Fixing corner grip on bumpy surfaces?

kannibul

The Z seems to hate bumpy surfaces, even more so on corners - a great example would be highway interchanges.

Seems there's always a bumpy interchange ramp, at least in Tulsa, that if you corner even at the posted speed for the ramp, will still toss your car around - where you can feel it lose traction and move outward a few inches at least.

I know my truck used to have a problem with this, but that was due to blown out shocks and worn out tires. Replacing both of those, fixed that problem.

My Civic and my Truck (and definately my motorcycle (not a crotch-rocket)) handle uneven cornering surfaces better than that Z...which is unexpected, to say the least.


So, how does one go about fixing this?

import111

Maybe you have too much toe in the rear. That can cause the rear to get really sloppy, especially on bumps. Also too much tire pressure could cause that issue also.

kannibul

Tire pressure is good. Rear Alignment toe is something like .01 according to the alignment paper I had.

I've misplaced it so I don't know the other info right off...

tooohip

KW V3's have fixed that problem for me. ;-)

__________________
Lance
KW Variant 3 Coilovers | Stillen Sways | Stillen Gen III Intake | AAM HFC | AAM True Dual CBE | AAM Comp Oil Cooler | Hawk HPS Pads | Volk TE-37 | Hoser Keg Tap

Modshack

This is generally the result of shock tuning..

__________________

Steal my car! (SOLD)...Now Porsche Cayman S
Oil Cooler DIY: Here!

bullitt5897

I combat my issues with different lines and throttle modulation I found that with a lol more gas the backend settles out. Or should I say steps out a slight bit but it's very smooth when it does.

__________________
Shop Cars: 2013 318whp Nismo VspecII 370z *SOLD*, 2009 1000hp+ 93oct 4.0L TT 370z Fast Intentions STAGE 4 #054

vpn2001

I had the same problem with my S2000. It was due to suspension geometry. A couple of aftermarket manufacturer came out with an anti-bump steer kit. Hopefully someone will have one for our Z.

kannibul

I will say this much for it, you definately FEEL the G-forces more in this car than anything else I drive...it's odd and I can't explain it - but when you corner in this car, you feel yourself being thrown harder...

At least I know it's not uncommon.

RCZ

This is all bound and rebound + spring stiffness and how they work together. Get a set of good coilovers and voila.

kannibul

Any recommendations?

I like the stock height, with Tulsa roads I damn near need a lift kit...lol

It'd be for street use too...

kannibul

Disregard previous post

Found a relevant thread...

RCZ

What you are feeling is a car with sticky tires and a relatively soft suspension. The car leans and rolls into the corners because the suspension isnt stiff enough to counter the load. That lean makes you feel like you are building higher g-forces when you aren't.

You also can't just throw a stiff spring in there with the stock dampeners because they arent designed to work with it. The car will become uncomfortable to drive and very skittish and nervous over bumps.

Depending on what you do with the car...you can opt to get a full coilover system...If you are looking for something comfortable and good, get the KW V3's.

Will do and glad you searched for your answer.

kannibul

Yeah, KW V3's are what I was thinking.

Then I saw the price, and figure that's a "later" item. Exhaust is next...originally exhaust was first, but then Stillen had a sale and I snatched the G3 intake

As for aftermarket adjustables...is that something someone who doesn't know a whole lot about it can do? I mean, I've got adjustable progressive shocks on my bike, but I turn that up/down depending on if I'm riding alone or not.

I figure with a car it'd be more complex (to a 4th!)

Also, how difficult would it be to DIY a coilover swap? I imagine the (rear) springs aren't going to be easy. I know when I swapped shocks on my truck, I cheated and used my car jack to compress them to where they'd bolt up. With the Z being as low as it is, I figure that won't be very likely.

willtangclan

Inexperience taught me to get aftermarket springs with stock shocks. Now i am feeling this effect very drastically (unstable on bumpy surfaces). I have the Eibach pro kit with stock shocks. Now instead of wasting money on those springs, ive read that you can order koni yellows and get them to valve them according to spring rates you give them. Is this true?

ChrisSlicks

Yes, Koni offers custom valving, both fixed rates and adjustable.

__________________
Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms