Ok, I recently installed my Koni's with RS-R ti springs and the ride is great and the handaling and flatness of the car are great. Now I also got a set of 18x8.5 and 18x9.5 FN01R-C's with 245/275 Toyo T1-R's.

I did a auto-x yesterday and I was experencing some push, so I reduced the rear pressure to around 34psi and increased the front Koni's to about 3/4 stiff. It greatly reduced it but I still felt some. The rears are set at 2.5 turns from soft. Also I've had Hotckiss sways set at med at both ends. Most of this push was felt in low speed sweepers and a very slow 90 degree box to the finish.

So with what I've got, how should I go about getting rid of it further?

I've searched and some people say to stiffen the front bar and some say to loosen it. What about the Koni's? Should I do anything different there?

Now, I am NOT building a competative car for auto-x but a fun daily driver and a more fun HPDE car. I want to do some auot-x events to get a better feel for my new parts. I know how I like the set up for track days at VIR and I never had it push even stock, so it's not a issue. I dont want to do a occasional auto-x and not have my car understeering all over the place either.

I am not new to this stuff since I auto-xed my old 180hp to the wheels Spec V for 2 plus years, but in that car it was everything stiff in the rear and soft in the front and that was it. So I need a little help with this RWD stuff.

Sorry for the long post and thanks for helping!

 

set the rear sway bars to stiff, front to medium. not sure about the shocks, but it would make sense to me to do the same: soften the front and/or stiffen the rear.

 

I have a bit of a different setup, with Tien Flex Coilovers with EDFC and 350EVO sways. I have both sways set to medium and all of the struts are set to full stiff and it is a very well balanced combination. Other than that, I have said this before, but brake earlier and enter slower to avoid understeer. You will never eliminate it with suspension settings so the biggest improvement will come if you adapt your driving style.

 

stiffening up the rear bar / softening the front should make it rotate more easily, but keep in mind that what feels good for autox will likely be scary loose at a track event. given the speeds / consequences are more significant at the track, I'd back off whatever your setup is for autox for a little safety margin.

ahm

 

I have to agree with 350ZNV. I had this issue somewhat too, when trying to carry too much speed into corners with this car. This car especially wants to understeer in slow corners. Slow down on corner entry, and you'll go faster.

The other thing that has just about cured my car of understeer is running the same size tire front and rear (275s). I even have slight oversteer with this combo, but I can deal with that better.

 

Alright I'll try to change my corner entry a little. As far as tires go I have Azenis on order 245/255 to go on my stock track wheels so I'm sure those will help also.

I was trying to also get a answer on which adjustment helped to get rid of understeer? stiffer front and softer rear or vice versa? I've read both on this sight so I was curious.

But thanks for the help everyone!

 

Axelerate,

I can only speak to A/X set-up, which I imagine differs greatly from a track set-up. BTW, the understeer you are referring to, does really exist in generous amounts on an A/X course. I understand you know A/X basics, since you mentioned being experienced in your initial post. And since you're coming from a FWD, I bet you were pretty surprised by the amount of understeer you got out of the Z.

The biggest improvement in minimizing the Zs understeer came with running the same tire size front and rear. Front Koni Sports are set full hard. The thought is to try and maintain as much front chamber as possible. Lack of front chamber keeps the Z from being a truly great A/X'er. Rear Koni Sports settings varies from site to site, course to course... but I start out with two turns off of full soft. Since I run in a stock class, I can't run an aftermarket rear bar, so take that into account when working with my sway bar setting advice. I run a 350EVO bar up front. I've run the bar set on Med & Hard. I can't say that the Hard setting is hugely better, but seems to help in mid-turn grip. Having an adjustable rear bar should give you some nice alternatives to what I have at my disposal.

BC