LSD Ramp angles questions/ G50 3.6 IROC Tribute

[jmz]

Hi All,

I'm ever so slowly building an IROC tribute. It is an 81 SC Tub will have 3.6 varioram and G50 Gearbox.

I am looking at a refurbished Motorsports limited slip. ...It apparently can be setup either 60/40 or 40/60 is what I'm told.

This car will be a street/event car with some track use as well.

Can anyone share their thoughts, advice or opinion on ramp rates for this application?

Thanks,

JZ

[Bill Verburg]

Originally Posted by jmz

Hi All,

I'm ever so slowly building an IROC tribute. It is an 81 SC Tub will have 3.6 varioram and G50 Gearbox.

I am looking at a refurbished Motorsports limited slip. ...It apparently can be setup either 60/40 or 40/60 is what I'm told.

This car will be a street/event car with some track use as well.

Can anyone share their thoughts, advice or opinion on ramp rates for this application?

Thanks,

JZ

The GT version of the LSD can be set up either or, never heard of the ZFs or GKNs being flexible

40 on acceleration and 60 on deceleration, usually describes as 40/60

[jmz]

Originally Posted by Bill Verburg

The GT version of the LSD can be set up either or, never heard of the ZFs or GKNs being flexible

40 on acceleration and 60 on deceleration, usually describes as 40/60

Tom at Carquip was saying this one could set either 40/60 or 60/40. Anyway, thinking it’s set to 40/60. …just got off phone with him.

[Bill Verburg]

Originally Posted by jmz

Tom at Carquip was saying this one could set either 40/60 or 60/40. Anyway, thinking it’s set to 40/60. …just got off phone with him.

He would know

generally, you want more lockup on decel to help w/ braking
964 was the first factory use of asymmetric ramps, 964RS was 20/100 and most disliked it

before that it was all ZF 40/40 which could also be set up 80/80 by rearranging disks

street 993 are 25/65 or 25/40
RS 993 are 40/65

motor sport 993 was 40/60 or 40/40

[Matt Monson]

You can’t flip the ramps on either my G50 LSDs or a factory GKN lsd. It will always be 40:60. If you put them in “upside down” it will jam into the housing locking one wheel and leaving the other permanently open. And these are locking percentages, not ramp angles.

Regards,

Matt Monson
Guard transmission llc.

[Bill Verburg]

Originally Posted by Matt Monson

You can’t flip the ramps on either my G50 LSDs or a factory GKN lsd. It will always be 40:60. If you put them in “upside down” it will jam into the housing locking one wheel and leaving the other permanently open. And these are locking percentages, not ramp angles.

Regards,

Matt Monson
Guard transmission llc.

I could swear that you had dual ramp selection lsds, must be getting old and even more senile

In fact I still have an e-mail from Paul G. mentioning it

This was a long time ago back when I did have a GT 40/60 in one of my cars, Paul had rebuilt it for me.

Still looking for the actual ramp angles, I have that somewhere too.

[Matt Monson]

Originally Posted by Bill Verburg

I could swear that you had dual ramp selection lsds, must be getting old and even more senile

In fact I still have an e-mail from Paul G. mentioning it

This was a long time ago back when I did have a GT 40/60 in one of my cars, Paul had rebuilt it for me.

Still looking for the actual ramp angles, I have that somewhere too.

There was a limited production model called the GT2R that stood for reversible. But the standard GT3 Club , GT2 Pro, and GT1 LSDs ,where all the volume is, have always been directional. The GT2R was still in production when I bought the company in 2009, but I discontinued it in 2012 because literally nobody ever reversed the ramps. I probably sold fewer than 15 of them ever.

But dual ramp means something else. Every LSD has 2 ramp choices. On the G50 that’s generally been 40/60 or 50/80. 80/80 has been available by special request, but again not popular. It’s really only for drag racing.

[jmz]

Thanks guys for the history and education.

[Bill Verburg]

Originally Posted by Matt Monson

There was a limited production model called the GT2R that stood for reversible. But the standard GT3 Club , GT2 Pro, and GT1 LSDs ,where all the volume is, have always been directional. The GT2R was still in production when I bought the company in 2009, but I discontinued it in 2012 because literally nobody ever reversed the ramps. I probably sold fewer than 15 of them ever.

But dual ramp means something else. Every LSD has 2 ramp choices. On the G50 that’s generally been 40/60 or 50/80. 80/80 has been available by special request, but again not popular. It’s really only for drag racing.

Ah, That explains it, I only wanted 40/60