Quaife ATB diff in G50 Ultima
Discussion
The Quaiffe diff will definately give better drive out of the corners. However, if you are picking up the inside rear wheel the diff will revert to working as an open type. In other words, for the Quaiffe diff to operate as a limited slip device both driven wheels must be transmitting torque. Get one wheel off the ground or on a particulary slippy kerb and it doesn't work. The alternative is a "plated" diff from ZF or loads of other people. This is a "genuine" LSD and works wether or not both wheels are transmitting torque.
In my opinion, the Quaiffe diff is "softer" and probably better suited to the road and the odd track day whereas the plate diff, if set to a high static load, is better for the track but can be more difficult on the road. Your choice!
Richard.
In my opinion, the Quaiffe diff is "softer" and probably better suited to the road and the odd track day whereas the plate diff, if set to a high static load, is better for the track but can be more difficult on the road. Your choice!
Richard.
Thanks Richard,
As most of my driving will be road, then I think a softer approach might be just the thing.
The car does corner rediculously flat, I don't think the wheel is lifting, but is losing traction (I hope I haven't contradicted myself there)- is that the time when the ATB would load up the outside wheel and set you into a drift rather than spin off the power??
Pete
As most of my driving will be road, then I think a softer approach might be just the thing.
The car does corner rediculously flat, I don't think the wheel is lifting, but is losing traction (I hope I haven't contradicted myself there)- is that the time when the ATB would load up the outside wheel and set you into a drift rather than spin off the power??
Pete
I just fitted a Quaife ATB to my Seven and I really like it, it's very predictable and controllable, and unlike a ZF Diff doesn't lock when you don't apply torque - great for slippery conditions when you're not trying...
On the other hand, I never had problems with the ZF LSD in the 928 even on very slippery roads in winter.
The Quaife won't lock once a wheel is in the air, so if you do a lot of kerbhopping, you'd better get a plate type (ZF etc.).
-Marin
On the other hand, I never had problems with the ZF LSD in the 928 even on very slippery roads in winter.
The Quaife won't lock once a wheel is in the air, so if you do a lot of kerbhopping, you'd better get a plate type (ZF etc.).
-Marin
Also fitted a Quaife ATB to a Caterham some years ago and was very pleased with the result. Just go carefully at first; where you were once able to spin up the inside unweighted wheel and get possibly some oversteer you will now get big oversteer because eventually both wheels will lose grip if you don't catch it quickly enough.
Kerb-hopping on the track with a Quaife equals huge shock loads on the drivetrain when the airborne drive wheel comes back to earth.
Kerb-hopping on the track with a Quaife equals huge shock loads on the drivetrain when the airborne drive wheel comes back to earth.
Did exactly that in a 993 C2 for the same reason.
Made a huge difference to the handling, nearly lost the car on the way home from the garage that fitted it.
Basically understeer on entry was increased and oversteer on exit was also increased, basically more work for the driver.
Never really managed to adapt my driving before i sold the car.
Made a huge difference to the handling, nearly lost the car on the way home from the garage that fitted it.
Basically understeer on entry was increased and oversteer on exit was also increased, basically more work for the driver.
Never really managed to adapt my driving before i sold the car.
porsche4life said:
Did exactly that in a 993 C2 for the same reason.
Made a huge difference to the handling, nearly lost the car on the way home from the garage that fitted it.
Basically understeer on entry was increased and oversteer on exit was also increased, basically more work for the driver.
Never really managed to adapt my driving before i sold the car.
Made a huge difference to the handling, nearly lost the car on the way home from the garage that fitted it.
Basically understeer on entry was increased and oversteer on exit was also increased, basically more work for the driver.
Never really managed to adapt my driving before i sold the car.
Oh....that's not the result I want. But I guess the oversteer on exit is due to being able to corner faster and get the power down earlier??
Does the understeer come from the additional traction pushing the front of the car on?
I have 335 rear tyres and if I get more traction mid corner, I'm off in the weeds!!
Pete
The understeer comes from the diff fighting the rear wheels wanting to turn at different speeds. It actually resists the car turning.
For many cars i have driven with LSD you can set the car up to turn in tight and when you get on the power the diff straightens the car up.
Unfortunately i never achieved that because the understeer was so much that getting on the power made it worse before making it snap to oversteer.
basically it was a mistake on my part to fit one in isolation.
I should have got a Porsche diff instead and had the car set up with much more initial turn in.
Put it in and see what happens, but you will have to alter both your driving and probably the front geometry to get the best out of it, don't be put off though cos who wants inside wheel spin anyway and an open diff can be very un-predictable mid corner
For many cars i have driven with LSD you can set the car up to turn in tight and when you get on the power the diff straightens the car up.
Unfortunately i never achieved that because the understeer was so much that getting on the power made it worse before making it snap to oversteer.
basically it was a mistake on my part to fit one in isolation.
I should have got a Porsche diff instead and had the car set up with much more initial turn in.
Put it in and see what happens, but you will have to alter both your driving and probably the front geometry to get the best out of it, don't be put off though cos who wants inside wheel spin anyway and an open diff can be very un-predictable mid corner
Just to put it in perspective, i welded up a diff to test in my BMW 325, i was looking for more stability and boy did i achieve that. Once you had the car turned in you could nail the throttle and it was so easy to drive on the throttle so what you lost trying to get the front end in you gained on the exit. Not really for road use but i know they are used on the track in BMW's.
I liked it alot and wish i had fitted on the last rally when i broke down from a broken driveshaft could have actually continued and got a finish. I have a specially modified plate type in my BMW but it was not enough for me to climb a slight hill to get out of the stage.
I liked it alot and wish i had fitted on the last rally when i broke down from a broken driveshaft could have actually continued and got a finish. I have a specially modified plate type in my BMW but it was not enough for me to climb a slight hill to get out of the stage.
Ta Ciro.
The open diff mid corner scenario is probably what is making me want to move to tha ATB. It is quite frustrating when the car looses inside wheel grip and kinda stalls you mid corner.
I'll do it!
Can anyone recommend a good transmission specialist in Surrey to fit the ATB and my naughty new 4th and 5th ratios (228mph @ 7000rpm!!)
Cheers Pete
The open diff mid corner scenario is probably what is making me want to move to tha ATB. It is quite frustrating when the car looses inside wheel grip and kinda stalls you mid corner.
I'll do it!
Can anyone recommend a good transmission specialist in Surrey to fit the ATB and my naughty new 4th and 5th ratios (228mph @ 7000rpm!!)
Cheers Pete
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