vlsd max hp?

SON240sx Automotive
1

what is the max hp/torque a stock vlsd diff can handle? From searching I have read that there are ppl pushing over 500whp on stock diffs but what would be a reliable number?

I’m asking because I blew my diff last year and its already happening again. It starts with a loud noise when I’m in gear decelerating anywhere from 3500 to 2000rpm. Last year this just keep getting louder until it was screaming at me all the time until I replaced it.

What other diff options do I have that would be a good for a daily driver? I don’t really want an aggressive 2.0 or 1.5 way. I would like to spend around 500 on something I know will be reliable and last a couple years.

2

I’ve heard of guys running upwards of 400+whp . Truthfully if you want 1.Reliable 2.Affordable a 1.5 or 2 way diff is the way to go. I had a 2 way before in my R32 and then traded if for cash and a VLSD but it’s honestly the way to go. You can usually adjust them to make them less aggressive

3

I’ll second him, about 500whp the rear end gets a bit questionable. Z32 diff is an opiton…

4

I think the main problem is that all the vlsd’s we get now are 15-20 years old. I’m tired of putting another used part on my car and it only lasting a year. This is also why I want to stay away from the z32 as well. I guess I’ll eventually go with a 1.5 but I wouldn’t call that affordable, it will probably be around 1500 to get that set up. I was thinking an s15 helical diff for a bit of a cheaper option but I can’t stand dealing with the japanese parts dealers.

5

It sounds like you’re having an issue with the actual gears, not the diff itself. I would say that you walked your pinion from pushing that much power through it given that it’s whining. Or you knocked a bearing out… Why don’t you price getting it rebuilt with a stock diff? S15 diff needs a bunch of work to work properly. You’d be better off keeping your stock housing and gears and just getting an aftermarket diff.

I don’t want to sound like I’m talking down to you (cause I’m not), but the diff is the part inside that housing, that transfers the power off the ring gear out to the axles. It sounds to me like your gear whine is a problem with the meshing of the pinion and ring gears. Usually happens with a diff when it takes out a carrier bearing, or possibly the crush sleeve used to set pinion depth has been damaged and your engagement is wrong now. If your diff still spins and runs, the differential portion itself is probably fine. You can drop it out the bottom of your car and get it rebuilt at a tranny shop, or if you can find all the specs and tools, you can set it up yourself, but the lash and tolerences do need to be checked with precision instruments to ensure everything is set up properly.

Differential work is tricky, but it’s not quite the voodoo that it’s made out to be, if you have the right tools.

6

^ this. i would definitely check the alignment of your ring and pinion. i’ve been debating checking mine in my welded, and possible getting a rebuild for it.

7

DJ your right it’s a back lash issue for sure. As long as I’m putting power through the pinon there is no noise it’s only off the gas when it makes noise. I use the word diff loosely as a unit. Where would I be able to find a rebuild kit? I have my unit from last year that I wouldn’t mind playing around with while I slowly kill my current one. How much would this cost at a tranny shop?

8

I would imagine it’s set with a crush sleeve. Check at the dealership, otherwise maybe somplace like Courtesy Nissan online might have it… You could also check with a local shop that rebuilds diffs, they could probably find something in their parts catalogue.

I’m not sure at a tranny shop, $200-500? It would really depend on parts, it’s only a few hours of work if the diff is out of the vehicle and you have the specs.

If you want to try it yourself, you’ll need:

gear paint (to run a pattern on your gears and make sure it’s set up right)
a FSM
dial indicator gauge with a magnetic base (you might be able to rent one from a tool store or CT/Partsource or something)
a torque wrench
a breaker bar, and another bar to hold the pinion at the flange (you can fab a tool with a piece of flat bar, by drilling some holes in it and notching it appropriately to bolt it to the flange)

Follow the instructions in the FSM to the letter: http://www.nicoclub.com/FSM/240sx/91-94/PD.pdf

Honestly, if you’re comfortable with rebuilding an engine, you can do this. Keep in mind, all you’ll be doing is measuring it first, and then replacing whatever is necessary. You shouldn’t need to replace the ring or pinion, just some bearings and the crush washer. Be careful when you’re setting the lash with the crush washer, because if you crush it too far you have to start over again. Check it lots.

9

I’ll look into it I helped my buddy put an air locker in his truck so its pretty much the same. Parts seem like the tricky part I’ll call nissan today but there usually not much help with this kind of thing. Is the crush sleeve a wear item that gets more crushed with use?

10

It’s similar to installing a locker, but you probably didn’t set up your gears again afterward, and that’s the tricky part…

It’s not a wear item per-se, but if you’re running enough power and enough tire, it’s possible for the pinion gear to walk up the ring gear and either take out a bearing, or possibly over-crush the crush sleeve and give you excessive play.

11

buy my s15 diff, install, enjoy

12

^possible, pm me price and if you know how many kms are on it.

I talked to nissan and rebuild parts are not available. When you a buy an aftermarket diff does it come with a new pinon bearings and crush sleeve?

13

Pinion bearing preload on an S-chassis R200 is set with a spacer and a washer, not a crush sleeve. It is the R230 that uses the crush sleeve. I had to get my factory spacer machined down to properly set up my rear end. Unless you have the proper tool (J-34309), it is pretty much trial and error to set pinion depth and pinion bearing preload.

14

^ That answers that. I’ve never been inside an R200 diff, only replaced entire units. I assume that J-tool helps you measure pinion preload so you can just get the correct sized spacer?

15

I’m still not clear as to what you get when buy an aftermarket diff. Are most people just swaping the ring gear and don’t bother resetting pinon depth and engagement, or is not nessecary? Can you buy spacer packs?

Could the oem spacer wearing down be the cause of the gear noise I have?

16

Most people are just swapping their ring over onto a new diff without resetting their pinion depth and backlash. It’s probably close enough to not really matter, but I would say that most people don’t set their diff up properly after installing an LSD. I don’t see how the OEM spacer could wear down. You’ve either thrown a bearing in there (probably a bearing whining, not gears), or there’s something cranky in your transmission. Depending on the bearing, it could be walking enough to induce some gear noise, but I would hazard a guess that it’ll be a bearing gone, not gears…

(ONLY DO THIS IF YOU TRUST THE OTHER PERSON AND CAN DO IT SAFELY!!!)
If you put the rear up on blocks, so the wheels can spin, and have someone run the car up to speed where the whining is starting you can listen to figure out which bearing it is before you even pull the case.
Block up rear end, and chock front tires
Grab a long screwdriver (stethoscope if you have one)
Have someone run the car up to whatever speed the whine is the worst at.
Put handle of screwdriver to your ear, and touch the other end to the front of the diff case by the pinion, and at the sides by the output flanges. You should hear the bearing making all sorts of evil noises, and this will allow you to hopefully pinpoint which bearing it is.

That should help you narrow things down before you start pulling everything apart.

If you die doing it, it’s not my fault, but this is a very accepted, and common practice for pinpointing a bad bearing. It’s much easier on a 2-post hoist.

http://www.rhdjapan.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/61157/Image/Normal/Image1.jpg

For illustrative purposes only…
41301 is the part you get when you buy an aftermarket LSD. That’s the part that actually transfers the power out to the wheels.
The Ring gear and Pinion gear are unlabeled in that picture, but I hope you know which two those are.

The measurement Face and I are refering to is the depth/engagement of the pinion gear onto the ring gear, and the subsequent backlash between the two gears. It’s a fairly critical measurement when installing a differential, but one that most people overlook. Most people, I would imagine, just pull the differential assembly out of the case, unbolt the ring gear, bolt it onto the new diff, and reinstall it into the case. Most forumites in my experience though, just swap entire housings when their diff dies, and never bother fixing the actual issue.

---------- Post added at 11:11 AM ---------- Previous post was at 11:08 AM ----------

http://www.kaazusa.com/lsd_nissan.html

The image at the top of their chart is what you get. It’s an exploded view. All the disks are the clutch packs that engage the axles and transfer power out. The gears in the middle are your spider gears (what gets welded in a ‘welded diff’)… All that junk gets bolted to your ring gear, and your axle shafts engage on either end. You get the diff itself, and possibly new hardware.

17

Q45 diff. Cheaper, been run on 800+ hp cars with no issues, pretty much bolt in. Got mine w/ the beefier axles, rear hubs + diff for $500.

18

I know the issue is not with my transmission. I had the car on a hoist last year to confirm it was the diff. I also put new rear wheel bearings in and a 1pc drive shaft. Now after replacing it with another vlsd and about a month of driving I’m starting to hear the same noise again. If bearings are going I can’t see how people are able to swap in aftermarket diffs into old housings and not have these issues as well.

As for the Q45 diff, I looked into that swap and it seems like a pia to find all the parts. I checked car-part.com and there are only 2 Q45 diffs on there are in bc. Let alone trying to get a z32 output shaft on its own. Plus its still old parts

19

You can check the diff for a bad bearing like I mentioned. There’re at least 3 bearings in your diff housing, any one of them can cause an issue. Do you have any driveline vibrations? A drive shaft out of balance could cause a bearing to go.

Unless those people don’t have bad bearings in their housing when they swap differentials. For that matter, I’d be curious as to how many people are actually running aftermarket diffs, and how many are just running factory LSDs and welded diffs…

20

the R200 is perfectly capable of >500hp… the z32 R230 isn’t really an upgrade in strength, the ring gear in the R200 is actually thicker, and as far as I know the Q45 pumpkin/stub are the beefiest of them all