RESCUED: Rear Spring Rates vs. Effective Rates
#46
Rennlist Member
Looking at the PCA rules for stock class cars, under the heading "Suspension" on page 13, line "G" reads:
Spring type must remain as supplied by the factory.
I believe this means that adding coilovers to a 944 S2 places the car in a "prepared" class, my guess is SP2.
If true, this makes the decision very easy for me; I stay with torsion bars for at least the next two or three years.
Spring type must remain as supplied by the factory.
I believe this means that adding coilovers to a 944 S2 places the car in a "prepared" class, my guess is SP2.
If true, this makes the decision very easy for me; I stay with torsion bars for at least the next two or three years.
There are the PCA letter classes (e.g. G class) and then there are the SP (spec) classes (e.g. SP2).
Now a days, the vast majority of 944s run in either the SP1, SP2 or SP3 class (S2s would run in the SP3 class). In SP2 and SP3, you *are* allowed to remove the torsion bars. In the letter classes, you are *not* allowed to remove the torsion bars, so all coil overs must be "helpers". (See my comments above about once upon a time needing to comply with racing rules... that was before the SP1, SP2 and SP3 classes were invented.)
SP1 follows the same rule set as Spec 944.
SP2 follows the same rules as 944 Cup (this does also have a "prepared" class where you can do some *limited* improvements but with a higher vehicle weight).
SP3 follows the same rules as 944 Super Cup.
Neither SP1 nor SP3 have a "prepared class".
All of the PCA letter classes have a "prepared" version of that class, too. But, again, the improvements are very limited (changing "spring type" isn't one of them).
My recommendation stays the same: either put in larger torsion bars, or remove the torsion bars and use coil over shocks. You have lots of choices for setup and vendors for both options.
#47
Rennlist Member
Either that, or the classes are confusing me. I think they started it...
Thanks for the clarification. If I put rear coilovers on it and remove the t-bars I'm running in SP3. If I keep the t-bars I can pretend to be a "stock" (letter) class car, which is what Porsche did with the CS and the IMSA rules I suppose, but that makes for a very complicated suspension setup.
That does clarify things. I'd planned to not enter in the SP3 class right away since I'm not yet committed to all that entails; it would put me at a severe disadvantage from an investment perspective.
So it's torsion bars for me I think.
Anyway, I apologize for driving this thread so far off topic. I do need to understand the rules impact of this decision, but this isn't the place to do that. Thanks for the discussion of effective spring rates, coilover + t-bar design choices, and how they effect ride height control.
Thanks for the clarification. If I put rear coilovers on it and remove the t-bars I'm running in SP3. If I keep the t-bars I can pretend to be a "stock" (letter) class car, which is what Porsche did with the CS and the IMSA rules I suppose, but that makes for a very complicated suspension setup.
That does clarify things. I'd planned to not enter in the SP3 class right away since I'm not yet committed to all that entails; it would put me at a severe disadvantage from an investment perspective.
So it's torsion bars for me I think.
Anyway, I apologize for driving this thread so far off topic. I do need to understand the rules impact of this decision, but this isn't the place to do that. Thanks for the discussion of effective spring rates, coilover + t-bar design choices, and how they effect ride height control.
#49
Rennlist Member
If you're going to get into racing, I suggest you pick the class you want to run in - based on what your friends are running, where you want competition, what will make you a better driver - and then buy or build a car for that class.
It doesn't make sense to go through the expense to build a car for one class to only then change your mind and then build a car for a new class. Unless you're independently wealth - but most 944 owners don't fall into that category.
And, you're always better off buying a race car someone else has built... Usually 30 cents on the dollar is a "good" price.
#50
Rennlist Member
If you're just going to watch you may as well buy a TV set and subscribe to ESPN. That's a hell of a lot cheaper.
*unless it's your wife's horse. Then it isn't really cheaper but you can get some of it back in the divorce...
Last edited by Otto Mechanic; 04-19-2015 at 02:32 AM.
#51
Rennlist Member
"All racing is a poor idea from an investment perspective!"
You and I need to meet somewhere they sell beer and I have conveniently misplaced my wallet
I'm going to quote you on this you know. It's going down in history as one of the most obvious statements ever made by a higher primate.
You and I need to meet somewhere they sell beer and I have conveniently misplaced my wallet
I'm going to quote you on this you know. It's going down in history as one of the most obvious statements ever made by a higher primate.
#53
Rennlist Member
Fair enough. How do you make a small fortune racing? Start with a large fortune!
I'm in SP2 class with my orange car. I also have a "spare" 944 race car that's in SP1, but I'm such a gluten for punishment, I haven't even driven it - only loaned it out to friends to race.
I also have a Chevy Sonic I'm racing in TCB class with Pirelli World Challenge.
I'm in SP2 class with my orange car. I also have a "spare" 944 race car that's in SP1, but I'm such a gluten for punishment, I haven't even driven it - only loaned it out to friends to race.
I also have a Chevy Sonic I'm racing in TCB class with Pirelli World Challenge.
#54
Rennlist Member
Sorry. It was just too good to let go unnoticed...
#55
Rennlist Member
This is my very first intentionally built track car, my racing experience is very limited. I spend much more time under my cars than in them, by at least a factor of 100. And I'm serious.
I want to find the best suspension for a letter class car and I came at the question from the wrong direction, which was trying to find the best solution without considering what was legal in a stock car. Now I know that installing rear coilovers on a 944 instantly bumps me to spec class. Not ready for that, so the solution is simple.
Thanks for all your help, you've saved me a lot of money and or angst.
#56
Rennlist Member