Anyone ever welded the spider gears together or know what i am talking about tell me the pros and cons to doing it.

P.S. I am making a pavement oval track racecar

 

i wouldnt do it unless your making a strict drag car. wouldnt it create alot of oversteer in a turn?

 

oh yeah both rear tires always spinning at the same rate=rears cutting loose real easy

 

breaks fast too if used on the street

 

People do it have have been doing it all the time, for dirt and paved oval track/road course.

 

Decreased turning radius. Outer tire squeeling on sharp turns. Overall......dont turn. Go fast, turn never.

 

 

My diff might as well be welded. If any power at all is being applied while making a sharp turn, it bucks and chirps and generally hates its life.

Shoulda seen the time I tried turning around in a wet parking lot last month. I thought I'd be a cool guy and just spin the car around. My "spin the car around" was still calibrated for snow, though, so what happened instead was I executed a very wide 180. Steering wheel at full lock, front tires shuddering over the pavement.

Didn't stop laughing for hours. The cute girl at the used computer parts store musta thought I was *nuts*.

 

would welding the spider gears be bad for the drivetrain and cause some early wear and tear?

 

dont think so, people have been doing it for years, since the days of big block engines, seems like someone would have said something by now if it was very bad for the Drive train

 

Not RX-7 specific but in general (especially with FWDs!) if you try to back up and turn sharply at the same time you greatly risk snapping an axle.

Yes it's bad for the drivetrain, specifically the axles.

You also need to make sure you weld it well. It's tricky because you NEED to make SURE that the side gears are positioned properly, not cockeyed to one side or the other. Normally they self-center, but when you weld... Anyway, welding: Of course you'll be welding the teeth of the side gears and spider gears together, but you also want to weld the side gears and spider gears to the diff housing as well. Don't be shy with the MIG - big huge welds are your *friends*.

 

peejay, check the differential link in my sig for a solution to your diff grabbing in low speed corners.

 

Skip the mig, go stright for some big *** sticks and stick weld that ****.

your gauranteed to get some good penetration that way.

I had my pops stick weld mine on my (gone now) black 14 sec rex

 

So.....will it make me faster around the oval track or slower or the same??

 

depends on your driving, I know some guys that can pull a welded diff through the oval, and sometimes autocross tracks at amazing speeds, I know some that spin on the first try, when in doubt find a spare diff in case you hate it or it pukes the weld and busts the gears only seen it once, but still, b safe

 

Im not familiar with the 7 diff. But would you not be able to just weld up the side gears like this?

http://www.redhavana.net/files/gear.jpg

 

I started with the open end rear end , not an LSD unit

 

I did it in a ford 9 that i have in my 81 7 but i eat up tires like crazy..also when you turn the axle on the inside is constanly snapping back since it is slowing down while the aposing tire is speedign up..

For drag racing its a cheap mod..but for road racing i do not recomend.

 

It will end up cracking over time. 14bolt guys were doing this a couple of years ago as a temporary traction aide untill they got a locker. Everyone who I have herd that left it that way eventualy broke the side gears...and thats with 4 spider gears. Its best to just weld it solid.

 

This is not true for a RWD car. However it is true for Front Wheel Drive. When backing up you transfer most of your weight to the front wheels. When a CV or U-joint is at an angle (like when turning) it sees alot more stress (side loads). Wheelers break front axle u-joints all the time by doing this.

Durring normal use its not that much harder on things. But when your realy hoging on the throtel you will have alot more traction and therefore could break things easier.

 

Well, first the pros:

-Greater straight line traction

Cons:

-Excessive rear and possibly front tire wear
-Excessive stress on rear axles
-Annoying squeeling going around corners
-Larger turning radius

Overall, its not worth it for a street car. I would be cheaper just to go with a real LSD in the long run. But for a drag car, or circle track car, it is a great solution to an LSD.

 

I did mine strickly for drag as well.
And sure I would still drive it on the street once and a while and the rear end would make a really cool squeel going around the "Michigan turn arounds" .
BUT...... I could not drive in the snow, and I usally wouldnt make it too far in the rain either.

The rear end just tries to "dog walk" off to the side of the road, unless your roads are perfectly straight which most are not to help rain and such run off to the side.

 

Here is a quick little search over on Pirate4x4 that gave be 102 threads on welding diffs.

http://www.pirate4x4.com/forum/searc...searchid=63574

I have a welded 14bolt in my wheeling rig and love it. I have been toying around with the idea of welding my gears in my RX7. Will probubly start this season and see how it does open.

I would say that if alot of people use spools in the type of racing you do than I would weld it.

So what does a shifter cart use in its rear axle...how about F1 or Champ Cars?

 

My only gripe with the diff is that it is not tight ENOUGH. I still spin one wheel sometimes.

"A LSD is only useful since it acts as a fuse to prevent the axles from breaking"

 

F1 use a LSD. A very expensive, complicated and sophisticated one, but definitely not a locked rear end.