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r33 rb25 or vg30 upgrade

netrati

By netrati,
in Engines & Forced Induction

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JimX Grand Master

JimX

Posted
Posted

RB25 turbos can run higher boost on RB20's because of the smaller capacity. Series 1 RB25 turbos are usually ok for up to 14psi on an RB25 engine, so they should be ok for up to maybe 16psi on an RB20.

If they are a straight bolt-on fit (I wouldn't know) then it should be a worthwhile upgrade if you can find one cheap enough.

TTT Grand Master

TTT

Posted
Posted

I have a RB25 turbo on my rb20.

got it running 13 psi.

it is a direct bolt on.

you don't need to modify anything to make it fit (I am refering to an RB20DET from the R32 GTST... don't know about the R31's)

Just make sure that you get the elbow pipe that the intercooler pipe connects to.

this is because the RB20 turbo elbow pipe is the same diameter but the bolts don't exactly line up.

so instead of having to drill the holes out like I did, save yourself the hassle and get the pipe aswell.

You may also need to take the compressor cover off the turbo and drill in to it to tap in the wastegate hose.

or you could also do it to the intercooler pipe like it is on the R33 skylines.

boost comes on at the same time as with the old turbo and stay strong to the redline.

definetely a good/cheap mod to do to your RB20DET.

Cool Hand Luke Community Regular

Cool Hand Luke

Posted
Posted

I have a series 2 rb25 turbo on my car running at 14psi and have had no problems, driven resonably hard for around 5000km, and is my daily driver. I was going to do for a VG30 turbo but it required different dump pipe and a few other mods, the RB25 has less lag and is a lot simpler to install. Definatley worth the upgrade, makes max power around 7200rpm, but pulls well all the way to the rev limiter. I still have an un-chipped ecu but still the power difference from the standard turbo was well worth it.

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