St-r >> Vr-4

[Oggie]

ok what i want to know is...

what is the real differences between a STR and a VR4?
are the engine internals the same? If so can i basically bolt on a turbo?
What modifications are needed to make my STR into a vr4 wannabe l:inquisiti
My STR has a triptronic gearbox and i am rapidly begining to love it.


I do know they are both 4wd, seems they have same engines, and thats all i know.

any and all help/advice welcome.

I would love to have a sleeper.

EDIT : If it helps... I have two turbos from a Subaru legacy...

[bradc]

The compression ratio is different in the engines, not sure if this is done by changing rods or pistons, but I would suspect the ST-R engine isn't as strong as a VR-4 engine.

The transmission, diffs, transfer case are all going to be lighter on the ST-R, they probably won't handle more power very well.

It's probably easier to buy a VR-4 and swap across anything you want from your ST-R than to try and modify your ST-R.

[Gly]

also the str has a 2.5l V6 SOHC
the vr4 is 2.5l V6 DOHC

str, non turbo,
vr4 twin turbos, in parallel

engine internals would be completely different

engine and cabin wire looms are different,
different ECU's

the str is usually a 4speed trip or 5 speed manual,
the vr4 is 5speed trip or 5 speed manual

the str has a higher comp ratio,
the intake plenums are different,

exhaust maifolds are different, exhaust is different.

front bumper is sometimes different.

[Nick Mann]

As said - too much is different to make it an easy job. Your best bet is to transplant the whole engine / loom /ecu, or better still, sell the STR, buy a VR-4 and then badge the VR-4 as an STR. Not many people will tell the difference from the outside anyway. That way you don't have to worry about whether the transmission is capable of taking the power or not.

[KHK]

that is exactly Gly's case

[bradc]

Nick, the stock auto box in a VR-4 isn't capable anyway :) (waits for the bite)

It really would be easier to just get a VR-4 than doing the swap, there is simply too much work involved.

[Nick Mann]

Nick, the stock auto box in a VR-4 isn't capable anyway :) (waits for the bite)I ain't biting! There is a picture of an output shaft from an auto VR-4 in my vbGarage!

[bradc]

I thought the output shaft was the same in evo's as well?

[Nick Mann]

Evos aren't quite so good on the old torque stakes though, are they!! :P

[Subaru ETA]

as said...just buy a vr4! it would be cheaper! the engines are too different to turbo the str and by the time you pay for parts and labour for the engine and trans you could have got yourself a jump in and turn the key vr4!

now do it...you know you want to....

[Gly]

yep, as has been said,

just buy a vr4, there fairly affordible to buy now,
just expensive to run.

[djb160]

And that way you don't ahve to put up with that terrible wooden steering wheel.