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Discussion Starter #1
Hi all
I've bought a B13 Se r race car with an Sr20ve engine and Sr16 tranny. I don't know how it's been done, but the LSD have been removed or disabled for class regulations.
I would like to have the LSD back !!
The car runs great and I haven't opened the tranny to see exactly what's been done.
Is it the differential that's been replaced ?
Can I find a used OEM one that I can put back in ?
Thanks for the help !!
 

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the oem lsd is a "viscous"one, which works a little different to a normal plated one, in how the gears bind to each other. the gears are encapsaluted in this gel (for the want of a better word) which works once its heated up, but most dont last that long (60-100k klms).

options are...weld diff, replace with another oem viscous one, replace with cusco plated diff , or mfactory/quaife helical diff. plated diff wins for racing/circuit. welded cheap option.
 

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Discussion Starter #3
Thank you very much for the reply @sss4me , very helpful informations!

For the oem option, what other transmission shares that same LSD diff and is there someone I could get a good one from?

I wonder how the car would behave in corners if I just weld the differential ? Would it be an issue to the tranny it self ?
 

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in australia, we have APRA (nissan pulsar racing series) which mandates welding the diff, and for racing only, its fine and predictable. only down side is its hard to drive around town, and around slow corners (wheel slip)
the sr16 trans is a RS5F32V, and there are many different ones. jn15 pulsars,autech's,primera's,almera's,sentra's, g20's, all have this gearbox, but ratios are different. it is recognised buy the bulge around the passengers side cv point
1861
 

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Have you verified that the LSD has been disabled? by lifting the front wheels clear of the ground and spinning one side (in neutral) and verifying what direction the other wheel turns?

There are basically 2 (simple) ways that I can think of that will disable LSD, one is to remove the fluid from the viscous section of the diff, the second is to machine the outer half of splines on the part of the CV joint that is inserted into the left side of the gearbox. The second would have been easiest and fastest as it would only require removing the LS axle.

If the second option is what was done, putting in a new or un-machined axle (or just the inner cup) would restore your LSD.
 

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Discussion Starter #7
@yoshoto When both wheels are of the ground in neutral, both wheels spin in the same direction, but once I put it in gear, each wheel turns in a direction.
Now I would need to remove the transmission from the car to open it and find out how it's been done. But what is really holding me from doing this is the hassle I'm facing to find anything for this transmission. It's crazy !! I must be searching the internet the wrong way !!
 

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WHP11 CVT M6
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when you turn it in gear does it turn relatively easily or does it require some force? you will feel a heavy resistance as opposed to in neutral?

u don't need to take anything apart at this stage, other than pull the left side axle out and look at the bit that goes into the tranny

If even they have removed the viscous liquid or some other modification to the diff(which I doubt), a replacement VLSD diff from many other transmissions will work, all u would have to do is swap the final drives, so unbolt the final drive gear and transfer to the donor unit if the # of teeth is different.
 

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WHP11 CVT M6
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look at the pics above, they are both of a left side axle, the top is a non VLSD axle, the bottom is a VLSD axle. we are only interested in the right side of the axle as it is in the pics above, this is the part that goes into the transmission. note the much longer spline on the VLSD axle. this is how it should look on an unmolested axle when you pull it out. What i think they may have done is machine about half of that spline off, not the end bit but more to the left. that entire spline normally engages through the viscous module(equivalent to a clutch pack) and then into the regular section of the diff, if they remove the splines that engage with the viscous section, the diff will act as a normal open diff
 

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Discussion Starter #11
I don't remember seeing the end of my left side axle machined any how, but I will definitely pull the axle out to check again. I have to admit that would be a very smart way to cancel the LSD 👏🤟!
What you've said before about finding a donor VLSD and switching the final drives, is exactly what I was considering but couldn't find anything over the internet.
How do you guys get these parts ?
 

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WHP11 CVT M6
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Mostly used parts, as I said many transmissions including automatic ones use the same diff, so first we need to determine how the VLSD was disabled and then seek to find a solution, the viscous pack is a replaceable item as well and you may be able to get this new.

Used Gearboxes or Auto Trannys like the RE0F06V (CVT) carry the same diff, also the older 4 speed transmission like RE4F03V, same diff, u should find those throwing away all over. typically an auto Tanny or gearbox of similar year range would carry the same diff, the V code at the end of the tranny part number denotes Viscous LSD as opposed to an A or B code which is open diff.
 

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WHP11 CVT M6
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"when you turn it in gear does it turn relatively easily or does it require some force? you will feel a heavy resistance as opposed to in neutral?" what is the answer to this?
 

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WHP11 CVT M6
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Based on that nugget of info my guess is they never actually disabled the VLSD, so u have nothing to worry about. U have taken 30 mins of my life that I cannot get back and lead untold readers of this forum on a wild goose chase. :)
 

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Discussion Starter #16
Trust me Yoshoto,
The LSD is disabled on my car.

1) That car have passed manny inspections to race in a category where LSD is not allowed !

2) Once in gear, the wheels turn to opposite directions.

3) When I smash the Throttle in second gear, it pulls violently to one side at a time. You have to really hold the steering wheel strong to keep the car straight.
I would like to share the videos of my last drag race against a Toyota MR2 so you could see how he left me at every start and how just one tire was spinning. I really had to work hard to catch him back before the finish line.

Is there a way to upload the videos here ?
 

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WHP11 CVT M6
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"2) Once in gear, the wheels turn to opposite directions." The VLSD will do this(because the ring gear is effectively locked), but it is hard to turn, you are turning against the friction of the viscous fluid, else the engine would have to turn in gear (usually in first gear) the ratio is high so u would be wanting to turn the engine at a high RPM. An open diff turns really easily. Viscous and clutch type LSD's don't prevent the wheels turning opposite like helical or mechanical LSD's in general.

So its either the VLSD fluid is worn, as before mentioned by sss4me, or they partially drained the fluid from the pack, it is a very thick sticky fluid and would be somewhat difficult to drain out completely without solvents.

I guess your option now is to get a replacement & open up the box.
 

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Discussion Starter #19
I might be able to find an RS5F70V JDM P11 Primera tranny.
Does anyone know the gear ratios it comes with ?

Thanks, couldn't find it in the search!!
 

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WHP11 CVT M6
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Not sure of the actual numbers but its a better final ratio, and some differences in the other gears to take advantage of the higher torque of the 2.0 motor. There was some info on these gearboxes but maybe on the other forum, the dash. Nevertheless it would be a better match to the sr20ve than the 16 gearbox as well in the lighter chassis.
 
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