Re: lsd FAQ(GIVE YOUR OPINION WELDED VERSUS LSD)KEEP IT SHRT AND TO THE POINT

[monstaru]

"Which Subarus do I look at to find an LSD?

 

Clutch-Pack LSD:

1985-1986 (production up to 3/86) XT 4WD is listed with a 3.70 LSD option (Subaru part # 7220 11000).

1986-1987 (production from 4/86-10/86) GL 4WD is listed with a 3.70 LSD option (Subaru part # 7220 11001).

1986-1991+ (production from 11/86) Loyale/GL 4WD is listed with a 3.70 LSD option (Subaru part # 7220 11002).

1988-1991 GL and XT-6 4WDs with single range transmissions are listed with a 3.90 LSD option (Subaru part # 22011 GA022).

July 1986 onwards LSD assembly (just the carrier) is also available new from your Subaru dealer if you wish (Subaru part # 22049 GA010).

Viscous LSD:

1991-92 Legacy 4WD turbo 4dr sports sedan is listed with a 3.90 viscous LSD option (Subaru part # 27011 AA131 or maybe 27011 AA070 -- the manual is unclear about the AA070 unit).

Any Subaru's since 2000 that came with an LSD came with a viscous unit.

 

Here is a table of various newer AWD Subarus with their respective drive ratios and VLSD Availabilities:

(from Wayne Chin http://wac.addr.com/auto/obs/lsd/lsd.html )

Model Year Model Trim Transmission Front Ratio Center Ratio Rear Ratio Rear VLSD

1991-1992 Legacy Turbo AWD 5MT 3.900 1.000 3.900 Yes

1992-1997 SVX AWD (R-180 VLSD?) 4EAT 3.545 N/A 3.545 Yes

1993-2001 Impreza 1.8L, 2.2L AWD 4EAT 4.111 N/A 4.111 No

1993-2001 Impreza 1.8L, 2.2L AWD 5MT 3.900 1.000 3.900 No

1998-1999 Impreza 2.5RS 4EAT 4.444 N/A 4.444 No

1998-1999 Impreza 2.5RS 5MT 4.111 1.000 4.111 No

2000-2001 Impreza 2.5RS 4EAT 4.444 N/A 4.444 Yes

2000-2001 Impreza 2.5RS 5MT 4.111 1.000 4.111 Yes

2002-2003 Impreza 2.5RS 4EAT 4.444 N/A 4.444 No

2002-2003 Impreza 2.5RS 5MT 4.111 1.000 4.111 No

2002-2003 Impreza TS, Outback Sport 4EAT 4.111 N/A 4.111 No

2002-2003 Impreza TS, Outback Sport 5MT 3.900 1.000 3.900 No

2002-2003 WRX 4EAT 4.111 N/A 4.111 Yes

2002-2003 WRX 5MT 3.900 1.100 3.545 Yes Other North American Subaru models with VLSDs, either as standard equipment or available as an option:

• 2000-2002 Forester S (All Weather Package)
  
  
• 2003 Forester XS
  
  
• 2000 Legacy GT, Outback
  
  
• 2001-2003 Legacy (all)
  
  
• 2003 Baja
  
  

NON-LSD

Most R-160s you see under Subarus will NOT be an LSD. There were no LSDs of any kind in 1995-1999 Subarus.

Look for the following Subaru part numbers (look at the foil sticker for part number and ratio):

7220 11010: 3.70 ratio

7220 11011: 3.70 ratio

7220 11012: 3.70 ratio

6220 06020: 3.90 ratio

6220 06021: 3.90 ratio

6220 06022: 3.90 ratio

27011 AA151: 3.90 ratio

27011 AA040: 4.11 ratio

27011 AA110: 4.11 ratio

27011 AA111: 4.11 ratio

 

 

 

 

What do the various differentials weigh?

 

• R-160 Subaru LSD (w/o mustache bar or stub axles) = 50lbs
  
• R-180 open diff from '83 Maxima (w/o mustache bar or stub axles) = 60lbs
  
• R-200 open diff from '87 200sx V6 (w/o diff mount attached without stub axles) = 75lbs
  
• He also weighed an open R-160 from a 510 and an R-200 LSD. They are both within 1-2 lbs of the weights listed above.
  

What's the deal with Phantom Grip LSD units?

Phantom Grip units are advertised as a way to convert an open differential into an LSD unit. They run $250-$300, and have applications for R-160 and R-180 differentials. From the looks of it, all this unit does is spring-load the side gears against their washers, turning them into half-assed clutches, while adding a wedge ramp to increase the pressure as the side gears try to turn relative to the cross shaft. There are several problems with this approach. First, those side gear washers have no clutch material on them, and the Phantom Grip unit doesn't appear to come with any that do. (Not that it would do much good, there being no provision in the differential case for a proper stack of frictions and steels.) As this unit operates, you're gonna be wearing away the side gears and differential case. With the spring pressure against them, but without the waffle surface of a clutch disc, there's not much opportunity for lubricant to get into the side gear washers. Since the "clutches" are just metal-on-metal, and running virtually without lubricant, the breakaway characteristics are not going to be very progressive, or predictable, as things heat up. The wedge ramp also induces stresses on the differential case that it was never designed to handle. When (not if) this unit chatters, the wedge ramps are gonna be trying to split the differential case in two. Incredible testimonials aside, this seems to be a very poor substitute for a proper LSD, and way overpriced for what is essentially a couple machined plates and a few springs. I would certainly not consider the Phantom Grip in the same league as PowerTrax or Air Locker."

What about other aftermarket Clutch-Pack LSDs?

With the popularity of higher-powered Subarus, as well as increased use of the 240sx in drifting, there are many quality Japanese aftermarket Clutch-Pack LSD units. Choices include Cusco, ATS, KAAZ, and Tomei Trax, with prices from $900 to $1500. Not all brands are available in R-160, R-180, and R-200 sizes, so check for actual applications to be sure. OEM LSD units usually have two pinion gears. Most of the aftermarket units have four pinion gears, theoretically making them stronger. The aftermarket units vary in construction and clutch plate material (steel alloys, carbon fiber) as well as mode of action. They usually have between 12 and 24 clutch plates, which depending on how they are assembled, can vastly vary the locking action of the unit, allowing the owner the ability to "tune" the LSD to their car and driving preferences. Furthermore, many of these differentials can be purchased in 1-way, 1.5-way, or 2-way configurations. 1-way units act as an LSD upon acceleration only. 1.5-way units act as an LSD on acceleration, as well as to a lesser extent on deceleration, but with less understeer than the 2-way units. 2-way units have full LSD action on both acceleration and deceleration. Some of the units can be easily changed from 1-way to 2-way, etc. Because of the tremendous hype surrounding the various brands, it is hard to know which unit to use, so do your research before your buy. "K.M. Hafer

 

 

There is an age old debate about an LSD against a welded diff.They will both argue that this one is better than that one.I have used both and honestly think that it is a moot point.I break ************ no matter what. I prefer the welded diff, but i do not offroad rocks very often , well, not like they have on the west side of the state......

 

I have had and built several r160 diffs.i have LSD'd 5 different diffs. i have welded 3 diffs. i dunno, a lincoln locker is cheap , LSD's are some coin....

MOnstaru......

 

some threads.....

 

http://www.ultimatesubaru.org/forum/showthread.php?t=105317&highlight=welded

http://www.ultimatesubaru.org/forum/showthread.php?t=101721&highlight=welded

Edited January 19, 2010 by monstaru

[monstaru]

To the top for opinions.if you have not run both , only speak of which you have run.if you have not run either, don't even try......i don;t want "my buddies jeep wrangler has a locker and it is cool....."

we are talking about subarus.and subarus only.......this is not a debate as to which is better.this is an informative selection of statements.cheers, brian

[The Beast I Drive]

I have run both.

 

The Clutch Type LSD is excellent in a car with small tires like a Hatch with 27's or an RX with stock-ish size tires. Its awesome for rally-style driving and offroading with smaller tires. They are almost worthless off-road with 31's though, the clutch disks are just too small.

 

For what I do and because I have such huge tires, I now run a welded rear diff, and I wont ever go back. Full traction, no clutches to burn, positive lock, etc. The downside is the tires chirp when I make tight turns, big deal.

 

Some people will say you will break more stubs or axles with a welded diff than a LSD. This has not been the case for me, I broke more stubs with my LSD because it still allowed my wheels to slip and spin, and when they suddenly caught traction the stubs just snap. With the welded rear both tires spin the same all the time, no matter what.

 

IMO, both are excellent, but you need to have the one that will suit your needs.

 

-Bill

[idosubaru]

The LSD is nice but my use is more utilitarian, like hunting, driving around my property. I don't do hard core or off road for fun (well it's fun but it's never the goal i guess) so I'm not pushing the limits. So I've never really thought about trying welded.

 

I think I notice it most when pulling someone or something heavy, seems less likely to start slipping if I'm on a slick surface.

[WoodsWagon]

LSD vs Open diff is a huge improvement. I mostly noticed it in mud, wet loose ground, snow, and climbing the car up out of pits. The rear end of the car would push much harder and help the car get up stuff without using near as much momentum. Once a rear wheel comes off the ground you are SOL though. You can shock load the rear diff which will momentarily lock it up, enough so that you can get the car back off of whatever obstacle you got stuck on. You will be replacing the rear output gears in the transmission shortly thereafter though. I snapped 2 stubs on my LSD. I snapped 0 stubs on my open diffs but I grenaded the spider gears out of 3 of them.

 

LSD's wear. Finding one in good shape is a crapshoot, though you can adjust the preload on the clutchpack to some extent. I think a lot of people that say they're worthless probably had a badly worn one. When I was running RWD for a bit, I could do effortless donuts on dry pavement with 30" tires. So they can lock up pretty hard if they're in good shape.

 

I commuted 350-400 miles a week so a welded diff wasn't an option.

[Gloyale]

I like Welded for some things. It definately makes for a more unstoppable wheeler.

 

But I got tired of swapping in and out my rear axle. I Put my Open diff back in. Nice thing about it with my lifted GL, is 7 bolts and 2 pins and the diff can be swapped back out. So I'll carry the Welded diff in the cargo area if I go somewhere hardcore and swap it out before the trail.

 

But for winter espescially, I Preffer open so I can keep both axles in adn be ready to use my 4wd at a moments notice. (having Dual front Ebrakes helps alot too)

[WRX2FFU]

I like LSD's They work well for most applications.

 

I have not run a welded diff in a subie so...

[SoobieDoo]

I never tried LSD.

I run with a welded rear and drive 'bout 60 miles round trip from work. Most of the time I just pull an axle, but I have gotten lazy and commuted locked also. U-turns, parallel parking, etc...no big deal. Yes, the tires chirp some, but I think most people first notice the fact that it's a lifted subaru. Tire wear is minimal too. The front drive tires will get more wear anyway. Off road it is the best traction available, period.

[NinjaTech]

Is there a rebuild kit for the LSDs?

[Numbchux]

LSD vs Open diff is a huge improvement.

 

This!!

 

 

I haven't run a locker/welded diff in a subaru. But have had substantial experience in other vehicles.

 

I did have a clutch-type LSD in my lifted '88 for a couple years. I always said the best way to think of it, is once you're teetering on 2 wheels, an open diff means you have zero forward power. When there's no resistance on the other wheel, an LSD will transfer about as much power as a person pushing on the back of the car.

 

Ever been hung up, teetering, and had a buddy get out and push? Yea, just like that.

 

 

obviously, in that situation a locked diff will transfer 100% of the torque. of course, that's a lot of torque to be put through one corner, and when the suspension at that one corner is compressed, the CVs aren't the weak link. the diff stubs are.

[backcountrycrui]

I am considering one of these options in my GL> Can someone talk more about the snow and ice driving with the welded rear end. Specificaly in a commuting mindset? I have never driven a vehicle, locked up, on the road at all, so this is a great thread.

Mike

[monstaru]

THIS IS NOT A DISCUSSION THREAD> THIS IS FOR ADDITIONS TO THE FAQ!!!!!!!

go start another thread if you wish.or search, that always helps......

[Subarutex]

My name is Tex. Not a whole lot of people remember it, but I used to offroad my wagon.

 

I went from Open to Welded very quickly. I felt the car didn't go anywhere "cool" with it open, but that all changed when I went welded.

 

Constant traction, made me feel unstoppable. As long as you are smart, you pretty much are!

 

With both rear axles in, mileage goes down. When turning on pavement, it chirps/binds.

 

I broke one stub axle, once. I drove welded (both axles in, TSL swampers) to Spokane... wheeled some, drove home, wheeled some, and then tried showing off for some friends with car flexed out and rear tire jammed into the wheel well. Tire hit car, I goosed it. Pop. Good thing about welded though... I pulled off the axle, and continued on my way!

 

I also have owned an 2 RX's, both with LSD's. For road cars, they are amazing. Great in the wet. Keeps the car from pushing in the corners like the welded makes you. My old RX I took up plenty of logging roads, and it never failed to get me through.

 

LSD's perform much better in snow than welded diffs. Car is much more predictable.

 

For pure offroad performance, I recommend a Toyota and solid axles... or a welded rear diff.

 

I recommend to make a list of what you DO with your car (not what you WANT to do, but what you actually use it for). One column for on road stuff, one column for offroad. Figure out which has the most, and install the appropriate diff.

 

For pure onroad performance, I recommend a LSD rear diff.

[backcountrycrui]

THIS IS NOT A DISCUSSION THREAD> THIS IS FOR ADDITIONS TO THE FAQ!!!!!!!

go start another thread if you wish.or search, that always helps......

 

Did search, found answers, had more questions. Im not asking for a discussion, just elaboration. Just like subarutex and others have already put in hear, opinions about their experiences. So thanks for answering my request. Again great thread.

Mike