Is S15 Helical Lsd Actually Good For Our Cars???

[Chingon]

Well, after much investigation, I found out that the s15 helical lsd has a final ratio of 3.692 which is the same as the vlsd off a turbo z32 which is for some reason "not recommended." Now the only lsd w/the same ratio as our stockers is one off a silvia k,lower class s15, hicas, or a na z32 which are all vlsd units w/a ratio of 4.083.

What ppl say is that we won't benefit from a spec r s15 hlsd or a z32 turbo vlsd because unless you have a lot of power, it will result in a sluggish ride....so how true is all this...and is an s15 hlsd the real way to go...?

[Chingon]

awww...c'mon...

[S13ChucKAT]

well.. the sluggish ride feel.. means that your first gear will go to like 55mph before you even redline.. sure it would be great for gasmileage, and HIGH speed pursuits.. but realistically speaking.. for daily driving needs.. dont expect to be swerving in and out of traffic.. and be weary of getting on freeways

[thelinja]

but realistically speaking.. for daily driving needs.. dont expect to be swerving in and out of traffic.. and be weary of getting on freeways

What are you talking about? How is the HLSD or the gearing going to do that?

If you don't want the lower final drive....

1. remove stock diff housing2. remove open diff from housing3. remove ring gear from both HLSD and old diff4. put old diff ring gear onto HLSD5. install HLSD and housing

I did it, it's not that hard.

[Chingon]

What are you talking about? How is the HLSD or the gearing going to do that?

If you don't want the lower final drive....

1. remove stock diff housing2. remove open diff from housing3. remove ring gear from both HLSD and old diff4. put old diff ring gear onto HLSD5. install HLSD and housing

I did it, it's not that hard.

I was thinking that since it's a six speed, you could somehow reduce gearing...but what kind of final does that result in?

[thelinja]

I was thinking that since it's a six speed, you could somehow reduce gearing...

I don't understand what you're trying to say here.

If you do the method that I typed previously, you are left with the stock 240SX final gear which is 4.083....because you'd be using the stock ring and pinion.

[Toast]

What are you talking about? How is the HLSD or the gearing going to do that?

If you don't want the lower final drive....

1. remove stock diff housing2. remove open diff from housing3. remove ring gear from both HLSD and old diff4. put old diff ring gear onto HLSD5. install HLSD and housing

I did it, it's not that hard.

I too have done this. Not Hard at all. So My car has the same final gear and HLSD. Very Simple.

[s13sr20chris]

wait, you guys swapped a s15 hlsd diff with regular 4.08 ring gear into the regular pumpkin? i was under the impression that the s15 hlsd was a r230. if its a r230 variant then the diff should not fit in the r200 pumpkin. maybe the s15 hlsd is a r200 variant, i dunno.

[IveBeenBad]

wait, you guys swapped a s15 hlsd diff with regular 4.08 ring gear into the regular pumpkin? i was under the impression that the s15 hlsd was a r230. if its a r230 variant then the diff should not fit in the r200 pumpkin. maybe the s15 hlsd is a r200 variant, i dunno.

The silvias and skylines got the r200, the Z 32 got the r230

[s13sr20chris]

ok, i just checked my s15 service manual and saw that the all s15's do use the r200 diff. the two options were helical with 3.692 and a/t with viscous coupling and 3.916. that means that all m/t models have the helical unit and all s15's have some form of lsd. that is the australian manual though. maybe in japan there is a non lsd model. fantastic, sorry to question you fellas.

[Chingon]

actually type s s15 had helical as an option i think and auto had vlsd as an option..

[thelinja]

Type S? Try Spec R.

[s13sr20chris]

maybe, but the australian fsm has no provision for a non-lsd model. how i would love to search through and aussie junkyard!

[Chingon]

Type S? Try Spec R.

oops, I mean spec s, as in the na sr20de poser car, not the spec r sr20det

[madtown240]

I have one in my 96' 240sx no problems so far and thats with the KA stock

[importer]

The S15 helical (which comes from the spec-R car in japan) will go right into the R200 on an S13, or S14.The diff has nothing to do with the drive ratio !!The final drive gears consist of the pinion, and the ring gear.There is no need to remove the pinion gear when changing the diff,and the ring gear bolts to the diff.So what ever gear ratio you have now, is the ratio you have after installing an S15 helical.

The only problem people get into is that if they buy an S15 helical without the output shafts.They are larger than the standard R200 shafts.

I have one S15 helical in stock, and several in transit from Japan.The one I have now does not have the shafts, but I also have new shafts from a dealer in transit.

There is a shop in Walnut CA (J-spec USA) that is advertising new shafts, and I ordered in 2 sets, but it was a scam !!!

The S15, like most other Nissan diffs takes 2 different length shafts (side 'A', and side 'B').When the shipment came in today, all that came was the side 'A'.This Rip-Off joint will not return my calls or e-mails - so beware!!

So now I will have to order 4 more side 'B' shafts from Japan.

For the complete set (S15 helical & both shafts) I get $650.And I will sell the new shafts (pair - left & right) for $350.

I expect these shafts to be hitting my door in about 6 weeks.

Thanks,GordonDuax Machine WorksSan Antonio, TX (210) 653-9572

[r0b]

is the s15 HLSD torque-sensing or tourque biasing?

i'm just wondering the burn-out/drift potential, because i've read that some helical-geared diffs need a particular amount of resistance from both wheels to "lock up". like if one wheel is on ice, only that wheel will spin. i'm pretty sure i read it in SCC when they installed a Quafie in their s13.

[2_Liter_Turbo]

The Quafie is a Torsen type Helical Diff.

"The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.... the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs...... However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero..." <Howstuffworks.com>

[r0b]

so the s15 HLSD is a different (better?) "type" than the Torsen?

please bear with the n00b. i think your "set of wheels" aspect has me confused, but i know you know what your talking (er, typing) about, so any info you can provide would be appreciated.

I'd like to do the HLSD swap (all gears, no plates an goo), and it seems that in every other forum i read they all have conflicting opinions that they pass off as fact. NICO has, by far, the more knowledgable enthusiasts, at least from what i can tell.

thanks,rob

[2_Liter_Turbo]

I believe they are the same. Helicals are great for roadracing in my opinion, where as the the clutch type is better for the whole drifting scene. If you live in an area that snows alot, then you might want to consider not getting a helical type because you won't get any traction on the ice. Where as a viscous or clutch based system will give you some grip with both tires... somewhat. For just "sporty everyday driving", and you live in a place that doesnt snow (or you don't care that it snows), then I'd go with a helical. Hope this all helps.

[r0b]

helped well, but i live in Michigan where it's crappy 50% of the time.

[s13sr20chris]

my 2 cents...i prefer to have the weakest diff possible while having just enough locking to get plenty of traction. for this reason i find a brand new vlsd to be perfect. unfortunately there are no brand new ones in the junkyard. clutch types are ok but seem too twitchy unless you mechanically weaken them(like scc did on their project 350z). i have very little experience with helicals but they seem to be a good compromise between the two.

[2_Liter_Turbo]

I am running a VLSD (which works great in the snow) for everyday use. I am getting a clutch type for competition use later on. So that way I can just swap the two in and out (only takes about 30 minutes to do with basic tools and a jack).

[r0b]

how much fluid has to be removed/refilled when swapping a VLSD with a clutch-type?

[importer]

how much fluid has to be removed/refilled when swapping a VLSD with a clutch-type?

What ever the factory says to use in your housing.The actual volume change is insignificant.The fluid that makes a VLSD work is sealed inside the unit it's self (called a viscous coupling), and has no effect on the gear oil volume inside the diff that is there to lubricate the gears & bearings.Basically, you fill the diff until the oil level is up to the bottom of the rear plug.

[spider_slayer]

couple things.......

1. no matter what happens i will never EVER drive my 240 in the snow again....it was horriable

2. so what is the difference between a clutch type lsd and a vlsd.....i'm guessing that a clutch type acts alot like a clutch to lock the 2 wheels together.....while i have very little idea of how a vlsd works

3. the hlsd sounds like a pretty good upgrade, so why has almost no one done this before?

[2_Liter_Turbo]

Go to Howstuffworks.com and Search for "limited slip differential". That's the best place that I have found, that explains exactly what you're asking.

In short the VLSD is kinda like an Automatic transmission versus a Manuel, like the Cluth type.

[Chingon]

couple things.......

3. the hlsd sounds like a pretty good upgrade, so why has almost no one done this before?

scarcity and price.

[spider_slayer]

For the complete set (S15 helical & both shafts) I get $650.And I will sell the new shafts (pair - left & right) for $350.

650 doesn't sound to bad......its about 500 for a vlsd isn't it?

[2_Liter_Turbo]

I got mine for 250 with 5 bolt axles. They usually go for about 300 +-