My LSD is getting pretty worn out and is acting pretty much like an open diff, making it less than ideal for solo II since I can't put the power down out of corners. Pricing out the clutch packs to rebuild my diff comes out to just over $250 and by the time I pay shipping and duty it will be well over $350.

Enter the Phantom-Grip!

http://www.phantomgrip.com/how_it_works.htm

Now they sell a kit for any '79-85 RX-7 for $299, which isn't much more than the rebuild parts for my diff. I was hoping that someone here had tried this product and could give me some insight on how well they work VS the stock clutch type LSD.

Oh, and if anyone has a working '81-'83 LSD that they want to sell me for cheap, that'd be good too.

 

I there
I have a Phantom on my civic

I broke 3 diff before installing the phantom. 2 years so far and holding ok. BUT, does not behave like a normal LSD. Its just not the same

 

^^Can you explain you setup? What kind of power is this diff capable of?

 

So far its holding around 200 crank horsepower
3 puck clutch
17 inch wheels
energy suspension bushings
yokohama parada2 205/40/17

Transfer to the ground is pretty good, but you do get tons of torque steer.

How much power can it handle? I dont know.

Im about to build the bottom end of my engine so I can crank up the boost.

I will let you know if it fails in a catastrophic way

 

The Phantom grip is a lock up style diff, not what you want for autocross or roadracing, good for the drag strip though.

 

Pile of ****.
Its basically just a block of steel thats forced into contact with the side gears by the carrier pin.Same basic principal as the stock LSD except there are no clutches or friction material or proper wear surfaces.You supposed to just drop it in and expect it to not eat your diff up!?
I cant believe they still charge that much for it when full ratchet lunchbox lockers in the 4wd community go for less.

Your better off tearing down the stock LSD,doing some measuring and replacing the worn parts.Chances are that only some of the discs will need replacing and thatll keep the cost down.And itll behave like its supposed to....

 

More info on the lunchbox lockers please. I'm not that familiar with 4wds and have not heard of these. Are they a viable option, will they convert a non-lsd unit and what are the performance characteristics/usage?

 

A luchbox locker is a slang term we use for any locker that inserts into the open diff carrier....basically just replacing the spider and side gears.A phantom grip is like a lunchbox locker,except its not a locker,its a slipper.A true lunchbox locker would be a LockRight,Aussie or Powertrax.They are simple and do lock up fully.The hardcore guys frown on them because they still run all the power through a single carrier pin and do nothing to beef up the carrier itself.But they are much cheaper (my Aussie was only 200 bucks) and they are fine for a vast majority of the crowd.The two halves of the locker resemble an old tin lunchbox.....mine was of the Transformers variety back in 84.Study this picture and youll see exactly how they work.....

http://www.pirate4x4.com/productrevi.../Aussie-10.jpg

A "real" locker would be an ARB,Detroit,Ox........something that is an entirely new carrier than you bolt your diff gears to and go.The whole carrier is new and strong so it can handle the abuse.Yes,they are better,but they cost 3-4 times more and many people cannot swing that kind of money....times 2 if your a wheeler.At the bottom of this site,youll see the Detroits internals are basically the same as the lunchbox locker,except that there is a 4 pin spider inside and a completely new carrier case to hold it all together....

http://www.detroitlocker.com/DL.htm

Either type,they are all full lockers and cannot be expected to behave well on the street.The selectable type of "real" lockers(air,electric,manual) are the only exception since they can be completely tuned off when not needed.The Detroit, and all types of lunchbox lockers are "lock up under power" types and you have to deal with their ratcheting nature.You learn to not hit the gas when turning abruptly,or push the clutch in when making a slow,sharp turn.Its a little herky/jerky at first,but you learn to subconciously drive around the quirks.

 

Thanks for the info steve.

I'll have to take out the pumpkin when the 7 gets put away for the winter and do some measuring. Hopefully I don't need the entire gamut of parts.

On a slightly different note, has anyone here rebuilt their LSD with the oversized friction plates that Mazdatrix lists? Am I correct in assuming that the oversized discs will 'lock up' harder than the stock units?

 

Depends, they can be used to increase lockup, they can also be installed to make up for thin worn ones, without replacing all of them.

 

Well come the winter I'll be back with a thread full of questions on how best to proceed then.

 

Heres my take....

Thicker plates will increase the unloaded friction of the discs...the preload.But they wont increase the surface area of the friction material because your not adding any more discs to the pack than stock.The increased "static" preload of the thicker discs means that the diff may chatter more when attempting to perform differential action.And the decrease in gap between the discs means the lockup will occur quicker.....
But the overall holding ability of the discs under power depends on two other factors...
1st.Friction disc condition.
2nd.Input torque.

Even with worn discs and no preload pressure left from flat cone springs and thin discs,its possible to lock up this type of LSD with judicious torque input.If the spider pins can push hard enough out on the torque blocks,then the discs will be forced to lock up,regardless of their condition or any gaps.
When rebuilding an LSD,Id put top priority on changing the cone springs so you get the preload pressure back,Then measure the discs and replace the worn ones to get rid of any gappage between discs.Replacing two worn discs with one oversized new disc might decrease the gap and get you some preload pressure back,but youve also reduced the overall friction surface area inside the LSD.Apparantly,the SE suffers from this condition of reduced friction discs,not sure why....

 

Good advice. What other parts did you change in the diff while you had it apart?