Does anyone know where I can get steeper than standard diff ramps for my 996GT2? we have measured the power ramp at 30 degrees, gut feel is a 45 degree ramp would be better. Does anyone know what Cup cars use. Cheers, Jon.

Sound like a more aggressive take up on the LSD to me but why? Is the OP having some issue with applying power out of a corner?

The 996 gt3 and cup diffs use the same ramps- 50 deg on accel, 37.5deg on decel from memory, giving a 40%/60% lockup.
The lower the angle is the quicker the diff locks up.

The cup just uses a larger number of better quality plates along with a thicker washer to make the diff more aggressive and give significantly greater preload.

997 GT3 diff is quite a bit less aggressive. This might be a simple option if you are looking for something with steeper angles (less bite).

The Cup set is massively more aggressive than the street one. If you think you are pushing now!!!
Are you 100% sure what Diff you have in there? Is it def a stock diff and def stock street internals.

You may need to just try to work with the diff more rather than against it. (trail brake harder)

Are you sure it's also not a setup based issue rather than diff based. It's perfectly possible to get at a balance where any throttle washes out the front and it's nothing to do with the diff.

Was it you I spoke to a few weeks back ? Have had two people on about this on a GT2....

Gotcha,
If the OP was trying to describe what you did in your post then that's really just working diff behaviour sadly.
The lowish speed push that catches you when you are just trying to get round a motorway exit ramp or similar?
The cup set up is exactly the opposite of what he needs then. Discs that hold much harder and have 10 times more preload are even less fun in those situations.

Practically speaking, all you can really do is run a weaker diff to avoid it and accept the lower assistance when pushing hard or suck it up and learn to be patient with the throttle in some situations knowing you will gain from it in others.
Experimenting in other areas (pressures for one) can sometimes provide surprising workarounds. (exact same issue on CS)

Sometimes, and it pains me to say it given my binary mindset, there's only ever imperfect solutions. Even the mighty F1 needs to swallow that bitter pill.
Maybe that's what used to be called the character of a car. All the little nuances that amazed or infuriated you.

My inner teenager is dying to shout, you've got bags of power and only rwd. Every single corner you encounter should require opposite lock. What's this under steer jibber jabber

we used an OS Giken diff in our yellow 965T race car, superb kit!.. I have a source for them also.

I bow to you superior knowledge on ramp angles. The one area of the car I can never fathom out is the gearbox or diff! I understand the principles, I've seen the parts, but I still couldnt re-assemble the jigsaw like i could an engine. Thankfully I know a man who can

I'm reading all this and if I understand your problem correctly you are suffering low speed power on understeer.

The first thing I thought was tyres. Buy new and buy sticky, a sticky trackday tyre. I find these allow the car to balance out, particularly with regards turn in. The front is light and the balance between grip and slip is extremely delicate. Far more so than the rear where all that weight is forcing the tyres into the Tarmac.

The next thing I thought was tyre pressures, my gut feel is too high on the front but you would need to work that out for yourself.

The final thing was suspension. Either the dampers themselves or the roll bars. Softer front bars / stiffer rears. I am assuming you have fixed dampers and so can't adjust bump or rebound.

I'm ruling out any driver error of course

I wouldn't be coming back into the pits asking for a diff swap at this stage.

A road car is designed to understeer first because it's easier to deal with than oversteer. In truth although everyone talks about taming the back end of a 911 I think it's all about keeping that front end in contact with the road. On a normally aspirated car it's much easier because you have a very progressive throttle. Turbo charged cars don't have this, the power comes in with a bang some time after you asked for it.

Good luck

I've done two changes so far, got it down to half an hour :-)

Can you clarify what you are meaning here?
The steeper the ramp angle, the less lock up you get. so 20% lock is something like 75 deg ramp angle.
The greater the preload, the less it takes for the diff to lock up.

It reads as though you are misunderstanding how the clutch plate type works. It doesn't work by resisting the urge to lock. You weaken preload to make it more gradual to full lock and increase ramp angle to make the amount of total lock lower.