Progress Report

[sopwith21]

Thanks to all who gave advice on how to best set up my 260Z car using our new struts, springs and coilovers. I re-wrote and printed out much of what you guys said and listed it for use at the track. Here's how things went and what we found:

First off, David and John B were right... a spring combination of 350fr/250rear can work. Perhaps its true that softer on the front would be better, but the car will drive with this spring setup and drive well. In the first session, we had the coilovers set too low on the front and the suspension bumped to a stop with only an inch or so of travel. Obviously, that gave us a huge push. We came in and raised the front coilovers by four rounds, went back out in the next session and picked up almost three full seconds (on a 2 mile track). We had a slight push on entry under braking, which I think will go away when we raise the coilovers one more round, and a loose condition from the center off that was drivable and controllable although sometimes it twitched a bit and you had to catch it. That's from the locked rear end, no doubt. On the last lap of the session, we broke a RR half shaft and had to park the car for the day.

We got no fine tuning done whatsoever, but we know that the car works with this setup and can be fast. There's easily another second available - maybe much more - when we can tweak it and get more practice time.

I switched to our backup car for the day's race (a GT3 car running in our GT2 class) and finished poorly, but we still hold a 55 point lead for the series title going into the last race. To make matters worse, our competition made one of the most unsportsmanlike moves I've seen in a long time once they found we were in a weak backup car. They entered another car and grabbed another driver to shove into the field, literally minutes before the race started, to try and prevent us from scoring points. That doesn't score any more points for them, of course, but it was an effort to take points away from us. In the qualifying race it worked and they shorted us ten points... in the main it backfired on them and their second car broke. A desperate move, I suppose, but shameful nevertheless. We've never tried to take points away from them.

So that's the scoop! Thanks again for all the thoughts and ideas. We may still switch the springs, unload or unhook the rear sway bar, etc., but for now at least we know we're in the ball park. We're very happy with what the car's doing.

[gramercyjam]

Glad to hear the setup is starting to work out for you. A backup car? Sounds like you are pros

[sopwith21]

No, we were desperate! :laugh: I didn't own it... I borrowed the car from some VERY kind people who wanted to help me win my first title.

[dspillman]

Sopwith,

You need to section or shorten strut tubes.....to gain more wheel travel.

May require different struts...Is there a spacer under your new struts now?.....Really sholdn't be bottoming out, bad on your equipment, speed.

Sounds like you got the hang of power on over steer!!

David

[sopwith21]

No, I won't need new struts when we lower the car. I bought the shorter ones on purpose and we had spacers put in at the bottom. When we cut the strut tubes they'll fit just fine. Didn't do it now though because a) we didn't have time and we didn't have the money to buy the camber plates.

The reason we were bottoming out is because the coilovers were dialed down too low on ride height and there wasn't enough travel to let the suspension work properly. We sacrificed a bit of ride height, but fixed it easily by raising the car about an inch. Went much faster then. Now we just need some more laps to dial it in. I think there's another full second available even on old tires. Then we strap on fresh rubber (already on the way), pick up another 1.5 seconds, then go win us a championship.

If we get some serious testing time, I do want to try swapping the springs front to rear and unhooking the sway bar. We might pick up a lot more bite that way. The more pressure I can put on The Bad Guys, the better. Our new tires are pretty soft, too. This is a one shot deal and we're going for it big time.

[sopwith21]

How much toe-out do I want? 1/16th? More? Looks like it has a lot in it right now.

[gramercyjam]

That depends on how strong you are and how fast you are going. I like the way my car turns in with a lot of toe out, but the wheel gets yanked out of my hands that way so I just use a little, probably between 0 and 1/16. I can't tell you with any precision since I use the at-home string method for alignment and a lot of trial and error testing.

[sopwith21]

Fairly strong and fairly fast. Doing about 120 tops, but average 72-74 over two miles. We've not measured it yet, but it looks to be considerably more than 1/16th. Its still drivable, but I wonder how much speed we lose to it.