Porsche Air-Cooled Cup USA Series
#91
Rennlist Member
Is there a real simple bolt-on change for the D cars that would yield enough of a power/tq bump that the BOP weight reduction wouldn’t need to be dramatic? Just looking for the lowest hanging fruit.
#93
Pro
Originally Posted by ace37
Is there a real simple bolt-on change for the D cars that would yield enough of a power/tq bump that the BOP weight reduction wouldn’t need to be dramatic? Just looking for the lowest hanging fruit.
#95
Rennlist Member
Thread Starter
Hey Gary, is there really 35 Hp delta between a D class 911 SC (9.3:1 compression 3.0 liter, you list as 190+/- HP) and an E Class 911 SC (9.8:1 compression 3.0 liter, you list as 225+/- HP)? Seems like the delta should be less.
#96
Rennlist Member
My newly rebuilt 3.2 with a Behe dyno came in at 226 HP, my newly rebuilt 3.0 from Dan Jacobs was 192HP, both at the wheels. Both had beautiful headers with Burns collectors and straight pipes, nothing left to do and still be legal. Weight difference was 2702 for D, 2777 for E (IIRC), gearing slightly different, both ran 15" Jongbloeds. I never had a chance to get used to my converted E car, bent it in my 1st race. My D car, I loved and wish I neved messed with it. The D car was taken down at TBolt (along with Sean's) to check the motor and Walt found it was legal, guess the E driver's at the time were pissed we were ahead of them and complained..
There was talk, when I got my car dyno'd, that some 3.2's were make 235+ but who knows..
#97
Drifting
Ok, here it is.
911CUP - 911 cars from stock- D, E, F & G
1) no changes from any existing stock letter class rules except weight.
2) Hoosier tire contingency awards for those running R7.
weight changes from existing rules:
D - minus 200
E - minus 100
F - minus 50
G - no change
We have polled numerous people and found that for E taking out 100 is easy. But for D taking 200 may be difficult but certainly possible. If the D cars are having trouble we may loosen the rules on ways to get rid of weight cheaply/easily.
Also, 200 may not be enough for D and if we find that it needs to be more than 200 then we look to the D guys and gals to help find the right number as well as suggest cheap/easy ways to reduce weight (fiberglass hoods, fenders, etc.??? I'm not the expert here). The biggest delta in times seems to be the D to E lap times so rules may have to change for D to get lighter. Alternatively, for about $10k a D can become an E by changing pistons and the fuel distributor thingy, thus becoming a Euro SC instead of American SC. But we are trying to include D cheaply and it's the hardest of the bunch. It's either that or drop D altogether. Would rather include it than drop D.
FWIW, dropping weight has little to no effect on the car setup. I know because we setup my car without me in it (almost 200 pounds) and then checked it with me in it and nothing changed on the laser dyno.
Trying to get this new class up and done before season starts at Sebring...
911CUP - 911 cars from stock- D, E, F & G
1) no changes from any existing stock letter class rules except weight.
2) Hoosier tire contingency awards for those running R7.
weight changes from existing rules:
D - minus 200
E - minus 100
F - minus 50
G - no change
We have polled numerous people and found that for E taking out 100 is easy. But for D taking 200 may be difficult but certainly possible. If the D cars are having trouble we may loosen the rules on ways to get rid of weight cheaply/easily.
Also, 200 may not be enough for D and if we find that it needs to be more than 200 then we look to the D guys and gals to help find the right number as well as suggest cheap/easy ways to reduce weight (fiberglass hoods, fenders, etc.??? I'm not the expert here). The biggest delta in times seems to be the D to E lap times so rules may have to change for D to get lighter. Alternatively, for about $10k a D can become an E by changing pistons and the fuel distributor thingy, thus becoming a Euro SC instead of American SC. But we are trying to include D cheaply and it's the hardest of the bunch. It's either that or drop D altogether. Would rather include it than drop D.
FWIW, dropping weight has little to no effect on the car setup. I know because we setup my car without me in it (almost 200 pounds) and then checked it with me in it and nothing changed on the laser dyno.
Trying to get this new class up and done before season starts at Sebring...
#98
Addict
Rennlist Member
Rennlist Member
R7's are certainly progressive, however, it degrades faster upon heavy wear. Hoosier produces street TD's and we used them in 2018. Regardless, this is not a thread regarding tire choice.
As you stated, Clarke is not taking suggestions which is clear. We are 3 working weeks away from our cars leaving for Sebring. We will all have choices to make whether we participate, run in PCA in a non-competitive manner, or compete in another series. Given the current chaos, perhaps I would be wise to consider other choices.
As you stated, Clarke is not taking suggestions which is clear. We are 3 working weeks away from our cars leaving for Sebring. We will all have choices to make whether we participate, run in PCA in a non-competitive manner, or compete in another series. Given the current chaos, perhaps I would be wise to consider other choices.
#99
Rennlist Member
Can you clarify a couple of things, Will this class run in conjunction with pca letter class cars at pca races. If I run in this class am I not running as a letter class car. Dose this class dilute the letter classes even more.
#101
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Don’t see why Hoosier can’t award free tires for contingency on other models of Hoosier tires. They do that in historics.
#102
Rennlist Member
You could not run in this class and letter class at the same time, as weights are being reduced. The only exception might be G class cars as their weights stay the same.for both G and this new air cooled class.
#103
Drifting
This is a new class. You cannot run in 2 classes at the same time in pca.
Class is called "911CUP" just like SP911, SPB, SP1, etc etc etc.
Correct, with weight change, D, E and F cars will no longer be D, E & F cars! Of course G will still be G because no changes. G will have to elect either 911CUP or G. Hoping the G drivers want more competition and will switch to 911CUP.
Yes, this will further dilute an already diluted and falling (and failing) number of cars in the letter classes. The idea is to boost the older 911 car participation. Already this has happened with the spec classes for the Chixster and the 944 and Caymans. Frankly, it is more enjoyable to race with similar cars rather than dissimilar cars, i.e. 911 v 911 and 944 v 944 instead of 911 v Chixster or 911 v Cayman (the 944s already left the building a few years ago).
Class is called "911CUP" just like SP911, SPB, SP1, etc etc etc.
Correct, with weight change, D, E and F cars will no longer be D, E & F cars! Of course G will still be G because no changes. G will have to elect either 911CUP or G. Hoping the G drivers want more competition and will switch to 911CUP.
Yes, this will further dilute an already diluted and falling (and failing) number of cars in the letter classes. The idea is to boost the older 911 car participation. Already this has happened with the spec classes for the Chixster and the 944 and Caymans. Frankly, it is more enjoyable to race with similar cars rather than dissimilar cars, i.e. 911 v 911 and 944 v 944 instead of 911 v Chixster or 911 v Cayman (the 944s already left the building a few years ago).
Last edited by GT3DE; 12-21-2018 at 11:59 AM.
#104
Rennlist Member
I like it. Two notes from the peanut gallery:
-F and G 964s are the exact same cars except F cars are 271#s heavier. So really instead of losing 50#s they will be able to lose 271# unless I'm missing something.
-We'll see what happens but 15" wheels will be a big/huge advantage and essentially a free R&P change for older 911s, and I see most of that advantage in all 60-70 mph corners but....even with the 100 lb weight loss 964s should still have the advantage at the end of the straights w/ more hp (even if heavier).
-F and G 964s are the exact same cars except F cars are 271#s heavier. So really instead of losing 50#s they will be able to lose 271# unless I'm missing something.
-We'll see what happens but 15" wheels will be a big/huge advantage and essentially a free R&P change for older 911s, and I see most of that advantage in all 60-70 mph corners but....even with the 100 lb weight loss 964s should still have the advantage at the end of the straights w/ more hp (even if heavier).
#105
Rennlist Member
If this is a go maybe we should run on Hoosier bias ply tire, cheaper and less stress on the chassis. Mark White ran them this year and said they were a hoot, about 2 seconds slower a t Road America.