Locker versus LSD questions

[gogriz91]

Just re-read the R&T article on the BRE 240Z and it mentioned they used a Detroit locker instead of a LSD. Anybody else done this before? What are the pros and cons? Is a locker a cheaper alternative to an LSD?

[boostedz]

Heres a good little right up that might help explain the differences for you

http://www.houseofthud.com/differentials.htm

Basically locked rears are good for straight line performance, where the limited slip is better for road course vehicles, though both have proven well at the track.

[jmortensen]

Lots of racers use welded diffs. Lockers act much like a welded diff, in that as soon as you put power to the pinion they are locked solid. I had a friend with an R190 in his 510 that had a Detroit. It was VIOLENT. When the locker ratcheted it banged so loud I thought the diff literally fell out of the car. He eventually took it out and put an LSD in. The lockers are about as durable as you can get until you start talking about spools. They work OK in big heavy trucks, but in a lightweight car they're just brutal unless you're strictly road racing or drag racing.

[gogriz91]

Thanks for the info, I think an LSD is a better choice for what I want to do.

[Ron Carter]

BRE used locked rear ends to maintain lower temps in the diff so that they would hold up longer under racing conditions. Locked rear ends are very violent and not something you would want on a street car. If you guys have a R190 with a detroit locker in it, I would be interested in it for my race cars.

Thanks,

R

[John Coffey]

A locked diff (welded) works very well for putting power down, but it affects trailing throttle behavior. Cars with locked rear diffs tend to have a lot of corner entry push and need a lot of trail braking to get rotation.

A Detroit Locker is only locked when power is applied so the understeer problem is eliminated on corner entry. As Jon said, there are NVH tradeoffs and the abruptness of the lockup must be factored into how the car is driven.

[Pennyman]

Asked some guys racing 240z's at Laguna Seca this same question.

They said for racing applications, the LSD would heat up after a long race and on the final turn the driver would get on the gas, and because the LSD was so hot, it would slip, causing him to potentially lose a position on the last corner.

After that, they said they went with a welded diff and they didn't have to worry about it.

LSD's are really expensive, and for racing or drifting, I'd reccomend a welded diff because they require little or no maitenence, and they're dirt cheap.

For street use, An LSD is good because it gives you the best of both worlds, if you're willing to cough up the cash.

I'm still debating whether to get another diff and weld it, or get an LSD unit for a 240sx and swapping it in. But there are pro's and cons for each choice.

[jmortensen]

LSD's are really expensive, and for racing or drifting, I'd reccomend a welded diff because they require little or no maitenence, and they're dirt cheap.

That's the real reason right there. If you want to have 4 diffs with 4 different ratios and a LSD for all of them, you're going to spend a lot of money compared to welding them solid. There are cons to welded diffs as well though, most notably getting the car to turn in.

As to the LSD heating up thing, I haven't experienced that personally but the longest I've been out is only a 30 min session. Might be different in an endurance race.