Nissan 370Z Forum - Need help eliminating oversteer

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Quote:

Originally Posted by BGTV8 (Post 4055328)

A lowered Z34 has rapidly increasing rear camber in bump. If the car is rolling into a corner with no rear bar, you may find you are only getting half the rear tyre on the tarmac in mid-corner and you are trying to put power down thru 5 or 6 inches of rubber.

It may be that standing the tyre up a bit might be the solution

I have a 500hp (hubs) Z34 that runs 250/650R18 Yokohama slicks on a 10" rim and I have good balance with an OEM rear bar. I run MCA double-adjustable shocks (made in Australia by a former Australian Rally champion) and I'll check my current rear spring rate when I get home tonight (on the train on the way to work at present).
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We found we had to lift the rear given the camber curve once we'd lowered the rear ride height to where we initially thought it should run. Eventually we found balance but our early lesson was "you can go too low" with OEM suspension dynamics

Softer rear spring will only exacerbate camber increase in roll but harder spring rate will kill squat which gives you drive and the end result will be a very twitchy car.

Is this why so many track folk have come to the unintuitive conclusion that a bigger front bar actually helps the car rotate?

many thanks for those first answers.

I'm convinced that the axle offset improves the rear kinematics for extreme lowering.
It will be a car with extreme settings, but it's a car that must be driven on the streets, and these extreme modifications are prohibited.

I received my 12k rear and 14k front coilovers, but they aren't adjusted or installed on the 370z; they're monotubes with rebound. From my experience with the 350z, which seems to have the same rear as the 370z, the 9k rear was too soft on bumps. Sometimes, rarely, the rear would flatten and touch the ground when there was a road defect while traveling at 50km/h / 30mph. But traction was good.

With a 12k rear, I hope it won't be too stiff. I'm planning on using Hotschkis sway bars, adjusting the geometry with adjustable arms, adjusting the alignment, changing the rim offsets, and maintaining the original tire width. with lift system on the coilovers.

Based on yours experiences:
With approximate values... with 14k front shocks.
What would the rear spring rate be (9k, 10k, 12k?) to achieve normal rear kinematics?
what needed difference in spring rate between the front (14k) and the rear (9k, 10k, 12k?)?

What would be the maximum lowering/drop, or minimum height, at the rear to maintain adequate rear kinematics?
And with what camber and alignment that aren't too extreme?

I'm planning on using the 35mm diameter Hotchkis Front sway bar, with a hard/strong adjustment.
I'm planning on using the 28.5mm diameter Hotchkis Rear sway bar with a light adjustment.
Will the Hotchkis 28.5mm Rear sway bar be too stiff (with the light adjustment)?
Would I need a different rear sway bar?

Thanks