Obviously a limited-slip would be ideal for road racing, but my new motor combo will run about 300 hp worth of nitrous at the drag strip, in which case a locker is a better choice. One guy I talked to runs a locker on the street and says it works great at Willow Springs.

How do the Winston Cup guys get away with this at Sears Point and Watkins Glen? And didn't most Trans Am cars runs lockers back in the day?

I just don't see how a car could rotate with the axles locked, but it has and continues to be done. I guess it may work on a road course, but a tighter autocross course is a different story? Will someone please enlighten me?

 

I will be running a locker in my car once I figure out how to mount a 3 channel ABS system on a 9" Ford. Almost all TransAM cars still use a locker in the rear. I don't know for sure about NASCAR but I imagine the same. They do not really have any moving parts, or clutches to wear out so they are pretty much bullet proof. One other thing is that they are lighter. Will it make noise? Oh you had better believe it.

I don't know for sure as far as how the car drives with one because I don't have it in the car but just going off of those that do use them in racing, yes the car will push a little under acceleration because both tires will be locked together, once you let off the throttle to enter a turn the diff becomes totaly unlocked so you can get a little quicker turn in....you just have to make sure you have the car pointing where you want it before you get back on the throttle because there again it is going to push itself out of the corner. And the only other thing I am going to say......throttle steer

I don't think it would be that good of a diff for a small track, or those that are still wanting it as mainly a street car that they drive everyday. I'm willing to put up with a little more than the adverage person, and I really don't care if its going to make noise as long as it doesn't break. If I have to learn how to drive the car a little differently so be it.


Maybe Lou or one of the other road racers would give some more light on the subject as I know Lou has had some experiance with this

 

A Locker has 2 sides to it, and an inner most part. There is a spring in the middle, which dictates the force required to "Lock up".

Keep in mind that a locker is an open diff when there is no foward torque acting on it. It only locks when power is applied to it.

At some races, if I dont remind Lou over the radio, he will sometimes drag the gas pedal a tad. This makes the car push like a train.

The TA cars use a locker, the daytona cars use a spool because the locker spring will wear out at the ~ 18 hour mark, the cup cars run a locker, or a spool depending on driver preferance.

A locker was my choice before I sold my car


Louis

 

Just realize that the _only_ reason they're used in NASCAR and Trans-Am is that the rules require them. A hangover from the idea that pro racing could be cheap.

If part of why you race is to learn to drive, you'll be driving around the inadequacies of the locker.

 

If the car sees significant street time, you had better "try before you buy". Your tolerance may be different than mine, but I couldn't tolerate a locker on the street. When it locks/unlocks there's a very loud noise. It's not just the noise, but it makes the whole car shudder. If you were on a wet or slippery road and accelerated around a corner, you could easily spin. Requires a very different driving style than a posi.

Rich Krause

 

I have a Dana 44 in my CMC road race car - just got a Detroit Locker for it. My experience with two different types of posis before the locker was VERY dissappointing with virtually no traction out of the turns.

My first event with the locker was a couple weeks ago. The first time out with it I used the same tire pressures as I did with my posis and got TONS of push. I was beginning to wonder about how driveable this combo really was until some of the guys with welded diffs (poor man's locker) in CMC advised me to increase my tire pressures. That made all the difference and I got more confident every lap. Push was greatly reduced although not gone completely.

The locker makes a neat "supercharger" type sound when it is in open mode. I do think this ability it has to be open off throttle makes it a whole lot more driveable than a spool or welded diff.

Nice to hear about your knowledge and experiences Lou! Any additional suggestions you could throw my way would be appreciated, that is, do you have to change your driving style drastically from driving with a posi, and how much can push be tuned out of locker equipped cars? Should I also be revaluating my swaybars? Tx.

 

Then what would you suggest for a high hp car that is going to see limited street use, mainly open track events and an occasional run down the strip?

Nothing in a 10 bolt is going to hold it. There isn't really anything that great about the diffs for 12 bolts. The posi ones are going to have to be rebuilt a lot depending on how much track time they see. There are a few opitions as far as Torsen diffs for the 9" but, I guess I look at it if its proven and works in a racing environment then why not use it, as long as you know the benefits and drawbacks of it. Maybe its just me but I would think that once you get to a certain point with the car your not going to have it as your daily driver anyway....so you wouldn't have to drive it in the rain...how ever I have seen Lou run the TA car around the track in the wet, on slicks with a locker....just one of those things were you are going to have to adapt to the car a little bit. If they were allowed what ever they wanted to run what could they use that would hold up better?

 

You are right, maybe the street isnt the perfect place for the street. Much like those that say that drag radials cant be driven in the rain, or solid rollers will never last on the street

Trans Am cars have FOUR options for diffs. Spool, locker, and the other 2 slip my mind. Trust me. Ive filled out more tech sheets in that series than I can remember and there are 4 spaces to choose for what diff you run. As far as the Cup cars, im not sure.


The ideal diff would be a gleason/torsen type. Buzz McCall and the American Racing TA team had extensive R&D in them back in the early 90s. It was all we could do to get our hands on one in 91/92. They have since been outlawed.

I believe that a "Gold Track" or similar name from the dirt oval ranks would work well. Its a torque biasing diff. The cars tend to have a weird feeling on corner exit, because the power is being transferred from the slipping wheel to the gripping wheel. Pretty neat.

As far as setting up a car for a locker? Everyone is different. If you are coming from a spool, the car will rotate a lot nicer, no mid-corner push, but as soon as you start track out, understand that you will have a solid axle at that point. Testing, testing, and more testing!




Louis

 

hey y'all...just saw this thread and thought it was kind of interesting. I've read about those "air lockers" and was wondering if that would possibly be an option for this kind of application...? Don't know about locking it out of every corner though, but they seem like a cool idea.

 

The ARB air lockers are popular with the off-roading set because you can manually lock them with the touch of a button. This is mainly for dual-purpose vehicles that go on both trail and street, turn them on when you need them off-road and stay unlocked on road or a flat part of the trail. This makes no sense for the full-time road racer as you would have no time to hunt for the activation button between turns.

The ARB air locker would also fit into my MSTGW (more sh$t to go wrong) category for road racing, cut that air hose with an off-road excursion and no more locky! At least in off-roading you are going at slower pace and there is less chance for that kind of damage. I doubt road race folks would want all the other hardware that goes along with that system anyhoo.

 

Cup cars run either a spool or a detriot style locker.