3rd gen autox-er with 4th gen questions

[KeithO]

Hello.

I just made a handshake deal to purchase a 1998 Z28 (LS1/M6). I plan on selling my two cars (a mint 83 Monte Carlo SS and an 88 IROC) to fund this and the seller is willing to wait at least until my SS goes.

I currently autocross a 1988 IROC-Z (L98/A4) in F-Stock. The 1998 Z28 that I will be purchasing is completely stock.

Mods from stock on my IROC include:
1) Maximum camber adjustment possible
2) Maximum caster adjustment possible
3) 4 Koni Yellows (all single-adjustable)
4) 5-pt harness
5) Dynomax cat-back
THe IROC is quite respectable. I am hoping that the newer Z will be a little better (or at least similar, but more reliable).

I plan on using the 1998 Z28 for my future autocross car and I have a few questions.

1) What is the maximum negative camber adjustment that I can expect with the '98? The '88 really didn't give me enough. Should I expect the same limitation with the '98?
2) Ditto for caster
3) Do any of you have the single or double adjustable Koni's in your 4th gen? Is the additional price of the double-adjustables worth the additional cost when compared to the single-adjustables?
4) Do any of you have a cat-back? Any opinions on my options for a cat-back system?
5) My IROC was my winter car. The new Z28 will have to fulfill this role. I bought a second set of 3rd gen rims and mounted Bridgestone Blizzaks on them for winter driving. The Blizzaks are 235/60 16's and are like new. Since both the 1988 and the 1998 Camaros are stock with 245/50 16's I am thinking that I can re-use these tires (but not the rims due to different offsets/backspacing). On my IROC, the front tires rubbed if I turned the steering towards lock on direction or another. Will these tires fit under a 4th gen? Should I expect some rubbing if they fit at all?
6) Were there any optional tire diameters available for the '98 Z28 (say, 17")? If so, did they come in an option package or were they available as a single RPO?

Any responses are appreciated.

[Dr.Mudge]

Max camber, not much. Caster, you should get +4 or more I believe.

I have koni doubles, I think the decision is up to you on wether you want one or the other, someone I know has singles in front and doubles in the rear. I got a good deal on mine which is why I went for them, I was origianlly going to get singles.

[KeithO]

Thanks for the feedback. I was kinda hoping that they would give me more camber. Maybe the better weight distribution of the 4th gen will be helpful. I think I'll go to the bookstore and see what the Haynes and Chiltons manuals have to say regarding range of adjustment.

On the Koni's, on my 3rd gen I set them to the softest setting (which is very harsh for street use) and left them alone. Do you find yourself adjusting your Koni's for a give circumstance or do you also leave them alone.

Thanks.

[sgarnett]

I have seen many different number quoted for stock alignment specs. In theory, caster can be set to +5 with camber at the stock setting, but as you max out the negative camber I think it starts to trade off against the caster.

You can definitely get to -0.5 camber, +4 caster. You might be able to get -0.8 or so on the camber if you're lucky. To get beyond that, you have to move from FS to ESP and lower it.

Regarding shocks, some popular setups for autocross are:
Koni DA front, Koni SA rear
Koni SA front, Bilstein HD rear
Revalved Bilstein front, Bilstein HD rear

I went with the Koni/Bilstein combo, but the rears haven't come in yet so I can't give any feedback.

[This message has been edited by sgarnett (edited July 01, 2002).]

[KeithO]

Thanks for the additional info. I still am getting over my sticker-shock on the price of the Konis. Maybe the hydrid idea would be a good tradeoff for me.

BTW - The guy with the 98 Z28 told me he wants the deal done next week. I really hope that I get buyers for my other cars fast... I don't want to go that far cash-flow negative...

[This message has been edited by KeithO (edited July 01, 2002).]