15+ WRX 6mt into 05/09 Legacy/OB

[tocinoman25]

Would the pictures I put up help? I can send you the originals on my phone if that'll help.

 

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I am no photochopper by no means lol. I barely transferred my pics from my cell phone to my PC hahahaha.

[Scottydunno]

After a week of driving there are a couple key notes per se'....

 

1. The gearing is way more linear I guess I can express it that way. The rpm drop between gears isn't large, so it really keeps the car in its power band.

 

2. Fuel mileage is noticeable and increased. Until I have my tank replaced, I can't give exact numbers.

 

3. The shifting is real good for a cable setup. It's not as mechanical/bolt action slide perfect, but it's close and feels good. It's definitely smoother IMO.

 

4. Reverse takes some getting used too. I'm used to reverse being over by first gear, like a getrag, tremec, or even like GM's T56.

 

Overall, I'd do this again and again. Price wise, parts commonality, can't beat it on a budget or a very high mileage car with little residual value.

 

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[Pleides]

I'm still hung up on the RPM thing. Are the RPM calculations determined by the transmission in some way? Pardon my ignorance. I've driven a few FA20dit WRXs and they always seem to be under 3K RPM for pretty much all freeway speeds that people do here in Portland (we're slow here), so I'm still surprised you don't notice a difference on the tach. Is the tachometer inaccurate from the trans swap the same way a speedometer is off if you use different-sized wheels and tires than OEM? Thanks.

[Scottydunno]

I'm still hung up on the RPM thing. Are the RPM calculations determined by the transmission in some way? Pardon my ignorance. I've driven a few FA20dit WRXs and they always seem to be under 3K RPM for pretty much all freeway speeds that people do here in Portland (we're slow here), so I'm still surprised you don't notice a difference on the tach. Is the tachometer inaccurate from the trans swap the same way a speedometer is off if you use different-sized wheels and tires than OEM? Thanks.

I know my speedometer is off by a few MPH, on average about 2mph. I'm chalking it up to old age.. 17 year old car and 252k miles on it, I mean sensors and stepper motors do lose their calibrations so....

 

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[Infosecdad]

I'm still hung up on the RPM thing. Are the RPM calculations determined by the transmission in some way? Pardon my ignorance. I've driven a few FA20dit WRXs and they always seem to be under 3K RPM for pretty much all freeway speeds that people do here in Portland (we're slow here), so I'm still surprised you don't notice a difference on the tach. Is the tachometer inaccurate from the trans swap the same way a speedometer is off if you use different-sized wheels and tires than OEM? Thanks.

 

Isn't the tachometer pure engine rotations? That measurement type shouldn't change with the different transmission, the MPH would for a given RPM.

[Pleides]

Isn't the tachometer pure engine rotations? That measurement type shouldn't change with the different transmission, the MPH would for a given RPM.

 

I thought it was the speed at which the crankshaft turned.

 

I just drove an FA20dit WRX we have on the lot at work and I couldn't get it to hit 3000 RPM at freeway speeds until 80 MPH. I guess I was wondering if some sensor factored into the equation for what the tachometer shows that maybe fits correctly swap for swap but does some math differently on both cars. Who knows.

 

If it drops 300 RPM at 70 MPH (I got 2600 RPM in the FA20dit at 70) then I'd say it's definitely a good swap. I'd wonder if the big turbo guys would like the swap. One of the nice things about the STi 6-speed is the gear ratios allow the car to be in the power band of our old-fashioned laggy turbos. The FA20dit transmission has relatively short gear ratios but they're pretty evenly spaced and it works well for the narrow powerband of the FA20 engine. I would think that, the smaller the turbo on your EJ engine, the better this trans experience will be.

[Scottydunno]

I thought it was the speed at which the crankshaft turned.

 

 

 

I just drove an FA20dit WRX we have on the lot at work and I couldn't get it to hit 3000 RPM at freeway speeds until 80 MPH. I guess I was wondering if some sensor factored into the equation for what the tachometer shows that maybe fits correctly swap for swap but does some math differently on both cars. Who knows.

 

 

 

If it drops 300 RPM at 70 MPH (I got 2600 RPM in the FA20dit at 70) then I'd say it's definitely a good swap. I'd wonder if the big turbo guys would like the swap. One of the nice things about the STi 6-speed is the gear ratios allow the car to be in the power band of our old-fashioned laggy turbos. The FA20dit transmission has relatively short gear ratios but they're pretty evenly spaced and it works well for the narrow powerband of the FA20 engine. I would think that, the smaller the turbo on your EJ engine, the better this trans experience will be.

Engine RPM is solely based on crankshaft speed. My average driving speed on the highway is 75-80. There is a definite rpm drop and is noticeable as far as fuel mileage goes. If you look over at the 6MT master swap thread, you'll see someone comparing an 05 STi 6MT to the old 5MT and complaining about the same rpm drop.

 

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[Infosecdad]

Yes, RPM is just crankshaft speed.

 

I was looking at calculators online.

Here are the RPM differences at different speeds.

I used my 225/40/18 Pilot Sport All Season (25.2")

 

Stock 5mt (4.44) = 75mph @ 3276RPM <- Me currently with an outback 5mt

Stock 5mt (4.11) = 75mph @ 3033RPM

WRX/LGT 6mt (4.11) = 75mph @ 2737RPM (6th gear at .666)

 

It's about a 300 RPM reduction for most legacy 5mt, going to be almost 550RPM drop for me with the outback 5mt. Something I'm seriously looking forward to.

[Scottydunno]

2½ weeks in...

 

Had a shifter cable come disconnected from the shifter. When I got the shifter assembly, this one particular cable was disconnected from the shifter. Upon install to the car, I reconnected it and had no issues till it randomly disconnected on an upshift. Reassembled just before the blizzard and have since did a ghetto zip tie mod to keep the cable attached in case it happens again. When I get time, I'll run to the dealer and see if I can get just the cable end, or if I have to buy the whole cable.

 

The mileage is from a 12 gallon fuel and drive throughout. 4 solid days of driving is something this car does in warmer weather, not the winter. My computed average is typically in the 18-20 mpg range. However I must add that partially is also the effect from a lightweight flywheel. My running theory on that is less rotational mass on the engine, less throttle used to accelerate. Either way, it's definitely a bonus.

 

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[Pleides]

Glad to see you're getting better MPG. It's a real push to get 22 MPG on my car and I religiously use cruise control and mostly drive on the highway. That tall 6th gear sounds like its right up my alley!

 

Is the cable mechanism broken, hence your issues? Or is it something due to your modified shift assembly thing?

 

Thanks for this whole thread man.

[xt2005bonbon]

Somehow, my 06 gets pretty good gas mileage on the freeway. When I did my last cross-country trip with it, I was usually getting between 26 and 28 mpg cruising between 70-80 mph depending on the state I was driving through. Car is a lowered outback, with outback gearing too. It was just me in the car though. Car was empty.

[Febreze Mee]

Empty Outback, not turbo here, getting about 22mpg doing mostly freeway between 70/80mph. I can get 25mpg at 65/70 when I try. For reference, I'm between 3500-3700 RPMs at 80mph in 5th gear. If you didn't know, 2.5i 5MTs are geared a bit differently than their turbo counterparts. And, obviously, I have an OB rear LSD (original to the car) so it has a little different gearing too

 

I don't use cruise control when really trying for high MPGs bc I notice it tanks them. Maybe it's just my experience, I don't understand all of the little intricacies and metrics cruise control uses to operate, but whenever cruise control is used the car's live data on the clock bezel, and my OBD2 gauge show that I can feather it and save more fuel better than cruise control can.

Edited February 4, 2022 by Febreze Mee

[Scottydunno]

Glad to see you're getting better MPG. It's a real push to get 22 MPG on my car and I religiously use cruise control and mostly drive on the highway. That tall 6th gear sounds like its right up my alley!

 

Is the cable mechanism broken, hence your issues? Or is it something due to your modified shift assembly thing?

 

Thanks for this whole thread man.

As far as I can tell.. nothing is wrong. Then again, I don't have another set to compare to. I suspect the issue is the cable end where it snaps onto the shifter. There is a grommet in the socket, but to me, it doesn't seem right. When I have time to get to the dealership, I'll research it more. Thankfully as a tow truck operator, I tend to get friendly with service and parts departments.... LOL.

 

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[Scottydunno]

@xt2005bonbon

100% highway driving, my car would see 25mpg on the read out. Those trips were with the 5mt and stock flywheel/clutch setup. I'll be making that same all highway trip this April.

 

@Febreze Mee

I'm suprised your NA OB doesn't get better mileage! I have a friend that had an NA Legacy and his wife routinely sees 27mpg in it! As far as cruise control is concerned, most are designed to keep you at speed without incurring a speed loss. When we feather it, we lose a little speed, but gain it back on the other side of the hill. The ECM doesn't know that.

 

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Edited February 4, 2022 by Scottydunno

[Febreze Mee]

That would describe exactly what it feels like it's doing. And that describes exactly what I'm doing!

 

Something must be getting tired then. I get 330mi to the tank doing mostly highway driving, that usually leaves me with a gallon in the tank. In the other 2.5i I could get higher numbers. Assuming his wife fills up when on fumes, she would be getting 405mi to the tank. I don't know if I ever saw the 400s, but I don't remember having to try so hard for 330. After seeing what all of you are getting, I started questioning things. It has to be a fuel filter. I haven't serviced it under my ownership, and I've put 20K on the car over the last year. Past due, I'd say. Thanks for helping me figure that one out, but I still want a 6th gear if I can have one. The research continues.

[Scottydunno]

That would describe exactly what it feels like it's doing. And that describes exactly what I'm doing!

 

 

 

Something must be getting tired then. I get 330mi to the tank doing mostly highway driving, that usually leaves me with a gallon in the tank. In the other 2.5i I could get higher numbers. Assuming his wife fills up when on fumes, she would be getting 405mi to the tank. I don't know if I ever saw the 400s, but I don't remember having to try so hard for 330. After seeing what all of you are getting, I started questioning things. It has to be a fuel filter. I haven't serviced it under my ownership, and I've put 20K on the car over the last year. Past due, I'd say. Thanks for helping me figure that one out, but I still want a 6th gear if I can have one. The research continues.

There are alot of things/factors that effect fuel economy. Filters, plugs/wires/coil boots, plugged catalytic converters, lazy O² sensors, etc.. etc...

 

I did read that later year WRX 6mt or even Crosstrek 6mt come with 4.44 FD. Something to look into..

 

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[Pleides]

That would describe exactly what it feels like it's doing. And that describes exactly what I'm doing!

 

Something must be getting tired then. I get 330mi to the tank doing mostly highway driving, that usually leaves me with a gallon in the tank. In the other 2.5i I could get higher numbers. Assuming his wife fills up when on fumes, she would be getting 405mi to the tank. I don't know if I ever saw the 400s, but I don't remember having to try so hard for 330. After seeing what all of you are getting, I started questioning things. It has to be a fuel filter. I haven't serviced it under my ownership, and I've put 20K on the car over the last year. Past due, I'd say. Thanks for helping me figure that one out, but I still want a 6th gear if I can have one. The research continues.

 

Cruise control definitely is better than exclusively using your foot unless you have extremely good hypermiling skills and know how to use drafting and hills to your advantage. When I drive my girlfriend's Grand Cherokee on road trips I consistently get 20-21 MPG while her driving nets us 17-18. I just use cruise control on the highway with very few exceptions. She'll sometimes make the computer drop a gear with her driving when there's nobody else around. Every car is different, of course, but I've never found the average driver to be able to beat a computer at MPG on long trips.

[k00laid83]

This is great information! What I'm wondering is how strong are these transmissions compared to our 5-speed tranny's and the STI tranny's? I'm not planning on launching the car or going super crazy. Just something I'm wondering. Also, how did you figure out what the gearing was on the 6-speed WRX transmission? I think it would be great to be able to keep my rear diff if they came with an LSD.

[tocinoman25]

This is great information! What I'm wondering is how strong are these transmissions compared to our 5-speed tranny's and the STI tranny's? I'm not planning on launching the car or going super crazy. Just something I'm wondering. Also, how did you figure out what the gearing was on the 6-speed WRX transmission? I think it would be great to be able to keep my rear diff if they came with an LSD.

My guess is under 400 is safe? I looked up a few nasioc threads already. I'm going to pull the trigger on one of these trans any day now myself. Seems good enough to have some more fun in the leggy.

 

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[Pleides]

My tuning shop Surgeline still recommends an STi 6-speed swap before 400 WHP, so I would wager it isn’t that much more durable, if at all.

[Infosecdad]

This is great information! What I'm wondering is how strong are these transmissions compared to our 5-speed tranny's and the STI tranny's? I'm not planning on launching the car or going super crazy. Just something I'm wondering. Also, how did you figure out what the gearing was on the 6-speed WRX transmission? I think it would be great to be able to keep my rear diff if they came with an LSD.

 

2015 WRX Gear Ratios:

 

WRX 6MT Gear Ratios / Max Speed in Gear:

1: 3.454:1 / 35 mph (6800)

2: 1.947:1 / 62 mph (6800)

3: 1.296:1 / 93 mph (6800)

4: 0.972:1 / 124 mph (6800)

5: 0.780:1 / 144 mph (6350)

6: 0.666:1 / 144 mph (5400)

Reverse: 3.636:1

Final Drive: 4.11:1

 

From https://forums.nasioc.com/forums/showpost.php?p=41839501&postcount=2

 

Which are the exact same as the 5th Gen LGT 6mt.

[Scottydunno]

@k00laid83

 

It's an open front diff trans, same as the 5spd. My LGT, came with an LSD rear stock. Everything works as it should.

 

@tocinoman25

 

I'm also assuming under 400/400 should be acceptable. What few threads I've read seems to be where they are at. There is a guy local to me that is tuned at 325/360 at the wheels. Been there for years according to him with zero issues.

 

@Pleides

 

This trans swap is something I'd recommend for a DD or even a spirited weekend warrior on a stockish setup. If your planning on making some very decent power and really plan on using it all.. all of the time, then I'd do STi swap route. It's a stronger transmission by design. Like I said, in situation it wasn't monetary feasible nor wise in case crap happens.

 

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[Scottydunno]

This fill up, I did my now normal 12 gallon fill up and decided to run it down to the light and see how many miles I got. I've never got 300 miles to a tank in the winter easily, never mind starting with a full tank. Also to note, my average speed was between 75-80 with a 2 or 3 blasts to the century mark.

 

Again, for me it's worth every penny doing this.

 

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[Scottydunno]

Finally found the procedure for adjusting the one shifter cable.

 

 

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[rhino6303]

Did you use regular 5mt single mass flywheel?

 

What fluid? Same as 5mt?

 

Same mount as 5mt?