Definately different! When I'm cruising at 80mph in 5th gear I'm turning 3400rpms.

 

example of final drive change to 3.09 on otherwise stock gearboxes.


G28.07 1983, 1984 Europe, ROW

Individual Overall Individual Overall
1st = 3.76 10.23 / 3.76 11.62
2nd = 2.51 6.83 / 2.51 7.76
3rd = 1.79 4.87 / 1.79 5.53
4th = 1.35 3.67 / 1.35 4.17
5th = 1.0 2.72 / 1.0 3.09
Reverse = 3.30
Final Drive = 2.72 / 3.09

G28.08 1983 USA, 1984 USA

1st = 4.27 9.65 / 4.27 13.19
2nd = 2.85 6.44 / 2.85 8.81
3rd = 2.03 4.59 / 2.03 6.27
4th = 1.53 3.46 / 1.53 4.73
5th = 1.0 2.26 / 1 3.09
Reverse = 3.75
Final Drive = 2.26 / 3.09

 

I'm in!
Hammer

 

Correct me if I'm wrong, but if 2.20 FDR is optimum for boosted apps, why are we discussing a group buy on 3.09? What application would this benefit from this setup?

 

Meant to ask what application would benefit from this setup.

 

imho only a car running drag slicks will benefit from this.

 

Anyone with a 2.20 or 2.63 rear-end that wants better performance in a normally-aspirated scenario such as PCA GT2 S or R club racing.

 

Why do Rennlisters, who are not interested in a particular modification, criticize those who do? If you don't want it, don't buy it! I don't give a damn if somebody wanted to put some steer horns on his 928 hood because he wanted the Texas Longhorns to win the BCS! That's stupid IMO. But it's none of my business so I wouldn't say a word unless asked. But for some reason everytime I see a 'lister say he wants to do a certain mod to his car, the critics come out of the woodwork.
A 3.09 gearset would cut a car's acceleration times from a standing start to redline. All things being equal, if a 928 with a 2.20 raced a 3.09 car in a QUARTER MILE race the 3.09 would win by A LOT! Yeah I know, that's because the gearset moved the engine power band in each gear to useable areas not because it increased engine power, but who cares if the goal is to win the race!
I think a little more tolerance of other's preferences is in order.

 

Hey Dave C.,



But wouldn't the transmission on a bored & stroked GT2 race car just break the trasnmission more often?

I wonder if the rev limiter would be an issue at Road America in 5th.

Are Mark. A, Joe F. or Don H. running 3.09s? or do they want to?

 

Hi Stan,
The higher you go (numerically) in the rear gearing, the easier it is on the drivetrain in front of the rear axle. It's easier to turn a 4 to 1 than a 3 to 1, etc.
Hammer

 

I'm not going here - this is kibort territory

Ok. Maybe just a little...

It all depends upon the intended use and the intended tracks and the intended horsepower. Mark A. and Don Hanson are using 2.73 FDRs. (i.e. GTS and GT AFAIK.)

And can you still run in GT2 with a 6.0? I though GT2 was limited to 5.0 and with either forced induction or 5.01 liters you got bumped to GT1.

A 3.09 would be helpful to a 928 with 'only' 300 rwhp at Limerock.

 

GT2 is large NA motors. GT1 is listed as turbo charged but likely would include supercharged as well. Mark A., Joe and Don are all bored/stroked, and are GT2 cars in PCA Club Racing anyways.

Thanks 6.0-928S, I guess that makes sense to me...

 

I'm pretty sure Mark, Joe and Don run 2:73, or at least they did at one time.
I've been running a 2:64 and it seems to work at most of the tracks I've run.

A 3:09 on a stroker makes 1 and 2nd almost useless on the track. Ask Scott M. about his GTS stroker w/ the 3:09, he has lots of fun keeping tirerack in business

 

And where do you use 1st or 2nd now?

Certainly nowhere at Lime Rock or Watkins Glen that I can think of, except to get the car rolling.

 

Sometime at the start depending on the group