Aircooled rear axle steer?

[ras62]

While Porsche intorduces it's trick new system on the new cars, here's a great video showing how late aircooled cars performed a similar trick with the Weissach axle

https://www.youtube.com/watch?v=3z5v_ZE69SY

Edited by ras62 on Tuesday 2nd July 21:14

[SRT Hellcat]

Great video. Yes 964 made an attempt at it. It was not great hence the 964RS having a different rear suspension set up.

[Steve Rance]

Yep, i think that there is too much emphasis on dealing with bumpsteer from the front end of a 964 and not enough dealing with the rear end. The vast majority of the bumpsteer on the front does not have much of an effect on the handling once the car is set up properly. If the rear end isnt modified the car will feel vaigue and unpredictable at 9-10/10ths after turn in. To deal with the problem I would reccomend Elephant sports bushes all round and Tarret rose jointed rear spring plates. These modifications will transform the handling and make the car quicker and more predictable through all phases of the corner. It a very big gain for - in relative terms - not a hight outlay.

[Yellow491]

Great bit of film.
Shows how much the wheel toes out,camber increase and most of all tyre deflection is measured in centimeters not mills.

[Slippydiff]

Yellow491 said:

Great bit of film.
Shows how much the wheel toes out,camber increase and most of all tyre deflection is measured in centimeters not mills.

Amazing what a few well-chosen soft/wobbly bushes can do !!
Bin the lot and go decent quality German spherical bearings wherever possible on the rear, then steer it with your right foot rather than the usual method...

[Slippydiff]

Steve Rance said:

Yep, i think that there is too much emphasis on dealing with bumpsteer from the front end of a 964 and not enough dealing with the rear end. The vast majority of the bumpsteer on the front does not have much of an effect on the handling once the car is set up properly. If the rear end isnt modified the car will feel vaigue and unpredictable at 9-10/10ths after turn in. To deal with the problem I would reccomend Elephant sports bushes all round and Tarret rose jointed rear spring plates. These modifications will transform the handling and make the car quicker and more predictable through all phases of the corner. It a very big gain for - in relative terms - not a hight outlay.

Were european/OE Motorsport (RSR) bearings/bushes not available Steve ?

[Paynewright]

The noise is fantastic !!

[Cheburator mk2]

ras62 said:

While Porsche intorduces it's trick new system on the new cars, here's a great video showing how late aircooled cars performed a similar trick with the Weissach axle

https://www.youtube.com/watch?v=3z5v_ZE69SY

Edited by ras62 on Tuesday 2nd July 21:14

It’s even funkier on the 928 where of course it was introduced. On the road, the Weissach is a Godsend in a 928. Not so much on track. It seems that Porsche didn’t account for the forces that can be generated by modern 295 section track day tyres like Pilot Cup 2s or full blown 18” slicks. Hence the Weissach axle gets pinned and the rubber bush that does half of the work and costs £475 from Porsche gets binned and replaced by a spherical bearing.

[braddo]

Cheburator mk2 said:

It’s even funkier on the 928 where of course it was introduced. On the road, the Weissach is a Godsend in a 928. Not so much on track. It seems that Porsche didn’t account for the forces that can be generated by modern 295 section track day tyres like Pilot Cup 2s or full blown 18” slicks. Hence the Weissach axle gets pinned and the rubber bush that does half of the work and costs £475 from Porsche gets binned and replaced by a spherical bearing.

Interesting.