Powertrax Locker Units???

[CHRISB]

I have asked before and no one knows anything about these units. They are no-clutch type differentials and are very strong. I was looking on the Powertrax website and they seem near bullet-proof [img]graemlins/burnout.gif[/img] . I know that Auburn, Eaton and Zexel/SLP units use clutch type friction disks to transfer power. These can wear out and get damaged from abuse and drag use. The Powertrax units are supposed to be quiet and very strong. Summit sells our 7.625 10-bolt unit for $399. I was considering this unit. Any comments?

[12secondv6]

Well, let me explain the differences between a locker and lsd for the rear.

For a track only car that never makes turns a locker is perfect.
They are usuallly much cheaper than LSD units
A locker will make both the left and right rear tires spin at the exact same speed.
If you make a left turn the rear tires (left and right) spin at different speeds or rates. The left rear tire will not spin that much but the right rear tire must spin faster to make the turn, make sense?
So, with a locker the tires would not be able to spin at different rates or speeds and the *** end would chirp and jump back and forth.
A lot of Race cars that are driven on the street seem to run them. You will know right away because when they attempt to make a turn the tires will chirp and chirp and chirp etc.

The LSD uses the clutches to allow the tires to spin at different speeds or rates.

Make sense?

[Dominic]

Please read my guide about differentials. The powertrax unit is not good on a sportscar at all - please stick with a real LSD even if its a clutchtype unit.

http://angelfire.com/my/fastcar/diffey.html

<blockquote>quote:</font><hr>
Powertrax - The ultimate differential, or is it?
The last type, and most oddball of the types of differentials I would like to cover is the No-Slip Traction system made by a company known as Powertrax. The No-Slip is commonly referred to as a locker, or locking differential, only it doesn't make a *clack, clack, clack, clack* noise when you go around corners. This company advertises their differentials as "The ultimate in differentials," boasting them over and above the likes of any open or limited slip differential, and making it seem as though everyone should own one. After reading their site, I found everything they said to be true, even in the technical article they said everything that should be said, but I noticed one minor flaw in their marketing. THEY NEVER MENTIONED CORNERING!!

Here is the good, the bad, and the pure ugly of the Powertrax unit. When you're going straight ahead, it locks the rear axles together creating a perfectly solid axle - like a spool. The axles are in everyway locked up, and they will not lose traction no matter what. Both wheels will spin regardless of what is underneath them, and in that simplistic notion it is the ultimate in traction.

The problem occurs when they claim their system is better than a limited slip. As I said before, the Torsen unit never wears out, its gear driven, and allows power transfer to occur from one, to both, and to the other wheel seamlessly and efficiently. When one wheel slips, it doesn't spin it, thereby conserving your energy and keeping your car going in the direction you intended it to for the most part.

Say you're driving along, and the Powertrax unit is locked up as usual, you're going straight ahead, and you hit a puddle with your right rear wheel. The puddle causes you to hydroplane, and dand your car darts off to the right because your differential kept applying power to both wheels evenly. You might possibly hit another car, or a nice cement wall, neither of which are comfortable thoughts in my mind.

Well, how would a limited slip have fixed this problem, you ask? A limited slip would have immediately allowed the free-spinning wheel in the puddle to coast through, instantly transferring power to the wheel with grip keeping you going mostly straight ahead and probably not affecting your direction at all. In this scenario, the limited slip (either kind) would be a lot better than a locked differential.

Okay, but what about turning? Well, remember how I said earlier that the best differential on the planet powers the outside wheel, allowing for zero inner wheel spin, which allows for more control in the corners? Guess what, the Powertrax works completely backwards! During a corner, when the differential differentiates (separates and unlocks) it sends all the power to the inside wheel trying to force you to go straight ahead! This means when you press the throttle your car will go into an understeer condition, something that normally never occurs in a high powered high performance rear wheel drive vehicle.

A brief lesson in understeer and oversteer:

Understeer = When you go to turn your car, and the front end slips around the corner, effectively making your steering "less" than what you intended... hence the term understeer.

Oversteer = When you go to turn your car, and the rear end slips around the corner while the front end maintains grip, effectively making your steering "more" than what you intended... hence the term oversteer.

Most racecar drivers prefer oversteer, since it is easily controllable with the throttle, and even though it is a slide it is very easy to pull out of by counter-steering. Understeer on the other hand is very bad, since you essentially instruct your car to turn and it doesn't [img]smile.gif[/img] . This is definitely not a good thing, since a car is supposed to go where you tell it right? The only way to reduce understeer is to decelerate and pray, which is not good for a race car, and is not expected from a high performance vehicle.

So the locking differential really bites in cornering, and during bad weather it can cause you to go sliding around all over the place... What in the hell was it invented for then?! Well, see, there's this little issue with limited slips that the locking differential and only the locking differential can get around. Pretty much, if you don't have any traction to push on a limited slip and let it know which wheel needs traction, no wheel gets traction, and you're back where you started with an open differential. The easiest way out of this condition is to just lightly apply the brakes, and is recommended in all off-road vehicles like the GM Hummer equipped with a Torsen style differential.

A locking differential, once locked, remains locked so long the vehicle drives straight ahead, and so if one wheel comes off the ground both wheels spin in sync and you continue to climb the hill with ease. About the only application for something like this I have found is a Jeep which is equipped to do rock crawling - often encountering areas where one wheel might come off the ground.

<hr></blockquote>

Excuse the grammatical errors if any, Im still editing it. I got so tired of reading lies about differentials so I wrote this anecdotal document to help people figure out what they were getting into before they did something bad wrong.

[CHRISB]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
For a track only car that never makes turns a locker is perfect.
They are usuallly much cheaper than LSD units
A locker will make both the left and right rear tires spin at the exact same speed.
<hr></blockquote>

That's exactly what my car will be used for
;) . I want to make my car a pure weekend 1/4 mile [img]graemlins/burnout.gif[/img] beast. I am planning on buying a truck to drive during the week. So are Powertrax units the strongest for pure drag racing??

I just went to Powertrax's website and it says that even though Powertrax units are locker type units, they still have wheel differentiation in turning. Here's the link

http://www.powertrax.com/traction.htm

They claim that only spools have full wheel locking and don't let wheels differentiate ;) .

[ November 18, 2002: Message edited by: CHRISB ]</p>

[Dominic]

<blockquote>quote:</font><hr>Originally posted by CHRISB:


That's exactly what my car will be used for
;) . I want to make my car a pure weekend 1/4 mile [img]graemlins/burnout.gif[/img] beast. I am planning on buying a truck to drive during the week. So are Powertrax units the strongest for pure drag racing??

I just went to Powertrax's website and it says that even though Powertrax units are locker type units, they still have wheel differentiation in turning. Here's the link

http://www.powertrax.com/traction.htm

They claim that only spools have full wheel locking and don't let wheels differentiate ;) .

[ November 18, 2002: Message edited by: CHRISB ]<hr></blockquote>

You will gain nothing on the strip running this unless you're already blowing limited slips. Redrum installed one on his V6 a while back thinking it would help at the strip, and it didn't. If you want to try you're welcome but a good strong posi is all you need... If you're not hooking up its the tires' fault, not the differential's!

[CHRISB]

<blockquote>quote:</font><hr>Originally posted by Dominic:


You will gain nothing on the strip running this unless you're already blowing limited slips. Redrum installed one on his V6 a while back thinking it would help at the strip, and it didn't. If you want to try you're welcome but a good strong posi is all you need... If you're not hooking up its the tires' fault, not the differential's!<hr></blockquote>


Gain nothing . From what I see, most of the members on this board who run at the track upgrade to a Posi unit for better 2 wheel traction ;) . I can't believe your telling me that having two wheels getting power to them, and traction, isn't better than all the power going to one wheel, or a smaller friction surface :rolleyes: . I know of a local gear shop who is very reputable, is a Powertrax distributor/installer and I am going to call them this week and see what they have to say about this.

[ November 18, 2002: Message edited by: CHRISB ]</p>

[pgriffith]

You might gain some if you currently have an open rear. But you will gain the same if you simply install an LSD.

[CHRISB]

<blockquote>quote:</font><hr>Originally posted by pgriffith:
You might gain some if you currently have an open rear. But you will gain the same if you simply install an LSD.<hr></blockquote>

OH [img]redface.gif[/img] . Oops! My rear is currently stock, with an open differential. That's why I was asking. Since all differentials are about the same in cost, I thought why not upgrade to the strongest. Powertrax is $399, Eaton $439, Auburn $300/$400 Pro, and I don't want the SLP units. I am asking because I plan on doing the V-6 to V-8 swap(see my post in Advanced Tech) in the future. So I want it to handle tons of power. Street performance is not a concern for me anymore. I have decided that to get maximum gains at the track, you have to sacrifice daily comfort. As long as a Powertrax unit doesn't risk an accident or loss of control on the street, I want to go with this unit.

[Jason McCallister]

FWIW: The take-off unit from SLP is not a clutch-type.... it uses gears! ;)

Here's more detail on the unit SLP sells...

http://www.torsen.com/products/T-2.htm

[pgriffith]

I know a lot of built up V8 people using there stock LSD. Im sure it will hold even doing a v8 swap.

[Fin]

The 10-bolt rears aren't known for their reliability, at least on V8 cars. Most of us don't make the power to break them, so simply upgrading the open-rear to a Zexel-Torsen LSD is fine. If you're planning on making your car a weekend racer with some serious power & want to dump some money into it, I'd look into a Strange rear-end or a Ford 9", especially if you use a clutch that grabs hard & run drag radials or slicks. These aren't cheap, but they will hold up a hell of alot better than the crappy 10-bolt our cars use. Like I already stated though, the Zexel-Torsen LSD that SLP sells is a good upgrade for the 10-bolt & will last (at least on our cars).

[ November 19, 2002: Message edited by: Fin ]</p>

[Dominic]

I'm proud of you ChrisB for not reading anything I wrote.

Open Rear = junk
Zexel Posi = All you need

If the zexel posi snaps, you need a 12bolt, not a locker. Getting a locker for the strip in a 10bolt is asking for trouble, you will GAIN NOTHING WITH A LOCKER over a zexel torsen posi in drag racing, and you will screw your cornering capabilities all to hell and back.

Was that clear enough?

btw, again, thanks for not reading a damn thing I wrote. :mad: :rolleyes: I hope you break your rear. [img]graemlins/burnout.gif[/img]

[CHRISB]

Sorry DOMINIC. I did read your post and understood it very well. But I just wanted to know if the Powertrax units are pure locker spools, or do they spin correctly in turns. I don't mean do ignore your advice [img]redface.gif[/img] .

As for the SLP Zexel Torsion units, are you refering to the $99 units, or the HD $499 units? That is why there has been some confusion on my part. I thought that if I am going to pay $400 for the posi no matter what brand, that I might as well choose the strongest. But I thought my choices were Eaton, Auburn, Powertrax or SLP($399) units. But if you mean the $99 take off, then I would agree fully with you.

I was tired last night and don't pay attention to everything sometimes [img]graemlins/fluffy.gif[/img] . Sorry, no dis intended :D .

[V6Bob]

Everyone's dead right about preferring a more sophisticated LSD to a locker. Lockers are generally used by people who have &gt;500HP and/or where the rules prohibit a better diff (NASCAR) and/or because they're cheap.

I gotta air a pet peeve. Dominic is right about everything except when he trots out a common misunderstanding...

"Most racecar drivers prefer oversteer, since it is easily controllable with the throttle, and even though it is a slide it is very easy to pull out of by counter-steering. Understeer on the other hand is very bad, since you essentially instruct your car to turn and it doesn't."

This is flat wrong. Every race car needs some understeer to accelerate properly off the corners. Watch any pro race. If the guy up front slides the rear, even a little, the guy behind will accelerate better and close up or pass down the next straight. As Carroll Smith says (somewhat less politely):

"The inexperienced race driver feels heroic when the rear slides. In some ways it's a pity it's not the fast way around the track."

Controlling the slide with the throttle may (or may not) be possible - but it costs time. You need enough understeer to avoid this.

[RED RUM]

alrite, i have the powertrax installed, and have had it in for, damnnn... almost a year now. my experience with it is this: for the track, i saw gains, but only because i went to the powertrax from an open diff... on the road, it's decent. i haven't had any problems with understeer, and on these island curves, i max it out, ya know. i noticed some binding a while back, and silly me, i had to make my own gasket for the differential, and it was leaking, so i didn't have any fluid in there. and actually, when i replaced the gasket, the powertrax didn't show any signs of wear and tear, at all. the install was fairly simple, i have pics somewhere if you're interested. it took about 2 hours from start to finish, and i'd never even seen a differential opened up before. all in all, i'm happy with the powertrax, and i think it'll come in handy when i'm flying down the track with the turbo whining, shifting gears like a crazy person... of course, i picked mine up for $150.00 brand new still in the box, so check on eBay before you buy from a dealer. just my 2 cents, good luck with whatever you go with. email me if you have more questions