6 speed conversion.. making my f*@King head spin!!
 

Hi everyone,

So I'm currently assessing whether a 6 speed conversion is going to be viable.

Everywhere I look, I'm getting slightly different information.. and its mainly due to the options that are out there!!!

So I'm looking at getting some answers to my questions.

1. Is the front suretrack diff in some 6 speeds (non-DCCD and 05 and earlier DCCD boxes) really crap like everyone says?

2. Can I run the DCCD unpowered in an 05 and earlier 6 speed and have 35:65 split i.e. same as Cusco Tarmac Gear?

3. What is actually required to get the 6 speed to work in my configuration.. I know that clutch/flywheel, shifter, starter motor, etc are required, but what else? Can I just bolt in the front shafts, or will I need to change hubs?

4. How many different ratios are there? I'm under the impression that there is close, normal and "long".. I think they were in the Forester and USDM STi's?

5. What should I be paying for a front to back setup including R180 and does anyone have anything for sale??

Cheers :)

have you spoken to doug (dtrally) at all joe? he does drive-in drive out conversions ;) if you want to buy your own... kris (sku81) on rexnet sells them really cheap and will supply you with all the extra stuff you need (auto tailshaft is required too iirc)

I have spoken to Doug, but rather than constantly annoying the sh*t out of him with questions, I was going to do my own research before making a decision :)

You will also need a speedo drive fitted to allow the cruise control to work IIRC.

I thought the 07 and earlier 6 speeds have mechanical speedo drive?

Its the Legacy and 08 onwards boxes that didnt..

05 has the highest split 65:35, but also has short ratios..

Ratios are identical from 02-05 i think changed to long in 05 but split is 59:41 i think??

I dont think u need new hubs unless u swap out the front diff?? and yeah the front diffs are average, i would get a cusco tarmac front and rear plated diff if u are going to track car..

if its going stay as a show queen then just get the normal diffs..

i think u really only need to swap out the rear diff but dont need to change hubs to do so??

1. The main downside of a suretrac LSD is that when the oil gets very hot, the LSD starts to behave more and more like an open diff. This is not a problem on the street. You will never be able to get the gearbox oil hot enough on the street for this to become a problem.
And even on the track, you have to be doing a fair few laps before the oil becomes hot enough to affect the operation of a suretrac LSD.

2. Yes, you can leave DCCD unpowered and it will behave like a cusco tarmac diff. My DCCD 6 speed spends 99.9999% of its time with no power going into the DCCD.

3. At a bare minimum, you will need: Gearbox, front stubs and seals (if using a post 2002 6 speed), clutch fork, 6 speed trans mount, 6 speed gear linkages, 6 speed gearknob, tailshaft and matching ratio R160 diff.
You can re-use your current front hubs and shafts, but because they will be female shafts, you will need stubs from an auto box to convert the front shaft output on the 6 speed from female to male. You also need 5 speed seals put into the 6 speed box as the conversion stubs have a slightly smaller diameter than 6 speed shafts. This is all assuming you use a 2003 or newer 6 speed. 2001/2002 6 speed is PNP with front shafts.
Stubs are around $100 a pair and seals are around $60 brand new from Subaru.

If I remember right, you have a Fidanza flywheel and Exedy Sports Tuff clutch. You can keep them. Its already a good setup so no point in changing it and it will work just fine with a 6 speed.

4. I think there are 4 different ratios to choose from. If you are going DCCD, there are only 2 to choose from. Close ratio (JDM 2003-2005) and long ratio (ADM 2006+) with the taller 5th and 6th.

5. Something like a 2005 DCCD + Plated R180 setup I would estimate to be around $8000-8500 mark drive in drive out

Thanks for that!

So an 02 STi 6 speed wouldn't require front stub conversion?

.. and 02-05 6 speeds (DCCD or not) have a suretrack in the front?

Sounds to me the best option would be an 02 6 speed with a Cusco tarmac gear and some sort of plated rear.

Does my clutch and flywheel bolt on, or are mods required to get it to work with 6 speed?

2002-2004 DCCD has a suretrac front LSD
2005 DCCD has a torsen helical but still retains the 35:65 DCCD.
2006-2007 DCCD has torsen front LSD and 41:59 DCCD
2008+ is the same as 2006-2007 but it has no speedo drive and no internal oil pump.

2001/2002 wont require front stub conversion. 2003 onwards requires it. But its not difficult or really expensive to get stubs and seals so dont worry about it too much.

Your current 5 speed clutch, flywheel and starter motor is bolt on for a 6 speed gearbox. No mods required. The only thing is you MUST use the 6 speed clutch fork with the 5 speed clutch/flywheel setup.

Once you buy a 6 speed and a cusco tarmac center diff. With the cost added together, you may was well get a DCCD 6 speed. You dont have to run the DCCD controller right away.

Good to read - Will want to do this when the 5 speed begins to feel a bit worn in mine. Still feels pretty tight, but have a vvveeerry minor notch when going into fourth sometimes, and i can't pop it into first when going any more than 10-15km/h.