noorj

iTrader: (17)

Hey everyone!

I made this thread just to share my first autocross season this summer and to ask questions/get any advice that I can from the pros on here. My first autocross event was today and absolutely loved it! I had never even seen an autocross event before but this spring I decided I wanted to start so I joined SCCA. The event was at a go-kart track (Mid-State Microds Groton,NY) with a road course section but was very tight and that definitely helped me! There were some sweet cars there (my favorites being a Lotus 7, Chevy Corvair and a couple e36 M3's) and I had a great time! Even volunteering was a lot of fun.

I ended up running in NSTC (Novice street touring compact) due to it being my first time but mostly because the Novice Chair told me to

Anyways I ended up winning the novice class! Not only winning but having the best raw time in novice, as well as the best raw time in the regular (non-novice) street touring category with a 68.420!

I also ended up finishing 13th overall with my PAX out of 35 cars running

Here is the link to the times of that day by class
Central New York Region, Sports Car Club of America - Event Results

Here are some pics from the event





















Anyways I had a few questions for next weekend:

How much tire pressure should I run? I was at 40 front 42 rear today and I think I could like a little more rotation, but I'm not sure. There was a 50ft radius turn I could never get down correct always understeering, which I think might have something to do with tire pressures?

Some guys downshifted into first a few times, but I left it in second the entire race except for the start. Is that ok? Should I start trying to downshift to first?

Any other advice please chime in!

noorj

iTrader: (17)

And some pics of other cars there

MastaShaKe_88

iTrader: (5)

What kind of mods do you have done?? did you feel it bog down at all comin out of slow turns in second at low RPMs?

noorj

iTrader: (17)

Mods:

Trifecta Tuned
K&N Typhoon Intake
LSJ Throttlebody / ZZP Adapter Plate
Bad-Mab Shorty Header
ZZP 2.5 Inch Catted Downpipe
MagnaFlow 2.5 Inch Catback

And yeah after the tightest 180 turn for a little when it was sub 2500 but after that it felt fine, not fast or anything but not bogged down

noorj

iTrader: (17)

Also a couple of the honda guys there said a i needed "compliance bushings" I didn't know what that meant at first but they explained it as under hard braking my control arm trailing bushings are too weak and flexing causing the inside wheel to vibrate back and forth.

This is the spherical CAB the powell sells correct? Can anyone verify that is it what I would need?

SaberD

Nice dude looks like a fun course!

noorj

iTrader: (17)

Thanks man! It was really fun, very technical.

noorj

iTrader: (17)

Anyone have advice on tire pressure?

madcitySS

iTrader: (4)

depending on track, temps, tires ect ect... I go with and average about 38front and 40rear. I have an entire notebook full of run data tire temps, tire pressures and I would sat thats about average for me.

scottherbert

I don't know how many miles you have on your Cobalt, how worn-out your CAB busnings are, but the fact that your tires shake under breaking would probably be corrected the the Powell CAB bushing set. I presently run the Powell Delrin bushing but I'm running a stock-type bushing instead of the Powell sphericals.

They work quite well, even with the very large slicks I run for autocross.

I've also drilled into my LCA over the front Delrin bushings (through the bushings into the steel shaft space), added a grease fitting, and I've started greasing the Delrin bushings -- stops the weird noises caused by rust on the steel shaft rubbing inside the Delrin.

Scott

noorj

iTrader: (17)

Thanks for the response! That's a really good idea, logging all your tire pressures. I ran 40 all the way around because I wasn't quite sure. I'm on my all-season street tires 205-50-R17 so I thought because of my taller sidewall I should run more, is this thinking correct? Thanks



Thanks man! I have 56k on it but when I did my springs everything seemed much more worn out then 56k miles. What are the pros of running the Delrin bushing instead or the spherical/Why did you decide to use that instead of the sphericals?

I heard that spherical is easier to install because you just need to press it in.

That grease fitting sounds like a great idea! Is there a greese passage in the bushing or does it just get distributed from the movement of the bushing?

turbo86

iTrader: (4)

I will backup what MadCity said about tire pressure.

I prob need to do the CAB as well, so good new info there.

Great job on your finish. Love the color of your car. Once you AutoX for the first time, you are hooked.... lol : D

noorj

iTrader: (17)

Thanks! Yours so right, I'm completely hooked already. As of the event I've been looking for a set of rims to throw some starspecs on

madcitySS

iTrader: (4)

You have a taller sidewall but not as much width. I run a 235/40/18 Dunlop star spec. Took me some time to find the right pressure where I was using the tires to their max. Keeping the front from rolling just enough but not to much. It's a dance but when you get it it's one less thing to worry about

Omnigear

iTrader: (4)

you need suspension mods =p

noorj

iTrader: (17)

Haha I know right. I was told by a few people that tires+rims should be before suspension though.


And I know everyone is gonna yell at me, but when I get to that point I'm thinking coilovers I know they aren't "the best" for performance but I want them for a decent drop too. I would love to get KWV2s but if I can't find any used when I'm ready to purchase I'll probably go BC racing for there spring rates.

madcitySS

iTrader: (4)

thats funny cause i am selling some used KW V2s for 800 bucks.

I scrapped my STX build. Sticking to stock in the Road Tire class.
https://www.cobaltss.net/forums/auto...-build-267727/
selling them without the swift springs.

noorj

iTrader: (17)

O_o interested. They have front camber plates correct?

madcitySS

iTrader: (4)

they do not. I think you have to buy those elsewhere. I didnt want to buy them as i was trying to fund Karting and autocross lol

noorj

iTrader: (17)

Ah gotcha, how is front camber adjusted then?

scottherbert

[/QUOTE]What are the pros of running the Delrin bushing instead or the spherical/Why did you decide to use that instead of the sphericals?

I heard that spherical is easier to install because you just need to press it in.

That grease fitting sounds like a great idea! Is there a greese passage in the bushing or does it just get distributed from the movement of the bushing?[/QUOTE]

Answers (sorry about the long answers, but some of this can't be easily described in a few words):

1. Both the Delrin bushings (that fit into the 'hinge' part of the LCA), and the spherical bearngs (fitting into the rear part of the LCA with a vertical bolt), are used on each side -- both sets parts are needed. You get both with the kit.

2. The sphericals "press-in" with a multi-ton press at an auto shop -- it's not something you can do by hand.

3. The shericals work great, however, they restrict the relative 'drop' of the LCAs so that putting 'stock' type springs in is almost impossible because you have to compress the springs to put them in the car -- it's an almost impossible task inside the wheel well and the strut tunnel. With stock rear bushings (not the Delrin parts), the LCA drops far enough that you can install struts with stock or stock-type springs, and it doesn't take much effort to bolt them in... The sphericals work great with coilovers because the springs are much shorter than stock type springs (my coilover springs are only 6" long up front). Even Eibach ProKit sprngs are almost impossible to install because they are too long without being compressed.

4. So, the reason I use the Delrin parts (they are the 'hinge' part of the LCA) but I've removed the sphericals and replaced them with stock type rear bushings, is so I can more easily change springs which I do fairly regularly during the autocross season.

5. There's no grease 'passage' in the Delrin parts, they're solid. So when I drilled the hole for the Zerk fitting (the grease fitting) on the LCA, I drilled on the top of the LCA bushing location and I drilled through the Delrin and into the space allowed for the steel bar to create a small grease chamber in the Delrin (plus, I'm using gravity to my benefit so the grease drains down into the space - very little space in fact) between the steel bar and the Delrin. When I use my grease gun, I can see grease squeezing out of each end of the bushing.

6. I should add that I had to do a lot of carefull 'honing' to get the Delrin parts to fit inside the stock hole in the aluminum LCA (after I had the stock front rubber bushings removed -- also done with a press at an auto shop -- also not easy by hand) -- I used a drill with a brake slave cylinder honing stones to hone the aluminum until I could force the Delrin into the LCAs (coaxed with a rubber hammer). I also had to hone the inside of the Delrin once it was installed onto the hole in the LCAs to get the replacement steel bar to fit without binding. I used the same brake slave cylinder hone to work the inside of the Delrin until it was a snug but freely moving fit (not 'loose' by any means).

7. The problem I addressed with the grease fitting is that over time (I drive on wet/winter roads) the steel bar rusted and was binding rather than allowing the LCA to move up and down freely. It was making horrible noises (kind of a 'crunching' noise) when it moved up and down. I removed the LCAs, removed the steel bars, polished the bars with emery cloth to eliminate the rust, and then drilled the LCAs and Delrin to use the Zerk fittings so I can now grease -- no more binding and no more noise. If this had been a 'summer-only' car or one that was being regularly disassembled and reassembled (in other words, a real race car), I probably wouldn't have had any problems.

8. About camber changes, you can't use any kind of camber adjusting parts -- like camber 'bolts' -- with a 'stock' class car. You can, however, drill out the lower strut mounting hole (there's a spec for this in GM documentation so it's legal) and get some negative camber in that fashion. You can get -1.5 to -2.0 degrees of negative camber this way. See your friendly local alighment shop to have this done if you don't want to drill-out the struts yourself. You can also have your friendly alignment shop 'shim' the rear out to -1.55 degrees of negative camber -- also lega -- but not more than-1.55 degrees.

Scott

SaberD

search strut grind mod. you can elongate the lower bolt hole in the strut where it bolts to the steering knuckle. I would advise torquing it to 110 lbs*ft. I've had it slip with the stock 89 lbs*ft spec.

LS6Rally

iTrader: (14)

Good info in here, subd for my use!

i will say that around here, Firestone offers a Lifetime alignment for $150. might be something to look into if you want to track the car in one setup and DD in another. not sure how much they would like that, but you can try!

Mark Aubele

I did upper and lower and got -2.8 on both sides. Not legal for stock, but just doing the upper hole (up to -1.8) is legal for stock. Doing both would be legal for OP's purpose in STX or SMF. And I also "torqued" the **** out of the bolts so they wouldn't slip on the A6s.

SaberD

Yeah I did both on mine as well. I'm running -1.5 and zero toe, but I still get some outer edge wear when I push it to the limit (which is pretty much on a daily basis). It's a decent setup for a street car though. I think any more, and I might start seeing excessive inner tire wear since I do a lot of highway driving.