Changed my 5th gear ratio (manual, non-turbo)

[subeman90]

So ever since I bought my Baja I have wished it turned fewer revs on the highway. Really I think the gas mileage is not that great either. I decided a long time ago I was going to do something about this someday. Well someday was finally last week Jan 5th 2012. Long story short I have a great friend that works at a Subaru dealer and he was nice enough to order me in some 5th gear sets for my Baja. In the picture below from left to right is a WRX .738, impreza .78, and Baja factory .85 5th gear sets. Part numbers are on the boxes in the pics if you are interested.


Here are a few pics of the inside of your manual transmission (5th gear is the one hanging off the end of the pic (sorry not my pic but borrowed from the net) and a pic of the case together with 5th gear exposed:




Now I am not going to sit here and tell you how to do this. Quite honestly I had a shop do it as I have no time for this nor can my car be down for an extended time frame. Here is what I can tell you. The transmission DOES NOT have to come out (unless you want to go that route) and those gears are kind of pressed on but a little heat and gentle love made mine come out. I had an independent Subaru mechanic do this for me and he charged me for 6 hours of labor. There were a few test drives in there and he was going into uncharted waters so I have no problem putting some extra $$$ in his pocket. In the end though...here are the numbers that matter to us.

Here are my numbers: ( speed, revs old, revs new) I installed the .738 set
40 1800 1600
50 2300 1950
60 2800 2350
70 3350 2800
80 3800 3250
90 4250 3550
100 4850 4000

So with that being said I have no data for gas mileage. I filled the tank and parked it for the weekend and I really have no plans for any good highway trips for awhile.

here is a pic of a semi-legal speed with the new gears in it.


here are the links for 3 videos that were shot on the test track (#1 is before, #2 is after in the lower speeds, and #3 is after in the upper speeds)

Subaru Baja factory 5th gear - YouTube

Subaru Baja factory 5th gear - YouTube

Subaru Baja new 5th gear with .738 ratio (part 1) - YouTube

Subaru Baja new 5th gear with .738 ratio (part 1) - YouTube

Subaru Baja new 5th gear .738 ratio (part 2) - YouTube

Subaru Baja new 5th gear .738 ratio (part 2) - YouTube

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[steven765]

I'm really curious once you get some mpg data.

[tibug]

Very nice. Looks like you can cruise at 85 at the same RPMs that you could at 75 before. Nice change. I was not that happy with my Outback's fifth gear either, but I got used to it especially after I realized how gutless the engine is. It is nice to not have to downshift to go up the decently big highway hills in CT. That said, it would be very nice in flatter areas or long distance crusing to be able to 80 and not get horrendous gas mileage.

[subeman90]

Originally Posted by steven765

I'm really curious once you get some mpg data.

you and me both. I just wish I have the time (and gas wasn't so expensive) to just pi$$ a tank away and get a base line.

I've got a trip planned for middle Feb to Maine and most of the "New England" states. That will tell the tale for sure.

[hocrest]

Have you tried to accelerate from 60 on any highway hills yet? I have a 5 spd with the .78 and if I'm cruising 70 and someone pulls out in front of me, it struggles a little to get back to cruising.

But then you don't have any real hills down there. Bring it up here and we'll race around on 81.

[subeman90]

I don't drive 60. I drive 75.

in all honesty though..I really haven't played with it. I've put maybe 50 miles on it so far.

[steven765]

How does it sound, any quieter at speed? Or does the wind noise blowing by our obnoxious barn door mirrors override it?

[hocrest]

Originally Posted by steven765

... our obnoxious barn door mirrors override it?

Really???

Legacy Mirrors from 2000-2004 are a direct swap and a little smaller if this is a concern of yours.

[steven765]

The 00-04 mirrors are the same, I installed them with heat already.

I'm curious if the 11 outback mirrors fit.

back to the topic really tempted by this 5th gear mod.

[subeman90]

it is a little quieter. The thing I was trying to get rid of was the roar of the engine at 75 and I have to say I believe I did.

[littletruckthatcould]

do you notice any difference in the 5th gear acceleration say on the highway with my car (non turbo 5 speed) at 3k im doing about 60-62 and to get to 75-80 doesnt take too long. with the gearing setup you chose is it any slower?

[subeman90]

I'm sure it is slower but for some reason I feel like I have more torque pushing me along. I know it sounds strange though.

[steven765]

What was the cost on the gear btw?

[Hawk296]

Wow, never thought about just swapping 5th and never thought about the fact its accessible without pulling the trans. this would is tempting to do on my turbo if I can find an appropriate gear ratio in the Subaru line. It would not only lower RPM for cruise but also provide a little more top speed as it's currently limited by gearing.

Neat idea!

[subeman90]

Originally Posted by steven765

What was the cost on the gear btw?

the .78 is around $165 list and the .738 is right around $135 list. Both are approx. but close.

Better ratio is cheaper....YES!

[CosmoTheCat]

Nice.

I much preferred the 3.90 final drive in my '98 L 2.2 versus the 4.11 in my 01 2.5RS

[twheats1]

Originally Posted by Hawk296

Wow, never thought about just swapping 5th and never thought about the fact its accessible without pulling the trans. this would is tempting to do on my turbo if I can find an appropriate gear ratio in the Subaru line. It would not only lower RPM for cruise but also provide a little more top speed as it's currently limited by gearing.

Neat idea!

A few years ago I had to have bearings done on my trans. I looked into getting a taller 5th gear and found that the Turbos already have a .738 5th gear. (at least on my 04)

[steven765]

Originally Posted by twheats1

A few years ago I had to have bearings done on my trans. I looked into getting a taller 5th gear and found that the Turbos already have a .738 5th gear. (at least on my 04)

Prolly why the N/A gas mileage is not all that better than a trubo, but subaru thought people would want the power so they went with the .85 *shakes fist*

[subeman90]

Originally Posted by twheats1

A few years ago I had to have bearings done on my trans. I looked into getting a taller 5th gear and found that the Turbos already have a .738 5th gear. (at least on my 04)

but the turbos have a 4.44 diff so there goes any advantage.

We really need someone with a stock turbo Baja with stock tires to go out and do a few pulls like I did and put up a video.

[Hawk296]

Originally Posted by twheats1

A few years ago I had to have bearings done on my trans. I looked into getting a taller 5th gear and found that the Turbos already have a .738 5th gear. (at least on my 04)

Bummer

[Benhart21]

I was wondering about the turbo ratios. Off the top of my head, I want to say that at 70 mine is running ~3000 rpm. If I could lower them by swapping to the 3.90 all around, I'd gladly sacrifice the off the line performance. I spend more time cruising at 65-75 than I do trying to get up to speed quickly.

[Eskimo1]

Originally Posted by Benhart21

I was wondering about the turbo ratios. Off the top of my head, I want to say that at 70 mine is running ~3000 rpm. If I could lower them by swapping to the 3.90 all around, I'd gladly sacrifice the off the line performance. I spend more time cruising at 65-75 than I do trying to get up to speed quickly.

I agree...and think first gear is too short anyway! But I don't hate it enough to drop the trans and the rear end to swap gears.

subeman, I could take a video like you requested with her bone-stock turboB next month if no one gets back to you more quickly.

[subeman90]

Originally Posted by Eskimo1

I agree...and think first gear is too short anyway! But I don't hate it enough to drop the trans and the rear end to swap gears.

subeman, I could take a video like you requested with her bone-stock turboB next month if no one gets back to you more quickly.

if you want to do that I would love to see what the turbo is doing. Thanks!

Where in Central PA are you?

[Eskimo1]

We're located near Bloomsburg.

And yeah, I'll take the vids, no problem. I'm always game for flogging a car..especially with a purpose!

[Subie_Sleeper68]

Is it even possible to change the ring & pinion setup in a Baja Turbo 5speed ?

I'd pull the trans & rear to go 3.90 or 4.11