Made lots of changes, now it pushes, Yes, I know I shouldn't have |
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Made lots of changes, now it pushes, Yes, I know I shouldn't have |
nhallman |
Jun 3 2007, 09:51 PM
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#1
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Newbie Group: Members Posts: 8 Joined: 21-March 05 From: Columbia, SC Member No.: 3,793 |
OK, so I finally decided to do some suspension upgrades on my autocross car ('75 1.8), and I kind of did everything at once (yeah, yeah, I know):
Koni yellow shocks/struts 930 tie rods 22mm Weltmeister front sway bar 180# Weltmeister springs disconnected (stock) rear sway bar I was sort of following an old (mid-90's) Weltmeister guide for autocross setup that I found on the Pelican board, except they recommended 21mm torsion bars up front. I sort of ran out of cash, so I left the stock torsion bars on the car. So, I figured that by not stiffening the front as much as recommended, but making all the other changes, the car would tend toward loose (especially since that's how I tend to drive it). Wrong. It pushes... badly. When I made my first few runs, I had the Koni's on full stiff. I took a full turn out of the front and that helped, but the car still pushed. I played with pressures, taking 3 lbs. out of the rear (Kumho V710's - an R compound tire), leaving the front at 35 lbs. and the rear at 32 lbs. That helped, too, but it did still push and was a concern because the car had been so neutral prior to the changes that I rarely had to adjust tire pressure. So... now what? I have all this adjustment available to me, and I don't know what to try. My fear is that in my quest to get the car back to neutral, I'll take away some of the major gains I've made in grip (did I mention it did stick like 500% better?). I don't want to do that. My thoughts (ranging from simplest to craziest): - adjust my driving style and deal with it - soften the front struts even more - loosen the front sway bar (currently set to full stiff) - reconnect the rear sway bar - set the rear toe to 0 (currently 1/16 toe in, front is 3/32 toe out) - cut a coil from the rear springs (only a consideration b/c I can only get ~1.2 deg negative camber in the rear - all shims removed) Any ideas? I'm a fairly experienced autocrosser with a lot of seat time in this car, but I'm a total novice at suspension setup. I just tended to jump in the car and drive it up till now. TIA... |
jhadler |
Jun 5 2007, 11:26 AM
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#2
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Long term tinkerer... Group: Members Posts: 1,879 Joined: 7-April 03 From: Lyons, CO Member No.: 529 |
Camber. Gotta get it. If you don't have it, find a way to get it.
Camber really doesn't wear out tires as nearly as much as toe does. And actually you can get longer tire life (for a car that autoxes) with more camber as you're not riding on the shoulder of the tire all the time. You'll also get better grip. Front camber can be found by lowering the front of the car using the factory torsion bar adjusters. But first start by getting the car aligned and set the camber plates to as far back, and in, as you can. A _very_ common practice is to have the slots for the bolts of the camber plates widened, so you can get more caster and camber. Rear camber can also be gained by lowering, but best to do it with the proper shims. In general, a 914 neds a little more front camber than rear. To solve your push, the cheapest and easiest thing to do is soften the front bar. Start by going to 50% on the adjuster (It's a welty right?). If it's still pushing, try 25%. If, after softening the front bar, you still have a push, look into getting a good alignment done. Get as MUCH caster, and as much camber as you can get in the front. If you have to sacrafice a little bit of camber to get a little more caster, do it. Caster is _dynamic_ camber. The more you turn the wheel, the more camber gain you get. The change from little caster to a lot will shock and surprise you. If you've only got minimal caster right now, dialing in a lot will plant the front end and the rear will have little choice but to swing around... Caster is gooooood. (IMG:style_emoticons/default/cool.gif) -Josh2 |
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