Thom no doubt you would benefit from larger rear torsions (33mm). Right now you're asking the sways to compensate for a basic imbalance.

Yup. The torsions, with the sways you now have, will result in an amazing car.

I cannot beleive how much better the 930 is than the old 3.6.
Perfectly set up. Yours is/will be almost identical to my car.

Have fun -

TRG sway bars have three different bars for front and rear that can be used, "A", "B", and "C". The external dimensions are identical, and can be interchanged in the bushings, the lever arms, etc...They are tubular construction, with different wall thicknesses, that correlate to a solid bar of a given size that I don't have the specific numbers right now. The "A" bars are the softest, "B" mid and "C" stiffest.

In retrospect, I think the sway bar came loose on the "lap from hell." On the next lap, the ass-end of the car was completely unmanagable, and I came in off the track. It just wasn't the same after that. I also bent my LF fender, probably bottomed out with the wheel turned. I drove it today and it felt great. Next to order some 33mm rear torsion bars...

Thom, you are basically compensating for improper spring-rate ratio F/R with the swaybars. What you did is a band-aid fix, but band-aid fixes do work.

You want to set the proper ratio and handling balance with the springs/torsions first, then use swaybars to dial things in after that.

But at least now you can see how much is on the table once you get things straightened out.

So 33mm or 34mm?

Then we move on to shock valving...

Well, 34 would be better spring-rate wise. But I wouldn't risk it with the issues they have in regard to stress-risers near the splines.

So 33mm. But you really should go to coil-overs in back with 450# or 500# springs to balance out the 23mm up front, taking into account the weight distribution of your car, and the aero.




Another option would be to drop the front to 22mm, and run the 33mm in back.

. . .or just weld it all in place and start tweaking the tire pressures. (TIC)

Serious Q; what vehicle has the fastest lap time on that track? . . a car or a shifter kart?

Hmm. Maybe if I sell a bunch of cab tops I can go to coilovers. In the meantime I'll bump up to 33mm rear t-bars and get the shocks re-valved.

I wonder if I should switch the sways back at that point...

http://www.thunderhill.com/timingrecords.pdf

Looks like 1:43 in a Stohr

Yeah, I didn't know what it was either: http://www.stohr.com/

http://www.stohr.com/images/StohrWeb3.1_08.jpg

Nope looks like a Formula Atlantic Swift at 1:39 acording to your link.

Guess I didn't look close enough...

How about 33mm with 150 lb helpers on RSR shocks in the rear?
MOre affordable than it sounds, and a GREAT combo.

Or keep your current T-bars and add the coilovers with a slightly higher rate. The nice thing about the coils is they are cheap if you need to change the rate... Adding the coils will also adress your shock valving at the same time.

Jeff

Thanks.

fwiw, it says those are SCCA times only.

A quick google gives http://www.nckroadracing.com/thunderhill_fast_laps.html

in the .125 to .150 liter (heh-heh) catagory they're doing 1:55's

unlimited (whatever that is) they're doing 1:48's

point being, most all their suspension is in the tire. . . . and it's not the massive power getting them around the track so quicky.

How does adding the coilovers address the shock valving?

When you add the RSR shocks to mount the springs on, have them valved to match your setup.

Jeff

Yep, Steve Weiner at Rennsportsystems in Oregon

Thread spoiler... :D

Ah; I thought there was some implied Magick inherent in coilovers themselves, which I wasn't gettin'