Sure, why not?

 

Im almost certain that it will all bolt up perfectly. The tranny will definetely bolt up to the block, that's for sure. The transfercase from the MR might be different but I also doubt it. There is no true benefit to a 6 speed unless you have stock power output . More HP will make it a waste of time to be shifting more. Lets see what happens when someone gets a thrashed MR.

Gil-superz

 

I don't doubt you, but where in the world did you hear that???

 

I think a daily driver might be the way to go, something cheap and reliable like a mid 90s civic that gets good mpg and a great longevity engine life its known for (just remeber to change the oil)

As for the 6 speed I would like to have one too, I dont belive if it was weaker or such a bad thing to have that Mitsu would have put it in their better car, it just doesnt make sense to me, but who knows.

 

i didnt take it that way i just wanted to make my situation clear.

 

The six-speed will not help you with this, rpm at sixty miles-per-hour is almost exactly the same as the five speed.

 

The transfer case in the MR will have to be different wont it? Our XCase has the front and center diffs in it. The MR will have the ACD and they removed items from the car to have room for the ACD and the XCASE.

 

The transfer might be possible, but if you really want to do this for mpg then you need to quantify the price of the swap as compared to the gas money that would be saved. I would bet that you would be looking at 250,000 plus miles to pay for itself. Now if you want it just because you would like to have a six-speed tranny then that is cool, that is what you want and it is your money. If you do try this then please let everyone else know how it went. Even if we do not want to do the same it would be interesting to see.

 

The difference is not that big between the 5 speed final and the MR 6 speed final.

MR 6 speed:
Top Gear gives 23.724 MPH/1000 RPM and a top speed of 166.066 MPH at 7000 RPM
Engine speeds in top gear:-

30 MPH = 1265 RPM 40 MPH = 1686 RPM 50 MPH = 2108 RPM 60 MPH = 2529 RPM

70 MPH = 2951 RPM 80 MPH = 3372 RPM 90 MPH = 3794 RPM 100 MPH = 4215 RPM


GSR/RS 5 speed:

Top Gear gives 23.106 MPH/1000 RPM and a top speed of 161.744 MPH at 7000 RPM
Engine speeds in top gear:-

30 MPH = 1298 RPM 40 MPH = 1731 RPM 50 MPH = 2164 RPM 60 MPH = 2597 RPM

70 MPH = 3029 RPM 80 MPH = 3462 RPM 90 MPH = 3895 RPM 100 MPH = 4328 RPM

At 100mph this translates to 113 rpm less on the 6 spd over the 5 speed

This graph made using the Quaife gearbox calculator gives a picture of speed vs rpm for each gear. The jury is still out which will be better for 1/4 mile...may have to do an extra shift.

 

is it true? it's depends on the gear ratio right?
one thing makes me laugh when watching the video is,
the stock 04 STI need fifth gear to finish the 1/4 miles.

 

well thanks for all the replys and everyone who took the time to give their opinion i appreciate it. but i guess the fact of having a six-speed RS would really stand out ya know? i mean we all modify our cars to our taste right? well i've always wanted a six speed car dunno why? but i do, and if in a brief moment of insanity i almost went for the MR because i figured the tranny would be stronger, not saying it isnt, but its not for sure just yet. besides i guess i cant complain about the lack of sixth this car fu**en rock's!

 

Just FYI, the center diff actually resides in our tranny. The front diff and viscous coupler resides in our transfer case. I'm not quite sure where the ACD is controlled though.

 

the viscous coupler is the center diff

 

No, the viscous coupler is not the center diff. Without the viscous coupler, the center diff is just an open diff. The viscous coupler is what makes the center diff an LSD. Look at page 22A-3 in the shop manual for a sectional view diagram of the tranny/x-fer case.

 

thanks for the clarification... i was looking at this one picture in this japanese book... and started wondering if i was wrong.