Built 5MT vs STi 6MT

So, I've built every aspect of my car other than the drivetrain. Limited my recent dyno tune to 372 wheel torque so my trans would last a bit longer. From what I know, our stock 5MT is limited to roughly 350 wheel torque. I'm only at about 50k miles and on my old Stage 2+ setup I had to replace my rear diff, trans, and viscous coupling (twice) all under warranty.

I've researched the STi setup, which looks killer, but I've also enjoyed the gearing of the 5MT, especially for road racing. Anybody have experience with PPG gears or any other options? I've searched the forum and I can't seem to find much on here about building the 5MT. Mind you, the car is mainly track only with occasional street/canyon use.

I've seen 400 on stock transmissions; I think you'll be ok if you don't pound on it. I'm thinking it's mostly shock load that kills most gears…

I agree with you on the gear spacing on the 5 speed, personally I like it better than the six speed. As far as gears, you'll pay a pretty penny.....and I believe they are pretty noisy from what I have read.

http://mnsubaru.com/threads/2011-wrx...r-gears.39792/

Check this link.

Noise is not an issue... I've already changed out all my bushings and mounts, so it's quite noisy already. This is NOT my daily driver. I also plan on pushing past 400/400 and I want the trans to be bullet proof.

Originally Posted by kongzilla

http://mnsubaru.com/threads/2011-wrx...r-gears.39792/

Check this link.

Wow... That's a lot of good info. Thanks!

I've owned, at one point or another, several different PPG gearsets. A straight cut 1-4 synchro set (while RWD), a straight-cut 1/2 helical 3/4 PPG set, and finally a straight cut dogbox.

Gear ratios are fantastic in the 5MT, and get even better with the PPG set. There are other companies out there, as well. PAR has made some interesting gearsets lately, and I'd probably suggest that route at this point.

Noise is only an issue on straight-cut sets. If you go helical, it is hardly any louder than stock.

What kind of things do you want to know? Synchro sets drive like stock transmissions. No real downsides, other than cost. You'll realistically spend about the same swapping a 6MT as you will building a 5MT.

I'm also stuck with a built 5 speed or a 6speed swap. It'll be something for me down the road that I'll need to figure out real soon.

Any time I've raced an STi, whether on a straight or in the turns, I've noticed my gearing advantage as they seem to be constantly rowing trough the gears. I just want to make sure I go the right route considering the cost. I plan on getting what I can from this turbo, which should be about 450/450.

The rule of thumb is shorter gears should be faster.

I would rather have the 6MT for the durability and the lighter clutch. I am a little jaded though because I lost 5th gear for no good reason. And IIRC you don't change out 5th gear with any of the built sets.

Originally Posted by kongzilla

The rule of thumb is shorter gears should be faster.

No it's not. Anyone who has even a basic understanding of performance knows that isn't true.

Originally Posted by mattg

I would rather have the 6MT for the durability and the lighter clutch. I am a little jaded though because I lost 5th gear for no good reason. And IIRC you don't change out 5th gear with any of the built sets.

The 6-speed clutch is heavier than the 5MT clutch.

Unless you mean pedal feel, which has nothing to do with the transmission and everything to do with the clutch.

5mt all the way. No racing/other experience except I sold my STi in February for my LGT, and one small reason was the 5mt was more DD friendly for my driving.

I want durability and I'm assuming a built 5MT would hold up better than an STi 6MT.