I currently have all of the parts for my motor, along with all of the supporting mods such as turbo/fmic/fuel etc. I have not, however, touched the drivetrain besides the flywheel and clutch.

To get an idea I will be running an ACT 2900 with the 6 puck disk and making somewhere upwards of 500 whp on race gas. No holding back on this motor...

So basically what I am looking for is what parts I should upgrade ASAP in the AWD drivetrain. I have heard something about the center differential from Jet, and I am familiar with upgrades in the transmission itself. Is it possible to weld the center differential, and if so what are the downsides to this approach? Also I am very unclear about the whole viscous coupler and it's function. Should I have it welded and run it welded or only use the welded viscous on the dyno? Anything else I should be worried about?

Thanks!

Chris Carey

Sheperd tranny, or cryo freeze your tranny parts. I won't pretend to be an expert on any of this stuff, and I'd like to know also.

You better have that tranny built or you're gonna be f*cked in the ass when it explodes ;) I'd weld the center diff if you don't care about turning. That's what I'm doing, as shep is gonna my shitty tranny next week.

I rebuilt my FWD tranny twice with no issues, so that is the plan for any problems with this one. I just don't understand the AWD aspect of it yet. I'm not as much worried about the syncros, forks, or rails as much as the things that would explode while dropping a 2900 lb clutch with 500+ whp!

So since the differential can be welded, what would the downside be? Just the clunking while turning that you had last year at the SO? I could make due with that...

Chris

I say get a spool from TRE, do not just put in a weld VC because the two gears in the center diff that ALL of the power goes threw will break like glass with a launch or a hard shift. My galant did this twice, once at 300hp and once at 400hp. Or you could buy a aftermartket center diff.

~John

I would go with the spool as well. That is a pretty decent solution if you can live with the bucking.

To answer your question Chris, the front and rear will be locked in 50/50 with a spool. This will make it hard to turn (I dunno if I would attempt it w/o power steering except a track only car, input from anyone that has run it?). The other thing is that a spool will put more stress on the transfer case because more power is going to the rear wheels. That is a good thing in terms of the takeoff, but bad for reliability.

If you want to keep it reliable you can put in a 4 gear center diff too. That is what I have. They are about $450 though.

The locked center diff and no power stearing is no worse then a open center diff. But the car does not want to turn real tight when going under 5mph. This will help with the 60foot time, and make the car feel more stable while cornering, but have oversteer issues when pussing on the limit of your tires. I would not waist my time with a 4gear CD, the Kazz(spelling?) is only like $500. Its a clutch type lsd so there are no gears to break inside, and I think you can still use a welded VC to dyno, in fwd.

~John

Sorry to say this, but the KAAZ unit has 4 spider gears in it also which could break. It just uses clutches to help equalize the transfer of power evenly.

arent spools known to break axels when on the street?

Not any more than hard launches. :3gears:

I guess I should have looked into the diff befor saying that, :headache: . If you have a 4bolt 1g rear end as far as I know you dont have to worry about it. But I have heard the 2g rear axels are more prone to breaking, but not as bad as the 3bolt 1g.

~John

i've broken axles and center diffs.
axles are 1 million times faster and cheaper to fix, plus the better 60's are well worth it :).
do it once, do it right, or don't do it at all.

I run a welded center diff. Or as the off road guys like to call them 'Lincoln Locked' center diff. It will spin the inside rear tire on tight corners. If you start into a corner to tight and off the gas it will throw your head into the dash cause it stops you so quick. You also will need twice as many guys to push it around the garage.

When you weld the center, don't weld the VC. You want to weld the gears inside the diff. You can get a sleave to hold the two little balls that are held in place by the VC to reduce rotational weight in the tranny. There is more surface area on the gears than on the VC.

I have only broken the main driveshalf launching. But you can remove it and drive home with a welded center. :thumbsup: