My First Build Thread, and a long time comin' Options

[skeates]

So...technically I started this restoration a month ago, but now it has a thread (IMG:style_emoticons/default/biggrin.gif)

A little history...This was my first car. I picked it up for $1200 back in high school and had it towed home with mice in the glove box and hoses going to no where in the engine compartment! My dad and I had it up and running off and on for three years before I shipped off to southern California for college. It has sat in the 'rents driveway for 5 years now (IMG:style_emoticons/default/sad.gif) waiting for the restoration that it deserves

Well...now that I'm edumacated and have a "real" job (and also have moved back to Northern California) my pockets are slightly deeper than in high school and the build has commenced!



So far I have stripped it to a tub, built me a rotisserie and washed off about 30 years of road grime and PO molestation. Along the way I even made a new friend! (IMG:style_emoticons/default/blink.gif)

[76-914]

If anyone wants some good info on Subaru transmissions let me know - I found some awesome threads on 'em!


[/quote]
You got my attention. What tranny info do you have.

[skeates]

You got my attention. What tranny info do you have.

Here are some good links to get you started:

Gear ratios for various tranny codes: http://www.catherineandken.co.uk/sti/trans.html
Overview of Subaru transmissions, weaknesses, and upgrade paths: http://forums.nasioc.com/forums/showthread.php?t=665334
More gear ratio discussion: http://www.rs25.com/forums/f8/t100042-lear...tml#post1598005

It seems like all the discussion about the weak spots in the Subaru transmissions come down to two theory's. The first is that the case flexes under load because of it's split design and messes up the gear mesh. The second theory is that it is shock loading the gears which aren't quite beefy enough. It was interesting to read that many of the failures were actually 3rd and 4th gear, not first! Either way since we use it in 2 wheel drive in the 914 the transmissions would be under quite a bit less stress. Less stress because excess torque is "dispelled" by wheel spin. With two tires we don't have enough traction to apply the full torque of the engine on hard launches (unless you are running wide slicks of course). Thus it should be able to handle quite a bit more torque/HP than in an all wheel drive application. I suppose I'll find out soon enough with the EZ36!

I noticed that some of the gear ratios in the thread I listed contradict with each other, particularly on the final drive. I ended up feeling fairly confident that the Legacy GT (Turbo) box had a 3.9 final drive ratio and had slightly taller gear ratios than the WRX boxes. Since my engine should have a lot more torque than the WRX (at least at the lower RPMs) I wanted the taller gears. Plus it minimizes my RPMs while cruising on the freeway. That said, the '06 - '07 WRX's had a 3.7 final drive ratio which actually makes 4th and 5th effectively taller than the Legacy GT. However, I felt that the lower FD would add more stress to the gears...of course, I was more or less at the mercy of the dismantler in terms of what they had available. (IMG:style_emoticons/default/biggrin.gif)

Way I figure it, if you are running a 6 cylinder or turbo then you ought to be fine with almost any transmission post 2003. In 2003 they "upgraded" the gears by making them thicker. Prior to then only the WRX transmissions had the thicker gears. You are probably already aware that you also need to make sure that you are matching the slave cylinder, fly wheel and clutch (push vs. pull type), but that has been discussed here at some length in some of the other Subaru threads. I can find those links for you if you want.

Hope that helps!