Question about transmission possibility

[Henry]

In my ongoing plans to build an SLC or GT-R (on the Fence) I am still trying to find a quality yet cost effective trans to keep the build a financial possibility for me. $8-20,000K transmissions throw my hopes out the window when you add that to all the other costs like kit, engine, wheels, clutch, etc.

With that said Ive been digging around the Subaru STI 6 speed 6MT transmission. Is there a reason this can't be used? I can't find one. It holds over 600WHP, over 550lb/ft, and people abuse the snot out of them. I know some people looked into the 5MT from the WRX but it wouldn't hold the V8 tq. The 6MT is a much stronger unit and handle it. LSX motors have been swapped into the STI's and are holding up well. Best part is they only cost $2-3,000.

I plan to use a coyote 5.0 out of a F-150 and supercharge it for a good 550WHP. If this trans works I can achieve the whole drivetrain for less than $8K and keep the dream alive.

Thanks,

Hank

 

[Scott Rowland]

Four things come to mind. Axles, shifter, adapter, flywheel. You will be in relatively uncharted territory, which equates in cubic dollars unless you have access to much machining equipment and time.
It also looks abit long after the axle centerline also. Other than all of that, it would work great. Lol.

 

[Justin]

Another possibility is MAYBE the Porsche Boxster S transmission. Except, I've never heard whether or not it can be used in an SLC/GT-R. There's already V8 adapter kits for it. I think the main concern is where the axle shafts come out. I'm not sure though, as I've never seen one used in a kit.

 

[Henry]

Searching around I found this from Fran in this thread:
http://www.gt40s.com/forum/slc-clubhouse/38206-subaru-gearbox-slc.html

"Not very strong is one of the major issues...

not designed for V8 torque....not bad with a Scooby engine but even then the break...I know as I have a broken one on my shelf that came from an RCR shop WRX.

They can be used as the axles are long enough that the driveshaft angle is not too bad but they are also pretty long too...so OK with a race tail but not a street tail"

He is referring to the WRX MT5 which is not as stout as the MT6 found in STI's but the axels are the same length and stronger.

I'm not as educated on how the shifters work with transaxles but I dont see why it can't be remote like the rest. Completely assuming here and please do educate me on the issue if you know.

I am trying to search what these people did as far as the adapter and flywheel for the lsx swap.

Thanks, just trying to think outside the box even if its far fetched.

 

[Henry]

Boom, adapter and flywheel figured out. Just need to figure the shifter.

Subarugears

 

[Henry]

Boom, adapter and flywheel figured out. Just need to figure the shifter.

https://www.facebook.com/media/set/?set=a.656323207753010.1073741844.192890167429652&type=3

Subarugears

Not the coyote I wanted to use but it works.

 

[Henry]

Just contacted Subarugears and they said they don't have an adapter for the Coyote but he will make me one without charging for development if I give him the measurements from the back of the motor.

 

[PeteB]

I plan to use a coyote 5.0 out of a F-150 and supercharge it for a good 550WHP. If this trans works I can achieve the whole drivetrain for less than $8K and keep the dream alive.

Thanks,

Hank

What supercharger are you going to use? I've never seen even a used one for a Coyote that was less then $5k. That only leaves $2-3k for engine, transaxle, axles, clutch, flywheel, and engine management system. :stunned:

 

[James]

I'm dying to see if this works. I decided to go ahead and do a G50, but would be very interested in seeing if the Subbie works. For one,, aftermarket gears are cheaper, and there are a heck of a lot more of those transaxles around then the Porsche.

Some questions that come up.

- Can you get the gears tall enough to work for a V8?
- How much angle would there be on the axles?

 

[Henry]

What supercharger are you going to use? I've never seen even a used one for a Coyote that was less then $5k. That only leaves $2-3k for engine, transaxle, axles, clutch, flywheel, and engine management system. :stunned:

VMP TVS 2.3 supercharger like I have on my GT500. I have a used one that I bought to use on my F150 for $1,300. Came complete with manifolds and intercooler.

F150 5.0 engines are much cheaper than the Mustangs but are essentially the same. Differences are the compression ratio is 10.5:1 opposed to 11:1, intake cams are different, and the tune which will be corrected for the supercharger anyways. 360hp/380tq to the mustangs 412hp/390tq
Found several of these engines for right around $2,000

Ford control Pack is $1450

MT6 transmission is around $2,000

Adapter with flywheel is $1,050 as I just found out.

Spec 3 clutch $389

Thats a total of $8,189 for Engine, transaxle, clutch, adapter, and engine management.

I'm sure there will be a few more costs in it but the point is if I can make it work thats the entire drivetrain for less than what most pay for a transaxle. Also one of the major costs of these cars and others like the GTM that prevent people from building one.

Maybe it won't work but you never know unless you try I guess.

 

[Henry]

I'm dying to see if this works. I decided to go ahead and do a G50, but would be very interested in seeing if the Subbie works. For one,, aftermarket gears are cheaper, and there are a heck of a lot more of those transaxles around then the Porsche.

Some questions that come up.

- Can you get the gears tall enough to work for a V8?
- How much angle would there be on the axles?

Gear ratios are not to different form the mustang 6 speed as far as I can tell. The final drive can be lowered a bit to give you longer gears.
MT6
1st - 3.636
2nd - 2.375
3rd - 1.761
4th - 1.346
5th - 0.971
6th - 0.756
reverse - 3.545
final drive ratio - 3.90

1st - 3.66
2nd - 2.43
3rd - 1.69
4th - 1.32
5th - 1.00
6th - 0.65
rev - 3.32
final 3.31
with wheel size I calculate speeds to be:
1st - 40.33
2nd - 61.75
3rd - 83.27
4th - 108.95
5th - 151.02
6th - 193.97

 

[Jimmy P]

Henry, what are the dimensions of the Subbie box? Length, weight, etc. Any photos of the box?

 

[PeteB]

Looks a bit tall, but it looks shorter than a Graz

I think this is a 6MT:

Graziano:

 

[Jack]

It does seem to be shorter than the Graz, however, it can also be shortened.
Have a look at the subarugears website.

 

[Scott Rowland]

A good bang for the buck motor is the truck L33 5.3. It is alum block also with the 243 z06 heads (iirc) and 9/1 comp. Find a low mile complete take out and a single turbo will get you 600rwhp all day long. theres a high mile complete take out motor for $1600 on ebay right now. Build your own drive set up and a decent intake and youre rolling.

 

[Henry]

Not sure the exact dimensions, still trying to find that. Here are a couple pictures though.

 

[Henry]

A good bang for the buck motor is the truck L33 5.3. It is alum block also with the 243 z06 heads (iirc) and 9/1 comp. Find a low mile complete take out and a single turbo will get you 600rwhp all day long. theres a high mile complete take out motor for $1600 on ebay right now. Build your own drive set up and a decent intake and youre rolling.

Very true, I looked at the potential of that motor a couple years ago. Capable of 500hp with LSX intake and cams.

 

[Graeme Stebbing]

Hi Henry, There are some good links here that I saved away on the subi transaxel, it does not say though if its a 5 or 6 speed but still some good info
LocostUSA.com • View topic - Subaru transaxles

and the 6mt workshop manual could prove usefull http://www.voisin.ch/subaru/docs_te.../sti_transmission/6mt_manual_trans_&_diff.pdf

and what models they came in 5 and 6 speed
http://home.gci.net/~cowdookey/818/TransmissionIDChart_Public.pdf

 

[Randy V]

A good bang for the buck motor is the truck L33 5.3. It is alum block also with the 243 z06 heads (iirc) and 9/1 comp. Find a low mile complete take out and a single turbo will get you 600rwhp all day long. theres a high mile complete take out motor for $1600 on ebay right now. Build your own drive set up and a decent intake and youre rolling.

True!!!!

Read this and believe! 1200+ HP and a surprise ending!!!! :thumbsup:
Stock GM LS Engine - Big Bang Theory - Hot Rod Magazine

 

[Eric McClellan]

True!!!!

Read this and believe! 1200+ HP and a surprise ending!!!! :thumbsup:
Stock GM LS Engine - Big Bang Theory - Hot Rod Magazine

Well Cripes RANDY!

If you're going to post a feature tech article, at least post one I WROTE!

Inexpensive Turbo Block - Staying Alive! - GM High-Tech Performance Magazine