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Discussion Starter #1 (Edited)
*Disclaimer- I do not work for or am affiliated with the vendor who makes this LSD upgrade kit. I simply wanted to be the guinea pig to try a lower cost option for an LSD upgrade*

I had looked at the AMS and Z1 diff upgrades and it seems like they were pretty expensive and in some cases required a core or shipping your center section back, so I began researching alternatives. I found a post where someone confirmed that the rearend in our cars is called the "R190" which has been around for quite some time in 1 form or another. When I searched for R190 LSD, I came across a company called Traction Concepts. They've been around for quite awhile in the racing scene (auto-x, rally, drag, etc.) and sell plate style upgrade kits to convert the 1 tire fire into an LSD for $350. They are made to fit inside the existing diff and apply spring pressure to the gears to keep both wheels turning when torque is applied, but still act like an open diff when there is light throttle or tight turns like in a parking lot. Being that you use the same ring/pinion gears, you don't have to worry preload/backlash/break-in etc. Install and go! I talked at length with their engineer who actually stated how robust the R190 rearend is, particularly with this upgrade. He said he has no concerns with 500/600/700 hp. Here is the process for the tear down and pics of the installed upgrade......
 

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Discussion Starter #2 (Edited)
Flikr won't let me embed pics, so attached below.

Boy it helps having access to a lift! Here is the view from underneath prior to teardown:
*1st pic*
Make sure the car is in neutral and the parking brake is off.
Begin by taking off the mid-pipe and 2 heat shields along with the cross member.
There are 2 braces- 1 on either side of the diff that must also be removed. Take off the rear sway bar.
Support the rear diff
Mark the rear prop shaft rubber coupler and the final drive companion flange- you must put these back with everything lined up to these marks. Do NOT remove the rubber coupler from the prop shaft. Once its marked you can remove the 3 bolts and gently pry the prop shaft forward to loosen it from the final drive companion flange. Loosen the center bearing mounting bracket on the prop shaft towards the transmission end of the prop shaft. This will allow the prop shaft to slide out of the front of the differential.
*2nd pic* /*3rd pic*
There are 2 large bolts on the bottom of the diff that need to be loosened and 1 horizontal bolt at the top of the diff that must be removed. Support the diff and lower it slightly so you can better access the 2 wheel speed sensors and diff vent tube that must be disconnected.
Get a pry bar and gently pry each of the CV axles out of the diff. There will be tension here so take your time and don't damage anything.
Get that that baby out!
*4th pic*
 

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Discussion Starter #3 (Edited)
Once you have the diff out, drain the oil and start breaking it loose. There are 6 smaller bolts and 4 larger bolts and then just split the 2 halves apart.
*Pic 1*
We took off the ring gear after marking its location so it went back exactly in the same orientation. Here are the machined axle/pin gears.
*Pic 2*
Machined gears back in:
*Pic 3*
LSD upgrade installed with machined gears
*Pic 4*
NOTE- You MUST remove the 2 clips and 4 dowels after the LSD upgrade is installed in the diff. This is what allows the upgrade kit to do its job and let the spring tension push against the gears.
 

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Discussion Starter #4 (Edited)
Once you've got he diff back in the housing, clean off all the grease and dried RTV and put down a light bead of new silicon/RTV. You'll probably have to use a rubber mallet to get the cover back on the diff housing.

Reassembly is the opposite of disassembly. Make sure the CV axles are pushed in all the way and that the C clips were still in place on the axles when you press them back into the housing. You'll have to play with the diff angle and height to get them to slide back in but its not bad. You can reuse the oil seals if they're in good shape.
*Pic 1*
We got the diff back in and used a pump to refill the diff.
NOTE- The service manual says to fill with 2 1/4 PINTS of oil. We ended up with more like 3 pints (1.5 qt) until it dripped out of the fill plug.
Make sure to reconnect the wheel speed sensors and diff vent tube.
 

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Discussion Starter #5 (Edited)
Driving impressions- once we got the car off the lift, I backed out and expected to hear some noise turning or something. NO SOUND. It's like we never did an upgrade at all. Traction Concepts states to take it easy for the first couple hundred miles as well as long slow figure 8s in an empty parking lot so that the kit embeds and "gets to know each other". I did give it to light launches and immediately noticed the sound of TWO tires spinning! I also hit it from a low roll and did NOT get wheel spin which is new to me. So far so good! Once I get a couple hundred miles I'll be comparing the 0 to 60 in the jb4 as well as going back to the drag strip to compare 60ft times.
 

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Was going to say you could just edit your Original post but it is probably easier to format sections if they are all separated, that said kudos to you sir
for giving it a shot it will be interesting to see if an affordable LSD modification is achievable.
 

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Thanks for putting in the work to get the community a deal. I put one in my prelude trans and it worked well for the price, withstood many 4k launches, but I was always concerned about the wear it was doing to the hub and gears. It's not a true helical or clutch lsd, and I would be concerned with introducing any extra metal shavings into our weakest point of the drive train. Just my .02
 

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This is awesome!!!

Thank you for being the guinea pig and trying this out. Will look into this, if only so I don't go sideways everytime I jump on the throttle.
 

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Discussion Starter #9
Thanks for putting in the work to get the community a deal. I put one in my prelude trans and it worked well for the price, withstood many 4k launches, but I was always concerned about the wear it was doing to the hub and gears. It's not a true helical or clutch lsd, and I would be concerned with introducing any extra metal shavings into our weakest point of the drive train. Just my .02
I was hesitant myself but after talking with them I felt much more comfortable. They have used these in plenty of makes/models with over 500,000 miles of racing abuse and he specifically said the R190 is NOT a weak link with this upgrade, it's actually robust. He also said he doesn't have a power number where he would be concerned about this LSD upgrade. I guess we'll see how it goes!
 

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So this is basically a phantom grip conversion for the diff?
 

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Discussion Starter #12
So this is basically a phantom grip conversion for the diff?
I believe they are similar in style. I'm taking the car out in a bit and will update my "impression" post.
 

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Just make sure to change the diff fluid after a few 1000 miles. That should get rid of the crud the gears polishing in will cause. They look like they need to "work in" some by looking at your pictures.
I'm going to change mine soon as well. That and my transfer case fluid and replace with full synthetic Nissan fluid in the TC and Motul synthetic in the diff.
 

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Discussion Starter #14
Just make sure to change the diff fluid after a few 1000 miles. That should get rid of the crud the gears polishing in will cause. They look like they need to "work in" some by looking at your pictures.
I'm going to change mine soon as well. That and my transfer case fluid and replace with full synthetic Nissan fluid in the TC and Motul synthetic in the diff.
I updated my driving impressions post. I agree about changing the fluid once everything has gotten to know each other lol. Also considering a thicker oil since I live in a hot climate.
 

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I personally am interested in doing this to my 2015 Q50 3.7.

I don't have the mechanical aptitude to pull this kind of job off myself. Any idea what a shop may charge to do something like this? Or any tech days in the Central Texas area I can attend and get hands on experience with somebody experienced with this sort of thing?

Thanks in Advance.
 

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3-4 hrs probably. So what ever the shop rate is X 3-4. (My guess)
 

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Discussion Starter #20
Pulled a tenth off my best 0-60 (including at the drag strip with no wheel spin) on unprepped surface today by messing with how it shifts and the new LSD...
 
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