The OBX Helical Diff Thread!!! Installed in S14!!! - Page 3 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

timtiminy · 08-23-2006, 03:23 PM

actually it looks as if the z32 is the same as the s14 cover with only 2 bolts instead of the 4 bolts on the s13 rear cover. well i made up my mind on what i will be doing, looks like i will take the diff out of the s14 housing and dissasemble and make sure the washer set is installed correctly as i heard that this helps with preload and the sensitivity of the torque biasing in this diff. after that red locktite and torque down all the bolts and install into the s13 housing. hopefully the shims used when installed in the s14 housing will work for the s13 housing.

99maxgtr · 09-20-2006, 12:46 PM

hey guy's any info as to what size shims to get? i was looking at that size tim and i see that have the one where you can pretty much peel off the laminated cover to get the right amount of thickness now all i need to know is the innner and outside size? any help would be appreciated...the guy who installed this before just took out the shims to make it fit.

timtiminy · 09-21-2006, 09:14 PM

Quote:

Originally Posted by 99maxgtr

hey guy's any info as to what size shims to get? i was looking at that size tim and i see that have the one where you can pretty much peel off the laminated cover to get the right amount of thickness now all i need to know is the innner and outside size? any help would be appreciated...the guy who installed this before just took out the shims to make it fit.

Depends on what size you need, you have to check what the specs are and check backlash from there and figure out what size shims you will need. it is different for every diff. just make sure your tolerances are in spec with the FSM. P.S. where did you pick your diff up from? how much did it run you?

99maxgtr · 10-16-2006, 10:54 PM

picked it up on ebay. for about 420~ shipped.

trsilvias13 · 10-17-2006, 01:53 AM

A little off topic, but I was thinking about getting a group buy status and get a group buy on this. Do you guys think there can be a market for this as a group buy? I can get it at a great price. If anyone local wants to pick one up. I am not a dealer or anything, but got hook up on this item and any obx item. PM if you guys like

timtiminy · 10-17-2006, 09:18 AM

I think there could be a good possibility that it would go well as a group buy.

I ended up dissasembling the diff, i rearranged the conical washers, there ended up being 8 washers instead of the 6 that i have seen people encounter in dissasembling the ones for fwd applications. i kept the 8 washers in there. the arrangement i used was ))(())(( and retightened the allen bolts to 20ft/lbs and went in a crisscross tightening pattern and used red locktite. everything looked really good when taken appart. i took pictures too so i'll post those when i get time. now i just have to get it shimmed up and in my s13 diff housing. I'll keep you guys updated.

99maxgtr · 10-22-2006, 10:56 PM

im sorry im a newb on this stuff but what is backlash and how do i check it?? and if i took this to a mechanic would they know what to do?

addikted2bass · 10-28-2006, 12:01 AM

message length

!Zar! · 10-28-2006, 12:17 AM

Quote:

Originally Posted by 99maxgtr

im sorry im a newb on this stuff but what is backlash and how do i check it?? and if i took this to a mechanic would they know what to do?

In a nutshell, it is the spacing between meshing objects. In this case, the ring and pinion. If they are too close, then you will have binding. If they are too far from each other, then you will strip the gears. So you can adjust the backlash with shims, and you can measure it with a feeler gauge.

Most knowledgeable mechanics can set backlash. Just take it to a reputable shop.

You can find the backlash spec thresholds in the factory service manual.

timtiminy · 10-30-2006, 04:25 PM

okay so after putting the diff into the s13 pumpkin and having the preload washers setup in the order ))(())(( now when i turn one wheel the other turns in the same direction, i thought that helical diffs act the same way as open diffs when one wheel is turned, that being the other wheel should turn in the opposite direction. perhaps the preload washers are tight enough to keep the two wheels together. i dont see it as a big deal, but should i be worried? havent put it on car yer

IMPerfection · 11-04-2006, 11:37 AM

Quote:

Originally Posted by aznpoopy

subframe bushings
differential bushings
tranny and engine mounts
various suspension bushings

99.99999% of the time the biggest offenders are the subframe bushings. unless you've already put collars in.

how's the supercharged ka doing? got it running better? you haven't posted anything about it in a while.

My subframe collars introduced this noise to my car, and my symptons are exactly as the OP describes. I'm gonna presume its normal, since my car is bone-stock besides the collars.

dans · 11-05-2006, 03:44 AM

Update of OBX HLSD on isle 4 please.

timtiminy · 11-05-2006, 07:04 PM

yeah i would also like to hear an update. i cant wait to get mine going. i have it all together but i think i am going to hold off on the install until i get a new chassis and motor swap with full suspension. no ttoo far off from that though so, maybe by in the next few months. i created a huge amount of preload on the obx helical i have, which should solve the problem with full power transfer to lifted rear wheel. either that or it may cause problems i still need to figure out if as high of a preload as i have is good or bad on a helical diff, i dont want to hinder the proper functioning of the hlsd.

naed240sx · 11-05-2006, 09:11 PM

I'm not quite sure why you guys are adding preload to these diffs. The torque biasing ratio is set by the cut of the sun gears and planetary gears as well as what metals are used in the construction, the finish of the gears, and what oil is used.

Unless I am looking at this wrong, the only thing adding preload will do is to make the diff harder to turn.

Also, timtiminy:

You CANNOT fix the problem with lifting wheels. Any helical diff in any application will bias all the power to the lifted wheel because the lifted wheel has effectively 0 frictional force on it. You cannot produce a functioning helical differential with an infinate torque biasing ratio, so you can never overcome this problem, unless you have some sort of advanced traction system that senses such a problem in power delivery and applies some braking force to the rear wheels (Humvee's or Hummers(I can't remember which) have helical diffs and use such a system for offroading)

In the end though, it doesn't matter, because a properly setup rwd car won't lift either of the rear wheels when racing.

timtiminy · 11-05-2006, 09:50 PM

so why are they preloaded from the factory? when i put the conical washers in the way i did it made the wheels turn in the same direction when one is turned. i would think by doing this it would add intial torque resistance so if there is a 0 frictional force on one wheel there would actually be some frictional force because the diff is preloaded with this force. that way if i ever get in a situation (ice one wheel road other) i could actually get out of it. should i lessen the resistance of the preload because it may make it harder for the normal function of the diff to work?

naed240sx · 11-05-2006, 10:21 PM

Hmmm. You bring up a good point. How much force does it take to spin the wheels in opposite directions? I'm curious.

I have an s15 diff, and if I turn one of the wheels slowly with both off of the ground, they spin the same direction, but when I turn harder, the other wheel reverses direction.

It's obvious that you have increased the amount of friction inside of the diff, but im pretty damn sure it's not gonna be enough to allow you to get traction if a wheel is lifted, because the difference in the amount of torque created by a tire on the road, and the amount of torque neccesary to overcome the added preload is very large.

I think that by increasing preload, all you are doing is increasing the friction between the gears inside of the differential and their respective bearing surfaces. The only way that I can see for you to fix the problem with lifting a wheel would be to apply the ebrake in such a situation to generate an amount of torque at the lifted wheel.

The ice situation isn't really comparable to the lifted wheel situation. Are you worried about not being able to get moving from a stoplight or something? At it's worst, the helical will have as much grip as an open diff, so I don't think it's much to worry about.

timtiminy · 11-06-2006, 01:20 AM

well the diff is off the car, i just got it in the housing and the cover back on, havent put any fluid in it yet, i cant really turn the output shaft that hard or fast plus with no differential fluid in it there is alot more friction on those cone washers. I am wondering now if it is bad for the differential to have as much preload as i have on it. I have heard that with higher preload it responds quicker though, i just dont want to tear it all apart again to lessen the force of the preload. I dont think it will be too much of a problem, the worst that can happen is those conical washers could wear down from rubbing against each other, but even then it wont really cause anything adverse. check this out should be helpful if you don't completely understand what i am talking about.
http://rbryant.freeshell.org/obx_washers

silnismo · 11-16-2006, 12:06 PM

i know this was disscussed, but never reached an answer, Can a VLSD work with OBX HLSD? or does the VLSD have different gear ring & bearing? i am also deciding if i should get the OBX unit...

naed240sx · 11-16-2006, 12:32 PM

Quote:

Originally Posted by silnismo

i know this was disscussed, but never reached an answer, Can a VLSD work with OBX HLSD? or does the VLSD have different gear ring & bearing? i am also deciding if i should get the OBX unit...

The internal dimensions for all R200 diffs are the same, except for minor differences like ring gear bolt diameter(s15 and r32 units use 13mm shank, 12mm threads bolts).

So to answer your question, yes it will bolt in. Problem will be with the output shafts. You can be pretty sure that they won't fit. You will need to get some open diff shafts to use with it.

Why not just leave it in the pumpkin, and sell/trade+cash for an open diff pumpkin?

djsilver · 11-18-2006, 02:13 PM

Quote:

Originally Posted by silnismo

i know this was disscussed, but never reached an answer, Can a VLSD work with OBX HLSD? or does the VLSD have different gear ring & bearing? i am also deciding if i should get the OBX unit...

I had been wondering myself since I bought one without thinking to ask the question first. It's still in the box so I opened it up and checked today. The distance from the the bearing stub ends to the beginning of the splines for the output shafts is the same on both sides. That points me to the open diff output shafts since they are equal length. The VLSD shafts are unequal length, since one side passes through the spider gears to get to splines in the viscous coupling, which is off-center to the ring-gear side of the diff.

silnismo · 11-19-2006, 12:11 AM

Quote:

Originally Posted by naed240sx

The internal dimensions for all R200 diffs are the same, except for minor differences like ring gear bolt diameter(s15 and r32 units use 13mm shank, 12mm threads bolts).

So to answer your question, yes it will bolt in. Problem will be with the output shafts. You can be pretty sure that they won't fit. You will need to get some open diff shafts to use with it.

Why not just leave it in the pumpkin, and sell/trade+cash for an open diff pumpkin?

THX for the answer

But for some reason my VLSD that was equipped with with my s14 SE stoped working at 65,000 miles (partilly dued to driving in snow). Now it just works like a open but when i look under at the VLSD pumkin case it looks like maybe there could be a leak. you think if u change the viscous fluid, that by doing that might fix this???

naed240sx · 11-19-2006, 01:04 AM

Quote:

Originally Posted by silnismo

THX for the answer

But for some reason my VLSD that was equipped with with my s14 SE stoped working at 65,000 miles (partilly dued to driving in snow). Now it just works like a open but when i look under at the VLSD pumkin case it looks like maybe there could be a leak. you think if u change the viscous fluid, that by doing that might fix this???

The viscous fluid in a viscous diff is separate from the rest of the differential oil. The viscous fluid cannot be replaced or refilled, becaue it is inside of the sealed viscous coupling. You can buy new ones from the dealer for like 600, but you would have to be an idiot to do that.

turtl631 · 11-19-2006, 02:40 PM

I'll probably be getting one of these soon. Are backlash standards universal, that is, do I have to bring the specs to a shop or can I just show up with the open pumpkin and the new OBX unit? I'm hoping it'll be more in the $100-$150 range. My friend here in Atlanta got an S15 installed in a pumpkin for $200. That seems pretty steep considering the backlash on those is usually right at stock levels anyways! So just any transmission shop should be able to do this? Sorry about all these noob questions, I don't know anything about this stuff.

naed240sx · 11-19-2006, 04:35 PM

Quote:

Originally Posted by turtl631

I'll probably be getting one of these soon. Are backlash standards universal, that is, do I have to bring the specs to a shop or can I just show up with the open pumpkin and the new OBX unit? I'm hoping it'll be more in the $100-$150 range. My friend here in Atlanta got an S15 installed in a pumpkin for $200. That seems pretty steep considering the backlash on those is usually right at stock levels anyways! So just any transmission shop should be able to do this? Sorry about all these noob questions, I don't know anything about this stuff.

When i was calling around about having my s15 diff installed, I called like 20 different general, gear and transmission shops. Nobody wanted to mess with it. The problem is, if a shop finds that backlash needs adjusting, they will have to order shims. It's not something that can just be done in a day, unless they happen to have tons of nissan diff shims laying around.

After researching and reasoning that since every oem r200 diff has pretty much the exact same dimensions, assembling like I dissasembled should be all that is neccesary to get a perfect fit, as long as the pumpkin that you are installing it into is in good shape and has not been tampered with.

I decided to do it myself. I used an r32 4.36 vlsd pumpkin. I removed the old diff, swapped the ring gear from it to the s15 diff, installed the s15 diff making sure all shims were in thier original places and bolted it back up. I did not measure backlash, but it felt exactly as it had when i had the vlsd in it. What i did do is get some gear indicator dye to check gear mesh. I got a perfect mesh pattern, and this was enough for me to know that it was about as pefect as it was gonna get.

However, since you plan on buying an obx diff, you might not be able to do this. Oem fits like oem, but you can't trust an aftermarket diff to do the same. I know kaaz diffs are close enough to bolt up, but I would never trust an obx diff. Either take it to a shop and eat a few hundred dollars, or be smart and get an s15 diff and install it yourself.

Edit: Didn't answer your first question. Backlash specs differ from manufacturer to manufacturer, and from different differential models. Of course all r200 diffs have the same backlash specs. When swapping in a new diff, you will want to make sure that the backlash spec is as close to the oem range as possible.

turtl631 · 11-19-2006, 06:24 PM

Hm, so it might be more economical to pay more for an S15 diff and just drop it in than to get a cheaper OBX and end up paying for shims and install. I would do it myself but I don't have a dial indicator and stand, vice, bearing pullers...this is kind of out of the practical range of my apartment workspace. I'd rather have a used Nissan part than a new OBX one anyways; I guess this just seals the deal for me.

naed240sx · 11-19-2006, 11:18 PM

Quote:

Originally Posted by turtl631

Hm, so it might be more economical to pay more for an S15 diff and just drop it in than to get a cheaper OBX and end up paying for shims and install. I would do it myself but I don't have a dial indicator and stand, vice, bearing pullers...this is kind of out of the practical range of my apartment workspace. I'd rather have a used Nissan part than a new OBX one anyways; I guess this just seals the deal for me.

Remember, i'm not saying that an obx wouldn't just drop in like oem. I'm saying that most likely you would have problems. What i do know is that i have never heard of anyone having to buy new shims for an s15 diff. As far as a bearing puller, you wouldn't need that because like 90% of the ones on ebay have the bearings already on them. As far as a dial indicator, yeah i looked into all that stuff myself. Decided not to fuck with it. I felt the backlash by hand before and after(yes this is extremely inprecise. However, it allows you to make sure that there is still SOME backlash, and that there is not a large amount).

I would say that if you are installing a quality diff (kaaz, tomei, etc) or an oem diff, and you check the gear mesh afterwards, the backlash is probably fine too. Just make sure that you do. Check gear mesh before and afterwards. If it is messed up to begin with, you might not want to use that pumpkin. Also, the only other problem with s15 diffs is the difference in ring gear sizing. If you are putting it in a standard s14 or s15 pumpkin you will need some .5mm wall thickness sleeves for your ring gear bolts. Apparently you can use ford starter bolt sleeves for this. I got lucky and didn't have this problem because i installed in an r32 pumpkin.

All in all, I make this sound complicated, but it's not. It goes in just like any other diff with the exception of the ring gear bolt size issue. Read the fsm about how to do it, and you will see that it is rather simple.

But yeah, used oem>cheap obx

turtl631 · 11-20-2006, 12:29 PM

Yep, I think I'm gonna go the S15 route rather than deal with shimming. The OP noted that his had 0 backlash when first installed, so I doubt a straight drop-in is a good idea with the OBX. I'm tired of gambling on things and having them take forever to get right. S15 HLSD, J30 finned diff cover, and 4.36 ring gear for me.

adamky · 07-01-2007, 01:19 AM

Sorry to bump an old thread, but I'm new here and didn't feel like creating a new thread.

I just installed this diff tonight. Only was able to drive it for less than 30 minutes, but so far I like it. I tried dropping the clutch from a red light, and both tires began spinning and the rear stepped out to the side a little. Banged 2nd and there was no wheel spin at all. (Car is mostly stock, KA-T to come eventually.)

Also had a chance to take a really tight U-turn, so I floored it. The inside tire squealed but the car just kept pulling forward.

Concerning install... we were able to reuse everything and the diff dropped right in. Only hard part was the "snap rings" that hold the output shafts in. Those had to be removed from the open diff and placed in the new diff. This was quite difficult and time consuming, but there is probably a special tool that can really speed that up. Once we had them swapped into the new diff, the output shafts popped in easily.

The guy who helped me with this is a friend/co-worker who has done quite a few diff swaps in domestic rear ends. After dropping the diff in, we checked mesh pattern, and everything seemed good. He was very impressed by the size/beefiness of this "import diff".

Overall, I love this thing. Favorite mod to my car so far. Coming from an open diff, it's like a night and day difference.

timtiminy · 07-09-2007, 12:58 PM

thanks adamky. So what is the most noticeable difference that you had? most noticeable in handling, or off the line traction?
I specifically got mine for grip driving as i figured it would be best suited for grip. I can't wait to feel what it will be like getting on the throttle earlier coming out of corners and feeling the push of the rear end grip.

kandyflip445 · 07-09-2007, 01:51 PM

Quote:

Originally Posted by naed240sx

Also, timtiminy:

You CANNOT fix the problem with lifting wheels. Any helical diff in any application will bias all the power to the lifted wheel because the lifted wheel has effectively 0 frictional force on it. You cannot produce a functioning helical differential with an infinate torque biasing ratio, so you can never overcome this problem, unless you have some sort of advanced traction system that senses such a problem in power delivery and applies some braking force to the rear wheels (Humvee's or Hummers(I can't remember which) have helical diffs and use such a system for offroading)

In the end though, it doesn't matter, because a properly setup rwd car won't lift either of the rear wheels when racing.

Use the e-brake.

10-22-2006, 10:56 PM	#67
99maxgtr Nissanaholic! Join Date: Nov 2005 Location: dirty jersey Posts: 1,705 Trader Rating: (22) Feedback Score: 22 reviews	im sorry im a newb on this stuff but what is backlash and how do i check it?? and if i took this to a mechanic would they know what to do? Last edited by 99maxgtr; 10-23-2006 at 12:27 PM..

08-23-2006, 03:23 PM	#61
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	actually it looks as if the z32 is the same as the s14 cover with only 2 bolts instead of the 4 bolts on the s13 rear cover. well i made up my mind on what i will be doing, looks like i will take the diff out of the s14 housing and dissasemble and make sure the washer set is installed correctly as i heard that this helps with preload and the sensitivity of the torque biasing in this diff. after that red locktite and torque down all the bolts and install into the s13 housing. hopefully the shims used when installed in the s14 housing will work for the s13 housing.

09-20-2006, 12:46 PM	#62
99maxgtr Nissanaholic! Join Date: Nov 2005 Location: dirty jersey Posts: 1,705 Trader Rating: (22) Feedback Score: 22 reviews	hey guy's any info as to what size shims to get? i was looking at that size tim and i see that have the one where you can pretty much peel off the laminated cover to get the right amount of thickness now all i need to know is the innner and outside size? any help would be appreciated...the guy who installed this before just took out the shims to make it fit.

10-16-2006, 10:54 PM	#64
99maxgtr Nissanaholic! Join Date: Nov 2005 Location: dirty jersey Posts: 1,705 Trader Rating: (22) Feedback Score: 22 reviews	picked it up on ebay. for about 420~ shipped.

10-17-2006, 01:53 AM	#65
trsilvias13 Nissanaholic! Join Date: Nov 2001 Posts: 1,994 Trader Rating: (5) Feedback Score: 5 reviews	A little off topic, but I was thinking about getting a group buy status and get a group buy on this. Do you guys think there can be a market for this as a group buy? I can get it at a great price. If anyone local wants to pick one up. I am not a dealer or anything, but got hook up on this item and any obx item. PM if you guys like

10-17-2006, 09:18 AM	#66
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	I think there could be a good possibility that it would go well as a group buy. I ended up dissasembling the diff, i rearranged the conical washers, there ended up being 8 washers instead of the 6 that i have seen people encounter in dissasembling the ones for fwd applications. i kept the 8 washers in there. the arrangement i used was ))(())(( and retightened the allen bolts to 20ft/lbs and went in a crisscross tightening pattern and used red locktite. everything looked really good when taken appart. i took pictures too so i'll post those when i get time. now i just have to get it shimmed up and in my s13 diff housing. I'll keep you guys updated.

10-28-2006, 12:01 AM	#68
addikted2bass Leaky Injector Join Date: Dec 2005 Location: illinois Posts: 94 Trader Rating: (0) Feedback Score: 0 reviews	message length

10-30-2006, 04:25 PM	#70
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	okay so after putting the diff into the s13 pumpkin and having the preload washers setup in the order ))(())(( now when i turn one wheel the other turns in the same direction, i thought that helical diffs act the same way as open diffs when one wheel is turned, that being the other wheel should turn in the opposite direction. perhaps the preload washers are tight enough to keep the two wheels together. i dont see it as a big deal, but should i be worried? havent put it on car yer

11-05-2006, 03:44 AM	#72
dans Leaky Injector Join Date: Aug 2006 Location: Central Ohio Age: 53 Posts: 64 Trader Rating: (0) Feedback Score: 0 reviews	Update of OBX HLSD on isle 4 please.

11-05-2006, 07:04 PM	#73
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	yeah i would also like to hear an update. i cant wait to get mine going. i have it all together but i think i am going to hold off on the install until i get a new chassis and motor swap with full suspension. no ttoo far off from that though so, maybe by in the next few months. i created a huge amount of preload on the obx helical i have, which should solve the problem with full power transfer to lifted rear wheel. either that or it may cause problems i still need to figure out if as high of a preload as i have is good or bad on a helical diff, i dont want to hinder the proper functioning of the hlsd.

11-05-2006, 09:11 PM	#74
naed240sx Zilvia Member Join Date: Jul 2005 Location: Houston, TX Posts: 206 Trader Rating: (0) Feedback Score: 0 reviews	I'm not quite sure why you guys are adding preload to these diffs. The torque biasing ratio is set by the cut of the sun gears and planetary gears as well as what metals are used in the construction, the finish of the gears, and what oil is used. Unless I am looking at this wrong, the only thing adding preload will do is to make the diff harder to turn. Also, timtiminy: You CANNOT fix the problem with lifting wheels. Any helical diff in any application will bias all the power to the lifted wheel because the lifted wheel has effectively 0 frictional force on it. You cannot produce a functioning helical differential with an infinate torque biasing ratio, so you can never overcome this problem, unless you have some sort of advanced traction system that senses such a problem in power delivery and applies some braking force to the rear wheels (Humvee's or Hummers(I can't remember which) have helical diffs and use such a system for offroading) In the end though, it doesn't matter, because a properly setup rwd car won't lift either of the rear wheels when racing.

11-05-2006, 09:50 PM	#75
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	so why are they preloaded from the factory? when i put the conical washers in the way i did it made the wheels turn in the same direction when one is turned. i would think by doing this it would add intial torque resistance so if there is a 0 frictional force on one wheel there would actually be some frictional force because the diff is preloaded with this force. that way if i ever get in a situation (ice one wheel road other) i could actually get out of it. should i lessen the resistance of the preload because it may make it harder for the normal function of the diff to work?

11-05-2006, 10:21 PM	#76
naed240sx Zilvia Member Join Date: Jul 2005 Location: Houston, TX Posts: 206 Trader Rating: (0) Feedback Score: 0 reviews	Hmmm. You bring up a good point. How much force does it take to spin the wheels in opposite directions? I'm curious. I have an s15 diff, and if I turn one of the wheels slowly with both off of the ground, they spin the same direction, but when I turn harder, the other wheel reverses direction. It's obvious that you have increased the amount of friction inside of the diff, but im pretty damn sure it's not gonna be enough to allow you to get traction if a wheel is lifted, because the difference in the amount of torque created by a tire on the road, and the amount of torque neccesary to overcome the added preload is very large. I think that by increasing preload, all you are doing is increasing the friction between the gears inside of the differential and their respective bearing surfaces. The only way that I can see for you to fix the problem with lifting a wheel would be to apply the ebrake in such a situation to generate an amount of torque at the lifted wheel. The ice situation isn't really comparable to the lifted wheel situation. Are you worried about not being able to get moving from a stoplight or something? At it's worst, the helical will have as much grip as an open diff, so I don't think it's much to worry about.

11-06-2006, 01:20 AM	#77
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	well the diff is off the car, i just got it in the housing and the cover back on, havent put any fluid in it yet, i cant really turn the output shaft that hard or fast plus with no differential fluid in it there is alot more friction on those cone washers. I am wondering now if it is bad for the differential to have as much preload as i have on it. I have heard that with higher preload it responds quicker though, i just dont want to tear it all apart again to lessen the force of the preload. I dont think it will be too much of a problem, the worst that can happen is those conical washers could wear down from rubbing against each other, but even then it wont really cause anything adverse. check this out should be helpful if you don't completely understand what i am talking about. http://rbryant.freeshell.org/obx_washers

11-16-2006, 12:06 PM	#78
silnismo Zilvia Addict Join Date: Sep 2006 Location: NJ! Age: 37 Posts: 730 Trader Rating: (2) Feedback Score: 2 reviews	i know this was disscussed, but never reached an answer, Can a VLSD work with OBX HLSD? or does the VLSD have different gear ring & bearing? i am also deciding if i should get the OBX unit...

11-19-2006, 02:40 PM	#83
turtl631 Zilvia Addict Join Date: Aug 2004 Location: Milwaukee WI Posts: 900 Trader Rating: (3) Feedback Score: 3 reviews	I'll probably be getting one of these soon. Are backlash standards universal, that is, do I have to bring the specs to a shop or can I just show up with the open pumpkin and the new OBX unit? I'm hoping it'll be more in the $100-$150 range. My friend here in Atlanta got an S15 installed in a pumpkin for $200. That seems pretty steep considering the backlash on those is usually right at stock levels anyways! So just any transmission shop should be able to do this? Sorry about all these noob questions, I don't know anything about this stuff.

11-19-2006, 06:24 PM	#85
turtl631 Zilvia Addict Join Date: Aug 2004 Location: Milwaukee WI Posts: 900 Trader Rating: (3) Feedback Score: 3 reviews	Hm, so it might be more economical to pay more for an S15 diff and just drop it in than to get a cheaper OBX and end up paying for shims and install. I would do it myself but I don't have a dial indicator and stand, vice, bearing pullers...this is kind of out of the practical range of my apartment workspace. I'd rather have a used Nissan part than a new OBX one anyways; I guess this just seals the deal for me.

11-20-2006, 12:29 PM	#87
turtl631 Zilvia Addict Join Date: Aug 2004 Location: Milwaukee WI Posts: 900 Trader Rating: (3) Feedback Score: 3 reviews	Yep, I think I'm gonna go the S15 route rather than deal with shimming. The OP noted that his had 0 backlash when first installed, so I doubt a straight drop-in is a good idea with the OBX. I'm tired of gambling on things and having them take forever to get right. S15 HLSD, J30 finned diff cover, and 4.36 ring gear for me.

07-01-2007, 01:19 AM	#88
adamky Leaky Injector Join Date: May 2007 Location: Kentucky Posts: 50 Trader Rating: (5) Feedback Score: 5 reviews	Sorry to bump an old thread, but I'm new here and didn't feel like creating a new thread. I just installed this diff tonight. Only was able to drive it for less than 30 minutes, but so far I like it. I tried dropping the clutch from a red light, and both tires began spinning and the rear stepped out to the side a little. Banged 2nd and there was no wheel spin at all. (Car is mostly stock, KA-T to come eventually.) Also had a chance to take a really tight U-turn, so I floored it. The inside tire squealed but the car just kept pulling forward. Concerning install... we were able to reuse everything and the diff dropped right in. Only hard part was the "snap rings" that hold the output shafts in. Those had to be removed from the open diff and placed in the new diff. This was quite difficult and time consuming, but there is probably a special tool that can really speed that up. Once we had them swapped into the new diff, the output shafts popped in easily. The guy who helped me with this is a friend/co-worker who has done quite a few diff swaps in domestic rear ends. After dropping the diff in, we checked mesh pattern, and everything seemed good. He was very impressed by the size/beefiness of this "import diff". Overall, I love this thing. Favorite mod to my car so far. Coming from an open diff, it's like a night and day difference.

07-09-2007, 12:58 PM	#89
timtiminy Zilvia Addict Join Date: Feb 2006 Location: Socal Posts: 624 Trader Rating: (0) Feedback Score: 0 reviews	thanks adamky. So what is the most noticeable difference that you had? most noticeable in handling, or off the line traction? I specifically got mine for grip driving as i figured it would be best suited for grip. I can't wait to feel what it will be like getting on the throttle earlier coming out of corners and feeling the push of the rear end grip.