ej20 twin turbo to single turbo

[bubaru21]

is it possible to run the twin turbo with one turbo or convert it to single turbo or would it just go BOOM!!

[Huffer]

The GT-B and RSK engines are essentially the same as a stock boosted Legacy engine (JDM spec), just with two turbos.

You can bypass the twin turbo setup, but that requires fitting a bigger overall turbo as the T18 and T19 (?) turbos are fairly piddly. The primary turbo is almost always spooling, and there is some lag between the primary and secondary turbos (this can be eliminated somewhat by increasing the diameter of the exhaust setup, and using a grounding kit as the GT-B grounds are not that great).

The major likely issue (besides the mechanicals) is the ECU.

Beyond that, it's just mechanicals and ensuring your exhaust manifold matches up with the oil lines etc for the turbo.

As for the BOOM! part - the GT-B is notorious for spinning big ends and block destruction when the secondary turbo is let loose without any restriction - probably because of the lag and then sudden kick when it reaches spool up.

[sheepdog]

you can indeed convert to single turbo, in fact you kinda have to to make significant power on those motors. Other than the twin turbos, it's essentially an EJ20. We ran a legacy twin turbo block on my buddies (wrxgc8, he was on here a while ago)'s v4 STi swap. However, its easier to start with a single turbo setup if you can.

[Wiscon_Mark]

Yeah, lots of people have done this conversion.

I dunno, Sheepdog...the EJ207 doesn't blow up very easily. I've heard some bad stuff about modding the twin turbo EJ20Hs. Maybe there was a crossover point where the H was phased out and they introduced the 207?

[sheepdog]

oh, theres definitely a difference, sorry I didnt make that clear. However, until you get to high horsepower levels, they both work fine. Also, a lot of the times people blow them up by over revving them, and the 207 doesnt like that any more than the ej20h haha. regardless, they have the same compression iirc, and thats what i was referencing

[Artemadorous]

You can do the EJ20H engine and convert it to single turbo but then you have to run a diff ECU... best ECU I would say for this is the EJ20G set up.

But for the headache of converting and then finding an EJ20G ECU you might as well just buy an EJ20G to begin with... thats my opinion anyway... Or just get a V8 STi clip and keep it twin cause that'll throw down some serious power :)

[bubaru21]

you know anywhere other than ebay to find good ej20s. my whole plan here is to eventually build a track bd. not drag strip but round course track car.

[sheepdog]

Any japanese motor importer, if youre going to go JDM get a front clip your life will be easier. Just google it youll find plenty.

[scottzg]

You can bypass the twin turbo setup, but that requires fitting a bigger overall turbo as the T18 and T19 (?) turbos are fairly piddly. The primary turbo is almost always spooling, and there is some lag between the primary and secondary turbos (this can be eliminated somewhat by increasing the diameter of the exhaust setup, and using a grounding kit as the GT-B grounds are not that great).

they're sequential? I always figured the 'twin turbo' motors were parallel. go figure.

[Wiscon_Mark]

They can be both. Ben's H6 twin turbo setup is parallel. Subaru's mid 90s experiment was sequential.

[SubiesportEd]

You can bypass the twin turbo setup, but that requires fitting a bigger overall turbo as the T18 and T19 (?) turbos are fairly piddly. The primary turbo is almost always spooling, and there is some lag between the primary and secondary turbos (this can be eliminated somewhat by increasing the diameter of the exhaust setup, and using a grounding kit as the GT-B grounds are not that great).



A ground kit cannot affect spool. A turbo's spool time is a function of engine load and increased exhaust pressure. Grounding your harness cannot increase the amount of exhuast pressure/engine load. Unless you want to say that your injectors, ECU and ignition system are not grounded and therefore you aren't ignighting all your fuel... but even then, that does not make sense. You would have misfires and everything else.

I bet cleaning your grounds can help, but seriously, Subaru did not half-ass their wiring harness, a bunch of thick gauge expensive monster cable is not going to change turbo spool at all. It just can't.

/hijack.

[sheepdog]

indeed