Discussion
Has anyone ever tried an ATB diff in their 986, 996 or 997? Quaife and wavetrack both do one and for the application I have in mind this would be more suitable to a plated LSD. If anyone has tried one I'd appreciate your thoughts.
Edited by CarreraLightweightRacing on Tuesday 5th March 20:02
I am sure it would be a great addition if set up properly (if they need setting up). I always found 911’s to have pretty good traction though.
I wonder if it would be worth lowering the final drive at all to close up the ratios and shorten the gearing a little?
I am thinking of using a Cayman box in my 6R4 build and they have long gears and no lsd so have been thinking the same thing....the Cayman is over geared.
I wonder if it would be worth lowering the final drive at all to close up the ratios and shorten the gearing a little?
I am thinking of using a Cayman box in my 6R4 build and they have long gears and no lsd so have been thinking the same thing....the Cayman is over geared.
CarreraLightweightRacing said:
Has anyone ever tried an ATB diff in their 986, 996 or 997? Quaife and wavetrack both do one and for the application I have in mind this would be more suitable to a plated LSD. If anyone has tried one I'd appreciate your thoughts.
My default thinking is generally Guards. What is your application? Edited by CarreraLightweightRacing on Tuesday 5th March 20:02
Fully agree Steve, Guards are right up there and for me would come as second only to Drexler, which are what MR use. They are however about twice the price of Guards.
In terms of my application I don't want the main benefits of a conventional plated diff as my key priorities are 'anti-roll' and 'no additional steering loads'. My car is set up such that mechanical grip is very high and I'm wondering if through fast transitions, with say light to no throttle, if an ATB/helical diff could in fact maybe work in an anti roll sense due to the nature of its operation.
A Guards CUP pack wouldn't really be suitable due to the sharp engagement and steering loads. I've tried a plated/clutch type LSD and it simply doesn't work in a very lightweight, non-PAS application.
In terms of my application I don't want the main benefits of a conventional plated diff as my key priorities are 'anti-roll' and 'no additional steering loads'. My car is set up such that mechanical grip is very high and I'm wondering if through fast transitions, with say light to no throttle, if an ATB/helical diff could in fact maybe work in an anti roll sense due to the nature of its operation.
A Guards CUP pack wouldn't really be suitable due to the sharp engagement and steering loads. I've tried a plated/clutch type LSD and it simply doesn't work in a very lightweight, non-PAS application.
I would be interested to see how this pans out for you.
I have thought about ATB v LSD for a long time but there is little info out there.
The M220, no parts, clutch packs are available from Porsche, so its throw it away or rebuild with aftermarket.
Guard is expensive plus you have the added faff or regularly having to test the plates for wear to benefit from its install plus the cost of doing so. - It will however do a job, but maybe not in your case.
A different car but there is more feedback from the M3 guys. - This is fundamentally what is being said.,
If you looking to maintain the drive when the non-loaded goes light, by all accounts the ATB will do nothing, it will also do nothing underbraking, even though Wavetrac claim theirs does assist underbreaking the M3 mob have stated it does not.
So with the above info it seems an ATB will only help when both rear wheel are planted, which then begs the question, why do you need it in a 911? - With the engine weight over the rear, sticky rubber and relatively meager power, how often are you breaking traction?
Let us know how you get on
I have thought about ATB v LSD for a long time but there is little info out there.
The M220, no parts, clutch packs are available from Porsche, so its throw it away or rebuild with aftermarket.
Guard is expensive plus you have the added faff or regularly having to test the plates for wear to benefit from its install plus the cost of doing so. - It will however do a job, but maybe not in your case.
A different car but there is more feedback from the M3 guys. - This is fundamentally what is being said.,
If you looking to maintain the drive when the non-loaded goes light, by all accounts the ATB will do nothing, it will also do nothing underbraking, even though Wavetrac claim theirs does assist underbreaking the M3 mob have stated it does not.
So with the above info it seems an ATB will only help when both rear wheel are planted, which then begs the question, why do you need it in a 911? - With the engine weight over the rear, sticky rubber and relatively meager power, how often are you breaking traction?
Let us know how you get on
BertBert said:
Isn't that just what an LSD does?
Yes, but I think it is the way and amount of lock up that could be in question.I spun a friends 993 RS Cup car in a tight bend at Bedford, I was talking to the mechanic after and said how it just snapped like pulling on a brake whereas my older car would be far more gradual, he explained that the diff was worn out and it was the type of LSD that did this and became more like an on / off switch which caused it to be like that.
I have a weir kitted Supra diff in the back of my cossied 4x4 Pug 205 and part way through a bend you can feel a grab or pull and the car changes angle a little, I THINK this is the diff fully locking at that point. My car on full lock parking is like having the handbrake on as I have uprated centre viscous, quaife ATB up front and then the LSD rear.
ALSO, see what Crashbang has said about the ATB above.
BertBert said:
Hope the slight thread distraction is ok, but I've never considered an LSD as an anti-roll device. How does that happen?
Bert
Sorry for the confusion Bert, I have a car that is not exactly normal and I do not intend on using an ATB diff for conventional reasons. My car has a completely different set up to a normal 996 and trying to explain it here in a few shorts lines would be tricky. I have spoken at length today with Steve Rance and the ATB question is no more. I was basically trying to find a solution to a problem that does not exist Bert
CarreraLightweightRacing said:
Sorry for the confusion Bert, I have a car that is not exactly normal and I do not intend on using an ATB diff for conventional reasons. My car has a completely different set up to a normal 996 and trying to explain it here in a few shorts lines would be tricky. I have spoken at length today with Steve Rance and the ATB question is no more. I was basically trying to find a solution to a problem that does not exist
ok, thanks for replying. Very nice car by the way!Bert
but me not smart enuff.... can we have a diff masterclass (in a pub) one day please? I'll buy the first round.Gassing Station | Porsche General | Top of Page | What's New | My Stuff