Still Got Axle Tramp Arrgghhh!

[Harey]

Hi,

I still have axle tramp on my R34 GTT, please help!

Car Specs:

R34 GTT with cooler, exhaust and tune 190rwkw

Rear wheels are 18" with 275 wide Kumho KU36 tyres

Conditions that cause axle tramp on my car:

- acceleration in 1st and 2nd gear (tyres cold)

- 2000-4000 rpm launch (tyres hot or cold)

- wet road, acceleration in 1st and 2nd gear with any amount of throttle that will break traction

- quick 1-2 change

- smooth or bumpy road

Conditions that do not cause axle tramp on my car:

- anything with full traction does not axle tramp

- big rpm launch in the dry does not axle tramp, just wheel spins

- spinnng wheels on a wet road in 3rd and 4th gears

Things I have tried with no change to the axle tramp:

- replaced japanese coilovers with sydney kid spec bilstein shocks and king springs

- changed a heap of bushes (not diff ones)

- Tried tyre pressures from 28-40psi

- installed pineappbles in the all round performance position (this actually caused the axle tramp to feel a bit more severe, I think it made no change to the axle tramp it just meant I could hear/feel it more ).

Suspension place have suggested trying the pineapples in the squat position.

Whats the point of a quick car that you cant use!!?? Driving me crazy and I have spent hours searching and reading threads on here.

[lachlanw]

have you checked your gear box and engine mounts ?

[Harey]

have you checked your gear box and engine mounts ?

I spent a few hours at the suspension place on saturday and he checked that. Is it possible for them to look ok but be buggered?

Would engine mounts vibrate the car with traction as well though?

[ARTZ]

put stock wheels back on it what happens??

pretty sure engine/box mounts wont cause tramp, just knocking on take offs, youd notice your gearstick jolt....

think u got too much traction not enough power...try a better turbo stop wasting cash on suspension...

Edited May 3, 2010 by Arthur T3

[bradsm87]

Pineapples by themself squashing the stock bushes are rubbish. I chop the tops off all the stock bushes, leaving about 3mm of rubber on the back 2 to avoid metal-on-metal contact and leave about 8mm on the front 2 to angle it towards squat a little, put the subframe back in place, THEN put the pineapples underneath. This makes a heap of difference and is still quieter than solid alloy bushes.

Also there is a huge amount of movement and bounciness in the rear lower control arm bushes. U can see marks on the metal where the bush has touched but the bush is about 5mm away when still! Grab some delrin rear LCA bushes from cazmanindustries.com and that'll stop a lot of tramping imo.

Unfortunately, the whole driveline is supported by rubber bushes so if u want it the best that it can be, u'd be going with nismo engine, gearbox and diff mounts too. It all helps.

Edited May 3, 2010 by bradsm87

[Harey]

put stock wheels back on it what happens??

pretty sure engine/box mounts wont cause tramp, just knocking on take offs, youd notice your gearstick jolt....

think u got too much traction not enough power...try a better turbo stop wasting cash on suspension...

These are the wheels that were on the car from Japan, so dont have easy access to any stock wheels.

My gearstick does shake all over the place when it does axle tramp, but Chris from Centreline thought it axle tramped first and then shook the gearstick.

Yeah few people have said about getting more power but I cant see how it would improve, its quite severe now. Ok so it will spin 1st hard but surely I will be on the edge of traction in 2nd or 3rd gears and will have the same problem but much worse!

[Harey]

Pineapples by themself squashing the stock bushes are rubbish. I chop the tops off all the stock bushes, leaving about 3mm of rubber on the back 2 to avoid metal-on-metal contact and leave about 8mm on the front 2 to angle it towards squat a little, put the subframe back in place, THEN put the pineapples underneath. This makes a heap of difference and is still quieter than solid alloy bushes.

Also there is a huge amount of movement and bounciness in the rear lower control arm bushes. U can see marks on the metal where the bush has touched but the bush is about 5mm away when still! Grab some delrin rear LCA bushes from cazmanindustries.com and that'll stop a lot of tramping imo.

Unfortunately, the whole driveline is supported by rubber bushes so if u want it the best that it can be, u'd be going with nismo engine, gearbox and diff mounts too. It all helps.

I just would have thought that if the pineapples were in the right direction that they would have helped a bit. If the pineapples reduced it but it was still there I would be leaning to your solution.

Hmmm the lower control arm bushes havent been replaced, but they have definitely been inspected.

[ARTZ]

These are the wheels that were on the car from Japan, so dont have easy access to any stock wheels.

My gearstick does shake all over the place when it does axle tramp, but Chris from Centreline thought it axle tramped first and then shook the gearstick.

Yeah few people have said about getting more power but I cant see how it would improve, its quite severe now. Ok so it will spin 1st hard but surely I will be on the edge of traction in 2nd or 3rd gears and will have the same problem but much worse!

I dont mean gear stick shake ..it will just jump to the left when u drop the clutch usually with a clunk noise.....but yeah that doesnt seem to be the problem..

Basically having bigger wheels tends to put more strain on your driveline, more power can make up for this...

If standard wheels stop the axle tramp, then more power is whats needed ..if it still tramps with stock wheels, then ignore everything ive said...

Edited May 3, 2010 by Arthur T3

[RBceffy25]

Basically put your coil overs back in, adjust your rebound, possibly lower the rear spring rate, and put solid (aluminium) spacers and bushes in your sub frame.

Read on for an informative explanation into this.

Ok this is all basically summerised/quoted from an issue of BOOST (ZOOM)

Understanding axle tramp: Consider the job of the rear wheel for the moment. When it becomes driven, it is - in turn - driven in a direction that is not only forward, but also in a vector angle that is tied into the pinion angle of the diff. Rarely it is ever a case of straight thrust that has the car pushing straight down the road.

Axle tramp occurs when the vehicle is suddenly shocked (dumping the clutch etc) and the driven wheels wind up energy in the shocks, springs and ultimately the vehicle subframe mount that impart a huge backload against the driven wheels as a reaction. In many cases the effective damping of the system is so poor that once you start the wheels tramping, the effect of the whole process becomes self-generating. So for each and every tramp there is a storing and release of energy that keeps the whole thing going and going and going.

Shocks and springs: First point is to consider the affect of the rear shocks and springs of your vehicle. It is indeed the job of the shock to control oscillations of the rear end, but there is really only so much work you can expect the shock to perform. If you have adjustable shocks, you need to work through the bump and rebound settings to check how much of an affect this has on your vehicles willingness to tramp. Regardless of the fact that most people will tell you that too much rebound will encourage tramp, winding some (rebound) out will ensure that the rear end stays smooth under all conditions. You want the most stiffness as possible but still soft enough to be able to control some of the tramp.

Tyres and Pressure: All that you will find with different tyre and pressure combinations is that having a different overall traction point will delay the onset of wheelspin long enough to mask the effect of tramp.

Bushes: Rubber bushes have a tendancy to 'wind up' and store energy which can be released as tramp when the wheels start spinning. Pineapples add a measure of stiffness to the rear end, along with a different stack height that can, in turn, change the directional vector of the rear wheel by altering the pinion angle of the diff. If you rum a thin pineapple(or put it one side of the mount) its good for grip and the opposite is good for drift. Stiffer bushes help to fix tramp by not contorting to the point where it 'winds up' the rear cradle. Full solid, aluminium bushes are made for this exact reason as they do not contort and wind up the sub-frame in any way. The downside is that there is increased harshness being transmitted from the road through to the cabin, which is why manufacturers use such soft bushes in the first place.

Springs: If all else fails then change the rear springs. The softer the spring, the easier time the rebound of the rear damper has in controlling the oscillation of the spring. It’s this basic mismatch of damper and spring that contributes to tramp in the first place hence why sport cars do the tramping and luxury cars just drive away.

Wheel Alignment: Always make sure your wheel alignment is up to par before you tackle any axle-tramp issue. It is quite possible to have a toe misalignment on the driven wheels which tries to pull the vehicle one way under acceleration, which can have the unintended affect of not only starting tramp conditions, but also exacerbate the condition.

I hope this is informative and helps you in some way.

Cheers!

[Harey]

I dont mean gear stick shake ..it will just jump to the left when u drop the clutch usually with a clunk noise.....but yeah that doesnt seem to be the problem..

Basically having bigger wheels tends to put more strain on your driveline, more power can make up for this...

If standard wheels stop the axle tramp, then more power is whats needed ..if it still tramps with stock wheels, then ignore everything ive said...

Anyone got 2 stock wheels I can borrow

I think thats a good test too. Hopefully thats the case, then I HAVE to get a bigger turbo hehe

[Harey]

It used to axle tramp with my coilovers with the shocks set on all settings. Currently my king springs are quite soft and the bilsteins and definitely in full control of them.

I wonder if my issue is slightly different to the one described by RBceffy25, because mine will also do it without a clutch drop just accelerating and getting wheelspin, so no real sudden initiation. We are going to try a different pinion angle on thursday with the pineapples in max squat position so hopefully that makes a difference. I just want to see something make a difference so I know where to spend more time on.

[RBceffy25]

Are you using these bad boys aswell?

[Harey]

Are they alloy subframe bushes or diff bushes?

[RBceffy25]

Are they alloy subframe bushes or diff bushes?

Have a look here

http://www.rhdjapan.com/gt-1-motorsports-r...dy-chaser-60154

Heres the diff mounts

http://www.driftworks.com/shop/p671/Solid-...oduct_info.html

You really want to do subframe mounts at the least.

Its a must have.

Edited May 4, 2010 by RBceffy25

[RBceffy25]

Also read this

http://splparts.com/SPL_SDB_S13.html

And heres a link for solid bushes (replace pineapples) for s13 only though. Im not sure if anyone makes 'em for R34

http://splparts.com/SPL_SSB_S13.html

Edited May 4, 2010 by RBceffy25

[Harey]

Thanks!

I think your both of those posts are links to the same type of items:

- Diff Bushes = Diff Mounting

- Rear member bushes = Subframe bushes

Please correct me if I am wrong.

The only decision left is alloy vs polyurethane. Its 99% a street car but I am all about no axle tramp and a tight feeling rear end so I am thinking about taking the plunge to alloy.

I think labour for the diff bushes is massive though so I would hate to make a mistake!

[RBceffy25]

Thanks!

I think your both of those posts are links to the same type of items:

- Diff Bushes = Diff Mounting

- Rear member bushes = Subframe bushes

Please correct me if I am wrong.

The only decision left is alloy vs polyurethane. Its 99% a street car but I am all about no axle tramp and a tight feeling rear end so I am thinking about taking the plunge to alloy.

I think labour for the diff bushes is massive though so I would hate to make a mistake!

Yeah man its all the same stuff. Some sites just give a better or clearer explanation on the details of it all. I put all those links up just so you can understand all of these parts functions clearly.

Go the full alloy gear. Better off getting it right the first time. As explained in that massive post I put up unless its aluminium you may still get some torsion with the urethane gear with will still manifest itself as axle tramp. The alloy is full-proof. If it’s a streeter (like mine: ) you will still have all the sound deadening and shit anyway with will reduce a lot of the transferred road noise associated with solid mounts.

[Harey]

Hmmm sounds good, I think this is what I will try next!

[Harey]

I dont mean gear stick shake ..it will just jump to the left when u drop the clutch usually with a clunk noise.....but yeah that doesnt seem to be the problem..

Basically having bigger wheels tends to put more strain on your driveline, more power can make up for this...

If standard wheels stop the axle tramp, then more power is whats needed ..if it still tramps with stock wheels, then ignore everything ive said...

Ah I just thought of something, it axle tramps in the wet in 1st and 2nd gear and I am pretty sure 190rwkw can overcome my tyres in the wet

[RBceffy25]

good luck with it all dude!

Let us know how you go!