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Thoughts on 944 Spec Rules
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TOPIC: Thoughts on 944 Spec Rules

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14593

Sterling Doc wrote:
As far as rim width, the 225 RR was specifically built for our class, and the 7" rim.


Eric, thanks for the response. I didn't realize the RR was engineered for the 944 Spec class. That's awesome!

Sterling Doc wrote:
Once you've driven the RR, any thoughts about the R-888 will vanish...


tcomeau wrote:
The R-888 was rejected because...



I wasn't arguing that the R888 was a better tire. I was saying that it was a cheaper solution. In fact my thoughts about tires and sizes were purely cost motivated. I was looking at it like the HP factor--equality and cost is more important than making the cars go faster.

I can see where a faster tire with better characteristics helps the class, though. As a driver I like going faster, not slower. I'm sure the RR will be well received and an awesome tire.

Sterling Doc wrote:
As an aside, I never found indexing the torsion bars to be that bad, though a lift helps a lot with the trial & error method of indexing that I use. Typically you only only have to do it once, as well.


tcomeau wrote:
Torsion bars are simple to install and index. You do it once and forget about them.



I respectfully disagree. While I agree that installing torsion bars isn't rocket science, the indexing process is a lot more difficult and time consuming than a coil spring on an adjustable collar.

It is nearly impossible to get a perfect corner balance without re-indexing. Even if you set the rear so the height adjustment eccentric is in the middle of the adjustment range, that only gives you a 1/4" of an inch movement up and down.

Book time for replacing the torsion bars is 7.8 hours. My shop charges less than any other Euro specialty shop in Dallas per hour-$85/hr. That's $663 just to get the bloody torsion bars installed. If you are going to one of the specialty Porsche shops, you'd pay $115 an hour or $900 for the job.

Now, for $900 I'd do nothing but install torsion bars all day! That's a lot of money to replace some springs.

So besides the complexity of making ride height adjustments, what if I want a different rate? There another stack of cash or 8 hours of your life gone, not to mention the expensive price of the bars themselves.

Sterling Doc wrote:
We run the Koni's because they are an inexpensive option that has a cheap fitment for our cars. As long as we're all in the same boat, and the cars are fun to drive, it matters less wether it's optimal.


To me this isn't a good argument. If performance isn't important, why not run a cheaper tire? A street tire maybe? They'd last forever and everyone would be in the same boat.

The truth of the matter is that we are racers, we like to tinker. We like racer parts on our cars.

Don't get me wrong, the Koni's are fine. (I'll ignore the Bilstiens in this discussion, because so few people are running them). There are issues with the Koni's, though.

They are street shocks. They carry no warranty for racing use. While the fronts for all the cars are nearly the same, the rears are vastly different. The early rears are monotubes and the late are twin tubes. The late shocks can be run lower than the early because of this design. Additionally the adjustment on both of the rear shocks is a pain.

For what we get, the Spec suspension isn't cheap. Here are prices from Paragon's site for an early car:

Front Coilover Kit - $265
Front Koni Sports - $190.40/ea
Rear Koni Sports - $141.40/ea
Sway-Away Torsion Bar Pair - $295.95

That's $1225. That's a lot of money for this setup.

Speaking hypothetically, what if there was a purpose built front and rear coilover setup engineered specifically for the 944 Spec class that allowed height adjustment, simple knob type damping adjustment, a multi year warranty that isn't voided by racing, cheap rebuilds, and uses standard size coil springs? If the price was within a $100 of the current Spec suspension, do you think people would want them? Would it be worth the pain of converting the entire class?


tcomeau wrote:
If we went to springs in the rear, I'd need at least several sets of springs for different tracks.
Remember, simple, cheap, equal.


To be fair, you could do this within the rules today. For example, you could run a 400#/30mm setup for smooth tracks and a 350#/28mm setup for rough tracks. No body does, because it would be a PITA.

We could simply specify a spring rate, or a max rate like we do now. I know we don't specify a max for the front, but by limiting the rear to 30mm, the rules effectively limit the max usable front rate.


Just thinking outside the box here.


Sterling Doc wrote:
If we were building the rules from scratch...


This is a fun one to noodle. I'm not even going to touch it, though. I'm stirring enough in this pot as it is.

-bj

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14594

  • joeblow
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Torsion bars are NOT conducive to promoting this class. If nobody was going to change them then maybe but the fact is you need to spend big money for torsion bars and then the insane amount of time to get at them. Coil overs are cheap and spring sets can be had for 1/3 the price of torsion bars or less. When this class started this was why I stayed away way back when.
Old Racer!

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14596

While I agree torsion bars are a PITA, they aren't that bad. I changed a set at the track last season after one of mine broke.

I had rear coilovers in 944 Cup. It was a whole lot easier to corner balance or change ride heights. If the class was starting today, I'd love coilovers. However, I think the horse is out of the barn and swapping now is just too big a change.

I did see some stripped lower mounts from coilovers and I've seen two cases of the aluminum trailing arms snapping in half with coilovers. The car was designed with torsion bars and I'm not sure of the long term reliability of coilovers and aluminum trailing arms.

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14597

944Racer72 wrote:
While I agree torsion bars are a PITA, they aren't that bad. I changed a set at the track last season after one of mine broke.


I get that it's subjective. I think doing a head gasket on a 944 is a cake walk, but not everyone feels that way. That's why my shop exists.

944Racer72 wrote:
I had rear coilovers in 944 Cup. It was a whole lot easier to corner balance or change ride heights. If the class was starting today, I'd love coilovers. However, I think the horse is out of the barn and swapping now is just too big a change.

I did see some stripped lower mounts from coilovers and I've seen two cases of the aluminum trailing arms snapping in half with coilovers. The car was designed with torsion bars and I'm not sure of the long term reliability of coilovers and aluminum trailing arms.


This is a good point. If it lowers reliability, then it isn't within the spirit of the class. I think it would take some long term testing to know for sure.

I'm not suggesting coilovers just because it makes life easier, either. If we could further enhance the performance of the cars and make them "more race car" like, I think that helps promote the class as well. I can't tell you the number of people that would see my 944 Spec car on the lift in the shop and comment on the Welt sway bar. They thought it was cool because it was a race car part. It's kind of like what Eric was saying about the 225 width tires making the car look the part.

-bj

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14599

loftygoals wrote:




I wasn't arguing that the R888 was a better tire. I was saying that it was a cheaper solution. In fact my thoughts about tires and sizes were purely cost motivated. I was looking at it like the HP factor--equality and cost is more important than making the cars go faster.

I can see where a faster tire with better characteristics helps the class, though. As a driver I like going faster, not slower. I'm sure the RR will be well received and an awesome tire.


The RR is worth it. I think the class would mutiny if we went back the R888!



I respectfully disagree. While I agree that installing torsion bars isn't rocket science, the indexing process is a lot more difficult and time consuming than a coil spring on an adjustable collar.


No question/argument here!


It is nearly impossible to get a perfect corner balance without re-indexing. Even if you set the rear so the height adjustment eccentric is in the middle of the adjustment range, that only gives you a 1/4" of an inch movement up and down.


My turn to respectfully disagree! I'm really fussy about corner balance, and I do it myself. After years of borrowing scales, I went in with another guy to get scales, because we do it quite a bit. I can get the car to within 20lbs per corner (nearly square, not just cross weights). A little ballast helps.

Get the chassis level to start - you'll be very close. Most of the time, I can get it perfect just using the front coil overs, keeping the ride height within 1/4". When I need to use the rears, they've got plenty of movement. It may be 1/4" at the plate, but it's considerably more at the wheels. I've re-indexed once over the years, when I went to a lower ride height.

Now, I'm not saying it wouldn't be easier with rear coil overs, but it's very possible to get a good corner balance as is.



Book time for replacing the torsion bars is 7.8 hours. My shop charges less than any other Euro specialty shop in Dallas per hour-$85/hr. That's $663 just to get the bloody torsion bars installed. If you are going to one of the specialty Porsche shops, you'd pay $115 an hour or $900 for the job.

Now, for $900 I'd do nothing but install torsion bars all day! That's a lot of money to replace some springs.

So besides the complexity of making ride height adjustments, what if I want a different rate? There another stack of cash or 8 hours of your life gone, not to mention the expensive price of the bars themselves.


This is the strongest argument. How much time does it take to remove the torsion bars? What would be the total cost for that & installing the coil overs?


Sterling Doc wrote:
We run the Koni's because they are an inexpensive option that has a cheap fitment for our cars. As long as we're all in the same boat, and the cars are fun to drive, it matters less wether it's optimal.



To me this isn't a good argument. If performance isn't important, why not run a cheaper tire? A street tire maybe? They'd last forever and everyone would be in the same boat.



OK, but first you have to show that the incremental cost is balanced by a significant performance difference, at the level of spring rate we run. RR vs. street tires is more than 3 (probably 4 seconds) per average lap. In 944 Cup, and in GTS-1, Koni shod cars are competitive. I don't see the bang for the $.


The truth of the matter is that we are racers, we like to tinker. We like racer parts on our cars.

But we don't like racer part prices! Adjusting rebound is useful. Double, or triple adjustable shocks take pros to set up well - out of our scope as a Spec class, I'd argue.


They are street shocks. They carry no warranty for racing use.


I don't know what shocks you have in mind, or what they cost, but I look at Paragon, and see this: The 30-Series rear damper is considered a racing component as such does not quilify for Life Time Warranty. At the price they run, the yellows are fairly disposable in any case.




While the fronts for all the cars are nearly the same, the rears are vastly different. The early rears are monotubes and the late are twin tubes. The late shocks can be run lower than the early because of this design. Additionally the adjustment on both of the rear shocks is a pain.


Interesting, and yes adjustment of the rears is a pain.


For what we get, the Spec suspension isn't cheap. Here are prices from Paragon's site for an early car:

Front Coilover Kit - $265
Front Koni Sports - $190.40/ea
Rear Koni Sports - $141.40/ea
Sway-Away Torsion Bar Pair - $295.95

That's $1225. That's a lot of money for this setup.

There is a small discount to order it a as set with antisway bars, or save a bit shopping around, but, OK, call it $1,200. It's $700 more for the Escort Cup 4 corner coil over, which is the cheapest option I see (and is only an option for late cars). But more than that, it's well over $2K to do the swap for the installed base of cars.


Speaking hypothetically, what if there was a purpose built front and rear coilover setup engineered specifically for the 944 Spec class that allowed height adjustment, simple knob type damping adjustment, a multi year warranty that isn't voided by racing, cheap rebuilds, and uses standard size coil springs? If the price was within a $100 of the current Spec suspension, do you think people would want them? Would it be worth the pain of converting the entire class?


Getting by all the hypotheticals, your proposing a roughly $1,300 cost per car for parts, labor, and re corner balancing - $2K total? While that is reasonable for what it is, as an added expense over a currently functionals & competitive race car, it's just not practical for what you gain (mostly convenience).

tcomeau wrote:
If we went to springs in the rear, I'd need at least several sets of springs for different tracks.
Remember, simple, cheap, equal.



To be fair, you could do this within the rules today. For example, you could run a 400#/30mm setup for smooth tracks and a 350#/28mm setup for rough tracks. No body does, because it would be a PITA.

We could simply specify a spring rate, or a max rate like we do now. I know we don't specify a max for the front, but by limiting the rear to 30mm, the rules effectively limit the max
usable front rate.


I'd agree, we don't need different spring rates any more than we do now. Max rates are soft enough that there's not much, if anything, to be gained by going softer yet.




Just thinking outside the box here.



Understood, and it is interesting to think through, but major, and expensive rule changes are a HUGE deal in a Spec class. Adding less than <$200 of cost in dynos this year generated 24 pages of discusion!
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd
Last Edit: 11 years, 5 months ago by Sterling Doc.
The following user(s) said Thank You: loftygoals

Re: Thoughts on 944 Spec Rules 11 years, 5 months ago #14602

Sterling Doc wrote:
I can get the car to within 20lbs per corner (nearly square, not just cross weights). A little ballast helps.

Now, I'm not saying it wouldn't be easier with rear coil overs, but it's very possible to get a good corner balance as is.


It's interesting that we've had such different experiences corner balancing. Of the cars I've done, I didn't do the t-bars at the same time. Maybe they weren't even left to right to start.

Out of curiousity, have you found that the front right sits really high after it's corner balanced? That's been my experience.


[quote="Sterling Doc" post=14599]This is the strongest argument. How much time does it take to remove the torsion bars? What would be the total cost for that & installing the coil overs?

True. I'd say 3.5-4 hours. Taking it apart takes a lot less time when you aren't worried about measurements. Going together would be a snap.

Sterling Doc wrote:
OK, but first you have to show that the incremental cost is balanced by a significant performance difference, at the level of spring rate we run. RR vs. street tires is more than 3 (probably 4 seconds) per average lap. In 944 Cup, and in GTS-1, Koni shod cars are competitive. I don't see the bang for the $.


I think there are too many variables to draw conclusions on a spec car vs. anything else. Real world testing on a Spec car would be required.

[quote="Sterling Doc" post=14599]But we don't like racer part prices! Adjusting rebound is useful. Double, or triple adjustable shocks take pros to set up well - out of our scope as a Spec class, I'd argue.

I totally agree. Cheap=good. Complex=bad. I would hate to see the complexity of setting up a spec car increase. Having a 3 or even 2way adjustable shock would be too much for a class that is about the driver, not the car.

Adjusting rebound is only useful if it adjust bump, too. The rates we run on these Koni's almost require that then shocks be run full stiff.

Sterling Doc wrote:
I don't know what shocks you have in mind, or what they cost, but I look at Paragon, and see this: The 30-Series rear damper is considered a racing component as such does not quilify for Life Time Warranty. At the price they run, the yellows are fairly disposable in any case.


I did have something specific in mind...

Sterling Doc wrote:
Getting by all the hypotheticals, your proposing a roughly $1,300 cost per car for parts, labor, and re corner balancing - $2K total? While that is reasonable for what it is, as an added expense over a currently functionals & competitive race car, it's just not practical for what you gain (mostly convenience).

Understood, and it is interesting to think through, but major, and expensive rule changes are a HUGE deal in a Spec class. Adding less than <$200 of cost in dynos this year generated 24 pages of discusion!


I completely understand. In my original post, I said that converting existing racers over would be difficult. I realize that it's a catch 22--once you have a ruleset in place it is difficult to change something even if it is for the good of the series.

Eric, I appreciate your time discussing this. My brain is stuck in car builder mode. It just drives me crazy that I could make a better car for the same money it already costs to build a Spec car. That said a change like this wouldn't be feasible unless the Koni's were going away or the series needed a major reboot to produce more interest.

Keep up the awesome work with the series!

-bj
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