Gripper Limited Slip Technical Thread

[Jordan]

Bringing this thread back. I pulled my diff out finally because it wasn't locking up properly and wanted to investigate. I think the problem was that when I swapped the washers out I must have installed the ramps in backwards or off somehow. I did notice one of them was chipped on the top of the 85 degree ramp. I'm wondering if it was because Jennifer and myself put them in backwards they saw more force in that direction then they normally would on decel and caused it to chip..just a guess. Not really a big deal, I'll smooth it out and maybe if you guys are still ordering some diffs maybe he can throw an extra ramp in the box. I don't remember them being terribly expensive.

[gmreider]

We finished installing 2 gripper units in 4 speed boxes today. One for Paul H and the other for Delorean. we had a good group work session and worked out the procedures to a T. They can tell you all about it .
So how many of the original 11 units are in use today and how many still un-installed?

[paulh]

Yeah, Gary said we should make a manual, but I'm not sure it's really neccisary. One of the things that was pretty confusing was the ramp angle situation, ours were in backwards like everyone else's, or at least I think so. This is a picture of the diff after flipping the ramps:



After we figured out how everything worked, the 2nd trans went really fast, spacers that Gary made up worked perfectly. Can't wait to get this thing into a car and try it out!

Paul

[Crazyswede]

The ramp angles work backwards to how you might think they do...so you dudnt double backwards them did you?

[paulh]

I did the thought process briefly on how they worked but just thought it should be okay though with the 80 degree angle on the bottom I wasn't sure how the pin would be loaded to shift power over to the other tire since it would be turning the wrong direction.

So, even before I put it in the car I wasn't sure, but figured it would be a simple thing to fix if it were and issue. Looking back I should have followed my intuition.

I called Tom today and he said if the crown gear is on the left than the ramp angle should face X.

I said Tom, I'm very sorry, but I can't visualize that way, and the crown gear is on the right and turns counter clockwise. He got a little flustered and I said again I have to visualize how it would work and the setup is for the crown gear on the right, not on the left.

He then simply said the lowest ramp angles should be furthest away from the direction of rotation. So, I said if the crown is turning counter clockwise than the lowest Ramp angle should be facing against the direction of travel. He said yes.


So, my ramp angles were backwards. I spent 3 hrs taking it apart in the car to swap them around. Major suck fest since I was under the gun time wise to go teach Martial arts, and just as I backed into the shop my exhaust came off. Argh more time.


ANYHOW, FOR THOSE THAT DON'T KNOW. YOU NEED TO CHANGE THE RAMP ANGLE TO 40 FACING AWAY FROM THE DIRECTION OF TRAVEL. Same as picture above. This has the correct direction of travel and correct planet angle

All in all, I'm glad to have it in and to be done with it. It does pull more evenly and I did one tire in dirt the other on pavement and the tire on the pavement was spinning.

I'll post more as I figure things out.

This is the post that makes me think we've got it right, I think she's referencing this diagram from an above post:



Now the confusing thing there is that the whole diff is flipped in the c900 from that diagram, ring gear is on the other side. That said, I don't think that matters, just the direction of rotation of the diff, which is the same as in the picture I posted, making the ramp angles that we've currently set up correct. Right?

Paul

[Crazyswede]

The way I have to picture the differential and its parts and ramp angles etc is to imagine that the wheels, axles, and inner drivers are welded in place and cannot rotate. The internal guts of the diff are attached to those frozen piece while the outer case wants to turn. So as you apply power the case rotates towards the front of the car. Then its a matter of whether the pin is rotating or fixed or the ramps are rotating or fixed...that will then indicate the ramps to make contact under acceleration.

[allessence]

great to see this is still alive.. What did everybody do for the bevel washers that were failing? Mine is still going strong.

[gmreider]

great to see this is still alive.. What did everybody do for the bevel washers that were failing? Mine is still going strong.

We used what we had , which were probably the ones that will break. We had so much fun doing these installs that we can't wait to check them after a season and replace the Belleville washers. If I read the old posts correctly, Luke may have some of the 20 odd replacement washers that were sent from Tom years ago.

[Crazyswede]

great to see this is still alive.. What did everybody do for the bevel washers that were failing? Mine is still going strong.

I sold my gripper and just bought an original Saab diff instead.

[allessence]

great to see this is still alive.. What did everybody do for the bevel washers that were failing? Mine is still going strong.

I sold my gripper and just bought an original Saab diff instead.

How come? was there a problem with hook up or reliability? I do know the original SAAB units were sweet... Nice to see you guys are still going strong..

I still have Rosie but sold off all my old SAABs (60's) to some guys from Sweden.. Only saved some NOS GT emblems and a wood steering wheel..

[Jordan]

Still using my Gripper. I had the trans apart and the washers did not break, but I replaced them with the updated ones anyway while I had it apart. I then installed it back together backwards, and had to pull it and replace it again. Might have to pull the motor again due to the rack needing to come out...

[DeLorean]

It is going to be interesting to see how these transmission's hold up in the long run. The transmissions we are using here Gary suspects Paul's is probably originally a 79 900 4 speed, and mine is a bit of an unknown.

My trans is a "Jorgen Ericsson" built box, which had previously had a standard gearcluster failure when Gary More blew it up on a track day behind a 300+HP C-900 with no oil cooler. Seems like it's probably originally a 78 99 turbo trans. It has different drivers (steel exteriors) different driver housings, pinion housings, shifter, forks, etc. I replaced the exploded gears with those from a standard 99 turbo that were still in good shape. Pretty sure it has the #7 primary drives (time is making me forget), so it should still have a good top speed but I might be able to just about hit 50 MPH in 1st. In theory, with a really good clutch and a massive amount of power (IF it holds together) the thing could be a real rocket, so long as I don't have to frequently slow down below the peak torque range - probably 20 MPH. It would make a shit autoX car with that sort of range in 1st, but for what I am using it for, might work well?

Pauls 4 speed the ITB racers have clearly messed with as well. It had the better pinion housing, very nicely welded diff, and possibly some other unknown modifications. - we never took it apart, as it worked fine on the street. Seems to have the original primary drives as the upper and lower cog look almost the same size. I think that makes it like a #4 or #5 there abouts? There was some gnarling on the inner case of the diff, so maybe it had had a failure in the past too? But at the moment, it is working fine.


In any case, they both have all the extra ribbing in the diff housing area as well as the 3 in the trans pan area... so, they should both be "best of the 4 speeds"

[Jordan]

Probably a 31/30 primary gear ratio.

[Crazyswede]

great to see this is still alive.. What did everybody do for the bevel washers that were failing? Mine is still going strong.

I sold my gripper and just bought an original Saab diff instead.

How come? was there a problem with hook up or reliability? I do know the original SAAB units were sweet... Nice to see you guys are still going strong..

I still have Rosie but sold off all my old SAABs (60's) to some guys from Sweden.. Only saved some NOS GT emblems and a wood steering wheel..

I sold it a couple of years ago because I was going racing in Australia and need the money. Last year I bought a comp gearbox with a saab diff in it so now I have one again.

[allessence]

I sold it a couple of years ago because I was going racing in Australia and need the money. Last year I bought a comp gearbox with a saab diff in it so now I have one again.

NICE!!!