Engineer

So my car makes about 350hp and it has a stock GXL rear end. MY tires are stock size, so I figured that fuse would save me for a while.

Yesterday, I peeled out from a stop, got some tire spin and a BANG from the rear. The car just started coasting. The engine revs fine and the trans shifts ok. In third I can get the car moving, but it seems like most of the power is lost, or just spinning something.

MY first question is, do you think it is my diff or maybe cv joints or outer hubs? Something is spinning and not moving torque.

My second question is, what is the best rear end I can build while staying with the rx7 rear suspension. I don't want a solid because this is an autocross car.

Thanks!
Tom

rxmclaren7

find a t2 rear and upgrade the cv axles. i think the driveshaftshop.com has some dont quote me though!! and get a good quality diff. here is one i found hope this helps!!

http://www.horsepowerfreaks.com/pric.../Differentials

and the link for the axels

http://www.horsepowerfreaks.com/pric...ivetrain/Axles

theflatlander

iTrader: (3)

http://www.carbonetic.net/- they have some of the best diffs period.

RX7Tuner.

I am a little confused. You are making 350hp and have a gxl rear end? A GXL is an N/A diff. You either have a 350hp N/A (if this is true than you should have more than enough techinical know how to figure this out yourself) or you built a 350hp car and made a custom driveshaft to accomodate a weaker/inferior N/A rear end. Niether of these senarios make any sense.

Sorry to hear about your car. No one is going to be able to tell you what happened based on your description. You would be better off looking under your car (maybe on jack stands) and finding out within a matter of minutes.

Good Luck,
Brian

MaczPayne

iTrader: (5)

You blew up the diff. Upgrade to TII diff.

Engineer

I have a V8 in my N/A GXL chassis. I always assumed I would run into this problem, I just finally have. I'm wondering what this best thing to do is. I have a custom drive shaft right now, but could make another. Is the answer simply getting a Turbo II rear and swapping it in? Or is it a completely different size, bolt pattern etc? Will my drive shaft fit? Do I need to upgrade the axles and CV joints?

thanks, you guys know everything!

Tom

P.S. I know how most people here feel about V8's. I don't mean any disrespect, it is just the way I ended up going.

marcus219

get a TII rear end

cb07

You threw a rod for sure.

Jk.

RX7Tuner.

The TII rearend will swap right in but you will need TII halfshafts as well. What tranny are you using? You will probably have to fab up a driveshaft that fits your tranny and on the other end fits your TII rear. I am amazed the GXL diff held up at all. I would have thought 350hp would shear it in half the first time you mashed the pedal.

hatemy7

im pretty sure u just blew ur rear end, but get a TII rear end and u will feel faster

RockLobster

iTrader: (7)

"BANG" almost always means rear end....

Engineer

I have a T56 6 speed transmission and a custom welded drive shaft. Right now, the GXL rear bolts up fine. Is the TII rear going to require any modification to the drive shaft if it fits ok now (ie: is the input the same bolt pattern and length)?

Yeah, the GXL rear lasted a few weeks and I wasn't too hard on it. I also assumed my little tires might save it.

thanks a lot for your help guys!

Tom

Syncro

iTrader: (1)

I think you're going to need to fab another driveshaft this time too since the NA and TII units on stock cars are not interchangeable.

Engineer

Nothing is ever easy, you would think I'd learn by now. I guess I'll plan on a Turbo housing, drive shaft and half shafts.

By half shafts, do you mean the two axles and 4 CV joints?

boost_its_what_for_dinner

why would you have to change the drive shaft? the actual diff. is the same just the insides and shafts are different? i would assume

NoDOHC

The drive shaft is definately different: Weight, diameter and bolt pattern.

I think that a TII is good for about 300 lb-ft at the flywheel and a transmission with a reasonably tall 1st gear.

I have a friend who got by for 2 years on a GXL differential, finally lost it after upgrading to 235 width tires (302 Ford V8.)

The Turbo II diff is pretty good, I know two V-8 Rx7 owners with Turbo II diffs and 2 or 3 years without trouble.

Most people won't yell at you for what engine you chose to put in YOUR car. (There are a few.)

BogusFile

Hello there,
I had the same thing happen in my V8 swapped 7. My set up was as follows... Chevy 350, powerglide, and a 3.90 automatic rear end. My rear diff gear broke at a roll, and the symptoms were very similar to yours. How was your differential mount? Did your car give you a nice jolt when you shifted from park to drive/reverse? Thats what usually kills them. If your car is automatic you should be just fine with another GXL rear end.... you may even want to go with the 3.90 to give yourself a little extra gear. Just remember to replace your (front)rear differential mount.

Whoops didn't notice that you had a t-56 tranny...... your gonna need that T-II rear.

Engineer

Thanks guys, I will begin the search for a TII rear end and half shafts. Grant at Grannys Speed Shop (made my drive shaft) says it will work if I drill some holes in the flange.