OBX Positraction Testing

[jawsgear]

If you have been following the OBX thread on SF, here are the results. Not good from my standards. We never even got to test the unit at the track here in Sacramento due to rain and multiple OBX dimensional problems.

1. The thickness of the ring gear flange is approximately .250" thicker than the stock flange. This is an issue due to the fact you have less thread engagement for the ring gear bolts.

2. The carrier shim combination is WAYYYYYY off. It does not even come close to setting up with stock shims. We ended up using about .275" on the right side and .060" on the left side. Would work but is really hoaky.

3. The major problem is the fact that the stub axles bottom out on the splines before the snap ring engages into the side gear, thus the axle slides in and out by hand. I believe they did not machine the snap ring groove into the correct location.

I am going to make some calls next week to see if there are any options to correct some of these issues. Until then we will NOT be installing into any car for testing. As is, on a scale of 1 to 10 I would rate this about a 3.28654 as is. If the changes can be made we will make a 2nd attempt at an install and actual road test. Matt(guy with the 1J) was extremely disappointed as he made a trip down from Portland OR just to try and break it. Maybe next time Matt! HaHa!

Jeff

 

[gixxer750]

glad to know you are trying to open up more options for us. Nice car BTW.... Hope you aren't putting one of those straight axles on the floor in it...

 

[Justin727]

lol good to hear. keep up the great work and thanks for the support and updates

 

[williamb82]

man, too bad you guys cant mod the truetrac to work. i got one in my 7m mjii and that thing is great. tried busting it and havent been able too and lots of people well over 400rwhp abusing it with no issues either. and thats just a 7,5in, the mkiii is a 8in.

 

[IJ.]

Will: You ever driven a JZA70 Torsen and if so how does the TruTrac compare?

 

[jawsgear]

Well Dr. Jones has informed of two different axle lengths between the MA70 & the JZA70 Differentials. We will be trying the JZA70 axles in the OBX to see if there is any difference. Follow up later today.

Jeff

 

[jawsgear]

New update:

Well after we overnited some parts from Okinawa! haha just kidding!

We installed the JZA70 stub shafts which are longer as Dr J informed. Still a problem with the snap ring groove. The stub axles do engage into the snap ring grooves but the seal surfaces stick out too far and do not allow the seal to ride on the stub shaft. In my opinion it can be fixed with some machining. The other problem this makes is that the stub axles push out further on each side make the overall width from axle flange to axle flange to be approximately 1/4" to 3/16" wider. This could be a prblem when you are trying to get the CV shafts bolted back in. I am going to purchase some new seals and offset them on the housing to get engagement with the stub shafts and we are going to attempt to bolt this thing in and maybe get a couple of street pulls as I do not think we are going to make it to Sacramento Raceway today due to the problems. Will keep you posted and hopefully have some video to post later. Thanks.

Jeff

Photo of LH Side Stub Shaft

 

[oneandgone]

[/QUOTE]

That's Duane's car isn't it? What's that doing there?! Hmmm......

 

[mattonedime]

No no.. we just liked Duane's car so much we decided to make a stunt double. :topsecretsmiley:

 

[jawsgear]

Well nobody in Sacramento had new stub shaft seals on the shelf. Had to order a set from Toyota. They should be here on Tuesday or Wed. Will attemp to get the diff installed as soon as they come in.

Jeff