Camaro Autocross Update: Part 2 of 3 – Offseason Work Begins

When we last left off, we were headed into winter with a lot of plans, which I came to break down into a few simple objectives, in order of completion:

– Rolling (relatively) Quiet (new exhaust)
– Rolling Flat (swaybar mods)
– Rolling FAT (new tires and wheels)
– Stopping Reliably (upgraded calipers for road course duty)

There’s a ton of other possibilities, but with other projects and the holidays combining with the relatively short Texas offseason, this seemed like an achievable list. Did we get everything done?

Read on to see..

Speak Softly

The original 3″ exhaust setup uses SpinTech mufflers, which are only sort of classifiable as a muffler (see examples here and here) and dumped in front of the rear tire. A simpler way of putting this is that with the windows down it’s LOUD inside. And outside. And down the street. get the picture. We added some baffles into the pipes last year, but it was still loud enough to earn the name “that loud red 2nd gen” at the Camaro club event.

In addition to the extreme noise levels, the setup severely compromised ground clearance because of how the front section dipped down around the frame. The solution for both problems came in a move to smaller 2.5″ tubing (3″ was a touch overkill for the 377 anyway) and re-positioning a relief-cut x-pipe rearward, allowing the mufflers and turndowns to be located under the center of the car between the trailing arms.

Short of building a custom set of headers, this is as good as it’s going to get ground clearance wise. So far, it has worked out swimmingly. We gained around 1.5″ of clearance, which is huge. Combined with the stiffer springs up front, we’ve managed to lower the car a touch and still haven’t scraped them.

Best of all, the sound is much more tame, but still plenty aggressive once the tach starts climbing.

Rolling Flat

Next on the list was solving the, to use a nautical term, listing issues it had in the corners. After the first trip, we unhooked the rear Competition Engineering swaybar to make the rear more compliant, and thus, more grippy. This softened everything up and allowed a substantial amount of body roll, so something had to be done up front.

After evaluating several options, including mounting a custom bar above the framerails and getting a Speedway blade type bar, we settled on modifying the existing Suspension Techniques 1.25″ bar with adjustable links.

Using the swaybar rate chart on Speedway’s site, we were able to gauge how much shortening the length of the bar would increase the rate, and settled on 5 adjustment points. We also eliminated some of the few pieces of urethane in the suspension, moving to rod ends on custom machined endlinks.

Increased stiffness in the front means that we can now bring the rear bar back into the mix, and the result is a significantly stiffer car in both turns and transitions.

Rolling Fat

On to the rolling stock situation. Our original plan, thinking that space was limited more than it ended up being in front, was for an 18×10/275 combo up front, and 18×12/315 or 335 combo out back. After some test fitting and measuring using the rear Enkeis from the 350Z that we had been running before, a much, much cheaper (though slightly heavier) set of 18x11s were sourced from XXR. We’ll be rocking 315s all the way around, and this left room in the budget for brake upgrades.

Since we initially got it on the road, the wheels we’ve had have never been what I had in mind, but what we could work with at the time. I’ love with these already.

Of course, along with stuffing this much tire under the front comes a few challenges. On the inside, the swaybar was acting as a steering stop (less than ideal). Outside, matters were mostly ok except at the back of the fender, where the tire hit the lip at the bottom the wheel opening. No worries, that’s what air tools are for, right?

And, a few minutes later..clearance, Clarence! We ended up opening this up a fair amount more, but the end result is hardly noticeable.

We did a matching cut on the drivers side, which is a reproduction fender that is made completely different at the back, but still lacked a bit to be desired for clearance. We’ll paint these exposed edges with POR-15 to protect against rust, and maybe add an aluminum trim piece to tidy it up later.

Then, it was time for road testing – and gratuitous amounts of pictures, just because. It actually drives great on the highway, way better than I expected with a bit a toe out and that much rubber up front.

Stopping Reliably

With the Optima Ultimate Street Car event at TMS, which includes road course sessions, being on the to-do list for the year, a brake upgrade was in order. The front Dynalite 4-piston calipers are a great drag racing piece, but we just don’t trust them to whoa this car down very many times reliably given how small they are. Fortunately, Wilwood’s kits for these cars are largely interchangeable, so we were able to swap in 6-piston calipers with little headache.

These utilize the same 12″ rotor, and we have the capability to move to a much thicker 14″ rotor down the road if needed. That will involve a complete swap as it takes different calipers, though. This setup is still relatively economical on the consumables, and should be safer for prolonged track time.

The plan is to feel everything out in the slower orientation session in the morning and go from there.

It’s Almost Time..

That’s it for part 2 – check back soon for the final installment when we’ll get rained out, rained on, do some final prep work, and still manage to have a little fun in the midst of it all.

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