Cheap and Effective TorSen Front LSD for Subaru 5MT

[BrandonDrums]

As most of you guys know by now, the stock WRX/Impreza 5MT comes with an open front diff. That's fairly okay in AWD configuration although it induces more understeer than you'd really want. Well, there is a fairly inexpensive and effective option. The OBX TorSen LSD

http://www.eracingzone.com/ProductDetails.asp?ProductCode=OBXLSD39

There's a huge thread on this on NASIOC. Many of the guys buy the new unit but replace the belleville washers and ring gear bolts as they are really the only weak link.

Here's the Nasioc thread with one of the better post series on how to upgrade the unit
http://forums.nasioc.com/forums/showthread.php?t=700370&highlight=obx+diff&page=26

Here's R Bryant's OBX upgrade store, he sells full Belleville and Bolt upgrade kits for the OBX diff
http://rbryant.freeshell.org/obx_washers.htm

I'm considering going ahead and doing this to my WRX weather or not it ends up in an 818 one day. Since it's a fancy Torsen style diff vs. a clutchpack or viscus coupling since it can transfer the majority of the torque to the wheel with grip vs. 50/50 which is essentially torque vectoring. The reaction time is also instant.

Don't be fooled by the price, there are weak points but it's easy to fix them, subaru guys have run some insane torque numbers through these with no issues after upgrading.

Just FYI. Hopefully I didn't miss a whole thread going over this same stuff.

[StatGSR]

+1, i have actually heard good things about OBX LSDs so long as you rebuild them and properly torque them before putting them into use.

[Exidous]

The biggest downfall to this type of diff is that if one wheel is not touching the ground they become useless. I have one in my Rx-7 (helical style factory) and couldn't be happier for a street car. For the Rx-7 I'd go with a Quaife unit due to weight and torque. (ls swap) but the 818 would be perfect for the cheaper OBX.

[BrandonDrums]

The biggest downfall to this type of diff is that if one wheel is not touching the ground they become useless. I have one in my Rx-7 (helical style factory) and couldn't be happier for a street car. For the Rx-7 I'd go with a Quaife unit due to weight and torque. (ls swap) but the 818 would be perfect for the cheaper OBX.

True but so does the factory open diff. Most of the things I post are about cheap and effective more than being the top of the line option. There is some quite extensive feedback on that nasioc thread about these. If you ever did find yourself with one wheel in the air on an 818, you've either wrecked or are about to. If not, a little left foot brake will provide enough resistance to get the TorSen diff to lock.

[riptide motorsport]

Someday all this info you guys have been giving me is going to "click" and make great sense to me. Funny how if it were US stuff I would get it in a second.......but then again I'd already know it!

[SixStar]

Bumping from the dead a bit, sorry.

So just so everyone is on the same page - Torsen is a brand name like Kleenex, torque biasing differential or TBD is the generic name like tissue. And technically a TBD is NOT an LSD fyi. They will work until you unload. That said if you're lifting a rear wheel on an 818 you have other issues!

We're going with a smaller company for our TBDs, they've been rated to 400whp and proven to over 1200. I have one in my SCCA Solo car and it ROCKS! We have a few spares new in the box and some already inside rebuilt 02-05 WRX transmissions if anyone is looking (shameless plug, just trying to help, don't kill me!)

:D

[Mechie3]

Too bad nobody makes inexpensive ones for the 06 transmission with male axles.

[Stickshift84]

I bought a Carbonetic LSD (1.5 way clutch type) for my 06 tranny. Not installed yet but it comes with female splined ends and would require adapter shafts to fit in an earlier WRX. Best part is it was 673 shipped. The worst part of this LSD is maintenance and expensive oil.

[SixStar]

Too bad nobody makes inexpensive ones for the 06 transmission with male axles.

All you have to do is run 02-04 front axles.

02-04 axles are female, trans has male stub shafts coming out of the diff

05-07 axles are male, trans has two gaping holes

Here's the diff we're using - 20019

[RM1SepEx]

I had to do the same thing with the Quaife installed in my 05 trans.... just bought new axles for 02-04 with female CV joints

[freds]

I had to do the same thing with the Quaife installed in my 05 trans.... just bought new axles for 02-04 with female CV joints

I had to do the same thing with the OBX installed in my 06 transmission.
Just got an email saying my FFR axles have been shipped today and will be here next week. Then I can finish the axle assemblies.

[longislandwrx]

How much did you pay for oem Subaru axles/cvs?

I'm not sure aftermarket units will work with the FFR supplied axles

[freds]

How much did you pay for oem Subaru axles/cvs?

I'm not sure aftermarket units will work with the FFR supplied axles

Jim cautioned me that Cardone axle splines are definitely not the same as Subaru and so Cardone CVs could not be used with the FFR supplied axles. There might be other aftermarket CVs that do have axle splines that are the same as Subaru. We don't know (yet).

Your question brings up a good point. If your Donor has aftermarket Axle assemblies you may have to get genuine Subaru CVs!

I've been checking prices and have asked FFR to ship my axles early....and I'll have them next week.

Prices:

New Subaru CVs (and you can buy them separately...ie don't have to buy complete axle assemblies) cost about $240 each.

Salvage axle assemblies cost about $70 each....and without the FFR axles to check, buying "unseen" you may not get genuine Subaru parts.

So either way you are in for at least $300 and a max of $1,000 for new.

I anticipated a problem and in January/February asked about the mismatch problem before I actually installed my OBX LSD. (on the forum and to FFR). No one actually answered my question and I even got a mild flame or two saying the question had already been asked and FFR was supplying...etc. Anyway I couldn't wait so took the gamble and installed the OBX figuring I could sort it out later. That's what I am doing now and am going the salvage route. I have the necessary CVs now all cleaned and ready to assemble with new boots and grease and a missing end-cup which Erik is kindly sending me.

That's the full story so far

[C.Plavan]

All you have to do is run 02-04 front axles.

02-04 axles are female, trans has male stub shafts coming out of the diff

05-07 axles are male, trans has two gaping holes

Here's the diff we're using - 20019

Where can I get one of those? And is this who I think it is in Colorado? Matt?

[fateo66]

Where can I get one of those? And is this who I think it is in Colorado? Matt? Matt is not on the 818 band wagon just yet but he is keeping a close eye on the projects.

[longislandwrx]

Where can I get one of those? And is this who I think it is in Colorado? Matt?


http://www.flatironstuning.com/p-1973-modena-front-tbd-for-the-02-07-wrx.aspx

ain't too much poppin' off in Colorado without these guys.

[SixStar]

Keith, nice to meet you.

And those are Modena's, Matt makes them.

[carrera1984]

My trans is an '08. The OBX LSD should work correct? (everything FFR spec'ed for an '03 wrx doner). what stub axles(or part) would i need? 02-05 Right? I would imagine i need different seals too then. My trans never came with the '08 male stubs anyways.