Rear axle tramp

[laura]

VERY(!) occasionally I have been known to be a hooligan when making standing starts - the legacy of competing for 17 years in speed hillclimbing! Is it usual to get severe axle tramp with a standard setup on our 993? I've driven far less exotic motors that would seem to have a far better located drive train and don't have this problem. I have to say I am now very restrained as I don't want to snap a drive shaft etc but as I will occasionally compete in the car as it is, is this normal for the car (in which case I will adapt) or can I do something about it? The car has done 90,000 miles but a respected friend who works for an independent specialist has said it is one of the nicest 993s in standard form that he has driven - so I don't think there is anything that is particularly loose. Any ideas guys?? Thanks.

Charles - the other half of Laura

 

[kennyboy]

I only once intentionally tried to power slide my '96 993 in the dry and axle-tramp caused me to not try again!

maybe only does it al low speed in the dry?

 

[Sundeep]

out fo interest what is "axle-tramp" ?

 

[laura]

Hi Sundeep

The term "axle tramp" is a throw-back to the days when many cars had a live rear axle with leaf springs. When you built up the revs and dropped the clutch the wheels would try to spin but beacause of the less than solid location of the suspension/axle, you would get a very violent juddering as the tires alternated between grip and spin. Most cars these days should break traction smoothly and then you play the throttle to maximise forward acceleration. I know a number of people who compete in 911s of all types and racing starts with smooth wheel spin is the norm. I believe a car like ours, 993s, should be perfectly capable of smooth straight line "racing" starts (not just throwing the tail out when, say, booting it out of a junction) - but then the basic suspension design may have traded this "rock solid location" for other benefits and what I am experiencing is the norm on a standard car...???? Have I got a "normal" 993 or are there some of you out there who have no problem with wheel spin and "Blue" needs some new bits?

Cheers

Charles - the other half of Laura

 

[Guest]

Well I don't usually pull away like that but I just put some new rubber on the rear today so a few days ago I did have a go at dropping the clutch and yes I had the experience you describe as "axle tramp."

 

[paul howells]

Hi Laura
I think your car has the traction control up to around 40mph,called ABD automatic braking differential,this applys the abs etc.But no good for standing starts,i disconnected mine!The gt2 comes with out this.Also ltd slip diff may help,along with grippy tyres!
You may have a ltd slip diff already.
Paul.

 

[phil993]

Definitely you should not get axle tramp - I would suspect your shocks and also have the bushes checked.

Mine was a 96 Varioram car with 30k - as far as I know traction control wasn't available on 993s....was it?

Phil

 

[38F3E1]

ORIGINAL: MoC2S

ABD was option, not standard on C2's.... M224 ?? LSD MP08 .. all this standard on TT and RS, ABD standard on C4's ..

cheers, Maurice []

Are you sure? I always assumed my C2 had it. I just looked in the driver's manual and there is nothing saying it only applies to the C4. The manual generally notes where there are model differences such as brake booster, etc.

This is the blurb on ABD. "The ABD system is a traction control aid which reduces the tendency of a driven wheel to spin on one side of the car at speeds of up to 44mph. The ABD is deactivated at speeds of more than 44mph".

Ian.

 

[phil993]

Would this not be a limited slip diff?

I'll have to search out my manual - I've not read it yet....

 

[Guest]

Hi Charles,

I've always assosiated axle tramp with American cars, I had a Mach 1 Mustang (yes I know, but I was young!) when I was at college and in those days I hardly ever pulled away without burying the throttle.
Axle tramp was just accepted as 'normal' with that type of cart spring set-up but a 993 shouldn't have an axle tramp problem with its far superior suspension, I dont get it with my Carrera 3.2 and I do often pull away in a 'spirited' fashion.
I'm pretty sure you should have a smooth take off even when 'giving it some stick' from standstill.
In fact, to anyone who's not quite sure what axle tramp is, just watch the film classic Bullit and you'll see the mustang that steve McQueen's driving demonstrating it perfectly!

Cheers Glenn