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I drove my Eclipse with a welded center diff for 2 whole days, and I hated it with a passion. It was awful. You don't notice it when driving straight or during light cornering, but in tight places it's terrible. Some people aren't bothered by it, but I hated it. I tried to pull it into my garage and ended up leaving a huge skid mark across my driveway because it was dragging the right-rear tire along.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

Well I still have my viscus coupler and the stock 2 gear center differential, so if I don't like it I'll just have to pull the spool back out. I do like the Colt's ability to turn tiny circles.

There's a rattle in my transmission sometimes when it idles in neutral, so I plan to open it up regardless.

Colts have a smaller wheel base than DSM's so the tight turning loss affects us a little less. If you don't have to make crazy tight turns on a daily basis then I say do it.

I don't have to make tight turns on a daily basis, I guess I just do it because I can. I do however like the idea of keeping the spool in there after I finish my AWD conversion (assuming it will launch better). Do the benifits really outweigh the drawback? I just drive the car part time in the summer, with several trips to the dragstrip. I never tried auto-x, but it looks like something I might like to try.

I feel that the benefits blow away the one draw back. Even at autocross the car is a blast and turns good times (although you will be in XP which is a free for all of engine/chassis swaps). Look up "dsm slow motion launch" on youtube.com it shows the difference between open and welded center diffs.

I watched the videos, and WOW! I'm sold on it. The open diff was chattering back and forth: front slip, rear slip, front slip, rear slip... It looked violent. I've been worried the center spool would put too much stress on the rear diff, transfer case, and rear axles, but the viscus coupler looks like it causes more stress on the drivetrain and the whole vehicle for that matter.

Not really. Having a welded diff or a spool definitely puts more stress on the rear-end. You're putting more power back there than was ever intended from the factory.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus

In theory I agree completely, but looking at the video it appears that having the viscus center diff resulted in violent wheel hop. It looks like the front wheels overtake the rears, then slip, while the rears overtake the front, then slip, and the whole process starts over.

I realize there's a bunch of variables involved, such as tires, chassis rigidity, suspension, etc., but if the results are typical, then it almost seems like a solid center diff would break less parts due to smoothness of launch.

The welded center gives a constant and shared stress on the rear end. The viscous allows sudden snap torque transfer. Tonus those rear ends have been used in ridiculously high power DSMs. If they can withstand that abuse then a daily driven 300hp Colt won't even make that rear diff sweat. It is better to break all four loose on a launch than to slip the fronts, then the rears, then the fronts, etc....

Here's the links to the vids:
http://www.youtube.com/watch?v=DBjDyKeL_dI
http://www.youtube.com/watch?v=XKgml8rHIvs


This one is fun to watch too:
http://www.youtube.com/watch?v=HSgcbav2Ewk