98 2.5RS transmission differences

[chevyman1968]

Alright, so I picked up a 2.5rs transmission from my OBW because the center diff went out in mine. My question is what are the differences. The guys I got it off of pretty much pull Subaru parts for a living and they said it would work. Do I need new cv axles? Any other things I need to pick up off an RS to make it work?

[86bratman]

Should be a straight swap, speedometer may read wrong where it's speedo gear is set for 205/55r16s though.

[chevyman1968]

Should be a straight swap, speedometer may read wrong where it's speedo gear is set for 205/55r16s though.

Ah okay, thats good to know. I haven't done cv axles on the front of my car so I didn't know if they had the pin or just push straight in like the newer subarus. I should be able to swap my speedo gear right over correct? It looks the same to me. While I am at it should I install the Kartboy bushings while I have the transmission out? I would assume its easier out of the car?

[Garrison]

The front CV axles have a punch pin in them right next to the transmission end

[Grafton]

the bushings are SO much easier with the transmission out, and check the shifter linkage, if those bushings are gone grab a new one from the dealership or from turn in concepts, really helps with the shifter feel.

[chevyman1968]

okay, I saved the shifter linkage off my old trans because it had a smoother feel and not sloppy like the new trans. I will swap it in with the new bushings after New Years. I am pulling the engine out to do a hybrid EJ25D/EJ22E build so I will just work on everything else then.

[Grafton]

no sure I'd go for the hybrid if your starting out with a complete 2.5L engine anyways

most of the power gains are from the displacement bump from 2.2L to 2.5L

[Garrison]

And then you'd need to run premium. Why not just turbo it and enjoy more power than a hybrid can give you?

[chevyman1968]

And then you'd need to run premium. Why not just turbo it and enjoy more power than a hybrid can give you?

Well, I am not building a Frankenmotor. I am doing the opposite. I am mating the EJ25D heads with the EJ22E block to have a lower compression engine. I need better mpgs since I will be driving 160 miles round trip to school every day. My old block I am going to pin like lordflash and build the bottom end for when I get out of school. That way I can turbo afterwards. Right now anything that goes on the car is for better economy.

[Grafton]

lowering the compression wont give you an mpg boost, it will be quite the opposite, but it shouldn't be by too much

by definition the lower compression gets less energy out of combustion, until turbo which allows you to crank up the boost to make power (effectively raising the compression ratio)

[86bratman]

^^^this^^^
A properly tuned/driven turbo build can get pretty darn good mileage and be fun when you want it to be. Same goes for higher compression, as long as you drive sensible you will get better fuel economy. But that rule could be applied to a completely stock engine as well.

[elislider]

The only practical difference is that your speedometer will be a off a bit since the RS uses smaller diameter tires than the Outback, so the tiny little gear that feeds the speed sensor is a different ratio

[chevyman1968]

I am basically looking at doing a build like EJ22Ds. I love my 2.5, but I want the lower compression so that I could put a turbo on in the future. It isn't a huge drop in compression though.