OBX Helical LSD
06-24-2011, 10:30 AM
#181
Well I'm happy to report that after an hour and a half of beating on this thing doing donuts, drifting, 4k launches (Rotrex'd and it's about 4PSI at 4K) and lots and lots of twisty roads it is doing great. It locks very well and much better than my old Maruha and I might even say my old old T1 Torsen. I'll be taking it to a hillclimb this weekend and will report back after then as well.
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06-24-2011, 10:33 AM
#182
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Join Date: Aug 2010
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Hmmm - Okay. 
I will admit that my understanding of the TorSen is pretty rudimentary - While the car was on axle stands, it behaved like an open diff when I checked it?
As for the 'box - The ratios on the 6 speed are different, and I understand it has a 3.9 diff instead of a 4.1? (Which I guess the OBX diff is?)
I will admit that my understanding of the TorSen is pretty rudimentary - While the car was on axle stands, it behaved like an open diff when I checked it?
As for the 'box - The ratios on the 6 speed are different, and I understand it has a 3.9 diff instead of a 4.1? (Which I guess the OBX diff is?)
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06-24-2011, 10:50 AM
#184
Want fries with that?
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Location: Twin Cities, Minnesota
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Hmmm - Okay.
I will admit that my understanding of the TorSen is pretty rudimentary - While the car was on axle stands, it behaved like an open diff when I checked it?
As for the 'box - The ratios on the 6 speed are different, and I understand it has a 3.9 diff instead of a 4.1? (Which I guess the OBX diff is?)
I will admit that my understanding of the TorSen is pretty rudimentary - While the car was on axle stands, it behaved like an open diff when I checked it?
As for the 'box - The ratios on the 6 speed are different, and I understand it has a 3.9 diff instead of a 4.1? (Which I guess the OBX diff is?)
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06-24-2011, 11:11 AM
#185
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Join Date: Aug 2010
Location: 70% London / 30% Scotland
Posts: 17
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My car's a '99 1800 RS - A JDM import, and they had them as standard from the factory. (That said, gawd knows what's been done to it over the past 12 years!!)
Believe it or not, this is my first RWD car with a (supposed) LSD - My Elise didn't have one (none do - It's an option for race cars), and neither did my Caterham. Most cars in the UK seem to be FWD...(!)
Hence the noobness - Back on topic!
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06-24-2011, 11:19 AM
#187
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TorSen = Torque Sensing, with both wheels off the ground there's no torque therefore the diff acts as open.
Trust me your diff is fine, that LSD test is used in error a LOT on a TorSen.
Trust me your diff is fine, that LSD test is used in error a LOT on a TorSen.
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06-24-2011, 11:22 AM
#188
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Join Date: Aug 2010
Location: 70% London / 30% Scotland
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As above, apparently the 6 speed box has a different ratio LSD to the 5 speed - In my ignorance, I didn't realise that it was the ring / pinion which determined this ratio and was interchangeable - It's the first car I've owned with an LSD fitted, so I've got a bit to learn it seems... 
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07-11-2011, 03:03 PM
#191
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Join Date: Oct 2010
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So I took my diff apart, deburred everything (gears installed correctly, had 12.9 grade bolts, but the belleville washers were complete junk) and bolted it back together with loctite 242 to 35 ft-lb.
Inspecting it on a crankshaft balancer, I found that the ring gear flange is out 0.007" in concentricity and about 0.005" on the ring gear mounting surface (with respect to the thrust bearing surfaces.) FML
I'm considering just installing it and messing with the ring gear orientation to see if i can get the backlash in spec. Any insight there?
Inspecting it on a crankshaft balancer, I found that the ring gear flange is out 0.007" in concentricity and about 0.005" on the ring gear mounting surface (with respect to the thrust bearing surfaces.) FML
I'm considering just installing it and messing with the ring gear orientation to see if i can get the backlash in spec. Any insight there?
To follow up: I finally installed it after avoiding it for months. I decided to just install it regardless of the ring gear flatness.
Backlash: I got it to .002" backlash at the high point, 0.006" backlash at the low point (spec is 0.0036 - 0.0043 i think.)
It drives fine, can't feel any ill effects of the goofy backlash. With the top up i can hear some quiet rear end hiss/whine that wasn't there before, but it hasn't gotten louder and isn't cyclical-sounding.
It does appear to lock really well. I haven't been able to drive too hard yet but I can tell it's working fine. Off the accelerator, it turns in like an open diff, under power it locks up the rear end as expected. Haven't gotten any 1-wheel-peel yet.
I'll keep you all updated if anything changes or explodes
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09-03-2011, 01:26 PM
#192
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Join Date: Oct 2009
Location: The Netherlands
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I ordered one. I also ordered the washer/bolt kit and bought a 1.8 diff + shafts. I will install it this winter and might find some time to put the turbo on too.
Small question: I got the 1.8 diff from a NB with the shafts that slide into the diff. From what I understand these are 5mm wider. Do I need the uprights too?
Small question: I got the 1.8 diff from a NB with the shafts that slide into the diff. From what I understand these are 5mm wider. Do I need the uprights too?
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01-08-2012, 11:35 PM
#195
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OP sold the car to me. The car has been off the road for a few months but all throughout the summer and for the couple times I autocrossed it, the LSD has been holding up awesomely. The car has been driven pretty hard with no signs of the LSD giving up - and thats on turbo power
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08-05-2014, 12:55 PM
#199
First of all, I apologize for the Necro Bump...
..but I'm looking for any feedback from the last three years on people using these OBX LSDs. I'm trying to sort out what I want to do with my open diff, and dropping $500-$700 on a 150k (or unknown) mileage torsen doesn't seem smart if these OBX diffs are up to the task.
They can still be had all over the internets for about ~$360 shipped. Looks like the previously posted hard-ware upgrade is still available, or they can be had from this place: OBX Ltd. Slip Differential They also offer to inspect the diff and preform the upgrade for a $175 premium.
Thoughts? Torsens in decent shape seem to be getting harder and harder to find and a Giken totally blows away my budget.
..but I'm looking for any feedback from the last three years on people using these OBX LSDs. I'm trying to sort out what I want to do with my open diff, and dropping $500-$700 on a 150k (or unknown) mileage torsen doesn't seem smart if these OBX diffs are up to the task.
They can still be had all over the internets for about ~$360 shipped. Looks like the previously posted hard-ware upgrade is still available, or they can be had from this place: OBX Ltd. Slip Differential They also offer to inspect the diff and preform the upgrade for a $175 premium.
Thoughts? Torsens in decent shape seem to be getting harder and harder to find and a Giken totally blows away my budget.
Last edited by Scrambles; 08-05-2014 at 11:44 PM.
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