Limited slip diff - Page 2

JP · 05-21-04, 04:45 PM

My old M coupe had a really nice LSD. You could power through corners with great confidence knowing that any stepping out was easily controlled by shouting at the car. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]

Bill Musarra · 05-21-04, 04:50 PM

If I remember correctly, there was a lead to a site that discussed the different Porsche LSD's( 20-80, 40-60 etc) and how they worked. I think it was one of the Porsche racing web sites. Was great, I know I have it. Just can't locate it.
Bill

Ron Earp · 05-21-04, 08:18 PM

That is one thing about turbochargers that that it is not so nice in one respect - power delivery. Really, I think with the contact patch and suspension the Lotus should stick pretty well without the LSD. But, the problem is power delivery < 3500 RPM nothing, > 3500 RPM everything it has. So, it breaks free rather easily.

But, that Cleavor you and Roy call an engine with 500+ rear wheel would break free just about any time too, I'm sure!!

Robert Logan · 05-21-04, 09:59 PM

The LSD we are having made for thr OIE 6 speed Audi box is a Quaife style (ATB) LSD. I was hoping that the OI6 5 speed LSD could be adapted for the OIE box but we started from scratch. The old additave of the compromise made is ALWAYS a compromise !!!!

The first 6 speed LSD was due to be finished this last week and I expect it next week in my factory and into the box again next week. The engine front is being dressed at present (problem with fitting an A/C compressor, alternator and a dry sump oil pump all inside that small area under the water pump on a GT40 has caused INTEREST to say the least0. The car has over 500 hp and with all the other goodies I am sure I can presuade the owner to pass on coments about the LSD and the other things to our readers.

Regarding price , I said earlier in this thread that they would be approximately the same as the OI6 LSD which we sell at US $ 1550 if I remember correctly.

Best wishes,

Robert

ps,

Ross's LSD in his BMW M1 ZF gearbox is the type known as a Salisbury diff and I can only support the coments above about the pre loads.

Peter D · 05-22-04, 10:19 AM

Anyone got any advice on LSD's for the Porsche G50 box - after reading the above, I am getting a bit nervous about the first drive up to the local shops !

Kind Regards,

Peter D.

Lynn · 05-22-04, 01:54 PM

Peter,

You have three choices that I know of: the factory ZF clutch type (Porsche sold a Torsen style for a very short while, but no more), Guard Transmission has both types and, of course, Quaife with the torque biasing. Guard Transmission sells both because the arguments for either are non-decisive and so subjective that they just said "we'll make and sell both and let the customer decide."

Regards,
Lynn

Peter D · 05-23-04, 01:25 AM

Thanks Lynn, I'll check them out.

Kind Regards,

Peter D.

Ken Mason · 05-24-04, 01:02 PM

God I love this site - so far I have had 26 extremely helpful replies to my query about an lsd and whether I should use one. Given the massive weight of opinion for - yes I have decided to go ahead and get one.

I have driven the car in the wet and got loads of wheelspin (despite Ron's disparaging comments about the Che**y engine! [img]/ubbthreads/images/graemlins/smile.gif[/img]) but was worried about how it would behave in the dry, which let's face it is when most of us use our cars.

When the new diff is installed I'll let you know how I get on....

Dan Weilacher · 05-24-04, 01:34 PM

Has anyone heard if the Phantom Grip has worked out for the person that was installing one in a GT.(i think they were in the nothwest US ) I am sure the install/fitting procedure would be very critical as to how well it performs.

**patbarry** · 05-24-04, 07:31 PM

I believe Neil had installed one, but never heard back whether it worked or not. Not sure if Neil still hangs around.

Malcolm · 05-25-04, 06:08 AM

Reading the above, clearly there is more than one type of diff and I think the most used type in 40 replica's is the Quaife ATB. Common link is that all types clearly give you an improved handling car. Certainly yesterday I was using a lot less opposite lock than I normally do and would put that down to an LSD!

ChrisL · 05-25-04, 09:06 AM

From all that I have read, an LSD makes the car push (more understeer, or less oversteer) a little more with a LSD. That is consistent with Malcom's observations, and can only improve stability in a mid-engined car.

Incidenatlly, I have an LSD in my car and it does not create any problems under road conditions.

Neal · 05-25-04, 10:25 AM

I have a Phantom Grip. It simply translates pressure to the spiders in the diff. I'm not on the road yet so I can not comment on the performance. I did speak with a number of local autocrossers that use it with success before purchasing. It's not as elegant as a Quaife but I think it will be sufficient for a mostly road, sometimes track car.

BarryD · 05-25-04, 02:28 PM

Wheel in the air you say ?
That's more like it.
You ain't living with more than two wheels on the ground.

BD

Dan Weilacher · 05-25-04, 03:49 PM

Thanks Neal, please let us know how it does, also how those Webers perform. Looks like your car is getting close ,I visited your nice build site.

Bigend · 05-25-04, 04:34 PM

I have a Quaife six speed sequential box with LSD, and I agree, it does give considerably more understeer, but once you get used to it you can use the increased grip to good effect.

Bill Musarra · 05-26-04, 08:11 AM

For an informative set of articles on Porsche LSDs go to Rennsport http://www.rennsportsystems.com/ and look at the "Performance Parts" and "Let's talk about Porsches" for all the info you eveer wanted to know about Porsche transaxels. There is a site in Ca. that has a big inventory of Porsche transaxels, 6 spds. 5 spds. 930s lsds and regular. Not many bargains though. I'll post it if I can come across it again. Browser is being finicky.
Bill

Bill Musarra · 05-26-04, 08:12 AM

Found it.
http://www.911pcar.com/Porsche_Parts...nsmissions.htm

andys · 05-26-04, 02:33 PM

[ QUOTE ]
Found it.
http://www.911pcar.com/Porsche_Parts...nsmissions.htm

[/ QUOTE ]

I've done business with them. Sometimes a bit difficult to get to the right person to answer your questions. Todd runs the business, and he's the one you really need to get ahold of. Pretty standard P-car salvage pricing. They do get in some good stuff, if you catch them at the right moment. They owed me a Carrera sway bar from a previuos purchase, and offered to send it to me and pay shipping. Rare that a salvage yard makes an extra efffort to be sure that you're completely satisfied with your purchase.

Andy