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Front LSD vs a VLSD


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42 replies to this topic

#1 1-3-2-4

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Posted 05 April 2011 - 12:24 PM

My message was not deemed good enough in the other thread...

Anyways I want to know what makes a helical front LSD so dangerous over anything else? understeer?

#2 renob123

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Posted 05 April 2011 - 12:48 PM

My message was not deemed good enough in the other thread...

Anyways I want to know what makes a helical front LSD so dangerous over anything else? understeer?


Zap likes to keep his threads very tidy, so I'll put my front LSD info here. I haven't had enough time with it to establish any concerns about over/understeer. The thing that makes it dangerous is that when you corner, then hit the gas, it wants to straighten out the steering wheel very quickly.

The people on NABISCO probably don't notice that because they have power steering. I think it's great, though, because in rallyx, the steering wheel straightens out by itself faster than I can turn it back. If you're not as big as me, and you drive like a retard, though, it'll probably get you into trouble.

Jacob

#3 1-3-2-4

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Posted 05 April 2011 - 01:36 PM

ah I see I would not mind a little quicker return to center with PS.

#4 Twitch de la Brat

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Posted 05 April 2011 - 07:02 PM

How much did that front H-LSD cost you?
I've been hunting around for one, before going for a rear which would only do
me good in 4WD. (Rears are a lot easier to come by as well)

Twitch

#5 GeneralDisorder

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Posted 05 April 2011 - 07:28 PM

OBX through ebay - you can "buy it now" for $358:

http://cgi.ebay.com/...sQ5fAccessories

And yes - I can confirm that this will fit ANY 5MT including the D/R from '85 to '06 at least..... it will work beyond that if you change axles in the newer stuff....

I'm not sure Jacob really stressed this enough - it casters itself back to center in a HURRY. Like the wheel is almost a blur even at low speeds of 20 to 30 MPH. If you are an idiot driver - you definitely do not want one of these. If you let go of the wheel the car will basically instantly straigten out and continue going wherever it was pointed when you let go......

GD

#6 renob123

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Posted 05 April 2011 - 07:32 PM

How much did that front H-LSD cost you?
I've been hunting around for one, before going for a rear which would only do
me good in 4WD. (Rears are a lot easier to come by as well)

Twitch


Oh yeah, I mentioned a while ago that I'd tell you when I was considering selling my VLSD. That time is approaching.

The helical cost me about $400 from eBay. It's the OBX one. There's a thread on it on NABISCO. There didn't seem to be too many issues/failures with it, so I opted to give it a shot.

I'd forget about hunting. Any used one will go for a lot of money, and a new one aside from the OBX will be even more. There's always Phantom Grip, but lots of people dislike it.

Jacob

#7 Twitch de la Brat

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Posted 05 April 2011 - 07:36 PM

OBX through ebay - you can "buy it now" for $358:

http://cgi.ebay.com/...sQ5fAccessories

And yes - I can confirm that this will fit ANY 5MT including the D/R from '85 to '06 at least..... it will work beyond that if you change axles in the newer stuff....

I'm not sure Jacob really stressed this enough - it casters itself back to center in a HURRY. Like the wheel is almost a blur even at low speeds of 20 to 30 MPH. If you are an idiot driver - you definitely do not want one of these. If you let go of the wheel the car will basically instantly straigten out and continue going wherever it was pointed when you let go......

GD


Thanks GD.
I did a quick search via Yahoo to see what I could come up with.
I saw that one.

I understand about the massive reaction of the steering wheel.
I will definitely be easy on it and get used to it after I get one installed.
I have a feeling it will greatly improve the handling and stability of my BRAT
and Legacy in low traction situations.

Twitch

#8 edrach

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Posted 06 April 2011 - 11:20 PM

Getting back to the cost aspect. $350 to $400 for a front LSD unit; what's the cost in time and/or money to have it installed in a 5MT gearbox?

#9 Scoobywagon

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Posted 07 April 2011 - 05:40 AM

I've not had this done, so this is really just an educated guess. That said, I'd treat this as a front diff rebuild in terms of labor. Book time for R&I on the trans (5MT in a 93 Legacy wagon) is 6 hours. Most transmission shops that I know of have shop labor rates right around $100 per hour. That's from memory and its not quite 4am, so take it for what its worth. I don't know what book time is on the front diff. My guess is probably somewhere around 8-10 hours.

#10 Twitch de la Brat

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Posted 07 April 2011 - 10:39 AM

So basically a weekend project with some buddies and a case of your fave brew :)
Sounds like a doable upgrade if you have the skills and time.

It may be one of my first tranny splitting experiences :)
I wonder if Monstaru would be willing to help out for a half rack???

Twitch

#11 renob123

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Posted 07 April 2011 - 11:20 AM

If you're on an IWSTI.com budget, you'd get the Quaife and have a shop do everything. If you're on a USMB budget, I'm betting most people would prefer to buy the one I have and do the work themselves.

Edrach: I'm sure James would give you some kind of senior discount:lol:

Jacob

#12 GeneralDisorder

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Posted 07 April 2011 - 02:30 PM

If you're on a USMB budget, I'm betting most people would prefer to buy the one I have and do the work themselves.

Jacob



Agreed - but I don't think there's a high percentage of members here that have the skills to do it. No offense to the crowd but proper setup on the front diff is a pretty critical operation.... you were there when I did your's and it took me.... probably a couple hours (?) to get it setup where I was comfortable with it. And that's *just* setting the R&P clearances. That's not dissasembly and reassembly and if you are going to install a $400 front diff upgrade then you would be pretty foolish to not also install $150 worth of new syncro's and replace any suspect bearings *at the least*. I bet I have 30+ hours into that transmission of yours with reaserch on part numbers, dissasembly of a couple donor tranny's, and all the work pressing the shafts apart and back together again.... it's a mess inside these things and if you aren't experienced with bearing fit's, press work, and precision measureing, etc.... DO NOT attempt it. You will just end up throwing away a lot of money.

GD

#13 renob123

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Posted 07 April 2011 - 02:55 PM

Agreed - but I don't think there's a high percentage of members here that have the skills to do it. No offense to the crowd but proper setup on the front diff is a pretty critical operation.... you were there when I did your's and it took me.... probably a couple hours (?) to get it setup where I was comfortable with it. And that's *just* setting the R&P clearances. That's not dissasembly and reassembly and if you are going to install a $400 front diff upgrade then you would be pretty foolish to not also install $150 worth of new syncro's and replace any suspect bearings *at the least*. I bet I have 30+ hours into that transmission of yours with reaserch on part numbers, dissasembly of a couple donor tranny's, and all the work pressing the shafts apart and back together again.... it's a mess inside these things and if you aren't experienced with bearing fit's, press work, and precision measureing, etc.... DO NOT attempt it. You will just end up throwing away a lot of money.

GD


My comments aren't geared toward the flatbills that may be lurking here. I doubt they'd make it this far into reading a thread like this. They're for the people on here that take these things apart and put them together. In Edrach's case, his transmission is a pretty recent rebuild, and his synchros work very well.

Also, I'm betting with practice, you'd get faster:)

Jacob

#14 grossgary

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Posted 07 April 2011 - 03:26 PM

I think GD talked me out of the idea! I've pulled motors apart but that sounds miserable. When I checked a few years ago I couldn't find enough information on reliability to bite the bullet on one, I think I even posted on here about it. I'd want one that's going to last 100,000 miles at least.

Would this OBX helical be any good for daily driving and snow covered roads or probably not? Given the number of switch backs i have to drive every day from my house the snapping back doesn't sound too good.

If I paid a transmission shop to install it - is the R&P set up something they'd be familiar with (common to trans rebuilds/diff set ups) or is that something you wouldn't trust to anyone?

#15 GeneralDisorder

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Posted 07 April 2011 - 03:49 PM

I think GD talked me out of the idea! I've pulled motors apart but that sounds miserable. When I checked a few years ago I couldn't find enough information on reliability to bite the bullet on one, I think I even posted on here about it. I'd want one that's going to last 100,000 miles at least.


I don't see why the diff itself wouldn't last that or more. There's not much to go wrong in a Torsen type 1 (the OBX "Helical" is such an animal). It's just a bunch of gears that bind with each other in turns..... nothing to wear like a clutch type and no fluid to break down like a viscous.

Would this OBX helical be any good for daily driving and snow covered roads or probably not? Given the number of switch backs i have to drive every day from my house the snapping back doesn't sound too good.


Jacob would be a better source for this question. It's going to be more "work" to drive the car with a lot of switch-backs, etc.... but I imagine with power steering it wouldn't be nearly as much.... but I would expect the power steering to actually "help" the diffs ability to recenter the wheels so it would still be something you would need to get used to and pay close attention in turns because it does affect how the car pulls.

If I paid a transmission shop to install it - is the R&P set up something they'd be familiar with (common to trans rebuilds/diff set ups) or is that something you wouldn't trust to anyone?


If it was a shop that is familair with Subaru transaxles then I would say..... probably. But a very respected Subaru performance shop in WA quoted the kid who Jacob bought the '96 STi tranny from something like $1500 to rebuild it. Which is rediculously low considering what needed to be replaced on the transmission. In fact if it weren't being used expressely for rally-x racing and I were actually going to charge someone for parts and labor I wouldn't have rebuilt it at all - the gears were chewed up something feirce from a bearing cage that "went missing" :rolleyes: into 5th gear.... 5th gear was totaled and completely unusuable and 4th, 3rd, and 2nd had enough wear that they make a "ghost turbo" whine when you are in them.... this would have been enough for me to condemn the transmission to the scrap heap if I were a legitimate business and a man-off-the-street wanted it rebuilt. Either that or it would need a whole new gearset and that would run about $1500 just for the parts. How they could have possibly quoted $1500 for parts and labor is beyond me - unless they didn't see the gear wear and were planning on reusing them.... at which point I would have to say their tech was incompetant because there's no way you could use 5th and with how much metal went through it all the primary bearings were suspect as well. Add in the syncro's, labor, etc.... not happening for the quoted price.

GD

#16 renob123

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Posted 07 April 2011 - 04:15 PM

I don't see why the diff itself wouldn't last that or more. There's not much to go wrong in a Torsen type 1 (the OBX "Helical" is such an animal). It's just a bunch of gears that bind with each other in turns..... nothing to wear like a clutch type and no fluid to break down like a viscous.



Jacob would be a better source for this question. It's going to be more "work" to drive the car with a lot of switch-backs, etc.... but I imagine with power steering it wouldn't be nearly as much.... but I would expect the power steering to actually "help" the diffs ability to recenter the wheels so it would still be something you would need to get used to and pay close attention in turns because it does affect how the car pulls.



If it was a shop that is familair with Subaru transaxles then I would say..... probably. But a very respected Subaru performance shop in WA quoted the kid who Jacob bought the '96 STi tranny from something like $1500 to rebuild it. Which is rediculously low considering what needed to be replaced on the transmission. In fact if it weren't being used expressely for rally-x racing and I were actually going to charge someone for parts and labor I wouldn't have rebuilt it at all - the gears were chewed up something feirce from a bearing cage that "went missing" :rolleyes: into 5th gear.... 5th gear was totaled and completely unusuable and 4th, 3rd, and 2nd had enough wear that they make a "ghost turbo" whine when you are in them.... this would have been enough for me to condemn the transmission to the scrap heap if I were a legitimate business and a man-off-the-street wanted it rebuilt. Either that or it would need a whole new gearset and that would run about $1500 just for the parts. How they could have possibly quoted $1500 for parts and labor is beyond me - unless they didn't see the gear wear and were planning on reusing them.... at which point I would have to say their tech was incompetant because there's no way you could use 5th and with how much metal went through it all the primary bearings were suspect as well. Add in the syncro's, labor, etc.... not happening for the quoted price.

GD


I consider the whine a benefit because it makes it sound like I'm driving a WRC car:)

As for daily driving, I've been daily driving mine since it got put in. It's obvious that I have a monstrous traction advantage, and I haven't really noticed it being inconvenient in any way. Given how it worked in the mud in the last rallyx, I'm betting it would be a marked improvement over any other Subaru 5-speed. Having power steering, like GD said, would probably make it more of a thing to get used to, rather than in my case, where it's a thing that requires more strength and grip.

Jacob

#17 1-3-2-4

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Posted 07 April 2011 - 05:10 PM

has anyone ever did a rear LSD?

#18 GeneralDisorder

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Posted 07 April 2011 - 05:42 PM

has anyone ever did a rear LSD?


The vast majority of LSD discussion here and elsewhere is *about* rear LSD's. Those come stock on many models from the mid-'80s on. All WRX's and STi's have them as well as my '91 Sport Sedan (SS) and many others including some turbo Foresters, and Outback XT's, etc. The other recent post by Zap in this section deals entirely with rear LSD's and what people have noticed about how they react depending on type.

GD

#19 1-3-2-4

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Posted 07 April 2011 - 05:51 PM

But the older models used a VLSD? I swear someone had a site up that showed what years used what.

#20 GeneralDisorder

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Posted 07 April 2011 - 05:56 PM

But the older models used a VLSD? I swear someone had a site up that showed what years used what.


No - older models used a clutch-type LSD. The VLSD was (AFAIK) introduced on the '91 SS (in the US) though there has been rumor of 3.9 VLSD's coming out of XT6's.... aparently it may have been an option that you could order.... '80s models all used the clutch-type though. No production models have used anything but viscous since the late '80s with the exception of the STi. And no production models have come with front LSD's except the STi. All you can get (stock) in anything that isn't an STi is a VLSD since '89.

GD

Edited by GeneralDisorder, 07 April 2011 - 05:58 PM.


#21 1-3-2-4

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Posted 07 April 2011 - 06:14 PM

Hmm I see I found a site that talks about the subaru rear diffs I guess for use on Nissan cars all the 80's models seem to be 3.70 or 3.90

#22 GeneralDisorder

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Posted 07 April 2011 - 06:33 PM

As far as anyone can tell - they are all 3.7. The *mythical* factory 3.9 LSD hasn't shown up that I have seen. You can take the guts out and put them into any other ratio diff including 3.9, 4.111, and 4.444. It's not a hard swap.

GD

#23 1-3-2-4

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Posted 07 April 2011 - 06:38 PM

As far as anyone can tell - they are all 3.7. The *mythical* factory 3.9 LSD hasn't shown up that I have seen. You can take the guts out and put them into any other ratio diff including 3.9, 4.111, and 4.444. It's not a hard swap.

GD


I just checked ebay and I saw nothing unless I searched wrong.. most everything was all new rear diffs from a forester XT or wrx or the sti.

#24 GeneralDisorder

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Posted 07 April 2011 - 06:40 PM

Why would you check ebay? I don't understand what you are trying to determine using ebay as a reference??

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#25 1-3-2-4

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Posted 07 April 2011 - 06:56 PM

I wanted to see what the going rate was...




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