I got a CUSCO 4.1 sitting here.... I have a few people interested in taking it off my hands...I could use the money elsewhere, but I am debating.

KNowing my luck, as soon as I sell it... I'm going to blow a hole in mine, LOL.

Well, for right now.. I do not drag the car... no boost off the line, no 2 stepping, just boost on the road. I'll be putting down around 500hp with 20-22lbs of boost with alcohol injection.

I wanted to see how many people use the stock diff, and have been using it for quite awhile with high horse power applications without a problem. I hear it's a gable with the FD... some people break them at 350hp, some people have them as high as 600hp without a problem.

Depending on what I see here is going to determine my decesion on keeping my CUSCO or selling it to use the cash elsewhere.

Thanks guys,
-Darren-

 

I've never heard of anyone peaking at 350, there are tons of people running 400+ on the stock diff but you already said that...

 

If your not drag racing then the stock Diff is fine. I have a kaaz 1.5, and I hate it. The only thing I notice about it that I like, is that it seems to keep the car in a strait line when the tires break loose.

 

I have been making more than 400 for a while now with no problems. Of course, I havent launched the car. I have a TII S4 diff sitting on the shelf looking for a good home (read:inside my casing) once my torsen explodes

 

I have a friend who broke his on the 1-2 shift at 10 psi with a 35/40.

 

I hear of people using a TII Diff rather than a Torsen. I am assuming this TII diff is better?

 

Alot of people say that the T2 diff is stronger.

 

i've shattered the case on a diff with ~370-380 whp, and i've driven 400+ whp cars where it holds up.

all depends on how much you beat on it. power doesn't kill them nearly as quickly as dumping the clutch and shifting hard.

 

Damn, well there's always isolated incidents but in theory that shouldn't happen..
What was he doing just launching?

In all honesty if you're gonna launch the car and what the stock diff to last get a diff brace. It eliminates wheel hop completely.

 

I think I might pick up one of those, you get vibration at high RPMs though... feels kinda funny =P

Although Launching it is out of the question until I get axels and some better rear end support. I don't plan on tracking it for time until I get a setup I am comfortable with. I'd like to keep this engine for awhile... =P

 

The S4 T2 LSD is a clutch pack style and best bang for the buck upgrade over the weak Torsen. I put one in my FD housing and it works great and is also rebuildable.

The Kazz is essentially the same design but has much beefier construction and has larger surface area plates in it. OUt of the box it is setup up in full lockup mode. If it is driving you nuts and shaking the car around corners/clicking then you should read the directions and retune it (remove some clutch packs).

 

Yup, all good info.

I should have mentioned above that I have had a diff brace for a while now. wheel hop is definitely reduced....I either have traction or I spin, not much in between. Once the diff brace 'took a set' to my car the high rpm vibration went away. the only minor drawback now is that when the diff is cold there is a whine transmitted to the chassis. otherwise i love it--seems to have stiffened up the rear of the car as well, making the car feel tighter under hard cornering. i guess hardmounting part of the drivetrain to the chassis will do that

 

I think much of it has to do with how grippy your tires are and how hard you launch. Obviously, a drag setup (low tire pressure, slick tires) will put a tremendous amount of shock load into the diff.

Dave

 

i just put a set of drag radials on the fd.. i should be making mid 300's to the wheels... im scared as hell to launch it...

 

lol, i did that on stock twins...about 300 RWHP too. Mileage maybe?

 

Actually it's the opposite. Drag tires normally have soft sidewalls that are designed to flex and absorb a lot of the instantaneous shudders. With smoothly applied power it takes an enormous amount to damage a stock diff. The problem is the extreme loads that are applied during wheel hop for each instant the tire bites and grabs an enormous load is applied and released repeatedly, time is a major function. I punched a hole in my diff from this way back in 1994 or so on street tires. I never had another problem after switching to M&H's when I drag raced.

 

Thanks for the clarification. After I wrote that, I've been thinking that while a drag setup applies maximum *torque* to the drivetrain, the shock loading is lower. All things done to help avoid the tires from breaking loose or hopping (flexy sidewalls, low tire pressure) also reduce drivetrain shock. Makes much sense.

Dave

 

dang, this thread tought me a lot... im not as scared to launch her now, just gotta break in that new clutch... i got a question tho, didnt feel like starting a new thread. someone answer me this, are you supposed to break in an unsprung disk? ive heard yes, and no... ive got 150 miles on it, just wondering where i should go from here