6 speed consideration

SVXMAN2001 · #1 02-15-2017, 07:24 PM

Hi all, i've come across a 6 speed jdm transmission EI-TY856WB-AA. For this particular transmission i'd also get the rear diff, front and rear axles, drive shaft, used clutch, flywheel, pressure plate, slave cylinder. Because this has the R180 rear differential, I need to have the sti's axles as well correct?

Any need for the front axles? This seems to be sold as a complete package, however what else should i ensure or ask to include if available for the swap?

Thanks in advance. Chris

Svx95 · #2 02-16-2017, 02:39 AM

Chris,

To answer your question, in addition to everything you listed (minus the driveshaft, you will re-use the SVX driveshaft) you would need a master cylinder, pedal assembly(clutch and brake pedal), and the axles all around. (You can for sure re-use the SVX front axles in the 6 speed trans but you won't be able to reuse the rear axles from the SVX in the R180 because the stubs in the rear axles are different in the R160 vs the R180)

Just a heads up (maybe you have a specific reason to go with this transmission) why pick up such an old 6 speed swap, I mean a version 7 is from 2001, 2002 at best. Just imagine how beat up that thing is and for the price of $3000K, plus I'm sure that doesn't include shipping. There are many swaps listed online some on ebay and many others through the known subaru parts dismantlers (tae, subaru parts, just jap imports,etc..) from early 2004 up to 2008 models that can be had for $3500 shipped. Shop around and good luck.

-Sam

SVXMAN2001 · #3 02-16-2017, 06:50 AM

Thanks Sam, I appreciate your advice.

I've been researching options on the network and elsewhere and am getting differing results. When using the 6 speed, do I have to use the R180 rear differential? As I understand the R180 is larger than the stock SVX differential (R160) and requires modification to fit. If possible, I'd like to remain with the stock differential.

92 SVX · #4 02-16-2017, 07:01 AM

Quote:

Originally Posted by SVXMAN2001

Thanks Sam, I appreciate your advice.

I've been researching options on the network and elsewhere and am getting differing results. When using the 6 speed, do I have to use the R180 rear differential? As I understand the R180 is larger than the stock SVX differential (R160) and requires modification to fit. If possible, I'd like to remain with the stock differential.

The Rear diff will need to have the gearing match to the transmission, if that is a jdm early version 6 speed it might be 4.44 geared which means you would need 4.44 geared rear diff. And while the R180 is larger and does require a bit of clearanceing it also has mechanical (stronger) LSD

If you get an 06 or newer 6 speed it does use the 3.54 rear diff that the svx has so you could just replace the trans and leave the rear diff stock, That is what I did, however eventually I want the R180 for the benefits I listed.

Tireiron · #5 02-16-2017, 02:11 PM

Only the USDM 06 and 07 STi 6MT have a 1.1:1 center differential and use a 3.54 rear differential. That is the only 6MT that would allow you to retain the factory r160 rear diff without changing the gearing in the r160.

The r180 requires such minimal modifications to fit that it is totally worth doing. You will use the STi rear axleshafts with it, which also makes replacing shafts in the future easier than sourcing the correct rear SVX shafts.

You can use the front SVX shafts by adding the stub shafts and seals into the 6MT, although some of the older 6MT already had the shafts in them. Adding the shafts is incredibly easy so that is not a worry.

I used the SVX driveshaft, but I have heard the STi shaft is the same length and works for the swap, best to check the length and confirm. It certainly will make sourcing a driveshaft easier if the STi one is the same length.

Some of the older 6MT are non-DCCD and may be a better option if you do not plan to add a DCCD controller. Although a 6MT with DCCD will work perfectly fine without a controller, you will not get the full benefit of the center diff without it.

As mentioned you will need a clutch and brake pedal set. I used a set from a WRX/STi (mine was an '05 specifically but that whole body range has the same ones). I also swapped the brake booster in from the WRX/STi which made the linkages bolt right up. You will have to cut the firewall for access to mount the clutch master cylinder and will need the line to the slave cylinder. It is a tight fit under there, but after pulling the auto tranny wiring harness back into the car there is a little room at the firewall. I had to modify the SVX gas pedal a small amount just to get it to clear the clutch rod, it just had to be shortened a small amount.

92 SVX · #6 02-16-2017, 09:25 PM

Quote:

Originally Posted by Tireiron

Only the USDM 06 and 07 STi 6MT have a 1.1:1 center differential and use a 3.54 rear differential. That is the only 6MT that would allow you to retain the factory r160 rear diff without changing the gearing in the r160.

The r180 requires such minimal modifications to fit that it is totally worth doing. You will use the STi rear axleshafts with it, which also makes replacing shafts in the future easier than sourcing the correct rear SVX shafts.

You can use the front SVX shafts by adding the stub shafts and seals into the 6MT, although some of the older 6MT already had the shafts in them. Adding the shafts is incredibly easy so that is not a worry.

I used the SVX driveshaft, but I have heard the STi shaft is the same length and works for the swap, best to check the length and confirm. It certainly will make sourcing a driveshaft easier if the STi one is the same length.

Some of the older 6MT are non-DCCD and may be a better option if you do not plan to add a DCCD controller. Although a 6MT with DCCD will work perfectly fine without a controller, you will not get the full benefit of the center diff without it.

As mentioned you will need a clutch and brake pedal set. I used a set from a WRX/STi (mine was an '05 specifically but that whole body range has the same ones). I also swapped the brake booster in from the WRX/STi which made the linkages bolt right up. You will have to cut the firewall for access to mount the clutch master cylinder and will need the line to the slave cylinder. It is a tight fit under there, but after pulling the auto tranny wiring harness back into the car there is a little room at the firewall. I had to modify the SVX gas pedal a small amount just to get it to clear the clutch rod, it just had to be shortened a small amount.

Couple of things, from what I see the 08+ Sti continue to use the 3.54 rear diff, problem with them for our purposes the speedometer reading is off the ABS sensors so the 08+ transmission does not have VSS. That being said Mapdccd makes a ABS to speedometer converter. It might be worth it for the extra's that the converter gives you such as the ability to input tire size and have the speedometer read dead on.
As I bolded absolutely I would/will change out my R160 for the R180 when I get funds enough

As to the underlined, No all the impreza line have a shorter wheel base, the sti 6 speed driveshaft would fit the wrx auto trans cars though.

SVXMAN2001 · #7 02-16-2017, 09:26 PM

Great info guys. I've been researching TAE auto parts and they seem to have a good supply. However, further research has shown that if I were to go with the R180 differential, I would also need the hub/knuckle as well? Apparently the axles associated with the R180 are larger in diameter and require the wrx/sti hub assembly for fitment.

If this is true, shocks and struts would need to be modified as well no? I can't imagine everything else bolting right up to the knuckle.

A quick question on the R180 (3.9 final drive ratio) vs the R160 (3.54 final drive ratio). If I were able to obtain a 2006-2007 6 speed as mentioned above, i could remain with the stock svx rear differential. Will this mean that my final cruising speed would be similar/exact to the auto? meaning, at 60 mph in 6th i'd be at about 2k rpm?

Thinking this through (i am doing a lot of calculations and reading, while writing this)...the rear differential associated with the 6 speed is the R180 with a 3.9 final drive ratio, however effectively 3.54 due to the 1.1:1 center differential, correct? So then i'd have two options, remain with the stock svx differential and if i so choose down the road go with the 180 which would require modification for fitment and the WRX/STI axles, correct?