DIY Posi-traction

ChrisSuich · **Posted:** Sun Dec 21, 2008 6:54 pm

Keith and I want to lock the differential in our Sentra to have posi-traction.

It seems our options are the following
o Weld
o Fill the entire cavity with an epoxy

Any advice out on performing this?
Will a weld hold?
Epoxy sounds good but I suspect it might fail and if it does would trash the rest of the gears.

Any volunteers to help weld? We've already opened the case. We have the diff unit out.

Aaron Buckley · **Posted:** Sun Dec 21, 2008 7:43 pm

ChrisSuich wrote:

Keith and I want to lock the differential in our Sentra to have posi-traction.

It seems our options are the following
o Weld
o Fill the entire cavity with an epoxy

Any advice out on performing this?
Will a weld hold?
Epoxy sounds good but I suspect it might fail and if it does would trash the rest of the gears.

Any volunteers to help weld? We've already opened the case. We have the diff unit out.

Welding it will work, but I've only seen it done in RWD cars. I'm not sure what issues you may have on throttle and steering at the same time. I can remember driving Scott Johnson's old Celica with a welded diff, and during slow speed stuff, you could feel it pulse. - AB

jeremy gast · **Posted:** Sun Dec 21, 2008 9:07 pm

I have done welding on several round track dirt cars. Never had the weld break, but def interesting to push the car. I dont see y you would have any problems with it.

George Bright · **Posted:** Sun Dec 21, 2008 10:13 pm

Welding will work but I expect it will plow like a dump truck and have a lot higher steering effort too.

You might want to consider shimming the spider gears so that they are really tight. This should give you some positraction effect too.

Carl Fisher · **Posted:** Sun Dec 21, 2008 11:23 pm

Back in the day some of the Dodge rally guys would weld up their (FWD) differentials. Made the car very difficult to turn, particularly at low speeds, but they would compensate by adding an inch or so of toe out at the rear. Not sure how it would work for rallyX, but hey, it'd be fun to watch!

Vincent Keene · **Posted:** Mon Dec 22, 2008 8:23 am

ChrisSuich wrote:

Any volunteers to help weld? We've already opened the case. We have the diff unit out.

I'll be glad to help with the welding. FYI, I'll be in Apex this coming Sunday. If you can bring it to me I can do it then.

WalterHouston · **Posted:** Mon Dec 22, 2008 11:00 am

I think it will be fine as long as you stay on dirt. It will be hard to turn at slow speeds, but you guys never go slow!

Pete Guthrie · **Posted:** Mon Dec 22, 2008 8:41 pm

the toyota is 1wd. believe me, you have not rallied.. until you run sloppy conditions, 71 whp. and 1wd... that is a riot, you spend the whole time thinking you are on black ice. :P although it sits up high enough if you pay attention and keep your foot in her, she has yet to get totally stuck. except for the one time at rockingham.. then she got high centered, not really stuck. but having a LSD on my sentra, i love it. i can see why you want a lsd-ish for your sentra.. if it is not really expensive, why not find a se-r in a junk yard, take the diff out and put it in your car. provided it still works that may be another route as well. 1991-1993-ish they had the diff still. afterwards they took it out. try city auto salvage in durham or nines wrecking yard too. try to find the diff out of a early se-r. put that on if it is not too expensive.

ChrisSuich · **Posted:** Mon Dec 22, 2008 11:03 pm

Pete Guthrie wrote:

why not find a se-r in a junk yard, take the diff out and put it in your car. provided it still works that may be another route as well. 1991-1993-ish they had the diff still. afterwards they took it out. try city auto salvage in durham or nines wrecking yard too. try to find the diff out of a early se-r. put that on if it is not too expensive.

It's my understanding that the SE-R drivetrain is completely different. Like transmissions would not swap. I would not believe that the gears would be interchangeable.

BretLuter · **Posted:** Tue Dec 23, 2008 5:14 pm

welding will work fine- you only really need to jam the spider gears together, so just weld to your hearts content, just be careful to not get too much spatter on the ring + pinion gears.

Brad Mackey · **Posted:** Wed Dec 24, 2008 2:28 pm

How about the "Jam-a-Block" Phantom Grip?

http://www.phantomgrip.com/catalog/index.php?cPath=44&osCsid=c6b923338fd2ec5a606312314e30c6dc

George Bright · **Posted:** Wed Dec 24, 2008 6:42 pm

Brad Mackey wrote:

How about the "Jam-a-Block" Phantom Grip?

http://www.phantomgrip.com/catalog/index.php?cPath=44&osCsid=c6b923338fd2ec5a606312314e30c6dc

Welding is about $300 cheaper.

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