944 vs 944S

[seckerich]

I have also raced Kip in the BMW as well as the RX7. Kip is a good driver and is willing to spend the time and money to develop a car to the max. I would hold off on the "cheater" terms with no proof.
Steve Eckerich
ITS Speedsource RX7

Originally posted by Bpickettx:
Is it Kip Van Steenberg, who built a 944S in your area? I dont know if his car will be a good representation of a legal ITS car. He has built 2 ITS cars one a black e36 that smoked everything in sight. Heard the car was caught for something, then sold and vanished. Other car was a RX7, ran in Northeast, broke all trake records, sold to local guy, now mysteriously much slower in hands of new owner.

The plot thickens.

[lateapex911]

Yea....fact setting time...car DQ'ed at the ARRCs for a ballast infraction. It was 12 " or so from where it should be. Is that what made it so fast???

Then he sold it and it vanished? Maybe it was sold to a club guy? Maybe it was wrecked testing? Who knows?

A car slower post sale? Like that's never happened? The guy who bought mycar never gor it within two seconds of my time at Lime Rock, and I set that time the 3rd trip to the track...and those who race with me can tell you I'm no Kip VanSteenberg!

So, I'd be careful with what I implied...

On the other hand, Andy...was the entire engine torn down? Or jsut the standard ARRC teardown? if it's the latter, it just proved that the engine didn't have certain work done, but it isn't proof of legality either...


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Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[timo944]

Another advantage with the Advance designs - they are very light.

Vaughan - Safety - I am putting a new cage in. I agree w/ you about the lemming problem. And I'm guilty. I spent untold $$$ on Kokeln sway bars and they are a pain to set up with no advantage, other than the factory bars have rubber bushings in the a-arms that I don;t like. I'd liek to hear what you have to say about suspension set up. So far I have played mostly with camber settings, and a little with toe. But it's all a moot point until I get new torsion bars. I was planning on 30mm rate hollow bars (which I think measure 32-33mm), no more. I can't see going higher than that and don't want to buy them to find they are too stiff and them have to ebay them afterwards. Any comments?

timo

[924Guy]

Sure - I think you'll find that the 30mm are still soft; that's what I've found on my car, and I run right at 2620lbs (min spec weight plus room for error). I suspect you'd be better off with at least 32mm. This, combined with your monster swaybars, might well be a decent starting point. Then it's matching up the shocks to the suspension; in my case accomplished by shipping them in and having them redone. But you're going go with the AD's? Is there any statement out there what range of suspension they can deal with/are valved for? I'd hate to buy a shock and find out after the fact that I'm out of the range of adjustment...

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Vaughan Scott
Detroit Region #280052
'79 924 #77 ITB/GTS1
www.vaughanscott.com

[Blix]

On the Kip Van Steenburg thing...

Kip also has, in the past, had a VERY nice and VERY complete Data Acquisition system in the car, that he knows how to use VERY well. He has been nice enough to sit down and show me what he does, and why, on a couple of occasions, just because I've asked. I would add that to reasons that he and his car are fast. He knows exactly what is going on with the car, and his driving, and can make very positive changes every time he gets in.

[Tom Donnelly]

Kip's car was legal. From what I had heard, it was originally owned by Dino Steiner and run by him and Ian James in IT and GrandAm as a dual purpose car. The car hasn't vanished, its just been repainted by the new owner. And its still fast and legal.

Tom

[timo944]

Vaughan - I already have the AD's. They are valved for 600lb. front and back, but can be revalved by the customer. Far as I know there's no maximum limit. They can also be serviced by the customer.

32mm bars - sounds pretty big but then ya gotta keep up with the Joneses

About Dino Steiner - that is one fast car. I think he got protested by Tremblay so many times he quit IT. Was the car legal? he never got busted as far as I know...

[timo944]

More thoughts about torsion bars and springs:

My understanding, you pick front springs to get a good balance between suspension frequency and braking. I started with 400# and upped it to 550# in order to reduce the dive under braking. It's pretty much gone. According to calculations I picked up in a race car design book, the suspension frequency is around 165Hz. The book recommends a suspension frequency of b/w 120 and 150, but it's an old book, probably printed before the age of high-tech shocks.

Rear: The rear should be high enough to prevent the rear of the car drooping under power. The 944 has low power, so less need to have a high spring rate. So i figure pick a value to match the front. According to the book i have, the suspension frequency needs to be 2-3% off the front, higher or lower doesn't matter. If I calculate suspension frequency for a 34mm bar, it works out to 146 Hz.

These numbers vary according to the front/rear weight distribution and the unsprung weight.

I assumed 700 lbs at each corner (w/ driver), and unsprung weight of 100 lbs on each corner in the front and 70 lbs in the rear.

So it looks like a 550#/34mm set up would be right on the money.

timo

[924Guy]

Pretty much agrees with my estimations for balance (keeping in mind that I have a relatively soft front bar, requiring just a bit more front spring to keep the car from getting too tail-happy). Always found the car indecently stable in heavy braking, which, coupled with the indestructible brakes, allows for LOTS of passing in the braking zones. Only way to pass much on track with 115hp!

Another pleasant surprise was to talk with the guy at Bilstein Motorsport about valving; he recommended I stick with what I have to start with, and only make changes as I feel a need to tune. It's apparently all within the realm of tuneability at this point, one setup vs. the other. I'm really happy about this now, as I'll probably run my first weekend with the same (current) setup, to get a good baseline before switching over.

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Vaughan Scott
Detroit Region #280052
'79 924 #77 ITB/GTS1
www.vaughanscott.com