How to weld a rear diff?

[Spdrules5]

I tried searching for previous posts, but couldn't find the info I needed.

Where would I have a welder weld to make the stock "Open diff" a full time "Posi" rear diff. I am cleaning and draining diff tomorrow and opening it up to see what is needed. Anfo help would be appreciated.

Yes, this will not be driven daily, VLSD for that. Oh yeah, it'll be driven to Drift events.

[Redtop_240]

I tried searching for previous posts, but couldn't find the info I needed.

Where would I have a welder weld to make the stock "Open diff" a full time "Posi" rear diff. I am cleaning and draining diff tomorrow and opening it up to see what is needed. Anfo help would be appreciated.

Yes, this will not be driven daily, VLSD for that. Oh yeah, it'll be driven to Drift events.


For some reason I dont think this would be a good idea......But to each his own.........

[Spdrules5]

Please elaborate. All info is appreciated.

[nismo2491]

a welded diff means you are always 50/50 on the rear. its really only good for drag. when you take turns one of the tires will always scrub through the turn. you need to be able to have some slip in the rear so you're not scrubbing through turns. like I said. its really only a good thing for drag. ever heard of a spool in a drag car? its the same thing. it locks both rear tires/axles togethor.
KEvin

[Whisky S14]

a welded diff means you are always 50/50 on the rear. its really only good for drag. when you take turns one of the tires will always scrub through the turn. you need to be able to have some slip in the rear so you're not scrubbing through turns. like I said. its really only a good thing for drag. ever heard of a spool in a drag car? its the same thing. it locks both rear tires/axles togethor.
KEvin

I take it drifitng isn't terribly common out there yet. He knows that he wants a fully-locked diff (its pretty hard to drift without one) but he doesn't want to pay the cash for a real 2-way clutch-type LSD (Kaaz or Nismo) so he wants to weld it. I've never had mine welded, but I can say that I've seen mixed results with the welded diffs, one in particular didn't last more than a few weeks. Its pretty hard on the diff to simply weld parts together, nowhere near the shear-load resistance of a clutch-type or even a viscous diff.

I don't know where to weld when welding a diff.

[phrozen]

its been covered... and there was a lot of mixed reactions... if i were you i wouldnt do it because no matter how good you are at welding it WILL break sooner of later and your going to have to fork out money to get it fixed plus get ur car towed and all that other stuff when it brakes down..

[Bone]

I have personally ran alot of welded diffs both off road and on road. They will make the car handle alot different. Going into a corner with anykind of power will most certainly put you drifting. I have always welded my diffs and all my freinds and have never had one break. I have seen alot of them break but it could be related back to poor welding or no experience welding diffs. .02

[Chernobyl]

Bone, can you please explain exactly where the welds go on a welded differential. I'm interested as well. Do you just put welds along the spider gears?

[element240]

i would have to say that welding the spider gears in the differential is a bad idea.
no matter how good of a welder your or your mechanic is, it will not last.
sooner or later you'll have to fork out the money to replace the rear end and that's more expensive than just getting a good lsd.

[Bone]

When they are welded they have to be welded with the welder running very very hot. You want to weld the spider gears inside to one another. When you weld them I always burn all the teeth off of them not just weld them together but elimenate all the teeth. Once the teeth are gone start welding them up first filling in between the teeth until they come out even with the top of whats left of the spider gears. Once that is done I start welding them all the way around over and over to ensure they cannot and will not break loose. If the room allows I also weld them to the carrier so it pulls some of the pressure from the internals. Make very sure you dont get the gears to hot or it will be a biotch to turn. Only weld them with a stick welder a mig is not going to do it right. Make sure you get all of the slag out before running it. generally you have to drive the axles in and out a few times to get the burr's out of the splines. Again do not get it to hot or it will not act right. I recommend only burning about 3 rods max then let it cool down a while. Most of the welded spiders that bust are only welded in the corners. Some of them are welded better but the quality of the weld itself is poor. Make sure there are no teeth left on the spiders and the build up is about where the teeth would go out to. If you have any questions PM me.

[Spdrules5]

Thanks Bone.
I'll keep everyone and anyone whos interested posted. I will be testing it on Drift Day 14 here in So. Cal on Mar 21st.

[MorganS13]

just for reference: it is very possible to weld it so it would not come apart.. probably beyond the ability and patience of most mechanics though.. how long the other parts of the diff will last, i have no clue.

[nismo2491]

I still say its probably not the best thing to do. its very hard on the chasis. not to mention the breakage issues. and with sticky enough tires you can also say hello to axle issues.
KEvin

[Bone]

I would deffinetly agree with axle issues, However if he has made his mind up then hopefully he has weighed all sides. I have personally never ran into any axle issues on the cars we have done it on but they were not independent rears. Drive shafts generally go first since them and the U joints are the weakest link. So with an independent rear I would think the same could be said. If he is only setting it up to drift I would assume he will not be running sticky tires. And it would actually work better for just that providing the rest of the driveline holds up. I have a spare 240 that is going to go through the same procedures as soon as my 93 is finished. I'm not scared I know in advance drifting/racing is hard on them and if I didnt have the time or money I wouldnt do it. You have to expect some breakage issues everytime you are hard on your car. At least he has a driver and it wont be on the street.

[mellojoe]

If you do weld the rear together, please do not drive it on the street. You will plow through every corner, and wheel hop the whole time. Trailer it to the event. Its just not worth the risk. The car will be so difficult to control in any type of cornering situation (other than breaking the back end loose and spinning the wheels the whole time).

I just don't know. I'm very wary of a welded rear end. It sounds like a short-cut... and short-cuts almost always, invariably end up in disaster of one kind or another.

For track purposes only, sure. Give it a shot. Just don't drive it on the street where you put other people in danger should you lose control at a normally mundane corner.

[Chernobyl]

Funny how the thread starter asked HOW to weld it and not your opinions on why he should or shouldnt do it.

For all of you saying it will break and whatnot... who cares? Stock open R200s are dime a dozen and cheeeeap. Just keep a spare in the trunk! haha

[240 2NR]

I was just discussing this very topic this weekend and I'm kind of shocked that more buget drifters aren't doing this. Most drifters running a 2 way clutch LSD seem to go for pretty stiff settings that would seem to me to be only marginally more streetable than a welded diff, and a lot more expensive than buying a a spare open diff to weld and run at events and keeping an open one for the street. Technically just swapping the diffs is easier than repacking the plates.

As for welding diffs, I'm not entirely sure what's involved, but I do know my friend's 510 that he races in ITC (IIRC) has been trouble free for 2 seasons (2 mile track, 30 minute race sessions, two per race day, plus practice laps in the morning). As for it's dynamics, I haven't driven it first hand but my friend with several years of racing experience has said that basically it will understeer horribly under light or no throttle but rotates nicely under power. Around the paddock and the shop the tires (r compund) chatter around corners and would obviously not make for a tolerable daily driver. I'd imagine it's not a terrible drift setup though. Certainly better than an open diff and I'd guess better than the weak vlsd, or hlsd (which just isn't as well suited to drifting as it is to grip).

Personally I don't think it's as bad an idea as a lot of posters have made it sound. Obviously a limited slip will be more streetable and a good clutch diff ideal for drifting, but on the super cheap I'd say go ahead.

[nismo2491]

Ihe is only setting it up to drift I would assume he will not be running sticky tires. And it would actually work better for just that providing the rest of the driveline holds up.
actually good/professional drifters. the ones doing full 4 wheels drifts at 60+mph use sticky tires because its the only thing they can use to control the drift. go look at the tires on any drift built car, signal, rsr, etc. they are NICE tires.
KEvin

[nismo2491]

Funny how the thread starter asked HOW to weld it and not your opinions on why he should or shouldnt do it.


yeah but the fact remains we're not totally off topic. we're advising against what he's asking how to do. if somebody comes on here asking how to commit suicide are you going to tell them how to or try to say something to persuade them not too. yeah totally diffferent and more serious subjects but same underlying point.
KEvin

[Spdrules5]

I have enjoyed all the reading of everyone's opinions and recieved some good information. As I said, I will keep evryone up to date.
Oh, by the way, it is going on an Automatic, so that will be a bit interesting.

[nismo2491]

I have enjoyed all the reading of everyone's opinions and recieved some good information. As I said, I will keep evryone up to date.
Oh, by the way, it is going on an Automatic, so that will be a bit interesting.
no oh god it just keeps getting worse!!! :duh:
j/k :rofl:
anyways good luck with us man and keep us updated on if it breaks or not.
KEvin

[Bone]

If it breaks let me know I could be persuaded to weld one up.

[Spdrules5]

If it breaks let me know I could be persuaded to weld one up.
That would be great! But shipping would probably cost a fortune. Is it possible?

[bdubb]

anyone heard about making the stock lsd act almost like a 2 way by adding shims or something?....

[Bone]

Make a small crate weigh the rear end and the crate and go to UPS.com for a shipping quote to Cleveland, TN 37323

[blu808]

I have a welded diff in my s13 and my s14, I welded them akmost 8-10K Miles ago. I have never broken an axel, diff, or anything. Just to warn you though, you better like drifting if you weld your diff because you cant unweld it.

[nismo2491]

just for shits and giggles and drag days I might take my blown diff and try to weld it. its just minor gear clearance issues to fix it otherwise.
KEvin

[s0ldats]

FYI dd14 is rescheduled to march 28th, a sunday.

[HyperTek]

any update??

[Spdrules5]

No update yet. Still trying to install a pair of SR20DET's into my friend and mine's '89 240's. Hopefully all done before next DriftDay(end of April)