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Old 04-29-2011, 04:43 PM   #101
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OK i have the car back, and it actually drives!!!! The machine shop measured how far it was out, and it was out .007, not .010, but enough to cause massive problems. They said it appeared that it just missed that part in manufacturing or something. Anyways the differential is super quiet and very smooth, I've done a couple of boosted pulls from 3rd and 4th, but no launches yet. But so far it's doing great.

And it turns out my old differential was in fact an open diff. It's just an open piece of crud with the spider gears. So this should allow me to have way more traction in drag racing, and I'm expecting some good things. It cost me $100 worth of machine labor to make it perfect, so if you want to go this route, consider that cost.

On my way home tonight I'll do a launch and see what happens.
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Old 04-29-2011, 04:47 PM   #102
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technically an open diff gives 50/50 torque to the rear wheels when driving straight.

the torsen operates pretty much the same in that condition.
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Old 04-29-2011, 04:49 PM   #103
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technically an open diff gives 50/50 torque to the rear wheels when driving straight.
Right up untill one tire breaks grip and you do a one wheeled burn-out for 100 feet...
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Old 04-29-2011, 04:51 PM   #104
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true, but on a torsen, if the one wheel starts to spin it has zero traction and cannot transfer torque to the other...one wheeled burned out?

Open diffs supply torque to the wheel with the least traction

Torsen diffs transfer torque over to the wheel with the most traction. It's impossible to transfer torque that's not there (tire off the ground).

I guess in the least you'll have 50% traction as opposed to zero?
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Old 04-29-2011, 05:01 PM   #105
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Theoretically what you're saying is right. But these diffs have been a pretty hot thing with the big HP (500-600whp) Honda guys for a few years for drag racing and they all seem to love them.

I will be using mine on the track, where helical/torsens are best suited.
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Old 04-29-2011, 05:31 PM   #106
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clutch diffs are best for drag, but I'd rather have one wheel with some power, than 1 with zero (no drive) and the other with too much that just spins.
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Old 04-29-2011, 06:03 PM   #107
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Isnt the Type I better for accel locking, and Type II for decel?


but the Type II is quiter and smoother in operation?
If i'm not mistaken, yes. The type II also has nice cornering benefits, but at the limits it apparently has issues with the inner tire slipping too much, which is why the one guy switched to the OSgiken.

As far as I know, its not a hybrid of one type or the other, its pretty standard stuff....
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Old 04-29-2011, 06:41 PM   #108
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TI = hexicoil gears
TII = plane gears
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Old 04-29-2011, 07:18 PM   #109
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Well at the end of the day, the diff is $260, washers and 12.9 bolts cost $35 and install varies depending on your know how. So for some it will be a good upgrade from an open diff for under $300. I'd love to buy a osg but the bank account does not agree.
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Old 04-30-2011, 01:25 AM   #110
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Holy ****, the OBX diff is definitely working. I was turning right down a road and slowed down to low first. I turned the wheels and decided to give it some gas. Couldn't believe how sideways the car got... Then a little farther up the street I came to a stop and turned launch control on. Just as a refresher my car holds at 4500rpm with launch control on and makes 5psi of boost. Sweet monkey jesus I've never laid rubber down like that. There was a party going on in the rear end.

If you have an open diff, buy this. Do it now.
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Old 04-30-2011, 01:30 AM   #111
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**** you and your convincing review. My credit card is trying to bounce out of my wallet.
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Old 04-30-2011, 01:44 AM   #112
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**** you and your convincing review. My credit card is trying to bounce out of my wallet.
Dooo eeeet.

By the way, I've updated the very first post of this thread with the useful information.
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Old 04-30-2011, 02:00 AM   #113
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What did it cost for installation?
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Old 04-30-2011, 02:14 AM   #114
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What did it cost for installation?
It was 4 hours of labour at a transmission shop. With that, the machining, and taxes, it came up to $600.
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Old 04-30-2011, 11:33 AM   #115
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So did you do the polishing/deburring of the case or no? I'd be so interested in buying a few of these and polishing/glass beading and doing the washer mods and reselling them to interested parties. Pretty easy for me to do and I can charge less than a machine shop /etc for labor.

I'm more interested in hearing about your car after 5k miles. Also, what diff fluid are you using?
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Old 04-30-2011, 12:04 PM   #116
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So did you do the polishing/deburring of the case or no? I'd be so interested in buying a few of these and polishing/glass beading and doing the washer mods and reselling them to interested parties. Pretty easy for me to do and I can charge less than a machine shop /etc for labor.

I'm more interested in hearing about your car after 5k miles. Also, what diff fluid are you using?
I did not do the polishing/deburring because I did not think it was necessary. I used Royal Purple Max Gear 75w90 gear oil.
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Old 04-30-2011, 12:20 PM   #117
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I did not do the polishing/deburring because I did not think it was necessary. I used Royal Purple Max Gear 75w90 gear oil.
Cool and cool. It seems it was a discretionary thing, if you saw a lot of burrs/imperfection fix it is what i read. Sounds good, hope the long term test goes swingingly.
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Old 04-30-2011, 01:18 PM   #118
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Quote:
Originally Posted by chance91 View Post
So did you do the polishing/deburring of the case or no? I'd be so interested in buying a few of these and polishing/glass beading and doing the washer mods and reselling them to interested parties. Pretty easy for me to do and I can charge less than a machine shop /etc for labor.

I'm more interested in hearing about your car after 5k miles. Also, what diff fluid are you using?
I'll buy one.
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Old 04-30-2011, 01:21 PM   #119
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Got one sitting on the floor right next to the computer. Guess I'll have to get off my lazy *** and get it torn down.
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Old 04-30-2011, 05:17 PM   #120
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I'll buy one.
Somehow I 100% believe you. maybe i will seriously do this starting next week...

nothin better to do.
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