 15 bhp gain at the wheels and that meant a 30bhp gain at
the flywheel and thats where the 160 bhp came from. So what you gonna do ? sue
them? Think a judge is going to have the faintest idea what power figures mean?

So drag a load of independent experts into court at £200 an hour if you've got
any money left and hope that your independent "experts" are more believable
than their independent "experts". Save your money - have a good cry - kick
something - you're in good company - you're not the first to be ripped off and
you won't be the last.

You think I love this business ? - well you're wrong - I don't - I love engines
- I love building them right and making them go faster than other peoples - on
the track where it counts, where the bullshit stops when the flag drops. This
industry though sucks - the bullshit - the inflated power claims - the same old
crap going round and round year after year. The chips that just increase your
fuel consumption, the exhausts that drown out your radio and reduce power
instead of increasing it and then fall off in the middle of the rush hour
because they aren't made right and don't quite fit. The cam catalogues that
look like a custom cam for every type of engine but are really just 3 or 4
profiles put onto everything from a Ford crossflow to a rover V8. The
suspension kits that bottom out over bumps and float more in high speed corners
than the standard setup did. The appalling cylinder head work that most places
call "ported" that don't even have 3 angle seats and any proper shaping.

So how do you make a living in this game ? - by doing great quality work ?
don't be so bloody naive. You need full page glossy adverts in all the mags -
you need power claims bigger than anyone elses power claims - you need smooth
talking people on the other end of the phone who say yes sir, no sir, 3 bags
full sir to everyone who calls expecting 50 bhp more than is humanly possible
from their type of engine because those are the sort of figures they see
printed all the time but haven't got the faintest clue how engines work so as
to be able to make any sensible judgements.

I'll let you all into a little secret - I hardly ever do road engine work - its
a waste of time answering the phone calls - you know that person is going to
phone every single firm who advertises and in the end they are going to spend
their money with the firm who promises the most power for the least cash. So I
don't advertise at all - I ran a few for 6 months about 2 years ago and wasted
more time on the phone than I ever made up for in new work. All my business is
repeat business - I'm building the third engine in 7 years for one customer,
doing the 5th and 6 th cylinder heads for another, 3 heads for a customer in
Scotland who had 1 to try out on their race car last year.

It's shame to see so many people end up so disappointed and thats partly why I
spend time on here answering questions. I could make a good guess that Chris
does it for the same reason. Caveat Emptor goes the cry though - that and a
fool and his money. I think I might take to copying Andrew's sig though "relax
- enjoy life - that is if you don't let the dickheads grind you down first.

Dave Baker at Puma Race Engines (London - England)  - specialist flow
development and engine work. .

From: Dave Baker
Subject: Re: Help ID a 16V Vauxhall cams ?
Date: 16 Jun 1999

>From: "Ian Crocker" <>
>PumaRacing <> wrote in message
>> BTW - torque = power x 5252/rpm and 75 ft lbs per litre at peak torque
>> is top notch for 2 valve engines - 85 ft lbs per litre top notch for 4
>> valvers.
>Dave, while this even seems roughly right for F1 engines, how come touring
>cars get a much higher figure ?

Who says they do?

The highest normally aspirated torque figure I have seen that I would give any
credence to is about 93 ft lbs per litre from very oversquare 4 valve purpose
designed race engines like F3000 V8s. Any road based engine (many of which are
long stroke undersquare engines nowadays) struggle to reach 85 ft lbs/litre in
full race tune. If you have a big enough budget though and can spend hundreds
of hours on dynos testing different induction and exhaust lengths to find the
optimum pulse tuning you may get there or even a little higher.

Nothing like a bit of bullshit in the power claims though to get the other
teams worried and if you think touring car or even F1 teams are any different
from Joe Bloggs the general engine builder then think again.

How about this for a bit of top class bullshit though. In the March 4th 1998
Autocar they tested the supercharged Marcos Mantis. Claimed power 450 bhp at
6000 rpm, claimed peak torque 350 ft lbs at 4,400 rpm. The road tester had
grave doubts about the claimed power cos the car just didn't feel quick enough.

Run through the maths - 450 bhp at 6000 = 394 foot lbs of torque (450 x 5252/
6000). Hang on though matey ! - peak torque is only meant to be 350 ft lbs -
what the f**k gives here then ?

Now you don't need to be Einstein to realise that an engine can't have a
greater torque output at peak power than it does at peak torque - otherwise it
wouldn't be peak torque would it !

I ran a complete computer simulation of the car performance and it actually had
about 375 bhp to go as fast as it was tested at. Cos I'm a pedantic and
irritating SOB I phoned up Marcos and had a nice chat to one of their
"boffins". After a great deal of umming and erring he finally admitted that
they had never taken the engine to a dyno (or even a rolling road) - they just
guessed the power and torque figures! Seems that selling the car for £50,000
plus a pop isn't enough to enable them to spend £50 on a quick run on the local
rollers to get even a half arsed accurate set of figures for the advertising

Sadly none of them had enough maths to realise they had invented a set of
figures that were internally inconsistent and logically impossible for a single
engine to be able to produce.

So you still believe everything you see in print eh ?

Dave Baker at Puma Race Engines (London - England)  - specialist cylinder head
work, flow development and engine blueprinting. Web page at

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