http://cgi.ebay.com/ebaymotors/ws/eB...m=110215641008


I asked this guy about the diff, he claims it’s a stock “POSI” from the factory and it is NOT a LSD. I stated that positraction is a GM brand name for LSD and that Mazda did not make a “POSI” that the diff must have a “locker” or welded gears to make it full time both wheels. Here is the message I got back from this guy.


THIS IS NOT A LSD, GM IS NOT THE ONLY BRAND OF CAR WITH A POSI AND IT IS NOT GM'S "BRAND NAME" FOR AND LSD. A POSITRACTION AXLE CAN BE FOR JUST ABOUT ANY MAKE OF REAR WHEEL DRIVE CAR.A LIMITED SLIP DIFFERENTIAL AND A POSITIVE TRACTION REAR END ARE TOTALLY 2 DIFFERENT THINGS, I HAVE RACED THE PCA (PORSCHE CLUB AMERICA) FOR SEVERAL YEARS NOW, PREVIOUS TO THAT I DRAG RACED EVERYTHING FROM A FORD 5.0L MUSTANG (WITH A 3:73 POSI REAREND) TO A 1971 SPLIT BUMPER SS CAMARO (WITH A 4:11 POSI REAREND). MAZDA DID INDEED HAVE SOME POSI TRACTION REAR ENDS. WHAT I MEAN BY POSI IS THAT IF YOU SPIN THE LEFT AXLE FORWARD THE RIGHT AXLE WILL SPIN FORWARD ALSO. AN LSD IS TORQUE BIASING, MEANING A CERTAIN AMOUNT OF TORQUE OR SLIP HAS TO EXIST FOR BOTH WHEELS TO SPIN SIMUTANEOUSLY. OTHERWISE ONLY THE DRIVE WHEEL WILL SPIN. I HOPE THIS HELPS, I DONT KNOW WHERE YOUR INFORMATION IS COMING FROM BUT ID CHECK AGAIN, POSI TRACTION REAR ENDS HAVE BEEN AROUND SINCE WELL BEFORE THE 60'S, AND NOT IN GM'S ONLY.

My understanding is that "posi" and "LSD" are the same thing. Now I believe it is a full time both wheel setup, question being is it possible that it is built like this from the factory ?

 

I see your confusion. I don't know the mechanicals of the "Posi" rear end on the GM's, but know that some of ours came with LSD's which use clutches. Yes, I believe "Positraction" was GM's marketing name.

 

Right my S5 turbo rear has LSD, as did many other RX-7’s, GTUS etc etc. I just find it hard to believe that Mazda made it FULL TIME both wheels all the time from the factory, those are not very street friendly for every day driving. Is this guy blowing hot air or does he know what he is talking about?

 

His 5.0 Mustang also probably didn't have a PosiTraction unit in it... Ford's marketing term is TracLock IIRC.

 

full time as in welded or similar to that? No, no one is that stupid (except the idits who do weld their rear-end.)

 

I told the guy he is full of it, but just wanted to get more opinions on the matter. Based on the other racing merch he sells, it would seem he would know something, but now he revised the auction saying that it will fit turbo and NA and that it came off a NA, as if Mazda put out a locked diff on a 13b NA for everyday driving.

 

Also, an NA diff will bolt up, but the driveshaft wont because the bolt pattern is different. Great seller!!

Spec.

 

Not to mention the drive axles.

 

It's a waste of time to argue with these idiots.
There's a LOT of bullshit postings on ebay.
DUH

You're right.
"LSD" stands for "limited slip differential", so anything that allows power distribution between left and right (rear) tires (the "limited slip" part) that also allows the left and right (rear) tires to spin independently of each other (the "differential" part) is technically called an "LSD".

"Posi" is the term Chevy guys use.
You'll also hear "Detroit Locker" from the domestic guys.
"Torsen" is a trade name from Zexel-Gleason, but it's generic name is "helical differential".
They are all LSD's but some work differently than others.


-Ted

 

That is my understanding as well.

My question is - did Mazda make a diff that has both rear tires spinning/turning simultaneously at all times, stock from the factory, as this eBay seller claims?

 

88,
It is normal for any limited slip to rotate both sides in the same direction. Under loaded conditions there is a limited amount of slip to allow for turning, hence the name " limited slip". He is somewhat correct, but really doesn't understand what he is talking about. This is like calling all refrigerators "fridgidairs", which is a tradename. Many people refer to any limited slip as a "positraction" out of ignorance that this is a tradename. I sincerely doubt that you could ever win an argument with this guy, as he obviously has a limited knowledge base to draw from.

 

Has anyone sent him "The RX-7 list knows about you", or should that be something for the lounge?

 

My Lsd Spins Both Wheels At The Same Time And Direction When The Car Is Lifted In The Air, Just By Spinning Them With Little Force. So **** That Guy And Who Ever Else Says Anything Different!!!!!!!!

 

Per wikipedia, positraction is GM's LSD. Simple as that.

 

Calling a LSD a Posi is like calling all refrigerators Kenmores.

 

Tell him you're selling your McPhersons but they're not independent suspension components, that's completely different.