VR6 - Max power?
Ronnie Ang
with the VR6 engine and would like to know what mods are available to
increase the power and how much it can go up to.
What sort of suspension mods are out there as well?
Thanks!!
Gabe
erict...@earthling.net
hear, EIP ain't the best business people in the world.
In article <3626F1F0...@ix.netcom.com>,
--
Electricity comes from electrons; morality comes from morons.
E-mail: erict...@earthling.net
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Joe Lucchio
Ronnie Ang wrote:
> How much power can be gained from the VR6 engine?
I will assume you are talking about a 12V VR6 with 172 hp stock.
> I am considering a GolfIV
> with the VR6 engine and would like to know what mods are available to
> increase the power and how much it can go up to.
Well, assuming that the new Golf IV will come with the aforementioned engine, I
would assume that max power with such items as a 268 cam, shrick manifold, euro
throttle body, good catback exhaust and Garrett chip tuned for the above will
net about 225 or so hp. Headers may add a couple more. After this you need to
do head and valve work, increase fuel flow with larger injectors and a higher
pressure fuel regulator. How much more this will add depends on the extent of
the head work etc.
A second way would be going with a supercharger system with either a vortex or
eaton supercharger. AMS sells vortex unit which claims a 100hp increase at
8psi. NewDimensions is assembling an Eaton kit which claims something like
70-80 hp at around the same boost. The vortex kit has been available in europe
for some time now and a test in a UK publication confirmed about 280hp with no
internal or other mods - except the chip needed for the supercharger addition.
Sounds promising.
A third way would be a turbocharger system such as the one that is sold by EIP
(well at least they advertise it- from what is posted in the NG, they should be
avoided). A turbo system running at 12 to 15psi should net about 200hp
increase. However, this is not a simple bolt on installation and that the
transmission and drivetrain cannot handle much more that 225hp to 240 hp
stock. Many other things will need to be replaced with that much hp such as
the axles, clutch, tanny gears etc. The same would hold true for the
supercharger systems if you run them at high boost levels.
I own a 95 Jetta GLX and have been looking into modding the engine for some
extra power. Right now, the vortex supercharger system seems to provide the
most bang for the buck. However, I would replace the clutch, drive axles and
such with that much additional hp. You may also want to consider bigger brakes
and SS brakelines, which will require larger wheels etc. It really starts
adding up fast. And don't forget the Quiafe differential to drive both front
wheels.
Most of the good German tuners (and some american tuners) such as MTM and TAP
do not believe in more than 240hp for front wheel drive cars. After that point
it becomes difficult in putting all the hp to the ground. A good example of
this is the MTM 1.8T NewBeetle and the ABT 1.8T GTI. Both of these cars have
about 240-250 hp, but only post 0-60 times in the 6.4 to 6.8 range. Not much
faster than a stock VR6 GTI or Corrado. However, the ABT Golf is doing 0-100
in 15.9 seconds, compared to 19.2 for a GTI VR6, where the start isn't that
critical.
If you are going to drag race the car, just ignore everything I just said and
don't buy a VW.
> What sort of suspension mods are out there as well?
The suspension mods available are the same as those available for the A3 and
A2 chassis, just with a slightly different configuration to match the
different suspension design.
>
>
> Thanks!!
Gabe
reasons...
erict...@earthling.net wrote:
> Or actually getting your hands on the kit after you pay for it. From what I
> hear, EIP ain't the best business people in the world.
>
> In article <3626F1F0...@ix.netcom.com>,
> Ga...@ix.netcom.com wrote:
> > The EIP turbo VR6s make over 350hp... Dunno about reliability, though.
> >
> > Ronnie Ang wrote:
> >
> > > How much power can be gained from the VR6 engine? I am considering a GolfIV
> > > with the VR6 engine and would like to know what mods are available to
> > > increase the power and how much it can go up to.
> > >
> > > What sort of suspension mods are out there as well?
> > >
Joe Lucchio
Anthony SI1NO wrote:
> In article <36276A26...@castles.com>, eco...@castles.no_spam.com wrote:
>
> > Ronnie Ang wrote:
> >
> > > How much power can be gained from the VR6 engine?
> >
> > I will assume you are talking about a 12V VR6 with 172 hp stock.
> >
> > > I am considering a GolfIV
> > > with the VR6 engine and would like to know what mods are available to
> > > increase the power and how much it can go up to.
> >
> > Well, assuming that the new Golf IV will come with the aforementioned
> engine, I
> > would assume that max power with such items as a 268 cam, shrick
> manifold, euro
> > throttle body, good catback exhaust and Garrett chip tuned for the above will
> > net about 225 or so hp.
>
> What do you base 225hp on? Everything I've seen show that these mods are
> worth about 15hp on a stock VR6 engine.
I am talking about flywheel hp, not at the wheels. Based upon information that
NewDimensions have published on their dyno, their exhaust is good for about 10 hp
or so on a purely stock setup. According to Todd at Air and Water, Garrett has
dyno results of a 268 cam with one of his chips programmed for that cam putting out
200 hp at the flywheel. Assuming that the schrick manifold will net maybe five hp
and the throttle body another five along with 10 from a good exhaust, you should
see about 215 to 225 hp. This would make sense, especially if the chip was
programmed to take all these items into consideration. It won't happen on a parts
hanger with a "chip". It would have to be well setup. I am still a little
skeptical as well, but it appears that Garrett really knows his way around the
Motronic system and has been able to get much more out of it than other "chip"
tuners. Most of the info I had seen previously was more in the line of 200hp with
those mods.
What are you basing your information on?
>
>
> Anthony
>
> ****A. S 1 1 N O******************************************
> Spam has finally tested my patience to the limit. Replace
> AmericaOnline.com with aol.com to send private email.
> **********************************************************
PumaRacing
>From: Joe Lucchio <eco...@castles.com>
>Date: 18/10/98 03:03 BST
>Message-id: <36294C82...@castles.com>
>
>
>
>I am still a little
>skeptical as well, but it appears that Garrett really knows his way around
>the
>Motronic system and has been able to get much more out of it than other
>"chip"
>tuners.
<snip>
So he can make a fuel and ignition setting device magically produce more power
than anyone else? Hmmmm.
Dave Baker at Puma Race Engines (London - England) - specialist flow
development and engine work.
steve k
PumaRacing wrote in message <19981017233420...@ng37.aol.com>...
>So he [Garrett] can make a fuel and ignition setting device magically
produce more power
>than anyone else? Hmmmm.
>
Delete the word "magically" and your statement is correct[*]. He's the
best--does this bother you in some way?
[*] Unless you want to get really picky... combustion of gasoline is
producing the power.;P
niceguy
Anthony SI1NO wrote:
> Ok, I see what you mean but from the chart on ND website their exhaust is
> worth a max of 6hp. It's +9-10 with a chip, throttle body and p-flow.
> Assuming the Schrick manifold produces the 5hp, the Garrett chip would
> have to produce 10-20 *more* horsepower than other chips. I'd still be
> skeptical.
>
> -anthony
Ummm...what part of Schrick 268 Cams did you not see? That's prolly where the
10-20 *more* horsepower come in, and let's not forget torque too. Garrett gets
performance because he custom tailors chips for certain mods, so you get the most
bang for the buck, plus he's always experimenting and further refining his chips.
PumaRacing
>Date: 18/10/98 09:59 BST
>Message-id: <70c017$hvr$1...@supernews.com>
However, all a chip does is provide instructions that hopefully ensure the
engine gets the correct air/fuel mixture and the correct ignition timing. This
is no more than the carburettor and distributor did in the past.
For maximum power an engine requires approx 12.6 to 1 air/fuel by mass. Adding
more or less fuel than this will result in less power. Provided the person
programming the chip actually puts an engine on a dyno and alters the fuelling
until maximum power is developed there is nothing else that can be done and no
reason for one tuner to achieve more than another.
On a normally aspirated car the only scope for power improvement in a chip is
to tweak out any minor fuelling weakness that the OE manufacturer has dialled
in for the sake of fuel economy and emissions and this potential gain is
normally very small indeed. In addition there may be scope to take the ignition
timing a little closer to the "safe" limit where again the OE manufacturer may
have left a little latitude for safety to cope with poor fuel or overheated
engines.
Once an engine has been modified with cam, exhaust etc then the fuelling and
ignition will of course need tailoring to that new spec. Again though, this is
no more than any other engine would require in the past which would be done by
rejetting etc at a dyno session.
Most of this thread has been in response to a suggestion that 268 cam, exhaust,
chip, manifold, TB etc would show 225 flywheel bhp. i.e. over 50 bhp gain. IMHO
nonsense ! To achieve even 200 bhp without head mods on this engine and retain
street driveability is I would suggest an optimistic target. Don't forget that
dynos read differently and that people in the business of selling things are
not in the habit of being pessimistic in their claims.
The VR6 is a poor engine for power production with very limited valve area and
flow capability. It has smaller valves than the 4 pot 8 valve engine and to
achieve 225 bhp would be the equivalent of a 4 pot motor with 150 bhp. How many
of them see that in street trim. None I would suggest. You can of course dream
on.
With a custom 6 butterfly racing throttle body system, big valve head, hot
street cam and anything else required I suggest that 230 bhp is about the limit
for this engine given its cylinder head flow capacity. With a standard type
induction system you can knock 20 bhp off that. I will of course, as always, be
happy to be proved wrong and learn something in the process.
Marius Berntsen
>
---
>
> The VR6 is a poor engine for power production with very limited valve area and
Can you think of reasons why VW do not develop this engine layout into a
high performance engine for their transverse-engine cars?
Marius
Joe Lucchio
Anthony SI1NO wrote:
> In article <36294C82...@castles.com>, ecodev@castles_no_spam.com wrote:
>
> > I am talking about flywheel hp, not at the wheels. Based upon
> information that
> > NewDimensions have published on their dyno, their exhaust is good for
> about 10 hp
> > or so on a purely stock setup.
>
> Ok, I see what you mean but from the chart on ND website their exhaust is
> worth a max of 6hp. It's +9-10 with a chip, throttle body and p-flow.
Well, actually more like 12hp but that's picking nits. Let me set the record
straight. I still am very skeptical - even more so based upon what PumaRacing has
posted in this thread and threads in the past. And again, I don't beleive in 5hp
increases for P-flows etc, or adding hp figures together to get a total. Thats
"parts hanging" IMO. You need to consider all the mods together and how to best
maximize their potential as a whole. Based upon that statement, lets look at it
this way. The P-chip is a generic chip which will work with the stock throttle body
and the modified throttle body. It makes no differentiation between mods, whether
it be an exhaust, throttle body, cam etc. Plus, from what I have heard, the P-chip
is about the worst of the bunch. It is one of the reasons I wouldn't buy one. How
can the same chip improve performance without considering what mods have been done?
So.... if a chip is programmed to take advantage of certain modifications - and in
this case the 268 cams - which were not producing any significant increases in max
hp over the 260's with "generic" chip upgrades - I do beleive that if the chip is
optimized you should be able to squeeze more hp out of it, as well as improving the
power throughout the range of the engine. But PumaRacing make a good point - you
need to significantly increase flow to increase hp, whether it be through more
radical cams, bigger valves, porting and polishing etc. That is where the manifold
comes in. The original VR6 was designed with the VSR manifold which was later
abandoned due to cost and complexity issues. Assuming - again I said assuming- the
VR6 benefits from a variable manifold such as the Schrick or VSR for that matter, if
PROPERLY set up, I could see that increases of 5-10 hp might be possible in
conjunction with the cam, chip -which also controls the Schrick - and exhaust. You
would most likely need a header and hi-flow cat as well. But again, TOGETHER, they
may net a more sizeable increase, and the "individual" hp figures for each part
become meaningless. I believe that it would take a significant amount of set up
time to get this all to work well together, and the chip would have to be programmed
with ALL these mods being considered in order to get maximum hp.
> Assuming the Schrick manifold produces the 5hp, the Garrett chip would
> have to produce 10-20 *more* horsepower than other chips. I'd still be
> skeptical.
But it I am not saying the "chip" will give the extra 20 hp, no way. Set up would
be critical and based upon what PumaRacing has posted, you probably would need to
increase head flow through porting and polishing and a big valve job to really get
there. That is why I said in my original post that I would see putting a
supercharger on as an easier and more cost effective way of getting more hp out of
the VR6.
>
>
> -anthony
>
> > According to Todd at Air and Water, Garrett has
> > dyno results of a 268 cam with one of his chips programmed for that cam
> putting out
> > 200 hp at the flywheel. Assuming that the schrick manifold will net
> maybe five hp
> > and the throttle body another five along with 10 from a good exhaust,
> you should
> > see about 215 to 225 hp. This would make sense, especially if the chip was
> > programmed to take all these items into consideration. It won't happen
> on a parts
> > hanger with a "chip". It would have to be well setup. I am still a little
> > skeptical as well, but it appears that Garrett really knows his way around the
> > Motronic system and has been able to get much more out of it than other "chip"
Joe Lucchio
PumaRacing wrote:
> >Subject: Re: VR6 - Max power?
> >From: "steve k" <ro...@127.0.0.1>
> >Date: 18/10/98 09:59 BST
> >Message-id: <70c017$hvr$1...@supernews.com>
> >
> >
> >PumaRacing wrote in message <19981017233420...@ng37.aol.com>...
> >>So he [Garrett] can make a fuel and ignition setting device magically
> >produce more power
> >>than anyone else? Hmmmm.
> >>
> >
> >
> >Delete the word "magically" and your statement is correct[*]. He's the
> >best--does this bother you in some way?
> >
> >[*] Unless you want to get really picky... combustion of gasoline is
> >producing the power.;P
> >
> If he is the best then credit to him. I have no problem with that at all.
From what I have read, what separates Garrett from the others is that he looks at
what mods are being done and optimizes the chip based upon the individual or
collective mods. Most other "chip" tuners put out generic chips, which do not
consider what modifications are done, at least that's what I have seen for sale
here in the US.
> However, all a chip does is provide instructions that hopefully ensure the
> engine gets the correct air/fuel mixture and the correct ignition timing. This
> is no more than the carburettor and distributor did in the past.
However, you have a much greater control of those parameters with a chip,
electronic ignition and fuel injection, then you do with a carb and distributor,
don't you?
> For maximum power an engine requires approx 12.6 to 1 air/fuel by mass. Adding
> more or less fuel than this will result in less power. Provided the person
> programming the chip actually puts an engine on a dyno and alters the fuelling
> until maximum power is developed there is nothing else that can be done and no
> reason for one tuner to achieve more than another.
I can't vouch for what Garrett does or doesn't do, but from what I have read, this
is what he does.
> On a normally aspirated car the only scope for power improvement in a chip is
> to tweak out any minor fuelling weakness that the OE manufacturer has dialled
> in for the sake of fuel economy and emissions and this potential gain is
> normally very small indeed. In addition there may be scope to take the ignition
> timing a little closer to the "safe" limit where again the OE manufacturer may
> have left a little latitude for safety to cope with poor fuel or overheated
> engines.
>
> Once an engine has been modified with cam, exhaust etc then the fuelling and
> ignition will of course need tailoring to that new spec. Again though, this is
> no more than any other engine would require in the past which would be done by
> rejetting etc at a dyno session.
But wouldn't you have a much greater control with the electronic ignition, and fuel
injection system? Believe me, you know more about this than I do, I am just asking
questions so I can learn more about properly modifying my VR6.
> Most of this thread has been in response to a suggestion that 268 cam, exhaust,
> chip, manifold, TB etc would show 225 flywheel bhp. i.e. over 50 bhp gain. IMHO
> nonsense !
In light of the fact that the VR6 was originally designed with a variable manifold
in mind, won't this help?
> To achieve even 200 bhp without head mods on this engine and retain
> street driveability is I would suggest an optimistic target. Don't forget that
> dynos read differently and that people in the business of selling things are
> not in the habit of being pessimistic in their claims.
Well, I would beleive this from say Neuspeed or AMS or one of the other larger
tuners, but not from Garrett.
> The VR6 is a poor engine for power production with very limited valve area and
> flow capability. It has smaller valves than the 4 pot 8 valve engine and to
> achieve 225 bhp would be the equivalent of a 4 pot motor with 150 bhp. How many
> of them see that in street trim. None I would suggest. You can of course dream
> on.
Well, no need to get snippy. Doesn't the 2.0l 16V in European trim put out close
to 150hp stock? It put out almost 140hp stock in US trim.
> With a custom 6 butterfly racing throttle body system, big valve head, hot
> street cam and anything else required I suggest that 230 bhp is about the limit
> for this engine given its cylinder head flow capacity.
Could you elaborate? What can be done to improve its flow? You seem to
continually knock the VR6, but have not provided any suggestions as to how to
improve flow. Some of us want to learn something from these NG's.
> With a standard type
> induction system you can knock 20 bhp off that. I will of course, as always, be
> happy to be proved wrong and learn something in the process.
What about forced inducation such as the Vortex supercharger systems? Would this
be a better way to achieve power?
PumaRacing
>Date: 18/10/98 17:23 BST
>Message-id: <362A1612...@castles.com>
>
>
>
>> However, all a chip does is provide instructions that hopefully ensure the
>> engine gets the correct air/fuel mixture and the correct ignition timing.
>This
>> is no more than the carburettor and distributor did in the past.
>
>However, you have a much greater control of those parameters with a chip,
>electronic ignition and fuel injection, then you do with a carb and
>distributor,
>don't you?
Yes you have better "control" of these parameters but only to a certain extent
and lets keep in mind that this thread is about maximum power. An engine
requires a certain air/fuel mix and a certain amount of ignition advance at
whatever it's max power rpm is. Any system, whether simple carb and points
ignition can be set to give those requirements. Electronically mapped fuel and
ignition allow greater control of part throttle and low rpm settings but make
no difference to maximum power at all.
>
>> Most of this thread has been in response to a suggestion that 268 cam,
>exhaust,
>> chip, manifold, TB etc would show 225 flywheel bhp. i.e. over 50 bhp gain.
>IMHO
>> nonsense !
>
>In light of the fact that the VR6 was originally designed with a variable
>manifold
>in mind, won't this help?
It all depends on whether the manifold actually fitted in production was
designed to optimise power at high rpm or not. All a variable manifold can do
is improve low or midrange torque without sacrificing peak power. You don't
design an engine to work with a variable manifold, you design a manifold to
work with an engine. There is nothing unusual inside a VR6 engine compared to
any other engine which means that some great hidden reserve of power is waiting
to be unleashed.
>
>> To achieve even 200 bhp without head mods on this engine and retain
>> street driveability is I would suggest an optimistic target. Don't forget
>that
>> dynos read differently and that people in the business of selling things
>are
>> not in the habit of being pessimistic in their claims.
>
>Well, I would beleive this from say Neuspeed or AMS or one of the other
>larger
>tuners, but not from Garrett.
Until someone else independently tests his work we will both never know.
>
>> The VR6 is a poor engine for power production with very limited valve area
>and
>> flow capability. It has smaller valves than the 4 pot 8 valve engine and to
>> achieve 225 bhp would be the equivalent of a 4 pot motor with 150 bhp. How
>many
>> of them see that in street trim. None I would suggest. You can of course
>dream
>> on.
>
>Well, no need to get snippy. Doesn't the 2.0l 16V in European trim put out
>close
>to 150hp stock? It put out almost 140hp stock in US trim.
What has the 16v engine got to do with this debate? The VR6 is a 2 valve per
cylinder engine. I am trying to put into perspective the power levels that
people are talking about with the VR6 by comparing them with 1 and a half 4 pot
8v engines which are of similar design. The 4 pot GTi has 40mm inlet valves
compared to the VR6 39mm valves which gives it a small advantage even. The 8v
engine has been around for long enough for people to be familiar with what can
and cannot be done to it. 135 bhp in street trim for an std valve 8v motor is
quite respectable going. That would equate to about 200 bhp for a VR6 in the
same state of tune. For the VR6 to give 225 bhp with smaller valves than the 8v
engine and similar modifications in other respects would seem illogical.
>
>> With a custom 6 butterfly racing throttle body system, big valve head, hot
>> street cam and anything else required I suggest that 230 bhp is about the
>limit
>> for this engine given its cylinder head flow capacity.
>
>Could you elaborate? What can be done to improve its flow? You seem to
>continually knock the VR6, but have not provided any suggestions as to how to
>improve flow. Some of us want to learn something from these NG's.
What can be done to improve its flow is the same as any other engine. Modify
the port shape and fit larger valves. What other suggestions would you like? I
can't post a scale drawing of where to remove metal and I wouldn't give out
that information anyway. Go to the cylinder head specialist of your choice and
take your chances on his expertise. As I say above - even with a ported, big
valve head (say 41mm inlets) I still think that 230 bhp is a good upper target
for this engine. With a standard cylinder head with 39mm valves the target IMO
would be considerably lower. That is why I don't believe that 225 bhp is on
with just cam, exhaust etc as previously posted.
I am not knocking the engine - it is what it is. An engine tuner has to make
the best of the raw material that the OE manufacturer has chosen to fit. VW
could no doubt have designed an engine to give much more power than they did
but obviously this was not the design brief they chose to follow. If people
choose to buy and modify this engine that is fine but they must appreciate the
realistic levels of power available from the basic design.
>
>> With a standard type
>> induction system you can knock 20 bhp off that. I will of course, as
>always, be
>> happy to be proved wrong and learn something in the process.
>
>What about forced inducation such as the Vortex supercharger systems? Would
>this
>be a better way to achieve power?
Of course forced induction would provide more power but that is not where this
thread started out.
AWE16VR6
Ok, I'll chime in here.
Bolt ons for the 2.8l VR6 can yield approx 200hp and 210 ft/lbs of torque at
the crank, Dynojet measured with a 15% correction factor. The power making
parts would be Schrick 268 cams (for this particular test car), Garrett cam
chip, Techtonics cat back exhaust, and Schrick VG intake manifold. In our
experience, the ported throttle body adds zero power, but does significantly
improve throttle response. Since this thread is concerned with maximum power
that can be extracted out of the VR6 engine, this check list should be
sufficient.
The are many other factors that the max power goal ignores, however, and this
is what most street drivers should concern themselves with. By shooting for
big hp numbers, usable torque figures can be sacrificed. The above numbers
were achieved at approx 3700rpm for torque and 6000 rpm for hp. This makes for
a nicely balanced power curve, which stop and go American drivers would
appreciate. Items such as big valve heads and 276 cams produce bigger hp
numbers but at a cost to lower end power. But that's not what this thread is
about...
Todd
Air & Water
VW Tuning
Philadelphia
AWE16VR6
>In article <362941DF...@psu.edu>, niceguy <gti...@psu.edu> wrote:
>
>> Anthony SI1NO wrote:
>>
>> > Ok, I see what you mean but from the chart on ND website their exhaust is
>> > worth a max of 6hp. It's +9-10 with a chip, throttle body and p-flow.
>> > have to produce 10-20 *more* horsepower than other chips. I'd still be
>> > skeptical.
>> >
>>
>> Ummm...what part of Schrick 268 Cams did you not see? That's prolly where
>the
>> 10-20 *more* horsepower come in, and let's not forget torque too. Garrett
>gets
>> performance because he custom tailors chips for certain mods, so you get
>the most
>> bang for the buck, plus he's always experimenting and further refining
>his chips.
>
>
>
>then you are fooling yourself. The dyno figures I've seen for cams is
>more like 5hp.
>
>-Anthony
>
>
You are a little low in your figures. Count on a good 10-12 hp *peak* hp
increase with the 268s. Post peak is even better with approx 20 extra hp
available at 7k rpms over the stock cams. This is where the 20hp quote comes
from, and it is a bit misleading.
Joel Bell
but if you want more power...more displacement is a sure bet...
--
Joel Bell
jb...@ptd.net
1997 Vento GLX VR6
Kenwood-PPI-MB Quart-Image Dynamics-Stinger
Joshua Murray
--
Joshua Murray
Matrix Engineering
503.704.2956 fax 503.227.5941
Portland, Oregon
erman...@wrldnet.att.net
PumaRacing <pumar...@aol.com> wrote in article
<19981017233420...@ng37.aol.com>...
> >Subject: Re: VR6 - Max power?
> >From: Joe Lucchio <eco...@castles.com>
> >Date: 18/10/98 03:03 BST
> >Message-id: <36294C82...@castles.com>
> >
> >
> >
>
> >I am still a little
> >skeptical as well, but it appears that Garrett really knows his way
around
> >the
> >Motronic system and has been able to get much more out of it than other
> >"chip"
> >tuners.
>
> <snip>
>
> So he can make a fuel and ignition setting device magically produce more
power
> than anyone else? Hmmmm.
>
>
>
PumaRacing
>Date: 19/10/98 00:33 BST
>Message-id: <19981018193354...@ng96.aol.com>
>
>
>
>Ok, I'll chime in here.
>Bolt ons for the 2.8l VR6 can yield approx 200hp and 210 ft/lbs of torque at
>the crank, Dynojet measured with a 15% correction factor. The power making
>parts would be Schrick 268 cams (for this particular test car), Garrett cam
>chip, Techtonics cat back exhaust, and Schrick VG intake manifold. In our
>experience, the ported throttle body adds zero power, but does significantly
>improve throttle response. Since this thread is concerned with maximum power
>that can be extracted out of the VR6 engine, this check list should be
>sufficient.
>The are many other factors that the max power goal ignores, however, and this
>is what most street drivers should concern themselves with. By shooting for
>big hp numbers, usable torque figures can be sacrificed. The above numbers
>were achieved at approx 3700rpm for torque and 6000 rpm for hp. This makes
>for
>a nicely balanced power curve, which stop and go American drivers would
>appreciate. Items such as big valve heads and 276 cams produce bigger hp
>numbers but at a cost to lower end power. But that's not what this thread is
>about...
>
>
>Todd
>Air & Water
>VW Tuning
>Philadelphia
Thanks very much for that info - it a sounds about spot on from the valve area,
flow data and other general guesstimates based on experience of other engines.
This thread just goes to show once more how no matter which engine you pick,
people always over estimate the power they either think they have or think they
can get.
At the end of the day an engine's power producing capability is more dependent
on inlet valve flow and hence area than any other factor and this engine has
precious little of that.
PumaRacing
>Date: 19/10/98 00:55 BST
>Message-id: <70dv5u$p...@bgtnsc03.worldnet.att.net>
>
>How about a 3.0 or 3.1 conversion? I'm not suggesting it increases flow,
>but if you want more power...more displacement is a sure bet...
>
>
I'm afraid not - or at least not as much as most people think. Lets do a little
thought experiment and I'll explain why. Imagine a 4 cylinder engine with fuel
injection and lets say 100 bhp. If we take two of those engines and bolt them
together to make a V8 it would be safe to assume we would double the
horsepower. We have after all doubled the capacity as well as the valve area,
induction capability, exhaust capability and everything else. You can probably
see where I am heading now.
Now lets go for capacity increases more in line with what we can achieve by
machining an existing engine. If we take that 4 cylinder engine and turn it
into a 5 cylinder engine with one more identical cylinder we have made a 25%
increase in capacity and again we would expect around 25% more bhp. But what if
we just increase the bore and stroke of the 4 cylinder engine to create 25%
more capacity without making any other changes?
We still have the same valve area, induction and exhaust capability etc as we
started with. If the additional cylinder of the 5 pot engine gives 25% more
power because it is one more cylinder identical in all respects with the
original 4, what power increase will just the extra capacity give us?
The answer depends on the state of tune of the engine. In all out race tune the
extra capacity will give almost no more power than we had with the smaller
engine and maybe less. What determines the ultimate power potential of an
engine is the amount of air that it can "process" per unit time. What
determines this is the flow capability of the cylinder head and that in turn
depends on the valve area and the efficiency of the port design. What the
bigger engine will do is produce its power at lower rpm and the max power rpm
will scale exactly with the capacity increase. There will, due to the lower
rpm, be lower frictional losses and these will show up as a slight increase in
power.
In road tune we are not talking about the ultimate power potential of the
engine but similar principles will apply. We may, with no other changes, see a
small increase in peak power but NOTHING LIKE in proportion to the capacity
increase. Normally we might expect to see about 1 quarter to 1 third of the
capacity increase showing up as a power increase. So 10% more capacity might
show up as 3% more peak power. REMEMBER, we are talking about making, at this
stage, no other changes to the engine.
What we will see is more power in the low and mid range rpm band i.e greater
torque. This should scale very much more closely with the capacity increase so
we might expect say 8% more peak torque from a 10% capacity increase. Again
though, the usable rpm band will fall in line with the capacity increase so
peak power will be at 10% lower rpm and peak torque will also occur sooner.
What we end up with is an engine that lugs well low down but runs out of breath
very soon. Driveability will be better but ultimate point to point speed (like
1/4 mile performance) will not improve very much if at all.
However that is not the end of the story. We can take advantage of the extra
capacity to run a little more cam duration perhaps, because we can afford to
lose a bit of the new found low rpm torque. This may, in a perfect world,
bring us back to showing perhaps 4 or 5% more power from our 10% capacity.
Unfortunately in most cases we are stuck with the range of cams available to us
and the next cam up in a manufacturer's range will probably be too much of an
increase and we will lose too much low rpm torque.
In addition if we increased bore rather than stroke we might benefit from a
little more flow due to unshrouding of the valves but this depends on cylinder
head design. We might also take advantage of this bigger bore to fit more valve
area into the head and perhaps this will now scale better with the capacity
increase.
Hopefully we can now see that we only get a power increase in line with a
capacity increase if we also scale up the valve area and induction and exhaust
flow capacity by a similar amount. For most engines we tend to be limited in
what we can do in these areas by the design of the engine. Often we can
increase the valve size until the valves touch each other before they touch the
bore walls so a bigger bore makes little difference to what we can achieve in
terms of cylinder head flow.
Now go back and look at what happened to peak power when VW first increased the
size of the 8v and 16v engines from 1.8 to 2.0 litres. This was an 11% increase
in capacity but the cylinder head stayed the same. Peak power hardly changed at
all. In fact on the 16v engine in europe it went down from 139 bhp to 134 bhp
(if memory serves) until further changes were made later on with the tall block
engine. The 8v only went up from 112 to 115 bhp.
Finally, for anyone really interested in understanding engines properly, have a
look at Bill Jenkins book on the small block chevy engine. Many of the
principles in it are worth noting. For the drag engines where just peak power
was the main thing and tractability didn't some into it he used the smallest
engine sizes like the 327 cid. Only for track and street engines were longer
stroke cranks of use and the 350 and bigger engines performed better. It makes
you think!
Olaf Brescia
dyno
does not always directally translate into how the motor will perform on
the
street. Tuners can "optimize" performance in the dyno for good numbers.
VW, I think has done a respecable job with the VR6,
(at least for the engines available in the US), the 02A shifter is
another story.
1997 SCCA Central Division point champion Terry Coates said that he
preferred
running the VR6 (corrado) over the BMW M cars. He's raced both and
said the VW engine was smoother, quieter, a bit less power but more
satisfying to run.
Swept inlet area maybe part of the equation, but I would like to hear
from someone
that cannot make more power from the VR6 because they're hit the
inlet valve flow area "power wall". My 2 cents
- Olaf
PumaRacing
>Date: 22/10/98 02:16 BST
>Message-id: <362E8777...@intel.com>
>
>One more point that need to be made here, is that engine behavior on a
>dyno
>does not always directally translate into how the motor will perform on
>the
>street. Tuners can "optimize" performance in the dyno for good numbers.
<snip>
Perhaps you would like to elaborate on how an engine can perform differently on
a dyno than it does on the street (or vice versa).