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Brendan's STi 6MT Swap


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I can't imagine too many of us have made it to the top of 5th, let alone shifted to 6th on boost. I have made it into 5th and probably pushed 125-130, but tracks just aren't long enough or free enough of obstacles to do much more. Dare I say the STI trans will make your car faster as well as quicker!
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As far as the F/R power in "auto" mode, I believe it is 39/61.

 

The downside of the 2005 transmission is the shorter gearing.

 

I thought I had the table at work, but I don't, so no post showing the difference.

 

In a nutshell, I believe 4th gear runs out at ~95mph

 

Power split is 35/65 on 04-05. 06 changed to 41/59. I had an 06 prior to buying my 5th gen. I miss that trans and shifter. Drivetrain mods happened almost immediately on my 5th gen.

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Either your rev limiter in your tunes are set much higher than mine is or you are misremember which gear you were in. The 2.5i and 2.5GT share the same gear ratio's 1-4 and 4.111:1 final drive ratio. My car hit the 6350 rev limiter just over 90mph. I went to gear calculator (wallace racing) to verify to make sure I wasn't completely off as I have rarely do a 3rd gear pull. You would need something like 7366 rpm to hit 107mph with a 26" tire using 1.296 3rd gear ratio x final drive ratio of 4.111:1. Edited by dgoodhue
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Either your rev limiter in your tunes are set much higher than mine is or you are misremember which gear you were in. The 2.5i and 2.5GT share the same gear ratio's 1-4 and 4.111:1 final drive ratio. My car hit the 6350 rev limiter just over 90mph. I went to gear calculator (wallace racing) to verify to make sure I wasn't completely off as I have rarely do a 3rd gear pull. You would need something like 7366 rpm to hit 107mph with a 26" tire using 1.296 3rd gear ratio x final drive ratio of 4.111:1.

 

My rev limiter is at 7500rpm. Cams make a difference:cool:

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Either your rev limiter in your tunes are set much higher than mine is or you are misremember which gear you were in. The 2.5i and 2.5GT share the same gear ratio's 1-4 and 4.111:1 final drive ratio. My car hit the 6350 rev limiter just over 90mph. I went to gear calculator (wallace racing) to verify to make sure I wasn't completely off as I have rarely do a 3rd gear pull. You would need something like 7366 rpm to hit 107mph with a 26" tire using 1.296 3rd gear ratio x final drive ratio of 4.111:1.

 

Even the Cobb OTS tunes raise the rev limit. I don't know off-hand what it is, but I definitely know I've gone past the factory limit.

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The final drive in 05 and newer STI is 3.9 not 4.11.

 

My 4th gear is 1.137 while yours should be 1.346.

 

I hit 50mph in 4th gear at 3000 rpm. So, 4th gear at 6000 rpm is 100mph for me.

 

6500rpm/6000rpm = 1.083

 

100mph * 1.083 = 108mph at 6500 rpm with my 4th gear.

 

1.137/1.346 = 0.8447 (my 4th vs your 4th)

 

0.8447 * 108mph = 91mph at 6500 rpm in your 4th gear.

 

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So this morning I spent a few hours on mount number two. I should have it finished later tonight and I will post some pics. I have to say that the drivers side is a million times harder than the passenger. I had to negotiate between the heater hoses, steering rack, and the starter. Then of course I had the basic mount made and then I had to figure out how to get it in there. All I can say is that this one is a royal PITA. Almost finished with it though.
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So here is mount numero dos. As I said pain in the booty. There is not a straight line on this thing. This one goes around the starter, which was a real picnic to accomplish. It is pretty much done though. I checked it several times for strength by throwing it about 20 feet through the air and all seems well. I will install it tomorrow.

Next step is figuring out what I need to do to the shifter. More to come.

20170203_190412.thumb.jpg.7339edcc6bdbf5682aecf064130b76e3.jpg

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Is there a particular reason you went this route vs making mounts in alloy and welding them to the bell housing, other than not having access to TIG welding gear?
Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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Mainly the not having the tig available. Another big problem though is the STI trans takes up a ton of room. I am sure the passenger side would have enough room, but the drivers side is super tight now. I would have to mount some pretty serious anchors to the bell housing and diff area to hold the aluminum mount. I am just not sure that there would be enough room in there for that. Of course I am always open to other ideas. Once I get this all together my mounts may not work worth a crap at all and I will be back to square one. I admit my mounts are funky. I am just hoping they work.
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No no, it looks fine. Just wasn't the approach I had in my mind, but there's always more ways than one to skin a cat, as they say. I'd have welded a couple of feet onto the bellhousing like the 5EAT version has on the TC housing, and possibly tried to reuse the stock alloy mounts, or a copy of those mounts fabbed in steel. I'll just shut up and let you get on with it ;)
Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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Trust me no offense taken. I like your idea. The drivers side stock mount will not work without serious modification to the bellhousing though. Funny part is, last night after thinking about your idea I planned out a whole way to make it out of aluminum. At least that way I will be prepared.
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