Still Got Axle Tramp Arrgghhh!

[Harey]

chop the tops off the rear 2 subframe bushes. This will slightly increase squat and won't shock the wheels down to the road as much wen u dump the clutch.

Interesting idea, so is that similar to setting the pineapples up in a squat position?

My only counter question to this is why would solid mounting the subframe be the ultimate to stop axle tramp if the issue was squat?

[Harey]

Just a thought but you said it was the lower control arms that improved the issue. Now I figure that the new bushes will be better at doing the job they're supposed to than on old set. The thing that I want to know is what was the alignment before and after changing these? Geometry will play a part in inducing/affecting axle tramp in some way. If the new bushes are adjustable and you now have the alignment good, were you able to achieve the same settings with the old ones?

Diff bushes will take a little while to change but for a suspension workshop it shouldn't take too long with a hoist. The painful part is when you're crawling around on the ground to do this. Maybe change the fluid while you're at it? Changing the 4 subframe bushes is a big job.

Good Luck

Lots of info in this post! Just trying to decipher it all.

First question about alignment, the car was aligned after every stage of work. Chris at Centreline made a point of mentioning it and I also paid for it.

I dont believe the bushes are adjustable but could be wrong. Not sure about this question.

Are you saying that diff bushes are easier to change than the subframe bushes? That would be good because I think the pineapples are doing enough to tick off the subframe bushes.

Do you mean changing the diff fluid while they change the diff bushes? It has brand new redline diff oil in there.

[bradsm87]

It's a combination of both subframe movement AND squat. U should NEVER lower the subframe in any way. This lowers ur already too low roll centre. Putting pineapples above the front bushes for squat does this. A much better alternative is to raise the rear of the subframe. Then you're fixing squat without lowering roll centre. Less keyboard more car. Just do it lol.

Edited June 8, 2010 by bradsm87

[Harey]

U should NEVER lower the subframe in any way. This lowers ur already too low roll centre. Putting pineapples above the front bushes for squat does this. A much better alternative is to raise the rear of the subframe. Then you're fixing squat without lowering roll centre. Less keyboard more car. Just do it lol.

I have my pineapples set to all round performance (both on the bottom):

http://www.whiteline.com.au/instruction/203a_KCA349.pdf

This would not lower the subframe, if anything it would raise it slightly.

Also my car is not that low, ie 350mm centre of wheel to guard.

Found this but looks very major work and more for a track car:

http://www.skylinesaustralia.com/forums/Su....html&st=20

Edited June 8, 2010 by Harey

[bradsm87]

Maybe u need more squat than all round performance tho.

[Fry_33]

I have my pineapples set to all round performance (both on the bottom):

http://www.whiteline.com.au/instruction/203a_KCA349.pdf

This would not lower the subframe, if anything it would raise it slightly.

If you look at the images you can see between standard and all round performance that the subframe doesn't move. It isn't higher or lower the pineapples just go underneath to help stop some of the squirm/movement caused by the rubber subframe mounts. by grinding off the tops of the rear subframe bushes you are effectively doing the same as the max traction setting but instead of lowering the fronts by putting in a pineapple you are raising the rear. Since the urethane pineapples aren't solid there will still be a little movement and give there. This means that there could still be a way for the rear to store and release energy in the form of axle tramp. obviously there is a change to standard so this will change when/if it occurs. Any flexible joint in the system will add to this which is why some suggested the solid metal pineapples to do this. It effectively locks the subframe in place. There is a down side for street cars though as without the nice

new subframe mounts may solve your issue and help tighten up the rear. I hadn't looked up their website in a while but there is now an online catalogue for the Whiteline Plus range here. Your subframe bushes look like they'd be W92446.

I figured you would have had the suspension alignment done after all your changes but were they all the same settings? If your new control arm bushes are adjustable they allow you to achieve more or less camber etc. The new ones might be allowing you to reduce the amount of negative camber that you had previously helping to reduce some of your issues.

I used to get tramp with Bilsteins, Whiteline springs, 19x8 rims and 245 tyres on my R33 GTST but I don't anymore. I can't say I really went about trying to solve it though. I have changed most of the bushes over to Whiteline adjustable ones just to freshen up the rear. I have pineapples in all round setting (I think) and have replaced the front diff bushes. The rear ones need to be pressed in and out I think, front diff ones might be possible to do on the car?? I've got 18x9 rims with 265 tyres at the rear now.

[Harey]

If you look at the images you can see between standard and all round performance that the subframe doesn't move. It isn't higher or lower the pineapples just go underneath to help stop some of the squirm/movement caused by the rubber subframe mounts. by grinding off the tops of the rear subframe bushes you are effectively doing the same as the max traction setting but instead of lowering the fronts by putting in a pineapple you are raising the rear. Since the urethane pineapples aren't solid there will still be a little movement and give there. This means that there could still be a way for the rear to store and release energy in the form of axle tramp. obviously there is a change to standard so this will change when/if it occurs. Any flexible joint in the system will add to this which is why some suggested the solid metal pineapples to do this. It effectively locks the subframe in place. There is a down side for street cars though as without the nice

new subframe mounts may solve your issue and help tighten up the rear. I hadn't looked up their website in a while but there is now an online catalogue for the Whiteline Plus range here. Your subframe bushes look like they'd be W92446.

I figured you would have had the suspension alignment done after all your changes but were they all the same settings? If your new control arm bushes are adjustable they allow you to achieve more or less camber etc. The new ones might be allowing you to reduce the amount of negative camber that you had previously helping to reduce some of your issues.

I used to get tramp with Bilsteins, Whiteline springs, 19x8 rims and 245 tyres on my R33 GTST but I don't anymore. I can't say I really went about trying to solve it though. I have changed most of the bushes over to Whiteline adjustable ones just to freshen up the rear. I have pineapples in all round setting (I think) and have replaced the front diff bushes. The rear ones need to be pressed in and out I think, front diff ones might be possible to do on the car?? I've got 18x9 rims with 265 tyres at the rear now.

Thanks for the info. Diff bushes are definitely next on my list. I think I have done everything else.

[Harey]

Interesting thing to note is that if I spin the wheels out of a corner it doesnt seem to axle tramp, just nice smooth wheelspin. It only seems to happen in a straight line.

Does that point to anything?

My thinking is that the suspension only gets loaded side to side instead of front to back when it squats. So my side to side suspension must be ok but not my front to back. Hmmm diff bushes are front to back...

[giant]

i dont know whether a gtr is the same? but we use get shudder that appeared to be axle tramp alot, it ended up being the tailshaft centre bearing everytime!

we replaced it regularly but in the end we went to a one piece tailshaft.

[Harey]

Was that shudder always there under power or just on the edge of traction?

If you just spin the tyres hard did it still shudder?

Mine wont shudder/axle tramp when i completely overcome traction.

[Wacky Dee]

hm this is probably stupid .. but I haven't had my dose of stupid things to say today so here goes.. Are you sure the tyres are on the correct way ? The KU36 have an inside and outside wall and I'm thinking if you put them on the wrong way around ... I only mention this because I just read another guy's thread where he wasn't sure if he put his KU36s on the correct way.

[Harey]

hahaha interesting one, i will have a quick look tonight.

[Harey]

Yup they are definitely fitted the right way. Thanks anyway.

[lowbro]

Hi Jeff,

Just reading your topic: Do it right, do it once and be done with it if you plan to keep the beast!

Source a non-hicas cradle from a 34 GT in good cond, sand blast and paint as new, buy new uprated cradle bushes $220 get em pressed, purchase new diff mounting bushes front/rear and get a new sleeve made for the rears to accommodate the new bushes or source an aftermarket one that already has the sleeve.

Take a week off work, remove old cradle and diff end, re-do all your rear suspension bushes if not new already, clean down and paint all your arms etc.

Put back together in the right position with pineapples and hey presto, your rear is like new again, but better than before no-hicas and will look great in nismo silver, or black!

Then do the front after your back recovers from all the hard work! LoL!

Just my 50cents worth and a good project to keep you busy!

[THENIG]

Thanks for the info. Diff bushes are definitely next on my list. I think I have done everything else.

I just replaced my diff bushes (rear two that bolt to the diff cover) with the nolathane kit and it fixed 95% of my axle tramp. Only time it tramps is when the KU36's are cold first thing in the morning. Even then its not a gearstick shaking tramp like it used to be.

I went about fixing my axle tramp the long way, I originally thought it was because of leaky/worn diff cradle bushes on my R32 gtst, I did the math to pay someone for labour to press out & replace, didn't like the idea of pineapples or solid mounts, worked out cheaper to buy a whole rear end from a GTR with diff & bushes that were ok and swap the whole thing myself it myself without press out the bushes. Long story short, rebuilt the GTR diff, removed hicas, whacked it back in, took it for a drive & axle tramp was still there even with the diff mounted solid at the pinion end to the cradle. Drove it round for a week, deff didn't fix axle tramp, next weekend dropped the whole rear end out again, pulled diff out & cut old bushes out using hacksaw. Had to remove some of the rubber of the old bushes with a drill where I was trying to cut because it kept binding up on the hacksaw blade. Probably only took 20min to do both witht the cradle out. They fell out with a tap of the hammer, no press needed. New ones are just greased up and fell in, no tools needed. You could probably remove the old ones without dropping the whole rear end but in all honesty it will probably be quicker, a lot less swearing & grazed knuckles than trying to do it lying under the car with a hacksaw blade wrapped in tape from only one side. There isn't alot of room to move if you do it whilst still under the car. I did the whole thing in my garage with one trolley jack & a mate to help me line it up when it came time to lift if back into place. If you have access to a hoist then you will be laughing. I think the kit cost $130 from Repco, best money i have spent, PM me if you want anymore details.

Cheers

Rob

[Harey]

I just replaced my diff bushes (rear two that bolt to the diff cover) with the nolathane kit and it fixed 95% of my axle tramp. Only time it tramps is when the KU36's are cold first thing in the morning. Even then its not a gearstick shaking tramp like it used to be.

I went about fixing my axle tramp the long way, I originally thought it was because of leaky/worn diff cradle bushes on my R32 gtst, I did the math to pay someone for labour to press out & replace, didn't like the idea of pineapples or solid mounts, worked out cheaper to buy a whole rear end from a GTR with diff & bushes that were ok and swap the whole thing myself it myself without press out the bushes. Long story short, rebuilt the GTR diff, removed hicas, whacked it back in, took it for a drive & axle tramp was still there even with the diff mounted solid at the pinion end to the cradle. Drove it round for a week, deff didn't fix axle tramp, next weekend dropped the whole rear end out again, pulled diff out & cut old bushes out using hacksaw. Had to remove some of the rubber of the old bushes with a drill where I was trying to cut because it kept binding up on the hacksaw blade. Probably only took 20min to do both witht the cradle out. They fell out with a tap of the hammer, no press needed. New ones are just greased up and fell in, no tools needed. You could probably remove the old ones without dropping the whole rear end but in all honesty it will probably be quicker, a lot less swearing & grazed knuckles than trying to do it lying under the car with a hacksaw blade wrapped in tape from only one side. There isn't alot of room to move if you do it whilst still under the car. I did the whole thing in my garage with one trolley jack & a mate to help me line it up when it came time to lift if back into place. If you have access to a hoist then you will be laughing. I think the kit cost $130 from Repco, best money i have spent, PM me if you want anymore details.

Cheers

Rob

Thanks Rob, I just purchased some nismo diff bushes (all 4) and will get them fitted hopefully next week. I think that is the last standard set of bushes remaining in the rear.

[yogi000]

this is a good thread......waiting to see the outcome.

[Harey]

Picked up my car today with all new nismo diff bushes and AXLE TRAMP IS COMPLETELY GONE NOW!!! WOOHOO!!!

Transitions from quick takeoff to wheelspin really smoothly and does not axle tramp at all.

So in summary diff bushes have to be high on the list, with pineapples or full subframe bushes as the top two contenders IMO. Start with those two things first and then see how you go after that.

Thanks for all the help I have received in this thread, hopefully it helps a lot of people in the future!

[HEKT1K]

are you still getting wheelspin with (from memory) ~200rwkw and fat semi slick rear tyres?

[Harey]

If I launched with 4,000rpm while slipping the clutch for a smooth launch would result in wheelspin but good movement. Anything more was heavy wheelspin and I would have to backoff to get the car moving.

I did get the tyres up to temperature before doing this. Also a very smooth road.

If your about quick takeoffs on the street with a rwd then i think you should stop at ~200rwkw. If your more after second gear plus runs then keep going in power. I am sure with more power you could just launch with less throttle and still get away ok but i doubt you would beat the 1st gear of a std turbod car.

I expected more too! I thought i could just give it hell on a launch and the tyres would laugh at my power.