Autocrossers please read

[AustinL]

First of all do any of you use cordless impact wrenches? If so what kind is working for you? I am trying to find one that will work well for swapping tires at the track. I really like the snap on ct 350 and 3850 if I can afford them! I would like to find one that works that is cheaper.

Also, I just completed my first autocross in my new svo. I really loved the kuhmos they were amazing! I was curious what shock settings and tire pressures yall are using. My car has the rear shocks set pretty soft I think but I have not checked them yet. The front is two turns from firmest. my front tires were set at 40 psi and 32 psi rear.
At first I had a bad understeer issue with 35 psi front, and firmest shocks front. I then increased tire pressure to 40 and decreased shock firmness two turns with a much better response. The car really seemed to point in well after that. i would however like the car to trend towards oversteer under full throttle. Seems like a little oversteer would help me with the 180 degree turnarounds.
I also would like some opinions on camber and caster with a stock car and toe in. Yes I have read the how to make your svo handle post, I just want yall to reiterate that before I change it up. I am in g stock and the car is completely stock down to the radio.
Thanks
Corey

[gbeaird]

The car will be prone to understeer. The trick is to execute most of your braking early and turn in early. Essentially aim for the inside cone. If you hit it, you are going too slow.

For setup tips, look at some of the tech articles on William Prince's website, specifically;

http://www.wprince.com/CARSETUPGUIDE.htm

It does a decent job of indicating what you are doing by changing settings on the car. The only thing it doesn't do well is what happens with shock setting changes. Increasing or decreasing the shock stiffness is essentially increasing and decreasing the sprint stiffness and spring rate, so you can loosely follow that part of the matrix.
We have our 86 G Stock car set up with the fronts at 1/2 turn from full stiff and the rears 2 turns from full stiff. We are running 1 year-old shocks, though, and our driving style may be different. Remember, also, that we are running high tire pressures (53#F/45#R).

You can't get too much camber in a stock Mustang. loosen the onionhead bolts, jamb the top of the shock as close to the centerline of the car as possible and tighten everything back down.

You also can't get too much caster in a stock car. I have heard of some loosening the bolts that hold the K-member (that the lower control arms bolt to) and pulling it as far forward as possible then tightening everything back down. We stayed with the factory (or near factory) settings here.

For autocross/street, you will want to run zero toe-in to 1/8" toe-out to prevent too much tire wear. For a car that is towed to the events, you can go with closer to 1/4" toe-out. It will make the car twitchy on the street, and REALLY wear out tires quickly, but the car will turn in much better in the corners.

The impact wrenchs are great, but also carry a torque wrench to finish tightening the lug nuts after you get them on with the impact wrench. Because of the oppressive heat and humidity in Houston, we opt to NOT change tires at the event. We have seen a lot of heat exhaustion here in Houston that occurred when the victim was changing tires. If your drive is not too far, and there is a low chance of rain, just drive the car to the event with the Kuhmos on it. We _have_ driven in the rain with Kuhmos. Although not something I would do all the time, Kuhmos are many times used as 'rains' for rainy events. You may want to change tires with higher rain chances. You will also wear out the lug nuts quicker if you are changing the tires frequently. Get another set of lugnuts and save those SVO-specific lugnuts!

So, how did you place? We drove our 85 C Prepared Firebird at Houston's Regional last Saturday and placed 1st and 2nd.

Gene Beaird
86 2R SVO, G Stock
85 Firebird, CP
Pearland, Texas

[svobud]

you're pretty much running exactly how I keep mine set up....

Victoracer Khumos
40psi in fronts
36psi in rears (I adjust both from there after each run)
Eibach Sport Springs
Konis one/two turns from soft
Flaming River steering shaft (trust me - it counts)

No subframes (until now), no cage, no bushings, etc...straight up street car. I've even had great success running a 140TW street tire on the car as well.

I don't go crazy with the camber/caster. Why should I? I drive where ever I go and I'm not competing on a National level. I leave my stuff sitting straight up. I'm there to have fun - if I win, even better.

Paul Becker whipped out one of those niffty cordless impacts during a flat tire change on I-85 North earlier this year - I have to say, I was VERY impressed with it. I agree with Gene on this - they're great for changing the tires in the pits - but you still need to bring a TQ Wrench as well.

btw - this thread was moved as it had nothing really to do with Engine topics.

[indiana dave]

OK. I'm bringing this thread back from the dead...
Trying to remember how I set my car up last time I autocrossed and am looking for input.
There seems to be a misunderstanding here. Corey says he ran his front Konis 1-2 turns from full STIFF. Then Gene says he runs 1/2 turn from full stiff.
Bud, then you say "you're pretty much running exactly how I keep mine set up...." But then say "Konis one/two turns from soft"
Did you misread the posts, or mis-type your reply.
I think I set mine 2 turns from full soft. I've lost my little notebook of... notes.
I know I run 40psi to start in all tires, then ussually end up airing the rears down for a little more bite. But that was with theold Pep Boys tires. Ive only run these Khumos once.
Thanks in advance!

[SVOeric]

Honestly, it depends on the course --
the lot we auto-x on for the reunions in KY is SLICK! -- to help with grip, I was running down as low as 24psi in fronts, and about 28 in rears. for my driving style, I found that it was better to have mushy tires, than to try to keep them from scooting.

now -- I ran at another lot recently (the lot we will be running at for this years reunion) and the higher pressures were a must. Of course I don't have victor racers, just Kuhmo 711's

As far as susspension, I keep mine 1 to 1-1/2 turns off full firm, but sometimes go harder, depending on the course. The guys here in CKR (central kentucky region) have a lot of miata's, so we end up with a lot of tight courses (ie: good for those people that are horsepower challenged, but don't weigh anything)

a couple years ago, I got ticket off when they built a course with a turn that was so tight, my SVO wouldn't make it if I rubbed the entrance cone, and went full lock. I wasn't the only one either-- nice to take out cones on the parade lap before the auto-x even starts.
anyway -- but for turns like that, I like to go full stiff, makes it easier to slide the car into a turn like the one I just described

[indiana dave]

Yea. I have Khumo 712. Not Victoracers. I'm going to try 2 turns from full soft, and 40psi all around as a start point. Mark the tires with shoe polish and adjust accordingly.
Wish me luck!

[at8tc]

i did some autox this weekend, and i noticed some understeer, but my shocks are blown i have ecsta supra 712 245/40/17 all around i was running 35psi in all four. maby next time ill lower the psi..

[indiana dave]

I ended up 2nd in my class. Would've had first, but they say I hit a cone on my fastest run. I ran 39psi all around, front Konis 2 turns from soft, rears.... uhmmm... I don't even know where they're set. My front suspension is stock, except for lowering springs. REar is MM weight jacker lowers, FRPP uppers, lowering springs, and Koni reds all around.

[gbeaird]

i did some autox this weekend, and i noticed some understeer, but my shocks are blown i have ecsta supra 712 245/40/17 all around i was running 35psi in all four. maby next time ill lower the psi..

You'll probably want to try MORE in the front. The SVO is significantly camber-challenged. With 35# F, the tire is probably rolling under, lifting the inside of the tire (WRT the turn) off the course.

With street tires, that sounds about right for the back tires.

Gene Beaird

[indiana dave]

Got another autocross this sunday. I'm going to unbolt my rear Konis to find out where they're set. I also didn't bother markeing my tires last time. I will this time. I'll stay with the same air pressures to start.
I also have a turbocoupe front swaybar I might swap in. Seems like in one picture, my car was leaning a little more than I'd like to see.
Mostly, I think improving the nut behind the wheel is going to help me.

[gbeaird]

The TC sway bar will help noticably. The more they lean in the turns, the more the camber works against you. Controlling that, and you can help the car get more front wheel bite. That helps a lot of things, especially the understeer/oversteer situation.

Same thing with the shock settings. The stiffer they are, the slower the car reacts to inputs, so it helps reduce lean in quick maneuvers.

Remember, though, that I'm talking about a G Stock-legal car. There are a LOT of things you can do to the suspension that helps if you move to a different class, like street prepared, street mod, or prepared.

And autocross is 80% driver, 20% car. So yes, improve your driving and the car will get better. :-)

Gene Beaird
86 SVO, G Stock,
Pearland, Texas

[indiana dave]

Well, I pushed my struts in for more camber as suggested above. I left air pressures ay 39psi all around. Installed my turbonetics boost controller. Didn't get around to swapping the turbocoupe swaybar in though.
Mistake #1 I got there late, and had to speedwalk the course.
Mistake #2 Shoe polish was dried up, so couldn't mark tires.
Mistake #3 Ran first run waaay to fast, spent too much time wrestling the car. Hit a cone.
Mistake #4 Didn't learn, Ran 2nd run like first... Hit same cone.
Mistake #5 Still didn't learn. Ran a different line instead of slowing down. Hit two cones!
4th run, I took my own advice and "Went slower to go faster"
I hit no cones, and ran 3 seconds faster! Went from almost last out of 18 cars, to about midpack...
My car did plow badly in one turn, so the turbocoupe swaybar might help with that. in addition to changing air pressures in the tires.

[jayG]

Most people run too fast in the slow corners and too slow in the fast corners. Now that being said Im no were near an expert on auto-xing but I do have a championship in ESP last year in the scca-south carolina region. I run my struts all the way to firm and 60 psi in the front and 27 psi in the rear. I m running sumitumos 235/40 17 in the front and 245/40's in the rear and I have my toe set at stock specs( but im gonna change to 2 degrees in..toe out is better for open track not auto-x) and my camber is as far in as the slots allow. Im running stock springs(lowered by way of a heating torch...redneck engineering at its worst...lmao!) and stock brakes. No sfc's either. A strut brace will help greatly. I just installed a lower k-member brace that tightened up the car like a mofo...turns on a dime! But like I said before, fix the driver first. Have a local solo pro ride with you, it will help.

[coop]

hey you Texas guys should bring your cars out to TWS in College Station for a track day. Drivers Edge ( www.thedriversedge.net ) is having one the first weekend in June. Might be too late to sign up, but you should check it out. If I get a SVO by then, I think I will take it and leave the S2000 at home, just for the lets see factor.

[gbeaird]

That sounds like a cool event. Unfortunately, the Houston Region runs their Regional autocross events the first weekend of the month. As it turned out, we really didn't need to be there. Our Hoosier slicks were pretty much done. I believe the term for them is 'Levi's'. ;-)

Gene Beaird,
86 2R SVO, G Stock,
85 Firebird, CP
Pearland, Texas