6MT Question

[drewriviera]

My manual 91 SS is great around town, but now with a kid on the way it would be nice to go on a road trip in it without being tach'd out doing 65 mph. Isn't there a 6mt from an STI that would go in a 91 SS? Has anyone done this before? I would love to be able to drive on the interstate for extended periods of time.

[subaru_styles]

are you looking for just a longer 5th gear? wouldnt an outback 4.11 be a cheaper option than going 6 speed

[BiNiaRiS]

are you looking for just a longer 5th gear? wouldnt an outback 4.11 be a cheaper option than going 6 speed

A LOT cheaper. You can expect around $3.5-$4k for a 6speed before labor costs. Plus you'll need to regear or replace your rear diff.

That being said I have a 6speed in my 91 and its probably my favorite single mod. Wouldn't give it up for anything.

[Someperson]

Does it decel like the N/A 5 speed trannies? I let off the gas and its like im tappin the brakes lol. Haven't gotten to drive my turbo yet though

[Legacy777]

Check out my thread for info on swapping over a 6spd.

http://bbs.legacycentral.org/viewtopic.php?f=7&t=49917

If you're talking about a stock turbo legacy transmission, it has a 3.90 final drive reduction which is going to be the best you're going to get out of a 5spd AWD Subaru trans. Some of the newer 5spds may have a slightly taller 5th gear, but I can't say for sure.

The STi 6spd gearing is actually lower than the 5spd. So my rpms will be a little higher (250 - 500 rpm) for the same speed. So with that in mind and what I think you're wanting to accomplish, a 6spd (unless it's one from a Legacy Spec B) won't get you lower rpms for the same speed.

The Spec B's had a 6spd, but it was kind of a 5spd with an extra gear....or at least that's what I was told. They have a taller 6th gear compared to the STi's. I looked into what it would cost to retrofit the taller 6th gear into the STi 6spd and Andrewtech said between the machining and parts that it was going to be around $3k. No thanks.

[PhyrraM]

I remember the opposite. I seem to recall the spec.B 6 speed being an STI 6 speed (new ratios and no front LSD) and the 2010+ Legacy (normal and GTs) being the new (5 speed based) 6 speeds.

I'm gonna research this, because I've been on the lookout for a well priced spec.B and if it has the 'lesser' 6 speed, I'll just look for a rare 2005 5 speed GT wagon and do an STI 6 speed swap.

[mike-tracy]

Here's the newest revision of that tranny chart that we've seen:

http://forums.nasioc.com/forums/showthr ... ?t=2173258

[BiNiaRiS]

I'll just look for a rare 2005 5 speed GT wagon and do an STI 6 speed swap.

This. This. This. All day long.

[Legacy777]

The trans chart seems to indicate that yeah the Spec B had a viscous center diff and didn't utilize a DCCD.

[Alphius]

My manual 91 SS is great around town, but now with a kid on the way it would be nice to go on a road trip in it without being tach'd out doing 65 mph. Isn't there a 6mt from an STI that would go in a 91 SS? Has anyone done this before? I would love to be able to drive on the interstate for extended periods of time.

It is designed to go on the interstate for long periods of time. You have the longest geared 5-speed Subaru ever put in a car if you still have the stock transmission. It is definitely not "tach'd out" at 65mph. That should be around 2700RPM in 5th with your transmission. So what is your problem with driving on the highway exactly?

STI 6-speed would give you higher RPMs on the highway.

[drewriviera]

I wonder if someone changed the rear gear then, because it's well over that at 65 mph in 5th.

[Alphius]

Maybe your speedometer or tach is off. Where is it at?

[drewriviera]

Don't know right off without taking it for a spin but I have replaced the cluster with a fresh one and it is the same.

[jamal]

According to the info I can find, 65mph should be 2700rpm, and 80 is 3300. That assumes a 1:0.780 5th, 3.90 final drive, and 195/65-15 tires.

Most 6-speeds come with a .756 6th gear, which would drop your cruising revs down a whole 100 rpm.

The trans chart seems to indicate that yeah the Spec B had a viscous center diff and didn't utilize a DCCD.

That is correct. And it is in the big sti 6-speed case, just a different tail housing. It's also found in some JDM stis.

[Someperson]

Lol

[Legacy777]

The speeds Jamal posted are about right for what I remember with my turbo legacy 5spd.