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RenaissanceMan

What should I NOT be doing with a subaru trans?

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"What should I NOT be doing with a subaru trans?"

"(btw this is a 2wd 5sp)"

 

Ummmmmmmm.... You should be NOT driving in 2wd! :lol:

 

Seriously, tho.. Clutch drops, Burnouts, full throttle transitions from dirt to pavement, etc... lol Anything that shock-loads your trans.

 

<<I speak from experience...:-\:clap:

 

88RxTuner

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Sorry, I should mention this is for a dirt track car and someone who is determined to stay in the Fwd class. LOL, believe me I am scared myself. I can imagine CVs will go as frequently as oil changes.

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if its on dirt, wouldnt turning just throw clods of dirt instead of eating axles. or would it literally eat axles due to the bind. I would think the tires would loose bite and throw dirt before the axles.....:rolleyes:

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I wonder if welding the diff is going to cause the car to push really badly in the turns? Might be better if you could figure out some kind of lsd rather than welded solid.

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Please, excuse my ignorance... but let me Ask: What is the Idea / Purposses of a Welded Diff and what are the Advantages?

I Believe it is intended for Off Road use, isn`t it?

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Yup purely for offroad use. Its useless on road. Its basically a poor mans LSD...but never lets go lol. Hes planning on dirt track racing with it though so road manners are the last thing on his mind. Keep us informed. Sounds like fun.

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I really don't think that will work well. The inside tire will not slow at all in a turn so you will be pulled straight off the course....unless it's straight line drag racing in dirt...

 

But I've never tried it so who knows - maybe in dirt it won't matter so much. I would expect the handling to be very unpredictable - based mostly on how hard or soft the dirt is on any particular day. Welding is great for slow speed crawling and mudding, etc. It's not really a good choice for racing though. Lockers are one thing but you can easily turn them off.

 

GD

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right, locking the front wheels will cause the car to want to go straight under acceleration. If this were rear wheel drive it would work better because you can pitch the car sideways easier. I dont think that there is enough rear adjustment to overcome the pushing tendency. I will admit that all my dirt track experience is in rear drive cars, but I do have pavement racing experience in front drives. Lsd will give you better forward drive while still allowing you to turn in under power. You would have to slow way down to turn in with no front diff, and while you should be able to accelerate hard out of a turn I dont think you would overcome the slower entry speed. I am interested to see how this would work in actual application not just in theory.

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if the axles hold up keep your foot in it all the time.it understeers like no other when you let off,It will have very good turn in however when on the gas.Turns have to be taken a little differently.Come in like you are doing a scandinavian flick,flick the car where you want it to go and try to smash the pedal through the floor.You might have to experiement abit with that to get the right amount of flick.

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From what I have been reading, as long as the gears are welded properly (which they will be) then results have been good. The whole thing about "flicking" the car I can totally agree on. Its not that big of an investment so far and its worth trying to see how it performs.

 

There is a race on March 8th that the car will be in from what I understand. Plans are to have the "race" trans in by then.

 

Btw, I was just thinking it would eat CVs cause I know the guy is going to want to sneak it onto the asphalt every once in a while. I'll post results when I have them, on dirt and on tarmac.

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Dont wled the front diffs. This can make the car impossible to control even at low speeds on paved surfaces, and at some point the car will see paved ground. The front wheels have several jobs to do,m and there is no advantage even in dirt tracks to weld the fronts. Now if this was a 4wd I would say go ahead and weld the rears, as all they do is follow the front and you have some ability to control them. A welded front diff can make it very hard to steer the front wheels on anything except wet grass.

 

 

nipper

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At our last RallyX event a guy had welded the front diff on a Nissan Sentra. He said it sucked on pavement, wouldn't turn at all (he tried it just to see what would happen, but it is an off-road-only car that he trailers to races). I watched him in the dirt, and it definitely turned. The FWD cars use the e-brake a lot in turning. (But has this Sub been converted to rear-wheel parking brake?) He said he had to re-learn how to drive it, but it was working. We'll see how he does in the FWD class at the next race in March...

 

Is this Sub an oval track car? If so, they are set up way differently, with tire stagger, so that they always want to turn left (taller tire on right-side). I used to help a friend campaign a VERY successful 4-cyl Fox Mustang at several different tracks. When set up right, the car would turn itself - you had to work to hold it straight when you were on the straights. :)

 

I would imagine with staggered front tires and on dirt, it would turn left well with the welded front diff. I'm interested to hear what happens. :)

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Got the diff back from the welder today.

 

picture.php?albumid=98&pictureid=784

 

picture.php?albumid=98&pictureid=783

 

Looks excellent. For anyone who is interested in the metallurgy of it all...

 

Internals were cleaned with laquer thinner. (not the bearings, thats why they look ugly)

 

using a torch the spider gears were preheated to about 700 degrees. Each joint at a time

 

We discussed the alloy the gears were most likely made of, and decided upon TIG welding, with a filler metal that was a medium high carbon (similar to some tool steels), but with a little bit of nickel and copper alloying for greater ductility.

 

Post-welding was just general insulation for a slow cool rate (normalizing the welds).

 

The theory is that the bearings and stub shafts didn't reach transition temperature. I'll see how they look after I clean them up. If I question the bearings then I'll put on new ones.

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Hey guys, just wanted to give an update on this project.

 

Got the trans resealed and installed. drives awesome!!

 

Going around turns definately requires more HP from the engine, but with a little practice it gets to be second nature to get the back end to swing around.

 

Traction is amazing. If only I can get the engine to run right then we are set (modded the ea82T to fit a TDO4 & 3" downpipe)

 

I will post video hopefully later this week

 

picture.php?albumid=124&pictureid=1003

 

picture.php?albumid=124&pictureid=1005

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You have been fully informed that EA82Ts like to eat themselves, right? Make sure your cooling system is as rock solid as those welds.

 

Other than that, it looks like a blast. :D

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The theory is that the bearings and stub shafts didn't reach transition temperature. I'll see how they look after I clean them up. If I question the bearings then I'll put on new ones.

 

I would have removed the stubs first then welded just the spider gear contact faces. That way you avoid heating them at all, and you can replace them if they break. You have now welded in the stubs into the diff. if you do break one, you will have to replace that whole diff unit, including having the new one welded.

 

Sweet project. I'd love to take it for a few laps in the dirt. looks fun as hell.

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