Understeer questions

[cygnusx1]

I know this has been discussed to near death but is it possible for the Z to understeer on initial turn-in but then handle neutral after settling and during the rest of the corner? It seems to be the way mine is handling...or it could be my driving. I can correct it with driving style but it doesn't feel natural on turn-in. I will play with shock settings and tire pressures as soon as I get some time. Specs are in my signature...I think.

 

1.125" bar in front and 7/8" in the rear with urethane all over. The car has, I believe 250lb springs and is 1" lower than stock with spacers to correct LCA angle. I also run tokico Illuminas.

[johnc]

I know this has been discussed to near death but is it possible for the Z to understeer on initial turn-in but then handle neutral after settling and during the rest of the corner?

 

Absolutely possible and its kind of a normal behavior for the Z. The Z has always had a poor turn-in response.

 

What size and type of tires are you running?

What air pressures cold and hot?

Do youn take tire temps?

If so, what are they?

What kind of rear diff are you running?

 

Now assuming you're not causing the problem yourself via driving style (throwing too much steering at the start of the turn, sloppy off the brakes at turn in, trail braking too much at turn in) here are some options:

 

Alignment Front

Camber - 3 neg

Caster - 6 pos

Toe - 1/8 to 3/16 out

 

Alignment Rear

Camber 2.5 neg

Toe - 1/16 in

 

Rake - 1/2" forward rake

 

Reduce the size of your front anti-roll bar to 1" or 25mm.

Reduce the size of your rear anti-roll bar to 19mm or 3/4".

Reduce front spring rate to 225 lb. in. while keeping the rear at 250 lb. in. Replace the Tokicos with Koni 8610s or some custom Bilstiens (you're pretty much at the spring rate limit for the Tokicos).

[cygnusx1]

I just put on a set of Goodyear Eagle F1's 225/50-16. I used to have Dunlop D40-M2 225/50-15 and the car seemed to handle much better with those. The Eagles seem to slip more and give much less feedback...but I got a good deal on them.

 

Right now I run 34psi in all four tires. I use the R200 3.54 open diff. The car is a street driven car with occasional time trials. Eventually I would like to setup a set of slicks for the time trials. As far as tire temps, all I do is run my hand across the tread to "feel" if the temp is fairly even across the tires and it usually is. I checked this after street driving on windy back roads, not race track conditions which would be much more telling.

 

I am considering switching the front sway bar bushings back to rubber to see if that helps. I will check the alignments, but don't have much flexibility there as all my "links" are stock. I do have a bit of - camber from lowering, but not much.

 

Thanks for all the great pointers!

[johnc]

I will check the alignments, but don't have much flexibility there as all my "links" are stock. I do have a bit of - camber from lowering, but not much.

 

Change the toe out to the setting recommended when you're at the track. You'll have to set it back for the street. It will help but, without being able to change the other settings, you'll just have to live with the understeer at turn in.