[Nait Sirhc]

Well, maybe not.

But anyway, like some of you may know, my car has been driving like ass lately.... wouldn't go anywhere, even after the clutch, VCU, and transfer case had been replaced.

The car had been going synchronized w/ acceleration up to around 2000 RPM... any higher, and the RPMs would go up with no more acceleration. Going into other gears tended to fix this problem, and I could get it up to highway speeds.

I figured the back wheels weren't spinning.

So I jack the front wheels off the ground and tried to lay down some power. The front wheels spin (I was going about "60") and the back wheels didn't move at all.

Interesting.

I lower the car and now it won't go ANYWHERE. I put it in reverse to try and get it back into the driveway, and the whole car CA-CHONKS on me. It then has LOTS of power.

So now I have a car that's EASILY as fast as what it was before it broke... but I can burn the fronts all the way to 100 MPH. It's just like my DSM! Woohoo!

I HAVE A FWD CAR! I don't know whether this is good or bad, but at least it works.

I think I may have ordered the wrong VCU from CRS... apparently there are two different models of the VCU for a 93 VR4.

Oh well.

 

[Senlur]

I don't really know much about the drivetrain but it sounds like you're idea has some merit (wrong VCU). By jacking up the car and running it with the front wheels off the ground you probably succeeded in totally killing the VCU (read the BIG orange sticker inside the drivers door ). It would be kinda cool to be able to burn rubber like mad, though.

 

[advr4]

could be the vcu, or could be the output shaft. if you broke the output shaft or stripped the splines the rear driveshaft will not engage, making it a fwd vr4.

 

[KuJaX]

when i get home from hawaii, i'm going to have to see this. Sounds crazy.

 

[Nait Sirhc]

I don't know if my speedometer is working correctly.

Would being FWD cause the speedometer to be off?

I suppose it could just be the fact that I haven't driven it in three months, but this car seems to go a HELL of a lot faster on the freeway... 40-100 goes by in about 3 seconds.

 

[TajMan]

I would image that the car is a bit faster after your tires are already hooked up. The AWD is great for getting off the line, but after you really start going the extra drivetrain loss is a hinderance. Thats one reason why a supra is going to be a little faster than a VR-4 from a roll and up in the high end. You should race another VR-4 from a roll and see what happens.

 

[Master X]

Weird. Sounds like you took a chance in jacking up the front wheels. If the rears worked still it would have jumped the car off the jacks. That wouldn't have been fun.

 

[Grimster]

If the rears worked still it would have jumped the car off the jacks. That wouldn't have been fun.

".....Uhhh.....honey.....I put a hole in the garage again...."

 

[TajMan]

Ferris Bueler's Day Off. Ferrari off the jackstands and out the garage.

 

[sn0man1]

dont remind me, seeing that scene about the fake ferrari taking a dive just makes me wanna cry everytime

 

[Master X]

".....Uhhh.....honey.....I put a hole in the garage again...."

LMFAO!!! Exactly!

 

[Loco3KGT]

doesn't it destroy a VR-4 to spin the front wheels and not the rear wheels. As in, aren't you _required_ to get a flatbed tow truck for this reason?

 

[Mark]

if the front wheels are the only wheels with power you will weld your VCU. Part of it's job is to make sure is to make sure the front and rear wheels turn at the same speed. When you have power to the fronts and not the rears it will continually try to make the wheels turn at the same speed and it will over heat.

If the VCU isn't the cause of your problem (it indeed could be the output shaft) it will likely be a problem now.

There was a decent debate about this before. Search for it as the participants of the debate were Jeff L., Joe G., and Frank M. from Kormex.

 

[Import Power]

Ferris Bueler's Day Off. Ferrari off the jackstands and out the garage.

damnit, you beat me to it

 

[Curt93T/T]

If your rear wheels aren't moving then it's possibly your output shaft and or the sleeve that it fits into in the transfer case. The noise you were hearing was probably the teeth on the shaft itself catching, been there done that.

 

[Nait Sirhc]

Some people have told me it might be the spiders in the diff...

I'm gonna try and get all four wheels off the ground and then rotate each individual tire while the car is in gear, and see which other ones move.

 

[Mad Hatter]

I would image that the car is a bit faster after your tires are already hooked up. The AWD is great for getting off the line, but after you really start going the extra drivetrain loss is a hinderance. Thats one reason why a supra is going to be a little faster than a VR-4 from a roll and up in the high end. You should race another VR-4 from a roll and see what happens.

:stupid: He's still spinning the parts and soaking up the same HP's.

 

[TajMan]

:stupid: He's still spinning the parts and soaking up the same HP's.

Yeah thats the thing. He is having extra drivetrain loss because the parts are still spinning, but it doesn't go all the way through the wheels and to the pavement so its not as bad. You have to remember, the wheel itself is one of the biggest/heavest parts to turn. I'm sure it accounts for a major part of the drivetrain loss.