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AadosX
03-18-2004, 04:04 AM
I searched and found one long thread about someone installing one. It said all I needed was the unit and output shafts. Well, here's a picture of what I'm told is an HLSD for sale to me. I have no idea what splines and whatnot are... I've never even seen the inside of a diff. Does it seem to be the right thing, and I guess those are the output shafts? I'm a noob when it comes to these things...

Also, I read that there is a different final drive ratio for the turbo version, but the n/a version has the same ratio as our car stock? Is this true... and how can I tell if it's from a turbo or n/a?

Thanks,
John
mellojoe
03-18-2004, 09:48 AM
The difference in final drive ratio from turbo to n/a is for the 300zx LSD that people swap. The n/a 300zx has the same final drive ratio, where as the turbo version doesn't.

I believe on any and all versions of the s15, the rear end is the same.
okashira
03-18-2004, 02:26 PM
I searched and found one long thread about someone installing one. It said all I needed was the unit and output shafts. Well, here's a picture of what I'm told is an HLSD for sale to me. I have no idea what splines and whatnot are... I've never even seen the inside of a diff. Does it seem to be the right thing, and I guess those are the output shafts? I'm a noob when it comes to these things...

Also, I read that there is a different final drive ratio for the turbo version, but the n/a version has the same ratio as our car stock? Is this true... and how can I tell if it's from a turbo or n/a?

Thanks,
John

uh, thats the whole pumpkin. you dont need to worry about outputshafts and such. its already put together for you! just bolt it in.
be wary, you may need an ABS driveshaft for it. the s15 pumpkin is even longer then the usual abs pumpkin (j30) which is already an extremely tight fit with a non-abs D/S.
But if you wanted to keep your stock gearing(good idea since the s15 turbo rear is significantly different) Then yes, those are obviously the right output shafts.
By the way, please buy that. I would buy the Diff companion flange off of it, mine is a lil warped and ive been dealing with a vibrating driveshaft for 4 months now :( and I cant find a USDM equivalant replacement...

If the diff is from a turbo, it will be 3.692 gearing
If it is from an NA it will be 4.083. Only the turbo had the HLSD. others were VLSD and Open.
AadosX
03-18-2004, 04:07 PM
So the gearing is differet? Whats this mean?
Var
03-18-2004, 04:15 PM
i thought all s15's were turbo
AadosX
03-18-2004, 04:33 PM
Yeah so did I, that's why I'm confused...
okashira
03-18-2004, 05:32 PM
Yeah so did I, that's why I'm confused...

No, not all s15's were turbo. Why would they be?
not all of the turbo models got the Helical either. Has to be a 6spd.
okashira
03-18-2004, 05:33 PM
So the gearing is differet? Whats this mean?
what are you asking exactly?
AadosX
03-18-2004, 09:28 PM
Didn't all S14's in Japan come with an SR20DET? I thought all S15's were the same way...

So how can I know what the gear ratio on the LSD pictured above is?? I don't want a lower ratio like 3.xxx because that will make the car slower than it already is.
okashira
03-18-2004, 10:31 PM
Didn't all S14's in Japan come with an SR20DET? I thought all S15's were the same way...

So how can I know what the gear ratio on the LSD pictured above is?? I don't want a lower ratio like 3.xxx because that will make the car slower than it already is.

anyways...

If the LSD in the above picture is a Torsen/Helical/ATB diff, then it is 3.692.
you can buy it, and swap the internals and output flanges into your open diff housing. This will allow you to keep your stock gearing, and driveshaft.


And sell me the companion flange. :p

edit: clarification
Kaede
03-18-2004, 11:01 PM
Swap the internals and use your open diff ring gear to retain your stock final gear. It's really not that hard. I was able to swap a S15 HLSD in like 6 hours with a friend. Just remember where everything goes and have good tools, air tools would be very helpful.
mistert
03-18-2004, 11:04 PM
you CANNOT bolt an s15 spec R pumpkin into your car its too long(that's the only one that had the hlsd, the 6spd). if that's an s15 pumpkin then yes it's 3.692, the only way to tell is to open up and count splines if its not original. that'll be everything you need to have it swapped into your stock diff (TAKE IT TO A PROFESSIONAL DIFFERENTIAL SHOP! the ring gear has to be shimmed).

could you put me in touch with whoever is selling that to you? i have a unit that is all swapped and ready to go but i really need the 30spline output shafts, i only have stock 29 spline ones

and dont forget you need 90w-140 oil, no more 75w-90
Dousan_PG
03-18-2004, 11:15 PM
tony style S15 diff install:

pick up s15 diff
open dumpster
install.



"eat fuck!"
AadosX
03-19-2004, 01:11 AM
Man fuck this, VLSD here I come.
okashira
03-19-2004, 01:15 AM
Man fuck this, VLSD here I come.
can you give me the email to the guy selling the HLSD? I need the housing/companion flange....
sykikchimp
03-19-2004, 08:48 AM
lol.. people make this so much harder than it has to be.

Mistert - you don't shim the ring gear. The ring gear bolts directly to the diff. You may have to re-shim the diff inside the housing to adjust position left to right so that the teeth on the ring gear engage properly with the pinion gear. I've never heard of anyone to date checking tolerances and found them to be out of wack, and had to buy new shims. Doesn't mean it can't happen, just that it's rare.

Aados - Vlsd sounds like the best option for you man. Simplicity is what you need.

Dousan - if someone is throwing these diffs in the trash, they are an idiot.
Var
03-19-2004, 09:18 AM
so do all s15 have turbo or not?if not what's the other motor they come with?
AKADriver
03-19-2004, 11:01 AM
S15 Silvia Spec-S = SR20DE, 160hp, and a 4.083:1 open diff just like ours with either auto or 5-speed. ABS/VLSD option.

The Spec-R (turbo) w/automatic had a 4.083:1 VLSD.

Only the Spec-R w/6-speed had the 3.692:1 HLSD.

3.692:1 might be nice for a turbo KA. It's too tall for an N/A KA though. The 6-speed has short, close ratios of its own to make up the difference.

JDM S14s were also available with the 160hp SR20DE in the J's and Q's.

The S15 also had a rare 200hp SR20DE option. Higher compression, hot cams, modified intake, tuned header. Spec-S Autech version.
sykikchimp
03-19-2004, 12:48 PM
The S15 also had a rare 200hp SR20DE option. Higher compression, hot cams, modified intake, tuned header. Spec-S Autech version.


That sounds like a bundle of fun right there!
AKADriver
03-19-2004, 02:00 PM
That sounds like a bundle of fun right there!

Oh yeah :D I forgot to mention, the Spec-S Autech had a 4.083:1 HLSD. Don't ever count on finding one, though!
mistert
03-22-2004, 03:19 PM
sykikchimp-the shop here that has done my diff as well as a friend of mine's said that it is neccessary to shim, yes they did check the tolerances, maybe you can do it and skip this step but micrometer tolerances are a huge deal in the drivetrain where you have balanced parts and such, at least that's how the technician explained it to me.

anyways, if anyone is interested in buying an s14 open diff pumpkin w/ hlsd swapped in PROFESSIONALLY (it wasnt cheap), it has been shimmed and is using the stock 4.083:1 gearing. the helical unit has 40,000 km's on it. all you need is 30 spline output shafts from an s15 unit, you can order them from the dealership. other than that it's ready to bolt into an s14, s13 if you have the correct rear cover. this diff just isnt for me, i want a 2-way clutch type
sykikchimp
03-22-2004, 03:51 PM
Maybe I'm misunderstanding you, but it sounds like your saying that these shim would go between the ring gear, and the ring gear flange. If that's what your saying, you are wrong. check your FSM. The shims go b/w the bearing races on each end of the diff, and the diff housing where the output shafts go in. They dictate how the diff is centered in the housing.

You have to check backlash on the pinion to ring gear contact. If it's out of spec, simply follow the diagram in your FSM to figure out what size shims you need to reposition the diff left or right in the housing.

I never said you didn't need to check it. Just that I've never read about anyone that checked it, and found it to be out of spec.

I used my open diff races, and shims, and my backlash was right at the tight end of the tolerances at .0039.