I know some GSX guys rolling around with this mod done and they ran high 11's all day long. Has anyone else done this and what are the negative effects of this?

 

The only problem with that is when you go and try and turn your Evo around a fast sweeper prepare to crash. Its a great mod if all you care about is straight line performance. Ask those same guys how their care handles afterwards. It makes all 4 wheels spin at the same speed all the time pretty much. On the DSM's it also gives them a permanent 50/50 torque split as well if I remember correctly.

 

Your correct. The evo's already have a 50/50 split so it's not needed.

 

Yeah I would prefer a split of 40/60, but nothing is perfect.

 

Uhh, so do DSMs. Welding the center diff is done for an entirely different reason.

 

I thought a 1G AWD was heavily FWD biased? Hmm, maybe that was only the automatics.

Oh well-- the reason is to stop breaking the center diff's spider gears.

 

All DSMs have essentially the same driveline setup as a 2003 Evo. A limited slip center diff that utilizes a viscous coupler. A rear LSD, and an open front diff.

The split is 50/50 on both cars. When the front axles start to spin at a significantly different speed than the rears, the center viscous coupler locks up and holds the center diff axles so that they turn at the same speed. Essentially, locked at 50/50.

The reason to weld the center diff (or viscous) is to actually gain extra traction during launching. Some people think that is saves the transmission from the dual shock of the viscous locking up when the front tires start to spin faster than the rears. Personally, I don't think so. The rear driveline takes a real beating when you launch with a welded diff.

And driving on the street is awful. It really stresses every part of the driveline.

 

Take a 4x4 with a lockable center differential, lock it and drive on a paved road, preferably on a windy road - I promise that you will never entertain this modification for a road car ever again.

In the dirt however it's a different story.

 

I use to have a 91 GSX with a welded center diff. The reason I did it was because the center diff in a DSM is the weakest part of the drivetrain, and after exploding the spider gears in one, you dont want to deal with it again. I drove my car on the street with it and the only time you will notice it is turning at very low speeds, ie: parking. The rear end will chatter alot and the inside tire will chirp and skip. But at any type of normal driving speed it was not noticeable. It didnt effect handling at all on the highway, and made drifting and donuts in the snow alot easier. It also makes drag launches quicker and you wont be breaking the center diff anymore.

Now, would i do this to my Evo, probably not. My DSM was a 13 year old race car crap box stripped down with no A/C, abs, balance shafts, or anything else that was not needed to go fast. It wasnt a brand new $30K performance machine.

 

Ok, I was just wondering. Thanks for all the replys fellas...