I've been considering swapping the LS1 brakes onto my LT1 car. It looks like I could almost buy a complete LS1 rear end for what the brakes cost. So...

What gear ratios were available in the LS1 rears? I've got 3.42's now but would love to go to 4.10 or numerically higher...

Do all the LS1 rears have the torsen differential? I've heard good things about them in the 4x4 world, but here I read some dismay about the torsen. The torsens I'm familiar with use worm gears instead of clutches to limit slip. Is this the same design the LS1 rears use???

Any reason I wouldn't want to swap in the LS1 rear since I'll probably do the brakes anyway?

Paul 'X'

 

I believe they do use worm gears, I did not see any type of clutch when I took mine apart. Some LS1 rears have torsen, some have aburn, depends on the car and the year. most have torsens. Haven't had any problems with my torsen, even with the abuse it takes from me! Manual rears came with 3.42s, but autos came with 2.73s and I think 3.23s. I've heard people going as high as 4.11s, but I'm pretty sure u can put 4.10s in a stock rear.

 

I hear a lot of people complaining about the fact that once the Torsen breaks, it's done (as in, no repairing it.) They also say the Auburn is rebuildable, but works in a different way (forcing both wheels to spin.) I'm really not sure, myself. I had an Auburn put in mine since I had problems with the stocker (not sure which I had,) been happy with it. I've heard pros, cons, opinions, and everything between about all the kinds of differentials, most people will say something different.

The guy above is right about the gears. 3.42s for M6s, 2.73s standard for autos, 3.23s as an option. I also believe all SS and WS6 autos came with 3.23s.

 

Thanks for the info so far...

I forgot one important question!!! Will the ABS sensors on the LS1 work with my LT1 computer? And if not, can I swap the sensors or is it more complicated than that???

Paul 'X'

 

now ABS i'm not sure about. I think LT1 cars came with 3 wire abs sensors and LS1 cars came with 4 wire abs sensors. Someone correct me if I'm wrong. Seeing how you want swap brakes/rear I don't know if it would be a prob. I'm sure you're not the first to try. Hopefully someone else chimes in.

 

Traction control cars have 4 sensors.
Non traction control cars have 3 sensors.
Doesn't matter whether it's an LS1 or LT1. But I don't know if the sensor itself is the same or not.

 

What do you expect to achieve by switching to the LS1 rear brakes? Do you have a brake problem? It's something I wouldn't bother doing. Also wrt the posi, what are you trying to accomplish? FWIW, the rear brakes on my car are one of the only major components that is stock and I never even contemplated changing them.

Rich Krause

 

Overall, I agree. I'm not expecting any real street performance improvement from any aspects of the LS1 swap. However, there are a few reasons I'd still like to do it.

While the rear brakes aren't significantly larger, they are thicker. I am absolute murder (Yes, Yes, I know, I'm an idiot, maniac, etc...) on brakes in every vehicle I own. I warp a set of rotors at least once per year. Anything I can do to reduce rotor warpage will be worth the effort. I'm planning to swap the LS1 front brakes as well, and use aftermarket performance pads and rotors all the way around for better cooling.

I really like the much better parking brake design on the LS1 rear. As you said, this isn't really going to improve any performance, but I've heard of LT1 cars rolling quietly away due to lack of clamping force. Never seen it myself though so it could be BS... Either way, the LS1 design is better.

On the Torsen issue... I've never had one myself, and my only knowledge of them is from the world of 4x4ing, so it could be a whole different deal with street cars. I've always wanted to try one in any case. What I like about the Torsen is that it doesn't have the 'Breaking Point' that the clutch-style posis have... In other words, a clutch-style posi holds until the clutch slips, then one wheel will wildly freespin. With the worm gear design, (not sure exactly how it works) there isn't that 'on-or-off' effect with regard to one wheel breaking loose. In real world use, my LT1 rear rarely breaks loose a single tire. In standing, straight line performance it's more than adequate. However, in screwing around, (Yes, Yes, I know, I'm an idiot, maniac, etc...) I find that hard clockwise slides under power will frequently break loose the right rear. This is partly due to the right rear lifting under the torque of the driveshaft in conjunction with the extra weight being thrown on the left wheel. I realize this is probably not an issue that most owners care about...

In general, I think it will be a cheap and easy swap. I can get an LS1 complete rear end for $300 or less if I shop around, and I'm fairly confident that I can get close to that back out of my LT1 rear. Plus if I have to disassemble it all to put in poly bushings anyway, I may as well put something better back in, right???

Paul 'X'