FP 1G Solo2 prep questions

[wortdog]

For this autocross season, I've found myself occasionally in the seat of Eric Stemler's old ESP 1G AWD Talon. The current owner of the car has stripped the interior entirely, putting the car into FP or EP, can't remember and don't have a rulebook with me. Anyway, I was wondering what a good starting point would be for toe, camber, castor, shock adjustments, brake bias, etc. Front springs are 600s with a helper spring on top, rears are a strange combination of a helper spring, a 400lb spring, and a 225lb spring. Shocks are double adjustable ShockTeks that are probably blown anyway, or at least in need of a nitrogen charge.

The rest of the details on the car are here:
http://www.koumotorsports.com/frank.html

I ran the car once at an Autocross T&T, but it was without power steering and only at 10psi. It was basically impossible to get a good feel for what state the suspension is in. Hoosiers are hard to turn for my wussy arms.

 

[wortdog]

Ended up setting the car up like this:

-3.5 front camber
-2.25 rear camber
5 degrees castor
full rear brake bias
1/16 front toe-out
1/32 rear toe-in

It weighed in right at 2520lbs without a driver.

The car was competitive with stockish Z06 Corvettes on race rubber, but is very challenging to drive smoothly.

Here's a pic from yesterday:

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I didn't have any problems with the suspension, and braking was much better with the bias all the way towards the back, but I boiled the power steering fluid (I didn't know there was a special procedure for bleeding it). I'm also still only running 10psi, and the double ball bearing 50-trim appears to be leaking boost into the crankcase from a boost leak test. It also doesn't spool at all until 4500rpm or so. I think this car would be an absolute monster with a properly spooling turbo(T28/EVO3) and high boost. I'll try to keep posting my experiences to this thread if anybody is interested.

 

[jtmcinder]

I have been considering FP, but for a 2G. I think that first on the list is getting down close to 2400#. Then I would consider copying ACM's drivetrain, at least getting a 35/65 center diff. With struts up front, this diff would allow for more static front camber, which you will probably need with the added grips of full slicks.

But getting down to 2400# is the key.

- Jtoby

 

[wortdog]

The owner of the car is mainly concerned with drag racing, and is planning on parting the car out at the end of this year to switch to a rear drive 4G63 powered platform of some sort. That makes switching to the Cusco diff unlikely.

The largest contributor to excess weight on the car currently is all of the stock glass, which could be removed I suppose. The single stock seat will be tossed in favor of a Sparco seat soon. We may try to make composite body panels, which would also help.

I noticed that the FP rules have an allowance for McCrappy cars to swap to double-wishbone suspension, which could be an interesting mod to try out. We have a 2G parts car laying around which may be able to donate some parts.

Do you think even more static front camber could be beneficial with the struts? It was understeering some on corner entry, which could just be driver error also(I'm a mediocre driver at best).

 

[jtmcinder]

Camber, toe-out, and weight (e.g., trail-braking). It will turn in.

- Jtoby

 

[zephyr_8]

I had actually thought about doing a tubular front subframe and addapting a double a-arm suspension. Then I could use regular "coil over" shocks and hypercoil springs, and adjust camber, caster, anti-dive, wheelbase, track, SAI, and roll centers at my discretion. But then i would want to build a rear subframe, and then i might as well do a tube chassis, and then......

But i didn't say anything because i don't think i could do it for a year or so.