Perfect timing.......... (hit the credit card two hours ago)

 

I run 245/35 front and 255/40 rear

 

Have you tried simply lowering your car in the rear, adding some toe in in the rear or adding some downforce in the rear?

What's your rear camber set at? If it's OE spec that would explain a lot.

No sense in throwing money at the problem when you can just adjust what you have.

 

Well this isn't just a mild case of oversteer. This would make a Porsche 911 jealous.............

All my settings are in the original post, btw. Nismo S tune don't adjust.

 

I think the tires have a ton to do with it.

Once I installed the S-tune sway bars and Quaife, my winter setup had crazy snap oversteer. Once I went onto my summer setup with the Michelin Pilot Super Sports the car went right back to how it should be.

Stiff suspension and all season tires do not go together on a RWD car.

 

Tires were the first thing I suspected, actually. But since the same tires are on both front and rear, I don't think that would induce snap oversteer unless I added signif throttle.

Since you have the Nismo S and Quaife LSD, what is your opinion on 245/40/18 tires on all four corners for track duty (Nitto NT01s)? I'd like to not stagger if possible; my setup goal is slight understeer, correct with throttle, and I'm hoping to get there with four 245/40's and adjust my sway bars/tire pressures/etc.

 

I have never ran a square setup however it seems like that is the preferred setup.

Personally, I would rather deal with oversteer instead of understeer. That is the main reason on switching to the S-Tune sway bars.

 

THIS!^^^^^^^^^

​​​​​​​Time for an update - SOLVED!!! I got my NT01 track tires today (245 front, 275 rear) and burnt up the local twisties. The curves are still on fire. AWESOME!

​​​​​​​ The crappy Riken tires had no sidewall stiffness. Zero, Zip, Nada. I just ordered replacements, these are going on craigslist before I do another 360 in the middle of the road.

 

Glad to hear you found the solution. Those Riken Raptors must have been exceptionally bad. Never heard of a particular tire causing severe oversteer! You might want to post a review on the website where you bought that particular model to warn others. We always have folks here posting they are trying to skimp on tires for their Z...

 

The previous owner bought these tires.

I've never experienced cheap tires that had some grip but zero sidewall. Neither have I experienced how tires like this transform a balanced car into a 911 with slicks in the rain.