I know you shouldn't do so many things at once.....but.

From .5 to 1.9 camber

From Carbotech XP20/XP10 pads to Raybestos ST47/ST43 pads

I drove it with the above changes 3 weeks ago and liked the car.

Then I went ahead with:

From 32/19 bars to 35/22 bars

From the black SLP axle snubbers with spacers to the white Z28 snubbers with no spacer.

From Nitto NT-05 tires to BFG R1 tires.

Any "surprises" I should look out for?

You were using those aluminum spacers on the rear bumps stops? They were included in the early cars with 17 x 275's to limit rear bump travel so the tires didn't scuff up the inner fenderwells. They eliminate most of the rear suspension travel, they belong in the GM bucket of shame, not on a car. They were likely a major contributor to your oversteer problem. I suggest putting telltales on the bump stop, then driving for a session - if the axle contacts them under normal driving conditions then trim 1/4" off of the tips - repeat until no contact. With 275 or larger rubber you'll need rolled fender lips, hammered inner fenders, and a rod end panhard.

Bigger bars = less body roll. Make sure the the Dbushings are lubricated well, and the end links are not overtightened, esp if you are using poly bushings. The OEM style end links bind.

What do I need to trim the stops with?

I really need to do all that to the rear fenders with a 275 tire?

How do you know if you over tighten the end links? They aren't bottomed out but are tight. They are poly also.

Hacksaw or knife will trim them.

Depends on a lot of things, but ya, with sticky tires you'll rub. Pontiacs have more room. Rodend PH limits lateral deflection.

Try a turn or 2 past being able to spin the sleeve with your fingers.

I have a rod end PHB, I will get the fenders rolled.

I don't know your spring rates, but I'd be ready to put that 19 rear back on the car.

A lot of this gets into what corners are important on the track you're driving as well as your preferred driving style and how you like the car to get into the corner as well as what rear diff you have and if it rolls free when not being driven.

But regardless, I'd be ready to test the 19 back on the car.


Costas
cars and such...

Yeh, I don't like the 22 rear bar, too stiff. Even on 3rd gear corners I cant roll back on the gas without it spinning the inside rear tire. I have the stock diff in the car. I am about to put the 19mm back on.

I test drove it on the street not pushing real hard on my NT-05 tires and it spun the inside rear in 3rd gear, will the slicks help or hurt this situation?

Springs are 550/150

EDIT

I got on the bump stops just playing on the street so I cut a 1/4 of an inch off and will go with that for now.

I like to get back on the gas as the car is finishing rotating, that 22mm rear bar doesn't seem to like that at all

Slicks (once warmed up) will help the situation because you are giving the chassis more forward bite on each side in the rear. It'll also help cover up the dead diff.

I like the 150s and hopefully with the 19 back on, you're good. For grins, once you've driven with the 19 for a while at the track, pull out one of the end links to drive it with no rear bar and see what you think.

I've tuned many an fbody with the end links by having them either "tight" where you cant turn the bushings that touch the hole in the bar, to "snug" where you can JUST turn those bushings to "loose" where the things barely rattle (and use a nylock or two nuts jammed together to keep the assembly together).

Costas
cars and such...

I have a Detroit Tru Trac in the box here at home but I have already changed too many things at once.

I have the front bar bushings fairly tight, I will play with the rear bushings at the track.

I like it better with the 19mm on the rear, I drove it with the R1 tires to scrub them in.....car feels pretty good.

Do these links "look" too tight? This is the car off the ground and the suspension hanging.

First off, the best way to tell would be with the car's suspension flat on the ground at ride height. (Hard to take pictures that way, but easier for you to inspect.) With the car's suspension handing, unloaded there will be distortion from the natural twist of the sway bars as the suspension is in full droop. Back in my C2/C3 racing days when we had to use rubber bushings, we would tighten the sway bar mounting brackets until the rubber bushings just bulged enough to the edges of the retaining washers with the suspension at normal ride height. Here's my analysis of your bushings picture by picture where M = mushrooming (rounding of the bushing's contact surface due to normal movement), TT = too tight (bushing is bulging beyond supporting washer may be due to wear or twist of sway bar), and OK. If your rules allow it, I'd switch to nylon/delrin bushings. They're much more stable, last longer, and give consistent feedback.

Picture #1 - Upper sway bar (SB) frame bushing - OK; lower SB frame bushing - M, TT; upper SB bushing -TT, and lower SB bushing TT.

Picture #2 - Upper SB frame bushing - TT, lower SB frame bushing - TT, upper SB bushing TT, and lower SB bushing - OK

Picture #3 - Upper SB bushing - M, TT and lower SB bushing M, TT

Picture #4 - Upper SB bushing - M, TT and lower SB bushing M, TT.

Again, the distortion in some of the bushings may be due to the fact that the suspension is not a ride height which is the correct position for checking out the sway bar bushings.

Hope this helps!

Thanks!

So I should loosen them all up a bit?

Some of the bushings did not get put back where they were removed from. And yes some of the distortion is from the way the bar is hanging.

I only DE the car, no "class" to run. Just trying to go faster, learn how to drive and piss off as many Porsche, Vette and BMW owners as I can.

Fender lips turned out really good.





Difference in tire size.



On the car

I would first try adjusting the torque on the sway bar linkage with the vehicle on the ground at ride height to see if the rubber bushings will return to the desired shape and fit properly. The problem that I've had with rubber bushings in the C2/C3 Vettes with similar mounting hardware is that the bushing distort over time to the point that they just won't fit properly. Usually a clear indication of the need to replace the bushing is the mounting hole is elongated allowing the bushing to slide from side to side, the contact surface has "mushroomed" (worn down such that the contact surface resembles a mushroom cap), or the free standing bushing resembles a wedge with one side compressed and the opposite side bulging outward. Any of these problems will only get worse over time and reduce the effectiveness of the sway bar itself. (I used to break the grade 8 front sway bar bolts on a fairly regular basis while racing on 10" wide slicks until I switched over to AN hardware.) Rubber bushings were good for about one season of racing, but YMMV.

BTW, excellent job on rolling the fender lips. You'd have a job offer is I still had my shop.

Fenders look great!

BTW if anyone else here needs to do this, I have an Eastwood roller that I loan out for the cost of shipping. It has been across the country a couple of times.

Great advice from Mr BC, too, on the endlinks

An important thought to get out of this discussion is that the suggestions we are offering are intended to get your cars setup into the ballpark before you next head to the track. Once you're at the track, to optimize the car you'll need to make adjustments based on how the car is working. I suggest making a few mental notes of the most dominant characteristics of the car during each session, and as soon as the car stops, write them down. Then write down what you are going to change, if anything, for each of those items, make the changes, and note how the car responds the next session.

We (the collective experience of FRRAX) can't possibly tell anyone EXACTLY how to set their car up optimally, we can only help get it into the ballpark so the user can fine tune it.

IIRC these are the items that we've discussed in this thread that, if you want to optimize the car, you should be prepared to change at the track:

-rear swaybar
-tire pressure
-front toe
-front end link tightness
-rear endlink tightness
-rear bump stop height
-I don't think we mentioned rake but that is an important one

This is why I love this board, so much GOOD knowledge and no ego's.

My car only has about 1/2-3/4 of an inch on rake if memory serves.


I do have a question Alan, I shaved a 1/4 off the bumpstops, went and drove it and got on them again( I have a light coat of red grease on the axle pads).

If I keep trimming them until they no longer touch on track, what's the point of having them on the car? Shouldn't they be touching "some"?

That's my second set of fender lips, they did turn out nice I think. The hardest part is the spot between 1 and 3 o'clock on the well, it's the way it's shaped I think.

Alan, can you break down what adjusting each way on the above items does to the car?


I am really interested to know how much quicker the car will go with the changes. I will go back to NOLA this weekend, my best lap is a 2:05 on the full north course.

Alan, I did not know that! I might have to take you up on that offer. Funny, with all the tire we have under our car (still not much by CP 'standards'), that's something we haven't done yet. The problem, though, isn't on the outside, it's on the inside, although the rubbing is much-improved after the last trip to the body shop.

FWIW, I had a 22 rear bar, and it was great for autocross, but not for street. So I have the 19 back on. If the car were only for AX and *very occasional* road use, 22 makes it rotate very well. But yeah too much rotation for confident public road carving.