flatsics

Tristan, and the rest. Food for thought.
While you would think the "E" 944 S2 and 968 Firehawk cars should have an advantage over regular "F" 944 S2 and 968, if they do I don't notice it on the track. They just don't seem to accelerate quicker to me.
As someone who is working my *** off on trying to catch and beat Hupfer I feel some of your pain. I am getting closer but not quite there yet.
I think statements like some of the ones in this thread show how much people don't appreciate a lot of the subtleties that make one car faster than another.

Why does Hupfer accelerate off the corner faster than the "E" class 944 S2?
The 1981-83 Euro SC should best the fastest accelerating car in F. Motor should make @ 225-230 HP at the flywheel with headers. Weight 2702 w/driver.
Have you ever looked over Hupfer's car? I have, and I think a lot of people would be surprised with his tire and wheel combo.
--15" wheels-- 205/50/15 front 225/45/15 rear.
--15" BBS Motorsport wheels. Those wheels can't weigh much, 14 or 15 lbs.
The rear tires have a 22.9" O.D. and weigh 19 lbs.
I imagine Joe runs 285/30/18 on the rear, like most front running S2 and 968 cars.
--285/30/18 has 24.9" O.D. and weighs 24 lbs according to the 2008 Hoosier price list. 18" wheels probably weigh 18-20 lbs.

-- Brakes
SC brake Rotors 8-10 lbs 944 S2 MO30 17-19 lbs

So Hupfer has a significant unsprung weight and gearing advantage. He also has much lighter brake rotors. A light weight brake rotor has much the same effect on acceleration as a light weight flywheel has on how quick an engine revs.


**This is an excerpt from "Drive to Win" by Carrol Smith.**

I'M KILLING HIM IN THE CORNERS...
...But he's walking away from me down the straight.

"If I had $10 for every time that I heard that song Christopher would be in Formula One today. For some reason that escapes me many drivers (and all spectators and most commentators) are unable to understand the difference between time and distance on the race track.
It is very simple. Sixty mph translates to 88 feet per second. Two absolutely equal cars, one half second apart, traveling 180 miles per hour at the end of a straight will be separated by 132 feet, about eight cars lengths. When they finish braking for a 60 mph corner, they will be separated by half a second-- but the linear separation will be 43 feet, about 2 1/2 cars lengths.
To the uninitiated (ignorant?), it will appear that the following car has outbraked the unholy bejesus out of the leader. As they exit the corner and accelerate the time difference will stay the same, while the linear rubberband stretches and it appears that the lead car has a significant power advantage. It is astounding how many experienced racers flat refuse to understand this phenomenom Don't be one of them."

JR944

Hey Doug:
My car does have an advantage over the F class S2's. I can run at 2,900# where the F cars must be 3,082#. That's pretty substantial. I can also legally run the Firehawk chip which advances the spark timing and raises the rev. limiter (helps save a shift sometimes). I can also legally run 9's and 10's, where I'm pretty sure the F cars are only supposed to be on 8.5's and 10's (please don't jump on me if I'm wrong on this one). My car does not have to spin the AC pulley nor does it have an AC condensor blocking the radiator. My car also has the sunroof deleted, which saves a minimal amount of weight, but high in the car.

Just a quick clarification on my car. I'm probably dropping the value $10k here . It was never a "factory" Firehawk car. Mine was an '89 raced by Kelly Moss from brand new and was evolved by them to the '91 S2 ClubSport specs. when those specs became allowable for the series. Greg Turek's car is the same as my car (was). The factory built just 7 S2 CS's in 1991 and only 6 of them raced IMSA. There is actually very little left of the original car as raced in IMSA. The original tub had almost 31,000 track miles on it and was really just wrung out. (a rear side window shattered for no apparent reason while driving at Brainerd the last weekend it ran). It was re-tubbed with a beautiful cage and was finished last spring. I didn't bother to mess with moving serial numbers as I think the value of the car is in being a great club race car, not a museum piece. (If I had one of the 7 factory cars, my opinion would perhaps differ)

Your logic for why Hupfer can accelerate out of the corners faster than me is fair, especially considering the HP it makes. Your explanation of distance vs. time wasn't needed for me anyway. There's no doubt that Hupfer made TIME on me on the straight and I made it back up under braking.

I love that you posted the following. It seems to help confirm what I've said for a long time, that the "Euro SC's" with the combination of parts legally allowed in PCA CR should really be an E car.

"The 1981-83 Euro SC should best the fastest accelerating car in F. Motor should make @ 225-230 HP at the flywheel with headers. Weight 2702 w/driver."

OK, I know that there's a whole lot more to having a competitive car than just HP/WT, but that's pretty much how the PCA classes are split.

"Euro SC" at 227hp 11.9lbs/hp I honestly think your 225-230 is on the low side as I know of at least one totally legally built "Euro SC" that measured over 210hp at the wheels. At 235hp it would be 11.5lbs/hp

F class S2, published 207hp, my estimate 235 for a very good one 13.1lbs/hp

F class Carrera 2812lbs, equal hp to "Euro SC" at BEST I think since you can't legally make the same adjustments. (the '87-89 gets screwed on wt. IMO as I believe the "extra" 10hp published by Porsche was much more marketing than engineering. Anyway, early Carrera 12.39lbs/hp

F class 968 3236lbs, 236hp published, not a lot more available legally, I think. (Jim, please correct me if I'm wrong). Let's say 250hp. 12.9lbs/hp.

F class 944T. I have no idea what a legal one makes and haven't seen a lot of them lately. (cue Tristan's video, I think)

E class 964, 3181lbs, published hp 247, Lots of extra power available with only external legal intake and exhaust mods. Is 285 a reasonable # for a car that's been internally "optimized"? If so, then 11.16lbs/hp

My car, 2900lbs, high 230's hp according to Kelly Moss engine dyno in controlled environment when the motor was freshly built. I've installed good headers since then and will allow 12hp for those (a high estimate, I think as I really don't think I'm making over 250hp, but for the sake of argument, let's say 251) 11.55lbs/hp

E class 944TS 3148lbs, 247 published. Perhaps 280hp legally "optimized" 11.24lbs/hp. I've seen some much faster cars, but have run enough with Draper and Schardt to feel that their cars are legal.

Whatever reasonable # you use for the "Euro SC", it is clearly the out performer in F and with the better acceleration you mentioned than at least my car and the 944TS, it would definitely fit very well in E. IMO, the 964, with the now legal LWF is the best current E car.

I guess my point is that Hupfer's car probably isn't much/any faster than it should be, but should really be an E car. His results and those of other current and former "Euro SC" drivers (I'm thinking Bill Berard and Terry Heath) support that assertion too, I think.

Switch E's and F's as appropriate, I haven't adjusted to the new classes yet.

Joe
spent WAY too much time on Rennlist today and now going to bed!

Azikara

Doug,

Thanks for your post and yes, I agree with your assertions on power, weight and wheel diameter. In fact I very carefully looked at the setup but I noticed 225x15 all around rather than 205. Could be wrong. I was looking for some of those wheels to test by the way but could never source them. Perhaps another thought here is that the ratios of the transmission are more optimized for T10 and T4 which is where it was most noticeable. The other thing to notice is that the car hangs easily with Costa's C2 down the straight and those babies are not slow nor low on hp.

So going back to your comments on the motor being 230hp with just headers. Is that true? Can anyone provide data that supports a Euro SC running headers makes 13% more power than stock? Does a cold air intake and exhaust on a stock S2 make 18% more power? If so, these are the best bang for buck mods one can get. What does a header do for a 3.2 Carrera? I can tell you that when I dyno'd it for NASA (with Headers and a Weltmeister chip, which is too obvious to run in PCA) it was 194 hp. It must be less with the stock chip. I guess I should find out.

But Joe's point above is a good one: some cars are more 'tunable' than others. Racers work this out. They gravitate towards those cars because they are proven winners and that is how it goes. We all have to accept it.

http://www.youtube.com/watch?v=_SvxKoocWyc

Larry Herman

SCs are the most tunable in the class because they are still fairly mechanical in nature. A twist of a screw, and you can enrichen the mixture to compensate for headers. A turn of the distributor and you can advance the timing. A bend of a tab, and you can increase the redline. Almost all of the things that you cannot do to Carreras, 944s, etc. to unlock the power because it requires burning a new chip, you can do to an SC with rudimentary tools.

If I ever went back to F, I'd run one. Maybe I'd paint it silver too.

Azikara

Perhaps put the number '79.5' on the side of it too!

flatsics

[QUOTE=JR944;4993501]Hey Doug:
My car does have an advantage over the F class S2's. I can run at 2,900# where the F cars must be 3,082#. That's pretty substantial. I can also legally run the Firehawk chip which advances the spark timing and raises the rev. limiter (helps save a shift sometimes). I can also legally run 9's and 10's, where I'm pretty sure the F cars are only supposed to be on 8.5's and 10's (please don't jump on me if I'm wrong on this one). My car does not have to spin the AC pulley nor does it have an AC condensor blocking the radiator. My car also has the sunroof deleted, which saves a minimal amount of weight, but high in the car.

Joe,
Thanks for the video and your openess about the contact with #79.

I know on paper the Firehawk cars should have a nice advantage over normal 994S2 and 968. Maybe its just the Firehawk cars I've run against, but I never think they have a acceleration advantage--- it might just be the cars that I have run against. I'm pretty sure the M030 cars can run 9's and 10's.

Jim Child

Joe's S2 is definitely faster than my 968. He kills me on the starts and down the straights, just like the #79 car. 968's are limited to 8.5's and 10's, as the optional wheels were only 7.5's and 9's. I always assumed 944 S2's were the same, but I don't know that for a fact.

Jim Child

That's one of the reasons why I love the NASA GTS lbs/hp rules. They would put a well prepared Euro SC in GTS3 while all of the other F cars run in GTS2.

flatsics

Tristan,
I think the Carerra's biggest disadvantage is the stock rev limit-- 6350+/- RPM.
194 at the wheels transltes to 228 at the flywheel with a 15% loss.
A couple of good Carerra examples. I would get a Steve W. chip for NASA.

https://rennlist.com/forums/racing-and-drivers-education-forum/112497-3-2-litre-custom-race-exhaust-it-s-done.html

http://forums.pelicanparts.com/showt...teve+wong+dyno

Steve Jacobs (Hairy Dog G.) makes up a nice header. He uses the Bursch header, cuts off the colector and welds on a Burns Stainless merge collector.

Thread on headers
http://forums.pelicanparts.com/showt...highlight=dyno

I use SSI with the heater boxes removed. SSi work great for the 3.0 liter, but are a little small for the max power on a 3.2L. I have thought of adding a cross over pipe to see if there is an advantage. The mufflers J.Archard has are the Burns Stainless race muffler. I run them on my car, they are a great race muffler and rebuildable too. If any wants to get them, make sure you get the stainless packing-- the fiberglass packing burns up because the 911 exhuast is so short.

-78-80 USA/Euro SC(8.5/8.6:1) with good headers and tune should make 205-210 at the flywheel. Theese engines us the larger 4R intake runners and big port heads.
-80-83 USA SC (9.3:1) should make the same horsepower. They use the small intake runners from the 2.7 and small port heads. They seem to make more low end torque than the 8.5/8.6:1 motors, but power drops off earlier.
-81-83 Euro SC (9.8:1) good headers and tune should make between 220-230 hp at the flywheel. I think over 230 would be a very "healthy" motor, that number is difficult to get with 3.0l and CIS injection.
-81-83 Euro SC's have big port heads and large 4R intake runners.
Big port 39/35 heads were the stock issue for ROW SCs all the way though '83. Wayne from Pelican Parts engine Rebuild book and Bruce Anderson's book says the smaller port heads were stock for ROW SCs, but that's not what the PET says if you do the research.

I think the average would be that a race prep 81-83 Euro SC should make between 15-20 horsepower more than the same prep 8.6:1/9.3:1 3.0L.

flatsics

Jim,
You and Joe are right I just looked it up in PET and 7.5's and 9's are stock for M030.

I always thought the Firehawk cars should be faster, so maybe its just the cars I have run against.
Jim, our cars are very equal down the straight.
Did you get the Putnum DVD I sent you?

Jim Child

Agreed. Our cars are very evenly matched which makes for some great racing.

I never got the DVD. I'll send you a PM.

FredC

[QUOTE=flatsics;4994711]Jacobs (Hairy Dog G.) makes up a nice header. He uses the Bursch header, cuts off the colector and welds on a Burns Stainless merge collector.[QUOTE]

Tristan: Andrew Jenks was running his Carrera with the Dan Jacobs exhaust. That was pretty impressive.

JR944

"I always thought the Firehawk cars should be faster, so maybe its just the cars I have run against."

Hey Doug:

It's been about 5 years and I think 2-3 rebuilds ago for Turek, but when I last ran against him at Mid Ohio, his car was definitely stronger than mine. I don't know if he's still running them, but for years he ran the magnesium phone dials (8's and 9's) feeling that what he gave up width, he made up in gearing and mass.

I've only run against the two guys from Chicago with the 968 Firehawk cars once. Unfortunately, I was in a friend's 944TS that had a (lack of) boost issue. At the time, it seemed that they ran really well up the straight at Brainerd, but I can't really make a fair comparison to my car. My suspicion is that equally prepared and driven 968CS/Firehawk should be a very good race vs. my car.

There is a very nice imported 968CS set at E class 968 Firehawk weight in MN. The owner has run REALLY good times in time trials at Brainerd. He's decided it's too rare/valuable to race and has it listed for sale right now (and plans to race a regular 968 in F)

Up a medium length straight, my car is pretty darn close to a good 944TS, it's only at the end of a straight like Brainerd or Road America that a 944TS will pull me just a bit. At some tracks, the gearing of the TS is preferable to mine. A 964 without the now-legal LWF can make 4 lengths on me on the Brainerd main straight. I suspect that at the end of a long straight I may start gaining ground on a Euro SC, but haven't had the opportunity to test that theory.

Azikara

That was with a chip.

MTosi

JR944 My dad drove for kelly moss for 2 or 3 years and could have raced your car I found some pics online If you read the names on the side of the cars you'll see his on some. (This site goes up and down every few minutes http://64.233.169.104/search?q=cache...lnk&cd=3&gl=us) His favorite kelly moss car was the one they won they sebring race with. It was purchased at a dealer (white 944 s2 with no sunroof or AC so the team scooped it up) anyway he liked it because it was completely unmolested, it hadnt been crashed tinkered with etc. So kelly moss modified the suspension but never got a chance to get to the engine. My dad co drove with nick ham that race and they ended up winning. Im not sure if that was also the car they won the 24 hours of the glen (my dad drove 12 of 24 in that race including a SIX hour stint) or the other races they won that year. My dad has always wondered where those cars went. He was always fond of the S2's since he had been racing crappy little fwd buzz bombs and showroom stock for quite a while (when you race prof. you race anything as long as they pay you, lol) and the s2's were such a better car good brakes, handled well and drive wheels in the right spot. He said he never realy asked about how much HP they made since the methods were always a little questionable and the drivers didnt want to be aware of it, but he said conservative estimates at the time were they had about 265hp. Plus the kelly moss cars used to get blown off down the strait by the sandridge salad cars (may have been gearing or engine not sure) If anyone else here has one of the kelly moss cars I'd be interested in which one it is. I have plenty more stories about them.