6-spd conversion vs. 5-spd?

[McTaff]

Plz lock and redirect if this has been asked but:

What are the differences between doing a 5-spd and 6-spd conversion; and,
Can someone submit a nice in-depth set to SVXipedia?

I'm considering the swap, and I'd like to go for the 6MT instead of the 5MT. I'd like to know what technical and build differences I'm going to encounter should I choose to accept this mission. (This isn't a money-is-no-object project, but I will keep re calculating the financial position as we go.)

Is there a final drive ratio conversion for this? (Excuse my ignorance if not!).
Should we be looking for a lighter rear driveshaft or flywheel or anything crazy, or will dropping the tranny in as per 5MT going to be no trouble?
What other ease-of-use mods are useful on this type of setup (can you wire the internal neutral circuit as per http://www.subaru-svx.net/forum/showthread.php?t=26596 for instance?)?

Driveability and reliability are my primary concerns. Obviously an SVX that is continually stalling like a mongrel, or that continually spits clutch bearings out is no good.

The goal: I'm looking to do the brakes first, and then the tranny, suspension and exhaust at around the same time. I may then consider the ECUTune Stage III S/C, depending on how this all works out. Subafreak seems to be the man on the spot here , as he has the advantage of "been there done that".

I've seen lovely cradles being built and so on, but unfortunately aquiring anything from the states is not an easy task - I'm in Australia and for the most part I'll be stuck to getting the instructions, measurements and super-explicit instructions from my bretheren in the US and forwarding them on to others to build for me if required.

Input is welcomed, and if everyone gets energetic and starts co-writing a huge technical book, I'll pay my US$49.95 to get one if it's published.

Cheers,
McTaff

PS. My baby is a '92 Black on Pearl White. She enjoys long drives, high octane fuels and social outings with her younger brother, my '93 Black on Gun Metal Grey.

[mbtoloczko]

There's quite a bit of info on the network, but its dispersed among many threads. There are a couple options for the 6MT swap.

Option 1:
6MT (incl clutch slave cyl, throwout bearing, and front stub axles)
5MT/6MT clutch & flywheel (incl pilot bearing)
5MT/6MT clutch master cylinder
6MT shift linkage
6MT starter (USDM WRX starter will also work)
6MT tranny mount
5MT/6MT pedal assembly
custom rear cross member
R160 3.90 ring and pinion to install in SVX rear diff

Option 2: same as Option 1 except...
use R180 rear diff instead of R160 3.90 ring and pinion
6MT front half shafts
6MT rear half shafts

Option 2 provides a stronger rear diff. (The SVX half-shafts are already pretty strong). Unless you are pushing really big HP, option 2 isn't really necessary. Even then, its not absolutely necessary. The biggest advantage of option 2 is that the LSD in the R180 has a stronger coupling.

There are several different 6MTs available:

1) JDM 6MT with DCCD center diff and Suretrac front diff.
These are expensive and a DCCD controller is needed which adds another $800 or more to the cost. The DCCD can only operate in manual mode which isn't so great.

2) JDM 6MT with viscous center diff and Suretrac front diff. Probably the best option, but these are difficult to come by. They were only installed on a few MYs.

3) JDM 6MT with viscous center diff and open front diff. Very common, so not too expensive. Open front diff is not so performance-oriented.

4) USDM 6MT.
These are all DCCD with a Suretrac or helical front LSD. DCCD controller needed. Different gear ratios than JDM 6MT.

I'll let someone else fill in the details on the 5MT swap and add corrections to my 6MT swap.

[McTaff]

Originally Posted by mbtoloczko

There are several different 6MTs available:

1) JDM 6MT with DCCD center diff and Suretrac front diff.
These are expensive and a DCCD controller is needed which adds another $800 or more to the cost. The DCCD can only operate in manual mode which isn't so great.

2) JDM 6MT with viscous center diff and Suretrac front diff. Probably the best option, but these are difficult to come by. They were only installed on a few MYs.

3) JDM 6MT with viscous center diff and open front diff. Very common, so not too expensive. Open front diff is not so performance-oriented.

4) USDM 6MT.
These are all DCCD with a Suretrac or helical front LSD. DCCD controller needed. Different gear ratios than JDM 6MT.

Thanks!

Any ideas on what the breakdowns of the model/years for each of the JDM vehicles? (1 -> 3 you listed here?)

And what is the deal with the controller and manual mode only? (Is there a glossary of terms somewhere for this site? I run into so many acronyms here that I nearly have anuerisms reading it )

[svxpert]

mbtoloczko , whats the torque split if you don't use a DCCD controler in the USDM 6 speed. i have the 6-speed but no controler yet. thanks

[mbtoloczko]

Here's a chart that shows which MYs had which tranny:

http://www.rallispec.com/Transmission%20chart.htm

The controller can only operate in manual mode because there are some sensors that are absent from the SVX that the controller needs to operate in automatic mode. No one that I know of has been able to make a DCCD controller work in auto mode in a car that did not originally have the DCCD controller.

With no controller, the center clutch on a DCCD tranny is wide open (no LSD action), so the torque split is 36/64.

[Subafreak]

The six speed is stronger and slower in the 1/4mile becouse you shift alot. And it tops out around 130mph.





Not feeling real technical right now.

[svxpert]

thanks for the reply. is that torque split 36/64
36 front
64 rear

or the reverse?
thanks

[mbtoloczko]

36 front/64 rear

[black beast]

so a 5sp is faster? wow never would have thought that

[mbtoloczko]

But its not stronger. The 6MT also weighs about 100 lbs more than a 5MT. Another reason why the 5MT is faster.

[Earthworm]

Originally Posted by black beast

so a 5sp is faster? wow never would have thought that

But not as fastAr as an SRT-4

(sorry...had to do it once)

[TomsSVX]

the 5mt is more practical and has a couple different final drive ratie options. For someone who is looking to enjoy the speed of a naturally aspiratd engine or some mild mods, the 5mt is great. It turns some great times in the 1/4 mile and tops out around 145(i haven't done it so im lost on if thats right) The availability of the 5mt is probobly it's biggest plus, not to mention that 2 5mt's are cheaper than 1 6mt(I keep a spare trans in the garage )

On the other hand, the 6mt is more for big power applications. It is the strongest mt that suby ever came out with and will be a nice fit in the SVX. I have heard that the shifting can get to you quickly and the top speed and highway rev's are not too practical. If you are looking to run the stage 3 S/C I would suggest the 6mt. If you are looking for a fun car to drive around with some kick and play at track also the 5mt is probobly your best bet. Either way the mt in the SVX is a joy for me and many of the other owners who have them.

Tom

[Subafreak]

Originally Posted by tomssvx

the 5mt is more practical and has a couple different final drive ratie options. For someone who is looking to enjoy the speed of a naturally aspiratd engine or some mild mods, the 5mt is great. It turns some great times in the 1/4 mile and tops out around 145(i haven't done it so im lost on if thats right) The availability of the 5mt is probobly it's biggest plus, not to mention that 2 5mt's are cheaper than 1 6mt(I keep a spare trans in the garage )

On the other hand, the 6mt is more for big power applications. It is the strongest mt that suby ever came out with and will be a nice fit in the SVX. I have heard that the shifting can get to you quickly and the top speed and highway rev's are not too practical. If you are looking to run the stage 3 S/C I would suggest the 6mt. If you are looking for a fun car to drive around with some kick and play at track also the 5mt is probobly your best bet. Either way the mt in the SVX is a joy for me and many of the other owners who have them.

Tom

Well put.

[Rotorflyr]

For those running the 5mt, how much would you say it changes the GT nature of the SVX in comparison to the auto.
Jesse can sit this one out as I have seen his car, and cool as it is, other changes he has made kill the GT aspect of it reguardless

[TomsSVX]

my suspension is bone stock, infact my struts are shot. My car still sticks to the road but seems to flop around. Anyway, I love the drivabilityof this car and it's comfort is unsurpassed by any other car I have driven. I think it is a sports car now since it does perform very well but still has it's gt atributes

Tom