building a bullet proof dif?

[moturbopar]

Hi all, I have done some searching, but havnt found exactly what I need. Anyways I need a diff that is going to stand up to quite abit of power, but have heard that the stock lsd doesnt support that much power.
I guess I should explain what I need first, I do not plan on running slicks, but do plan on running stick street tires, I am hoping the engine will make over 500rwhp and up to 600rwhp. The car will be an automatic (sorry non toyota engine and trans) So it wont be as tough on the rear as a 5spd. So can the supra rear be built up enough to handle this, or should I look at swapping in a dif from another car? Also how much HP can the stock CV joints and axles handle?
Thanks
Shawn

[3000cc MK2]

stick a four link ford 9" rear end if you are gonna be sticking a 2.2L / 2.5L mopar turbo engine

[Donn29]

i would just go with a diff from whatever you took the engine from, what eninge/tranny is it?

[williamb82]

the truetrac lsd holds fine and the stock cv's have taken lots of abuse. wish russ m would have let us know if he had stock cv's or custom units when he was running 9's
william

[moturbopar]

Hi all thanks for the replies. Actually the engine and trans are a turbocharged 283 SBC modified LT1 EFI and a th350, I know its bastardizing the car, but I bought the car originaly for the 5mge for a land speed project, then figured why wast a good body. Anyways I was thinking of putting a solid axle in but not sure how much trouble that would be on this car. If I keep it independant I have been looking at using the rear section out of a ford SC thunderbird. They have a 8.8 limited slip and alot of aftermarket support.

[Funkycheeze]

those axles and CVs are basically the same design and size as the ones from mk4 - go ahead and try to blow them up =D

as for the diff, with a truetrac and a good rebuild, it will take alot of abuse - alot depends on the gearing of 1st in the transmission you are using, and the stall of the TC

[SupraFiend]

those axles and CVs are basically the same design and size as the ones from mk4 - go ahead and try to blow them up =D

not really actually. But you never hear of anyone killing mk2 axels.

[Funkycheeze]

i mean in terms of size of shaft, not length (they are a tad thinner) and CV style

[Norbie]

I strongly doubt the stock diff, even with a TrueTrac, will last long with 5-600hp at the wheels. If it was me I'd think about converting a MA70 diff with custom axles. Not cheap but it should take the abuse.

[Donn29]

<---- thought they used the same diff in the ma70, but mabye not eh? is that why there is a higher top speed(200kph versus 220/230), or that 7ms rev higher.

[BillyM]

7.5" in ours

8" rear in the ma70

iirc...

--BillyM

[supra_toy]

What would you say is the limit for the stock diff rebuilt with the true track?

[Funkycheeze]

all depends on the TQ multiplication from the transmission - but i'd say after 600 ft-lbs at the crank and a W58 you are definetly pushing your luck

with an auto it would be more, as they tend to have a taller first because of the multiplication from the torque converter, and they tend to be easier on the driveline as a whole

[williamb82]

ok, well, at 30-40mph i will put it in second gear, rev the engine to redline and drop the clutch and smoke the tires. this is with a 3.727 w/true trac, and a r154 and 7mgte. ive dont this many many times and the dif doesnt even make the slightest bit of noise. dropping in second like that is flat out abuse. i doubt with slicks and an auto he will shock the diff more then that.
william

[BillyM]

William, I'm going to have to report you for diff abuse... Get your diff into a safe-house or something along those lines. It can chill with the rest of the battered diff's from around the world.

--BillyM

[SupraFiend]

i mean in terms of size of shaft, not length (they are a tad thinner) and CV style

The shaft diameter is the only similarity then. The actual CV ends are very different, they use many more bolts on the ends. But still, the diffs will go long before the axels

[3000cc MK2]

that is right... the MKIII and MKIV has a different CV assembly that uses a bigger casing ofr the ball bearings...

[Norbie]

FWIW I've had my TrueTrac for almost a year now. The 2JZ has killed two gearboxes in spectacular fashion, but the diff shows no signs of being unhappy. I "only" have 305hp at the wheels though.

[moturbopar]

[moturbopar]

Thanks guys. I think I am going to try rebuilding the diff with a true track and see how long it will last. if it breaks I will probably swap in a solid axle.
I do have another question for you guys thogh. What is the tallest gear you can get for the supra diff? I would like to find something in the 3.25 to 3.55 range. Is there anything close to this?
Thanks

[Norbie]

Tallest I could find was 3.5 or thereabouts... if you can find a source for a taller ratio I'd like to know, I'd really like a 3.2!