6 Speed Buildup/Versions Recommendations

[SilverSpear]

Ok, the time has come for me to buy another 6 speed for the SVX, from the US. I am not in a hurry (I am flexible in a 3 months time), just waiting for the perfect price/location opportunity since I have a guy who can ship it for me is located in MA.

I read a lot about the 6 speed with and without DCCD and I want the one with DCCD. I also read about the guy Spiider who sells DCCD controllers for these trannies and I think I am gonna go this way.

Now I understand that there are two US versions of the 6mt DCCD, one which came out in the early 2000" and the other in 2005. I will be noobish in this and say that I discovered that the early 6speeds have a male type centre diff while the newer ones have female type similar to our stock autos.

I have read here and there about detailed swaps and stuff (sicksubie's for ex) and just to make things clear here are the Q's:

1- Can I buy the +05' 6MT/R180/Shifter/Pedals/Fork/Clutch/Slave MC/etc... and use my stock axles? In terms of strength, are the +05' axles stronger than the SVX's?

2- Any difference in performance/strength on the SVX between the early US 6MT, +05' US 6MT? What about the JDM 6MT?

3- Which (OT or YT) version 6MT DCCD do you recommend? In terms of strength and least costly in terms of parts needed to fit it in the SVX? Please take into consideration the interchangeable parts of the SVX.

4- What specific custom (SVX related) bits do I need for my project other than the tranny mount? Any seals/panels/ needed that we usually forget (because of the major parts)? Recommended sources?

5- Any other updated recommendations for the build-up? Anything related to the rear Diff versions?

And YES I have read the How-To Docs, this thread is just a question and parts more specific/refresher/new sources related.

Thanks in advance.

[Sov13t]

I have 04 USDM. The main difference between USDM and JDM are gear ratios, USDM is more friendly to highway cruising (~3k at 80mph) while JDM for high RPM acceleration (drag - i guess). Could be wrong on this.

You will be using STi rear axles, while keeping your front axles stock. I have kept my DCCD disconnected thus far, but am interested in purchasing a unit to manage it.

As far as versions, the SVX in it's stock and even everything that we have had in history of modifications can not even make the 6spd break a sweat... it is a very beefy transmission and per STi guys would require ~600bhp to start entering iffy territory.

Hope my .02 is useful,
-Sov13t.

[SilverSpear]

I have 04 USDM. The main difference between USDM and JDM are gear ratios, USDM is more friendly to highway cruising (~3k at 80mph) while JDM for high RPM acceleration (drag - i guess). Could be wrong on this.

You will be using STi rear axles, while keeping your front axles stock. I have kept my DCCD disconnected thus far, but am interested in purchasing a unit to manage it.

As far as versions, the SVX in it's stock and even everything that we have had in history of modifications can not even make the 6spd break a sweat... it is a very beefy transmission and per STi guys would require ~600bhp to start entering iffy territory.

Hope my .02 is useful,
-Sov13t.

Sure Sov13t, your assistance was definitely useful. I might also have given you some hints about who provides one of the best aftermarket DCCD controller for the STi (Spiider).

The side of the front axle in the SVX where it meets tranny, is it male or female? Because the early STi gearbox are males and their axles are females. I thought the SVX's axles are males.

[Sov13t]

Oh, if that is the case I guess with 05+ you would be using all 4 sti axles.

Sorry, I guess with 04 it doesn't apply to me.

Do you have any links on this Spiider guy? Does he make units with accelerometers that judge vehicle's force vectors and adjust vehicles power distribution?

[Sov13t]

Found him... looks interesting... might get one towards the end of the month and play around with it. Cheers!

http://dccdpro.com/main/?page_id=17

Will let you know how that goes :)

[SilverSpear]

Oh, if that is the case I guess with 05+ you would be using all 4 sti axles.



I meant the other way around :o

[SilverSpear]

I meant the other way around :o

Ok here is what I mean. The SVX axles are all male (Pic stolen from zombie (http://www.subaru-svx.net/forum/member.php?u=7320)):

http://www.tc.umn.edu/~deba0016/4SALE/IMG_2074.jpg

Here is a picture of the 2004 STi 6 speed:

http://img411.imageshack.us/img411/8880/2004stii.png

and here is the +2005 STi 6 speed:

http://img696.imageshack.us/img696/4148/2006sti.png

You can see clearly that the +2005 STi 6 speeds can use OEM SVX axles whereas pre 2005 cannot.

Any help guys?

[Gamesy]

ummmmm the front svx axels that attach the front diff are female. I remember because of the issue with the the pin i had in when taking my tranny out.
That pic of the svx axels has the axel stub still connected to it. I think all subaru tranny's are male( no pun intended :P) just some people find it easier to just pull the axel stub out with the axel instead of risking mushrooming the pin.

here's a pic

[TomsSVX]

If you get a 6mt that needs male axles...

Go buy a pair of front axle seals from subaru for the SVX 4eat

Remove the axle stubs from the 4eat, install them with the seals into the 6mt.

Its that easy, now you can use the stock front axles

Tom

[Boxersix]

The 04-05 6mt's have the earlier DCCD that can fully unlock, while the later gearboxes have center diffs that have a different internal mechanical transfer that still keeps the torque split going some 35% to the front. in the 04-05's, when you cut the signal to the DCCD the torque is heavily biased rearward, nearly making the car RWD in essence. I drove my WRX/EG33/04-6MT without a diff controller for a few weeks. Can't do that in the 06+ w/o burning up the DCCD clutchpack.

I'm also running the DCCD Pro Delux Auto controller. It is a superb piece for the price and does have yaw/pitch sensing via a 2 axis g-sensor and TPS input. Selectable between an auto or manual mode, and a pot to dial in the aggressiveness of the diff. Jeff(the owner/builder) is a GREAT guy and you WILL NOT find better customer service and support from any other diff controller manufacture. Period. He is that nice of a guy. His units have virtually no flaws. My only gripe is that in my car I get driveline binding at very low turning speeds(parking), but I just solve it by wiring in a switch to the DCCD PRO interrupt wire(also hooked to my shifter and my ebrake to S-flick/rotate the car). I flip the switch when parking and it cuts the DCCD power, thus unlocking the diff and eliminating any chance of binding. It's highly likely that the low speed binding is due to the gearbox fluid I'm running and not the controller itself.

Once moving under power(above ~7mph) it performs flawlessly.


Also the gear ratios between 04-05 and 06+ are different so pick your poison accordingly.

Also 04's and early 05's with the male stubs can remove the male stubs, and use the seals Tom mentioned, to fit male axles.

[BoxerFanatic]

just out of curiousity, and for future reference...

you mention different gearing...

Which is better for the H6? Something that has good pick-up in lower gears, and a nice tall cruise in 6th gear, smooth and easy, like the SVX 4EAT does... That is the one nice thing about the 4EAT... easy quiet cruising in top gear, once it slip-slide-shifts all the way to 4th.

Interesting stuff about the DCCD... sounds kind of like some of the Porsche Carrera 4 models that if you pull up one notch on the e-brake lever, and it dis-engages the front drivetrain for some RWD fun, but not enough up to actually engage the parking brakes at the wheels.

[TomsSVX]

just out of curiousity, and for future reference...

you mention different gearing...

Which is better for the H6? Something that has good pick-up in lower gears, and a nice tall cruise in 6th gear, smooth and easy, like the SVX 4EAT does... That is the one nice thing about the 4EAT... easy quiet cruising in top gear, once it slip-slide-shifts all the way to 4th.

JDM gearing is close ratio meaning it is a shorter ratio... My 6mt runs about 3800 at 80mph... USDM transmission with the lower gearing is only different in 5th and 6th gears allowing around 3200rpm at 80 if memory serves

Tom

[Crazy_pilot]

All 6MT's have the same ratios for 1-4. The JDM STi has the tightest 5th and 6th, followed by the USDM STi, and the JDM Forester STi has the tallest of all (best for highway cruising). The Legacy GT Spec B's 6MT has the same ratios as the Forester STi, but does not have a limited slip front diff.

IMHO, for the SVX the ultimate is the Forester STi's tranny. However, if you're looking to build a grand touring beast and not as concerned for the ultimate in performance, the Spec B's tranny will do you very well. The Forester 6MT is almost impossible to find though. Since I've known of this I've only seen one drivetrain imported. The Spec B's tranny can be had brand new for something like $3200.

[Boxersix]

JDM gearing is close ratio meaning it is a shorter ratio... My 6mt runs about 3800 at 80mph... USDM transmission with the lower gearing is only different in 5th and 6th gears allowing around 3200rpm at 80 if memory serves

Tom

Gear ratios change on 3/4 to space them more towards 5th and 6th gears. Supposed to have made the car "more drivable" but IMO the shorter gears are better.


GR's

04-06

Final 3.9:1
1st 3.64:1
2nd 2.38:1
3rd 1.76:1
4th 1.35:1
5th 0.97:1
6th 0.76:1

+07
Final 3.9:1
1st: 3.636
2nd: 2.375
3rd: 1.521
4th: 1.137
5th: 0.971
6th: 0.756


Biggest difference is the DCCD ratio(due to that DCCD design change i mentioned) which changed in '07 to 1.1:1 so the rear diff went from 3.9 to 3.54 so just make sure you match up the proper R180 if using the later gearboxes. The latest "fad" for the Sti guys is to swap in the '07 gearset. Weaksauce IMO

[TomsSVX]

the reduction is to help keep driveshaft revs lower... Great idea IMHO

Tom

[Boxersix]

the reduction is to help keep driveshaft revs lower... Great idea IMHO

Tom

This is true

[dynomatt]

Couple of things I found out

1) 05 onwards use larger axles, so although the SVX auto stubs will go in, you'll need to swap out the oil seals to the early 6 speed seals.

2) I had the Legacy ratios which were the same 1st to 4th, with the slightly taller 5th and 6th...didn't seem to make that much difference on the road, but for road cars, I would probably recommend it

3) The 05 or later STI's changed ratios from 2nd to 6th. They were very different...much wider spaced. Check out the following as an example

http://sti.subaru.com.au/showroom/impreza-wrx-sti/wrx_sti/hatch/specifications/

For my money, and for a road car, I'd reckon the lastest 6 speed out of the Legacy's might be a better option. Ratios even taller again, great for cruising, and nowhere near as heavy as the current STI 6 speed. Check out ther ratios (compared to the above link) here

http://www.subaru.com.au/models/liberty/2.5GT_Premium/sedan/specifications/all/

And before anybody asks, it's behind the current spec 2.5 turbo with 195kw and 300nm of torque. More than enough for an SVX.

Just my two bobs worth.

M

[BoxerFanatic]

All 6MT's have the same ratios for 1-4. The JDM STi has the tightest 5th and 6th, followed by the USDM STi, and the JDM Forester STi has the tallest of all (best for highway cruising). The Legacy GT Spec B's 6MT has the same ratios as the Forester STi, but does not have a limited slip front diff.

IMHO, for the SVX the ultimate is the Forester STi's tranny. However, if you're looking to build a grand touring beast and not as concerned for the ultimate in performance, the Spec B's tranny will do you very well. The Forester 6MT is almost impossible to find though. Since I've known of this I've only seen one drivetrain imported. The Spec B's tranny can be had brand new for something like $3200.

Good info..

I wish my Legacy GT were a spec B, although I did kind of think of them as a bit too $$$$ over the GT Limited at the time. Before the '10 Legacy showed how things could go so wrong.

But rather than finding a Forester STI gearbox... one would think that it would be easier to swap a front LSD into a Spec B gearbox for the same effect. Maybe an appropriate configuration Torsen, to match the rear differential's Torsen...

Both my Legacy and SVX have LSDs in the rear diffs, but open fronts... is there a big advantage for a front LSD in snow and such, vs. any drawbacks for dry tarmac driving, cruising drag, or steering resistance?

My previous vehicle was a 4x4 ranger, with no LSDs, and a transfer case, and it fought steering like crazy in the dry, if it was in 4WD, and HAD to be dis-engaged if the pavement was anywhere close to dry pavement...

I like the DCCD stuff, and the robust nature of the STI/SpecB gearbox, and the torsen rear diff (wife's Miata has one, too.)... but I would be interested to hear comparisons between an open front diff, and a front LSD equipped car, and which might be better suited toward SVX's GT role, not really an ice-racer/rally stage car. :D

[BoxerFanatic]

For my money, and for a road car, I'd reckon the lastest 6 speed out of the Legacy's might be a better option. Ratios even taller again, great for cruising, and nowhere near as heavy as the current STI 6 speed. Check out ther ratios (compared to the above link) here

http://www.subaru.com.au/models/liberty/2.5GT_Premium/sedan/specifications/all/

And before anybody asks, it's behind the current spec 2.5 turbo with 195kw and 300nm of torque. More than enough for an SVX.

Just my two bobs worth.

M


Just FYI... the '10 Legacy GT's 6MT... is a 5MT + another gear. from what I've read, the 5MT was a 4MT+1 before...

50/50 AWD. No VTD, No DCCD.

And it is cable shifted, not linkage shifted... not sure what implications that will have to retro-fit, and the shift action on the '10 is reported to be less direct.

And don't use the 05-07 Legacy GT clutch. 06+ WRX 5MT single-mass flywheel, and aftermarket clutch, or substitute an aftermarket flywheel as well. The OE 05-07 Legacy GT clutch is not that great for holding power, feel, or wear... and slipping even just a little bit makes the most horrible smell. That is something I do have experience with.

[TomsSVX]

open front diff versus LSD...

LSD helps counter the oversteer that the 6mt offers when cornering under throttle or heavy engine braking by using the understeer inherent with an LSD front diff...

As for the rear diff. It could be better, when I lift a wheel when cornering the LSD is not that great and I still have issues powering out w/o spinning the lifted wheel a lot

Tom

[McTaff]

Couple of things I found out

1) 05 onwards use larger axles, so although the SVX auto stubs will go in, you'll need to swap out the oil seals to the early 6 speed seals.

I was also going to point this out.

Depends on which axle stubs you use as to what you need to do - with mine, I needed to use SVX seals in the STi front diff, however I could have put a 1mm collar on the stubs themselves.

(I can't remember which stubs I have though!!)

[SilverSpear]

Thank you for your inputs guys, that was really helpful. Few more questions though, how can I make sure the tranny has front LSD? I need to know how can I check that out myself without "asking" the seller, any noticeable details?
And the second question, does the 2008 STi tranny fit our engine? I am pretty sure I have settled on the 2004, but this question is just for info, just in case.

Thanks in advance.

[Crazy_pilot]

Few more questions though, how can I make sure the tranny has front LSD? I need to know how can I check that out myself without "asking" the seller, any noticeable details?

Read this and be happy :D. Tons of good info.

http://forums.nasioc.com/forums/showthread.php?t=1225160&highlight=transmission+master+decoder+ring

[Pegdrgr]

Read this and be happy :D. Tons of good info.

http://forums.nasioc.com/forums/showthread.php?t=1225160&highlight=transmission+master+decoder+ring

Jeff has some great information in that thread, we used to post a ton of stuff like that. He is one of those sick guys who likes to stay up all night pulling PNs out of Japanese catalogs.

[SilverSpear]

Read this and be happy :D. Tons of good info.

http://forums.nasioc.com/forums/showthread.php?t=1225160&highlight=transmission+master+decoder+ring

Excellent post Chris, but he didn't mention if the US trannies had LSD :o

You can see that they are mentioned in the Japan/Eur ones.

[Seraphinwolf]

http://forums.nasioc.com/forums/showthread.php?t=1772793
and
http://forums.nasioc.com/forums/showthread.php?t=1489974

BAM!
PS best choice of 6mt's for us IMO is the 07' USDM STi 6mt.

Oh Tom did you ever get the DCCD all hooked up and working in your car BTW? I know you had an issue trying to get it set up after you first put it in.
04'/05' run a different FD ratio and front to rear slip bias than the 06'/07' BTW. Which is why I found an 05' specificly for my Impreza EZ30R turbo project, but I'd also personally look for a 07' for which ever SVX present or later I would swap.

[SilverSpear]

http://forums.nasioc.com/forums/showthread.php?t=1772793
and
http://forums.nasioc.com/forums/showthread.php?t=1489974

BAM!
PS best choice of 6mt's for us IMO is the 07' USDM STi 6mt.

Oh Tom did you ever get the DCCD all hooked up and working in your car BTW? I know you had an issue trying to get it set up after you first put it in.
04'/05' run a different FD ratio and front to rear slip bias than the 06'/07' BTW. Which is why I found an 05' specificly for my Impreza EZ30R turbo project, but I'd also personally look for a 07' for which ever SVX present or later I would swap.

Great info Gaddis! Thank you for the links.
But I am still convinced the best setup for me is the 04/05.

You have a lot of highways in the US, while we have a lot of mountains over here. Well it is mixed, there are some nice highways but a lot of traffic jams. I think the 3.9 final ratio will suit me the best.

[Seraphinwolf]

Great info Gaddis! Thank you for the links.
But I am still convinced the best setup for me is the 04/05.

You have a lot of highways in the US, while we have a lot of mountains over here. Well it is mixed, there are some nice highways but a lot of traffic jams. I think the 3.9 final ratio will suit me the best.

Sounds good. I mostly just speaking my opinion from a general average SVX. But yeah the 3.9 and the 35/65 F/R split is why I chose it for my Impreza.

[Pegdrgr]

I am not sure why someone posted you can't run the 07+ transmission with out connecting the DCCD controller. I have done that on a couple cars, including my own and it is fine. Actually With the DCCD Pro controller you can set it to that any time you want. If you have the base model rolling it to the rear applies no voltage to the controller. The automatic ones you can do the same, but they do not apply voltage to the differential until the conditions are such that it is setup to do so.

The main thing you will notice witht he 07+ is that it is a little harder to break the rear end loose without the DCCD controler, however once it does break loose the rear end will slide as long as you keep power to it. I happen to have the 08 transmission in my car as I do not need the speedometer output, and I don't have to have the tranny cooler. All of our customers who have driven the 07+ love the gearing better than any of the previous year.

Not saying one is right or wrong, just trying to add a little more information to the discussion.

For those interested in the DCCD Pro controller we really like them. We used to run the Neetronics controller, but once we moved to the Spiider we never went back. For a basic street/track car there is really very little fault to be found with the Spiider DCCD Pro unit. If you are running an STi dash you might consider the top model, but functinoally the middle model is the same, just missing the ability to control the display on the dash. The base model might work for someone wanting to save a few coins, but the automatic is pretty nice and worth the extra $100 or so.

Jarrad

[SilverSpear]

Wow, this thread came out better than I expected. I love feedback from people who have tried all 6 speed STi versions than rather reading theoretical specs.

So Jarrad do you prefer the 07 over the 04?

[Pegdrgr]

Absolutely! I only considered the 07 or 08 when I sourced mine. The jump from 4th to 5th in the 04 is unbearable for me, also I like the differential better in the 06+.

We recently put an 07 6 speed in a Forrester and the customer, who had driven older STis was very grateful we pushed him to wait for the 07. Then again last summer we put a 04 in a Legacy GT and the customer has been completely happy with it. I can actually drive mine in the snow with the DCCDPro set to full rear, while all reports from friends and customers says that the rear bias is too great on the 04-05.

We are in the process of putting a 04 6 speed into a 98 Impreza right now, but that is because the price was right. For obvious reasons you will commonly find the 04-05 for less than the 07.