Suspension settings -was in Bega 2007 Event report

[Glenn]

So anything you are going to share now you have made it public or do I have to scrutineer it on a wheel alignment machine somehow.

I was going to put a post in Technical, but haven't gotten around to it. :)

Paul and I had a good chat before the start about ride heights and wheel alignment. He was of the opinion that I've got it a bit wrong. I wasn't so sure at the time, but on reflection from Sunday, I thinks there's something in that ;)

The first thing I've found is that I'm lacking grip in the rear. Now this was fine when I wasn't pushing 100% as it really helped with turn-in and it made the car very adjustable in the corner (almost foolproof). But what is happening is that I'm washing off too much speed once I get to the apex on slowish corners. Probably the main reason for this is that I'm running far too much camber in the rear (about -3 deg) and the edges aren't getting much of a chance. Also as a result of this lack of grip I was running 2mm toe in each side in the rear to calm it down and this would be affecting outright grip too.

So I'm going to change to about -1 deg camber and 1 mm toe in each side and see how that goes.

The other thing is that I run my car pretty high. I mainly do this because I run a fairly soft setup to maximise grip and that I never back off over the rough stuff....now on an event like Bega, I could easily afford to run the car lower...so with The Bay and Coffs coming up (both have great roads) I'll probably take 10-20mm out of the ride height all round.

Finally there's front alignment. I run about -1.5 deg camber , which I think is OK. I also run about 1.5mm toe out each side. I know that Paul runs a little toe in on the front. I think this is more of a driver preference thing than anything. I like really lively steering, so it works for me.....but I'm prepared to be wrong here too, so I might experiment with that also.

[Whitey]

I also run about 1.5mm toe out each side.
:eek: Lively you say, geez that's a lot, i would have thought diabolical.

[Glenn]

It's pretty relaxed really. The turn in is pretty good.

But I suppose it's all relative. I compare it to the experience of driving the Suzuki with a tight LSD. Even with about 1.5mm toe in each side on the front it was a complete handful in a straight line!

[John C]

Probably the main reason for this is that I'm running far too much camber in the rear (about -3 deg) and the edges aren't getting much of a chance. Also as a result of this lack of grip I was running 2mm toe in each side in the rear to calm it down and this would be affecting outright grip too.

So I'm going to change to about -1 deg camber and 1 mm toe in each side and see how that goes.

Finally there's front alignment. I run about -1.5 deg camber , which I think is OK. I also run about 1.5mm toe out each side. I know that Paul runs a little toe in on the front. I think this is more of a driver preference thing than anything. I like really lively steering, so it works for me.....but I'm prepared to be wrong here too, so I might experiment with that also.

Glenn

After the Cerberus stages the boys at Kangan wheel aligned when they straightened the car and set the back end up as you have described. the car was a pleasure to drive at Bega and I don't think i will use a lot of rear camber on the rear again. Daniel arrived home with video of all the cars on one of the shire roads and your car was the only excel to arrive at a certain corner with oversteer.

[ernysp76]

JC any chance of getting the video up loaded to u-tube?

[Glenn]

Thanks JC.

I'd love to see the video. Any comparison we can have between the cars should be quite educational.

[Crazy Dave]

It all sounds good. I have brought my back camber back to around 1.5 degrees with 1.5 mm toe in and my front is about 1 degree with close to 0 toe in/out (about .1 to .2 out which allows them to pull straight under throttle and to be slightly positive on braking helping turn in (well thats my theory anyway)).
I am working on trying to run less sideways (bad habit) but as you say it is so much easier and safer in some aspects because you can adjust your corner speed and position so much easier but with the effect of reducing your exit speed. Caster I am still not so sure about and the next thing is what sort of shock settings, rebound etc as my shocks are going in for a rebuild. That is getting really into a black art of suspension stuff. It would be great to go out with externally adjustable to work out what the difference is and what works best as I have absolutely no idea on this.

[John C]

Thanks JC.

I'd love to see the video. Any comparison we can have between the cars should be quite educational.



I have spoken to the movie man and he is going to edit down the footage to all the excels and I will post or e mail

[Crazy Dave]

SO Glenn and others who have played with changing settings.

How has the car gone recently. You seemed to have a good run at the Bay, but did it feel any different. Do you like your new settings and did car speed improve, although the only constant to compare against (the civic) dnf'd again or have you been taking notes of others as well.

[Glenn]

Dave,

I've mentioned this briefly in my post for the event report for the Bay, but the changes I made to try to get some more rear grip were too effective and turned the car in to an understeery pig especially in the slow stuff. It wasn't nice to drive at all and as such it was slower.

I'm going to try a few things to get the balance back. The first of which is to remove the front bar and see how that goes or maybe put in a custom adjustable bar in the back. If all else fails, I'll go back to the old settings.

For reference, the current settings are:

Front:
1.5mm toe out each side
1.5 degrees negative camber

Rear:
1mm toe in each side
0.5 degrees negative camber

Hoping to get it sorted before Coffs.

Regards

Glenn