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So I just picked up one of these....Subaru Front LSD


whitetiger

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here

http://www.torsen.com/products/products.htm

http://www.torsen.com/files/Torsen%20Traction%20Differential%20Technical%20Sheet.pdf

 

 

ther are 3 different types of torsen diffs, 1 of them being a helical type. I wonder which is in the sti and 07+ spec b rear. From whatr i understand, the subaru front helica i have is a similar design to the type-2 torsen diff.

subaru-http://www.rallispec.com/images_thumb/rst1903.jpg

 

Torsen t-2- http://www.torsen.com/images/T2color2.jpg

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Yeah. For the rear I am actually thinking about putting clutch type diff, not Torsen. Have both (:rolleyes:). Bought the clutch one real cheap in anticipation of 6spd swap, and the tranny I ended up buying came with Torsen in the package.

 

I believe clutch is better for serious road racing, rallying and bad winter conditions. Stock JDM SpecC STI comes with clutch type, so FHI must think so as well. Torsen without traction becomes open diff unlike the clutch type.

 

For the center I'll just keep the VLSD... going to DCCD is too expensive unless I came accross a cheap take-off, but these are rare.

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Got front helical LSD installed in my 08 SpecB tranny at Rallitek in NJ. Will know how it works in few weeks after I put the tranny on the car.

 

Btw, install on 6-speed is pretty easy. I did not realize the bellhousing comes off separately so there is no need to disassemble the transmission unlike on 5-speed. Still one has to deal with adjusting backlash, getting the drive axles bearings adjusted properly and the side retainers require special tools.... better left to pros, I guess.

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Spoke to Jeff with DS1, Mfactory's LSD won't be out until 2009. I've been having a hard time sourcing a RST-1903 from Japan as they are on backorder. Jeff happened to have just put a RST-1903 into the shop's LGT and sold it to me for a good price.
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  • 2 weeks later...
  • 2 weeks later...

Whitetiger, I too am awaiting serious snowfall since getting my HLSD installed by RalliSpec back in March. yes, unclemat is correct, I had an 06 STI front HLSD installed in my 6MT. I think I'm one of the few (if not only) 07 USDM specB with 3 LSDs (2 mechanical and 1 viscous; fortunately I have an R180 rearend, stock).

 

It was also in my plans to upgrade from 215 RE050's to 225 at some point...and that point came earlier than expected when I found a hole from glass in one of my tires (yay, I get to upgrade...booo, I get to over-extend my funds), so I stepped up to 225 Michelin PS2 tires and that elevates the game even FURTHER!!!

 

And that's exactly it, power on in the corner and it's like the car is pulling itself through the corner (well, that's cause it is) and launches itself out of it!

 

I did loads of research before settling on the Helical design for my DD. I wanted low maintenance, seamless operation and proven reliability. I don't truly rally the car (so having 1 wheel off the ground is not really going to be an issue in the daily environment) so there was no real need to have a clutch pack front LSD.

 

Only daily scenario that would suck is being on sheer ice, as no tire would have better traction (in a true sheer ice situation).

 

But now, I'm back on 205 Nokian snows and am salivating at the upcoming snow storms (no more ice storms PLEASE!!)

 

Enjoy whitetiger and unclemat...now Christmas will be anyday there is snow on the ground and no one around!

"If we are to guard against ignorance and remain free, it is the responsibility of every American to be informed." - T. Jefferson
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  • 1 month later...

http://www.rallispec.com/Layout/product_titles/title_rst1903.gifhttp://www.rallispec.com/Layout/spacer.gifRST-1903 Subaru Helical Front LSD

 

So that is the part number? I should be able to get from my dealer or KOP?

 

Any special shimming required on install?

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Crap... I can't remember who but somone already dropped the STI HLSD into spec. B 6MT.

 

I believe that was GatorGT

 

nm - just saw his post above.

- Pro amore Dei et patriam et populum -
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So that is the part number? I should be able to get from my dealer or KOP?

 

Any special shimming required on install?

 

 

I dont think a regular deal can get it. Order it from rallispec.com Its where I got mine.

 

with any diff install, preload and backlash must be set properly. You'll want a knowledgable shop to install this for you.

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Hello all,

 

I have 2 questions and I would like both WhiteTiger and unclemat to comment as well as anyone else with relevant experience.

 

1) Is the front LSD that WhiteTiger purchased from Rallitek usable on both the regular 5MT and the Spec-B 6MT ? If not, which aftermarket one would do ?

 

I am looking to upgrade to a front LSD and a 6MT but I am not sure I have the money to do both at the same time. I understand the costs of taking the 5MT apart and installing the new diff but it is probably less expensive than taking/adding the front LSD to the 6MT which also requires the new rear torsen LSD.

 

2) If I choose to upgrade the front LSD, do I also have to upgrade the rear oem LSD ? If so, to which one ? Or can they function together ? I think Whitetiger already has an upgraded rear diff.

 

3) Who made this front LSD ? It is not an OEM part in another market is it ?

 

4) Was it money well spent ? While there are other things I could improve on the car like suspension, I really feel that a front LSD is what I want compared to say: coil-overs and bigger turbo and bigger intercooler. (currently pro-tuned Stage 2)

 

 

Thanks.

 

f1

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Ad 1) 5MT and 6MT parts are not interchangeable.

 

Ad 2) No.

 

Ad 3) Subaru in both cases. There are aftermarket units as well.

 

Ad 4) Don't know yet. Car has new engine and I've not had opportunity to push it yet.

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Btw 6MT LSD is easy to get because it's stock USDM STI part. Costs less than $500 new.

 

5MT LSD is JDM only and costs like $900 or so. I am not sure if it ever came stock, it probably did on old school STIs.

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Btw 6MT LSD is easy to get because it's stock USDM STI part. Costs less than $500 new.

 

5MT LSD is JDM only and costs like $900 or so. I am not sure if it ever came stock, it probably did on old school STIs.

 

Where did you buy the Spec B tranny and for how much and plz. answer the same for the 6MT LSD ? Given that it is so much easier to change, I would likely do both. You can also PM me if you deem necessary.

 

Also for the love of God, please tell me what is your rpm at 60 mph in 6th gear. I have seen a million calculations here that it makes little to no difference but I just never saw an rpm readout at 60 or 70mph. I would not upgrade to the 6-MT in order to better cope with insane horsepower...if and when I upgrade the turbo, I will level off at 300 whp which is more than plenty for me and the current 5-MT trannies do take it well (already have the better clutch).

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