MDv6man

Question pretty much says it all...

A friend of mine needs to know what type of limited slip diff is better. The clutch type or the helical type

Thanks

3.1RS

I don't know anything about limited slip differentials but why the hell are you driving a fuking Geo. I think i would have to drive myself off a cliff!

AGood2.8

Auburn cone-clutch diff are very smooth and perdictable and will last a very long time even on higher hp cars.

The helical type diffs (Zexel to name one) are more unpredictale in torque bias- they are not as smooth- there design is always under scrutiny for improvements.

I'd sticK with and Auburn for street/roadrace type applications.
Detroit lockers for street/drag type applications. I own both.
I've broken 2 Eaton posi's in my life time. I perfer Auburn.

MDv6man

Well I'm not driving it yet. But to answer your question

1. Have you seen Gas prices lately? The Metro got 37 mpg. 10 bucks got me through the whole week. It will help the budget when kids come along (I fear in the not so distant future).

2. Have you seen car #4? Why not drive a metro and save gas $$ so I can drive the GTO on weekends.

BTW -- Thanks AGood2.8

Nixon1

I had heard those Zexel Torsen differentials are a LOT better than POSI, just the fact that they can't handle a lot of power before they break...

AGood2.8

They are stronger- but how much power is a V6 going to give it?

The zexels don't distribute predictalbe pecentages to each side of axles. Its more like a Detroit locker- its either on or off and when its on its mostly 50/50 to each side even around a corner when you want more like 30/70 sometimes in tight corners. Your inside wheel will skip more often with the zexel and cause lose of traction in cornering. These things work great for offroad like rallycars and 4x4's.

RBob

iTrader: (1)

That is an interesting observation. All of my previous hi-po cars have had clutch type posi's in them. I liked and got used to the feel they have. Application of power pushed the car straight. Open end's always felt like they were sliding.

Then I replaced the open in my '92 with a zexel (SLP). It's weird. It almost feels like it is binding when I throw it around a turn and then apply power. Not having driven it alot with the zexel I'm still not sure of what to think. Not what I expected and definitely not like a smooth posi.

RBob.

rx7speed

acutally the clutch type LSD is more 50/50. though they can be tuned for different ratios like a 30/70 and such

the torsen type LSD's do not transfer 50/50 last I checked 40-60 was about the closest you could come which would be better then 50/50 being gives an extra 10% to the outside wheel giving less slip to the inside wheel for road racing.

the torsen is used on quite a few cars out there made for turns as well.

other adv is the clutch type does wear
toresen doesn't
for the rx7 the stock rear end has lived in cars making over 500hp running 10's in the 1/4
toresen doesn't need a LSD addative

but the torsen does take a little while to get used to being it does distro the power quite a bit different then a clutch type

AGood2.8

Zexel torsen units will be 50/50 when you a on the gas mild to hard whether in a corner or straight- No wear but you have wheel skip in corners thus loss of traction. when you slack off the throttle to very mild or completely lift, they will adjust to different bais'es in the corners based on how sharp you turn.

Clutch type posi's will be 50/50 while on the gas straight and will adjust to 45/55, or 38/62, 47/ 53 or what ever is needed to compensate for inner and outer radius traction based on the sharpness of corner- even under power, but does have prolonged clutch wear. Of course if you apply excessive power in a corner they will spring back to more 50/50 and both wheels will begin to possibly spin if enough power is applied.

Zexel is stronger but clutch posi's are smoother and better handling in corners.

Edit: another note that Zexels will snap in and out wiggling the rearend in a corner if you are feathering the throttle at all.

Nixon1

Yeah..I understand the Zexel concept quite a bit..the Zexel is, essentially, a worm gear setup isn't it? A lot of newer cars come with them...last I checked, the latest model F-Bodies came with them...possibly the stangs too..

Project: 85 2.8 bird

how about these guys:

Power Trax

Power Trax app. guide

AGood2.8

These are strickly for off road puposes (4x4's). What they do is lock the axle completely as if it were solid. If the left side of the axle/wheel is turning 10.247 mph then the right side axle wheel is turning 10.247 mph. It become in essence a spool type axle and does not give at all even when gas pedal is lifted- it holds positive traction to both wheels at all times which is ideal if you are stopped on or climbing a steep hill in a 4x4. You can not drive with this locked on the street, only in dirt or snow.

Project: 85 2.8 bird

you're thinking of THIS

the other, hard-core setup

Nixon1

Wonder how well those are for turns and such....hard for me to believe they're as smooth operating as the company says they are.

AGood2.8

I must appologize, I was thinking it was an air locker.

Project: 85 2.8 bird

Accepted . Took me awhile to make sure I posted the right one first, almost didn't . I think these are about $300 or so......

RBob

iTrader: (1)

Ah yes, the ultimate in traction. Ran one before I changed to the zexel. With the axles locked together both tires make you go. If one tire is on ice, the other gets all the power (as an example) and you pull out like both tires are on pavement.

The downsides? They cause the rear to wiggle through curves as they rachet. Even on straight sections it causes a strange pulling as the rachet mech takes up slack. This can be caused by a dip or undulation in the road surface as each tire needs to travel a different distance.

The strangest side effect is having to get used to people coming up to you to let you know that the rear in your car has some major problems. Or folks coming over and checking your lug nuts and shaking your car while telling you something is wrong. Kinda' funny that the stronger they believe something is wrong the less likely they know what a locker is .

Did I mention that they click while pulling into a parking spot?

Anyway, they do give some phenomenal traction. Wanted one in the truck this past winter, but it would have had to come out for the summer.

RBob.

rx7speed

are you sure the power is 50/50 under full power?
I always thought it was a torque sensing diff ( hence torsen) so based upon how much torque it takes to set one tire off in a spin it then will redirect power to the other wheel. so if you have 400 lbs/ft of torque going to the wheels total and in the middle of a turn it takes 100lbs/ft to make the inside wheel spin the differential will only give that wheel 100lbs/ a foot giving the rest to the outside wheel (full throttle or not) resulting in a 4:1 transfer ratio. problem I do know of with a torsen is it is a lot easier to get both wheels to spin at the same time where with a open diff you are just going to spin that inside wheel and you can rely on the outside wheel for some lateral grip still, so even though you still have the outside wheel giving grip you aren ot able to put as much power down to the ground as you can with a torsen up to the point both wheels spinning


with a clutch type LSD you have clutch packs that have a preload on them to overcome. more or less resulting in 50/50 power transfer at all times. goodthing with this vs an open diff is even though your inside wheel might still be spinning you are still able to transfer power to that outside wheel where the open diff feels that inside wheel spinning and so it keeps it spinning. another thing with the clutch pack is when it wears out you have an aopen diff for the most part


sorry if I have some info wrong here but Im sicker then a odg righ tnow but I;m trying


oh yeah I can name quite a few cars out there made for handling that use the torsen with no seeming issues... one of them pulls .99g and high 67.x in the slolam from the factory... could have sworn that most modern cars that go road racing use a torsen as well

AGood2.8

There has been many redesigns of torsen diffs and they have progressed much. The factory race cars that use these type have had many years of R&D and may have perfected them better- but as far as I have known they have not or are just now started reaching the street market. Their normal over the counter prducts as of years past have always acted more like a detroit locker in driving charateristics. Not quite as bad but close. I have a Currie 9" rear end with a Detroit locker in my truck that I drive daily and let me tell you wihile its builtproof, that sucker does wiggle when you lift and press the throttle. A neighbor of mine has a Zexel in his 1st gen Camaro that acts alot like this- he has never been fully satified with it.

rx7speed

I know they have been out on production cars since around 93 (rx7 came with them) and the ones that I know of haven't really had the problem you are describing.


and I know the miata has had them for some time now also (and I want to figure out howto switch there idff into my car )

maybe his zexel is a defunct version??? or something else is going on

RBob

iTrader: (1)

Good info on Torsen zexel differentials:

http://www.globalwest.net/torsen_tra...fferential.htm


Has drawings of the internal, descriptions and explanations. One of the better information blubs I've seen. I give it 4 *'s.

RBob.

pontiacguy1

I had one of those PowerTraxx differentials in the rear end of my Toyota. The rear was out of a 1976 Trans Am, and was an open diff before I added the locker.

The advantages: It will positively lock both wheels together when you are going in a straight line or under high power, come what may. It is cheaper than most of the alternatives. It is installed easily without having to remove the carrier.

The disadvantages: It will hurt you on cornering, since the only way it works is to allow the outside wheel to speed up to go around a curve. Neither wheel can go slower than the carrier is turning, but one of them at a time can turn faster, in the direction the carrier is rotating. It also makes some noise, and every once in a while it will engage harshly with a loud clunk. I am sure it cannot handle as much power as an Auburn limited slip or some of the other types of lockers.

I was very satisfied with it's performance in my truck. I wasn't too concerned about high speed cornering, though. It was a 2 wheel drive, but I did go offroad some times. The traction was great for what it was, and I could go some places with it where others would have to put their trucks in 4 wheel drive to get into.

My recommendation: If your emphasis is street/strip or off road, then get the powertraxx. especially if you are on a budget. If you are into road racing or are going to be dumping a LOT more power into it, then get another type of locker that will also have a stronger carrier as part of it.

AGood2.8

No offence but Miata's are a joke- your not talking much power to cause any *** end wiggle in one of them. Even Road&Track's V8 "Monster Miata" was a joke. I know 1st hand- I cleaned its *** in autocross here in So. Cal back in the early '90s.

If you Canadian guys remember this car, A Canadian TV crew came down to report on it and ended up putting my Vette into part of their 1/2 hour show. They sent me the footage on video tape

rx7speed

stock miata might not be worth anything power wise but they can be upgraded


have info on one running the stock block... actually nothing has been taken off the block from the valve covers to the oil pan ... running 10 second 1/4 miles right.and sorry to say it but the little miata prolly has more zip then a thirdgen v6.

but back to the subject the little cars can be upgraded to perform quite nicely. at one point they used a viscious type LSD *cough*piece of *cough*s<x>hit*cough*. with a turbo charger or supercharger they do quite nice. but yes stock they prolly aren't going to tax the LSD that much but still they where built as a roadster... fairly good handling. and they do a good job of that using a torsen, as does the rx7. if I thinkg hard enough I could prolly name a few higher end cars that are running a torsen as well

gurkgurkgurk

yes clutch type does where but it is rebuildable, torsen diffs are not, therefor u gotta pull out the pocket book for a whole new one, not to mention torsen differentials wont be able to handle large amount of horsepower, yes theyre good for a street car, but for a car that sees track duty, youll break that ****