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Brendan's STi 6MT Swap


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I think in 07 the gearing changed, but really it was small and the overdrives and final drives are the same. I think our forum has a new hero! :lol:

 

I think the only downside would be having to shift into third to hit 60, but being able to do it relentlessly without worry is something else entirely! Awesome job!

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Stu: I had considered going with a later model, but alas it comes down to what was available locally and how much I wanted to spend on a question. The one I got has relatively low miles. The two main things I wanted were dccd and the helical front diff. Those both came in the 05, so I went with it.

 

FL:Thanks. While the gears will be shorter our final drive is 4.11 so I am not sure what the real world difference will be. Should be quicker though. Just what I needed right.

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Stu: I had considered going with a later model, but alas it comes down to what was available locally and how much I wanted to spend on a question. The one I got has relatively low miles. The two main things I wanted were dccd and the helical front diff. Those both came in the 05, so I went with it.

 

FL:Thanks. While the gears will be shorter our final drive is 4.11 so I am not sure what the real world difference will be. Should be quicker though. Just what I needed right.

 

Now that you have the transmission we all wanted in the car, you'll need some more torque to send through it.

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I know your car is fully capable of 450+TQ. Like you're saying though it's just a matter of fueling.

Guess after you get to driving it let us know your impressions of the gearing differences. It's going to rip up to 100 real quick. Real quick. :lol:

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Nice work Brendan! I always wanted to do this on a 5EAT BR9 but CANbus is such a whiny little bitch.

 

It is possible to do per-gear boost control on the 5th gen, via limiting Requested Torque in a 3D table against engine speed. You can use this to increase WGDC in lower gears, or hold boost down in higher gears, or just hold WGDC down as needed. this is invaluable on larger turbos where spool rpm is very different through the gears, or where you're using stiffer actuators and it's very easy to overboost in higher gears.

 

The gear-determination thresholds are also there, at least in Opensource defs. I kludged up a simple spreadsheet to calculate the thresholds if you need to do this yourself. Note you need to plug in your own ratio data though, as well as your own tire sizes, as what's in there now is for the '08 GRB trans.

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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Spent a little bit looking at the shifter this evening. This is the STI shifter installed . It is a bit lower than our shifter and while I need to adjust a few things it actually is not that much. Maybe only a half inch. I also have to figure out how to mount it, but wait for it. This is the best part. In our trans tunnel at the back of the shifter hole, the bolt holes for the rear sti shifter mount are already there. Crazy huh. All I need is to buy the rear shifter mount and bolt it in and I am set. Maybe once it is all installed I will not have to modify it at all.

20170118_204822.thumb.jpg.8a29e3d103a72317d52960aebd8fb07e.jpg

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Following this is like checking out p*rn on dialup....

Literally spit out my coffee I laughed so hard.

 

This weekend I am going to start making the mounts. That should be the hardest part. After that everything else is pretty straightforward. At least that is the theory anyway.

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Literally spit out my coffee I laughed so hard.

 

 

 

This weekend I am going to start making the mounts. That should be the hardest part. After that everything else is pretty straightforward. At least that is the theory anyway.

 

 

 

Honestly, the mechanical stuff is not insurmountable. Just keep at it. A shop here put the trans in a car, mounts, shifter, shafts and everything. They just couldn't overcome the CANbus issues from 5EAT to 6MT. In the end the poor bastards had to put the slushbox back in because of the stupid electronics. You've got this.

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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Guys

Thank you so much for all the help and encouragement. I will be fabricating the passenger mount this weekend. It is pretty much just welding a bunch of pieces together. Depending how it turns out it might be nice to have one of you see if you could digitize the designs for others use. That is if they work of course.

 

fahr_side: Nice to hear that someone else has attempted this. As far as I can tell this is all just mechanical and fab work. The only real electronics will be in the dccd and hooking up the reverse and neutral sensors, but that stuff is pretty simple. I am just going to take my time and make sure to do this right.

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So I am almost finished with the passenger side mount. Between one daughters basket ball game and a birthday party for another I just did not have the time today. It should be finished tomorrow. It is coming along very nicely and I think it should work great. Most importantly it fits. I will post up some pics tomorrow. Here is a tease for the dialup.

20170121_192704.thumb.jpg.6f642b9ee846169db0f0b9c0f6f70c7a.jpg

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