Welded Diff?
 

I was at a meet reciently and a guy I met there asked if I had welded my diff yet...

I have no idea what that means or the point of it? Anyone know what he meant?

it means welding the spider gears together creating a live axle. but their only good in a straight line.

It means that both wheels will turn at the same rate... another words you will peel wheel doing 5mph pulling out of your drive way.

All it means mechanicly is taking your rear differential plate off and running a bead around the slip.

When it's welded or locked both wheels will turn together no matter what, there will be no 'differential' in their speeds. There will be more difficulty turning at low speeds because the rear will want to straight ahead while the front wheels will need more steering angle to get the car to change direction.

A live axle is when the two actual wheels are solidly linked to each other, not that they will turn with each other. If one wheel hits a bump, the other side will be affected, unlike an independent rear.

Welded diff?
I thought only rednecks from Alabama did that these days :egrin::)
Just go out to the junkyard and buy a LSD rearend off a GSL FB

Welded diffs are pretty much only used in low budget drag racing to my knowledge. Maybe some offroading guys still do it, but I have only seen it used on drag racers. Road racing and autocross is no place for a welded diff, and especially the street. You will put a lot of unneeded load on the axle shafts and will chew up the rear tires pretty quick.

Welded diffs are used a lot road racing. There are cars you can't get an LSD for but they are allowed in the class. Also they can be used in endurance races where you might break an axle or CV and without a spool(or welded diff) you are dead on the track and can't limp back to the pits.

If you have the choice(you do, its an RX7 right?) get an LSD. A welded diff is stupid on the street or at slow speeds like an auto-x.

you might also want a welded dif for budget drifting... but then again drifting a FB unless its hopped up to the max is reserved for nutjobs who dont fear for their lives.

Eh. A good limited slip behaves just like a welded diff. You should hear me try to drive my car in traffic - every time I turn has all four tires howling.

The difference is, a welded diff isn't "loose" inside - there's a certain amount of lash inside the diff case itself because of the ramp arrangement, and this leads to weird noises and vibrations sometimes. (Like trying to coast in Neutral on the highway)

I'm probably going to stop using limited slips and run a welded diff since nobody offers a spool. The biggest problem is making sure you weld the diff "straight", so the side gears aren't offcenter.

mine is welded i have a 4.77 kia pumkin i broke 3 gslse diff with just 337 WHP

that's a straight axle. my term live axle is when power is applied to both wheels equally. in a turn the inside wheel tries to turn at the same speed as the other.

Straight axle is when both wheels are attached to the same axle. (Old/heavy duty trucks had straight front axles, lots of FWD minivans have straight rear axles)

Live axles are straight axles that have the drivetrain built into them. (RX-7s have live axles)

And yes, there are "dead axles"... a straight axle on the drive wheels, but with the drivetrain separate. More commonly called a de Dion suspension. (original Cosmo had one of these, so did some Italian cars, and AWD Caravans)

Has anybody ever used arb airlocker ? Or would it even be feasible to use ?

Get yourself a Miata Torsen rear if you want a good diff, JDM makes one.
I bought one this past year from Japan, was a little over $500 with shipping.
I used to run a welded rear on my hillclimb car, but not for daily street use tho.
I loved driving the welded rear up the hills tho, could throw the car around a corner like you wouldn't believe!

welded diff and rain = drifting every turn lol

Aren't you the idiot who crashed your low mile FB while "drifting" on public streets? Just sell it and get yourself a 240SX. That way you'll fit in with the "drift" scene and can leave the RX-7's alone. Tool.

http://www.dsmtalk.com/forums/showthread.php?t=204298

If you're going to do it, do it right: http://www.pirate4x4.com/forum/showthread.php?t=763645

Welding a diff is just as ghetto as cutting your stock springs to lower your car. Personally i think it is the dumbest shit ever. If you want a welded diff then get a 240 brah

There are plenty of road racers using welded diffs. There is nothing wrong with it. Most oval track racers have welded or locked diffs as well. It's very common. I've been using welded diffs in my race car for years now.

Most important is to weld the spider gears to the casing, NOT to each other. Avoid welding the spider gears to each other, they will still have plenty of room to flex and move, crack the welds then chew them selves apart. When the spider gears are welded to the casing they have a solid base to resist movement.

Tire sizes, power output and track usage are considerations as well. If you do plan on running high HP, with strong DOT tires for auto cross, you won't have a great time with a welded diff. The high grip and speeds with the tight corners will be more welcoming to a proper LSD.

However, road courses with big sweeping turns will be rewarding to drive with a welded over an open diff. Drifting is great and more predictable with a welded as well over both LSD's and Open diffs.

thank you onerotor for the pirate4x4 link. made my whole day! HAHAHAHAHAHA

Meh ok then

Nah, at low speeds the car just plows forward. The steering feels pretty rubbery, too.

Alot of 4x4 down here have a welded Diff, just because its cheaper.

If you understand a little more this will make a little more sense.


If you do 4x4 you expect to break an axle or two so welding is not as big of a deal. It's cheaper and it's only meant for off-road. I wouldn't recommend driving it on the street though. It's the same reason 4 wheelers tear up when street driven. Just not meant for it...

If you change over to any of the more common rear axles -- Ford 8.8, Ford 9, or my favorite Toyota 8, you have a wide assortment of LSDs and spools available, typically for less $$.

BTW -- another advantage of spools is that they create less heat. All that friction inside an LSD can cause issues during longer races.

The OP was asking what a welded diff was, not that he was going to do it.

That's the exact opposite of what I've heard and seen. Weld the side gears to the case. Weld the spider gears to the case. Weld the gears to each other. Stick small squares of metal and weld them to all four gears. Make it as solid as possible, since any relative motion is what is needed to allow forces to start breaking things. (If I'm going to hit you with a hammer, wouldn't you rather i start with the hammer pressed against your skin, instead of holding it away from you?)