Oval Track Bone Stock Handling Options - Cobalt SS & Others

Hi Everyone!

Long time reader, probably read virtually every FWD Handling Thread on here. I have a 2006 Cobalt SS, 2.4L with the 5 Speed. In my first season of Oval Track racing, I had quite a bit of success and enjoyed it a lot. The track is a 3/8 Mile Asphalt Oval, which is fairly banked. The car weighs in around 2,600lbs, which I cannot lower any further based on class rules. The tires are Direzza DZ102 205/55R16 on the outside, and AS-03 General's in 195/55R16 on the inside corner to help create stagger. The main issue I have so far is understeer. We are limited to 400 Treadwear tires, hence the Direzzas.

I have added a Spring Rubber to the LF and RR, and playing with some tire pressures the car managed 2 feature wins in a fairly competitive class. This season, a CRX is running full time, which is very fast and turns extremely well. My car suffers from understeer, especially as the tires get worse and more worn. I have removed the Front Sway Bar for this season, as this comes highly recommended from sources at the racetrack I trust. This is supposed to help loosen the car up, and help the LF tire "dig" into the track and drive off the corner.

Any other suggestions for Oval Track racing? The class is a stock class, so I am to stick with OEM Springs, Struts and such.

Looks like Sunset Speedway

In reply to Mr. Peabody :

That's correct! I run weekly at Sunset Speedway. I live south of Innisfil but our cottage is in Port Severn, so I come down Saturday night and then head back up. What a fun sport.

Very cool.

I don't much about this stuff, but when you say the shocks/springs must be stock, what *exactly* does that mean? eg. could you swap in the OEM shocks/springs from a Cobalt SS turbo, or aftermarket equivalents?

Do you normally run front headlights? I have to imagine there's an aero hit in picture shown above. It looks like you don't have any rear glass. Could you run plexiglass back there for the potential aero advantages?

In reply to Snrub :

So since this is a SS 2.4, it has FE3 Suspension stuff. I plan to add FE5 Struts and Shocks, since they are stock Cobalt equipment. Are FE5 a lot better than FE3? I have since covered the headlight holes in, and plan to cover in the side windows with Lexan as well when I replace the windshield with lexan. The rear window is open, I'm unsure if the 100km/h is enough that it would help?

You can see in this photo the headlight covers I made. I cut the lens from the OEM Headlight, and then riveted it on. I covered the inside with duct tape so if it did get broken, it wouldn't shatter into many pieces all over the track!

Find the biggest "stock"rear bar you can.  Firm up the Left front as much as you can, leave the right front softer, so you can force as much effort as possible to the left front.

Then, hope the guy in the CRX never learns to drive, because he will kick your ass from here to Sunday.

Could you cut a coil from the springs and get away with it ?

Stiffer rear sway bar available ?

 Don't understand the LF spring rubber

Your different tire sizes could be exacerbating the under steer.   Are you locked or does the SS have a limited slip ?

Get as much negative camber on the right side that you can get away with.  You might want to leave the rear stock to promote a little oversteer.

Get as much positive camber on the left as above.

I disagree with this stiff left front theory.

In reply to Streetwiseguy :

I will see if the FE5 Cobalt had a different rear bar. I don't believe so though. I will leave the RF soft, maybe I can move the LF spring rubber down further in the coil to increase its effective rate and increase the spring rate on the LF. The CRX is out powered by my Cobalt, but outturns me. He also has to shift down each straight away, so he's at a major disadvantage there. Typically, we race neck and neck every weekend until he can beat me in the turn due to my understeer.

A little theory on springs from my library.

 The right front spring is the most important spring on the car.  More weight is transferred to the right front than any other during left hand cornering.

If the RF spring is too soft, it will be heavily  loaded and the car will UNDER STEER.  Caps mine.

The left front spring can be used for tuning and effecting the traction of the rear tires  Stiffer , the less wedge gain and will decrease the bite of the the left rear tire. A softer spring does the opposite.

So it seems the stiffer LF does help but not at the expense of a soft RF.   

A soft RF allows the car to lean more which is not good for a strut suspension which increases positive camber ,  not what you want.

Oh, increase your caster as much as possible.  Definitely helps in a corner.

Didn't say soft right front.  Too soft lets it roll, which screws with your camber and does many other bad things.  

I raced a Neon for over a decade, and I could, on the right day, have all six tire temps across the front within ten degrees.  Short, stiff left front, short, stiff right rear, longer, slightly softer right front works well for me, and Neons don't turn any better than a Cobalt does...and I was competitive with Civics and Integras...based on handling barely well enough to use the horsepower advantage of the Neon.

Also, don't ever tell your CRX guy about the VX gearbox...

Boyes50 said:

In reply to Snrub :

So since this is a SS 2.4, it has FE3 Suspension stuff. I plan to add FE5 Struts and Shocks, since they are stock Cobalt equipment. Are FE5 a lot better than FE3? I have since covered the headlight holes in, and plan to cover in the side windows with Lexan as well when I replace the windshield with lexan. The rear window is open, I'm unsure if the 100km/h is enough that it would help?

I think it might be. The FE5 setup out handled lots of oem cars in its day, stuff you wouldn't expect it to. See C&D lightning lap it beat; 135i, Evo, STi, S2k CR, Golf  R, current Civic Si, etc.

I'm no aero expert, but I'd imagine yes at higher speeds and maybe at your speeds.

I understand with a head port, tune, exhaust, intake the LE5 can make 200hp at the wheels. Is any of that legal for you?

In reply to Snrub :

I am permitted to run an exhaust and intake. It came factory with the "Big Runner" 2.4L intake manifold. I have added a 3" Intake Assembly and straight piped the entire exhaust. I cannot run a header nor can I run a tune. 

So the crx beats you because you eventually understeer too much? Force him to the outside, then hammer down and let the left side of his car fix your understeer problem. I jest. But I did race mini stocks a lot of years ago and that was the first thought that popped into my head. 

That's how we do it on dirt!

Paved track not so much

I don't kn ow if I agree with some of the advice in here, but I'm a dirt guy. In theory it should be the same, in practice it's different