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Registered:
March 2003
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Diff Jumping
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Tue, 29 July 2003 11:54
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Hello,
I have a GZ20 Soarer, with a 1JZ, how do I stop the diff from bouncing when it breaks traction (which is all the time). It is lowered 1" with kg/mm springs, stock shocks. 5 speed g/b, LSD.
Thanks.
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Location:
Canberra
Registered:
May 2002
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Re: Diff Jumping
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Tue, 29 July 2003 12:03
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screwed shocks and/or worn bushes are the first thing you should replace. I just fixed the same problem in my car with fitment of polyurethane bushes in the rear end.
cheers
Phil
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Registered:
March 2003
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Re: Diff Jumping
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Tue, 29 July 2003 12:46
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Last time I got Polyurethene bushes they sqeaked really badly!
So that's basically it, new bushes/shocks?
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Banned user
Location:
ADELAIDE - The Drift City
Registered:
July 2002
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Re: Diff Jumping
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Wed, 30 July 2003 00:38
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Axle tramp is the term used for this prob.
i suggest you read my Traction Brackets thread...
Generally when you lower a vehicle you are also changing the rear geomtry... which can cause tramp.
Oh and for squeaking bushes.. use a good quality bush oil.
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Location:
Adelaide, SA
Registered:
May 2002
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Re: Diff Jumping
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Wed, 30 July 2003 00:47
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Does the Soarer have an independant rear end? I notice this effect (stuttering and jumping) quite badly on my 1jz powered MA70 Supra - it has new shocks and pretty stock ride height.
I also noticed that Martin Donnon once wrote about it in HPI about his Soarer and polyurethane diff mounts/bushes didn't help at all.
The only thing I can advise is to launch at a higher RPM (seems to work in the Supra) - then it smoothly spins both rears without jumping around, but this does mean you lose some traction....and only regain it mid-way through 2nd gear!
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Location:
Madrid - Spain
Registered:
August 2002
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Re: Diff Jumping
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Wed, 30 July 2003 03:35
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Axle tramp occurs when the suspension cannot dissapate enough energy. It is common in high powered cars, particularly with leaf sprung live axles.
On a trailing arm live diff, traction bars wont help here, if anything they will make the problem worse.
To cure this you need to allow the car to put the energy down effectively. This means that the first thing you need to do is have a good look at all your pivot points and bushes and make sure they are in good condition. If the problem still exists, increase the damping rate of the shocks. Possibly look into rising rate springs as well. These allow you to have a relatively soft spring setup which will help with launching while still offering enough spring to stop it bottoming out.
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Registered:
March 2003
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Re: Diff Jumping
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Wed, 30 July 2003 03:39
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It was happening before I lowered it, the extra horespower did it. Thanks for your help guys, sounds like i need new rubber bushes and adjustable shocks. Although launching at higher rpm does light them up smoother.
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