Anti Dive.

[Roy]

We just cut the rear lower control arm front pivot point brackets off the subframe, move them downwards to the limit of the IP regs and then weld them back on. We have been doing that since the mid 90's on the circuit cars (R32's, S13's and Z32's). From what I have seen that is pretty much what Tomei do. Moving the whole subframe (with pineapples) is much easier for the DIY'er as it doesn't involve cutting and welding. The bonus is you get the ability to quickly change it for different disciplines, drag, circuit, drift and road. Plus it is easily reverseable when you sell the car.

Cheers

Gary

LOL...yeh the pineapples is the easier approach. When looking to do the GTR rear end i was planning on moding the mount as you mentioned...only i gave up on the whole GTR rear end thing...too much stuffing around with new shocks, bushes, diff etc etc. Already too far down the path of tweaking the GTST rear

[Sydneykid]

understood, i have the rear of the gtr well set up with the cradel rebushed and with pineapple bushes but looks like im going to do my own R and D for the front changing the pivot points of the lower arms, cradel and caster rods..

cheers.

Personally I wouldn't recommend changing the front lower control arm inner pivot points on a GTR. They have an intrinsic relationship with the drive shafts and even small changes effect the bump steer and Ackerman rather rapidly/badly. It took about 3 days to fix the bump steer on John's Z32 because of moving the front lower control arm joints. The Ackerman is still under reconstruction, very tricky to get right in the space available. Unless you have considerable experience with correcting those things, it is best left alone, there are more gains to be had elsewhere with far less downside.

Have a close look at the radius rods front mounts, the answers are quite simple once you work out what changes are required.

Cheers

Gary

[Sydneykid]

Already too far down the path of tweaking the GTST rear

I know exactly what you mean.

Cheers

Gary

[salad]

Plus we use polyurethane bushes in the standard radius rods with offsets so we can adjust the anti dive through a range from around - 5 mm to + 10 mm.

Can you elaborate on this? I've been under the impression that it's just the hard points on the chassis that the arms are connected to that affect geometry things like anti-dive. I didn't think changing the angle/offset in the arm itself did anything? Except change the effective length.

[Sydneykid]

Can you elaborate on this? I've been under the impression that it's just the hard points on the chassis that the arms are connected to that affect geometry things like anti-dive. I didn't think changing the angle/offset in the arm itself did anything? Except change the effective length.

As you know, you can rotate the offset bush to a forwards and backwards position to get more or less caster. But you can also use it in the fully up or fully down position to change the antidive. Remember the offset crush tube is locked (by the through bolt) to the subframe, so the effective pivot point is the outside of the crush tube. Got it?

Cheers

Gary

[robbieraver]

Personally I wouldn't recommend changing the front lower control arm inner pivot points on a GTR. They have an intrinsic relationship with the drive shafts and even small changes effect the bump steer and Ackerman rather rapidly/badly. It took about 3 days to fix the bump steer on John's Z32 because of moving the front lower control arm joints. The Ackerman is still under reconstruction, very tricky to get right in the space available. Unless you have considerable experience with correcting those things, it is best left alone, there are more gains to be had elsewhere with far less downside.

Have a close look at the radius rods front mounts, the answers are quite simple once you work out what changes are required.

Cheers

Gary

hmmm thanks for the heads up, im using a sherical bearing adjustable radius rod(tien) but im sure i will work it out.

looks like i will leave the lower arms well alone.

[salad]

As you know, you can rotate the offset bush to a forwards and backwards position to get more or less caster. But you can also use it in the fully up or fully down position to change the antidive. Remember the offset crush tube is locked (by the through bolt) to the subframe, so the effective pivot point is the outside of the crush tube. Got it?

Cheers

Gary

My mistake, I should think about things more next time...

Edited February 2, 2008 by salad