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Rb25 Turbo On Rb20

ako299

By ako299,
in Engines & Forced Induction

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ako299

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use your standard RB20 actuator and you should get approx 10psi. This is all I would personally run if I valued my turbo.

o so run less than a rb20 turbo? i have my setting now ( ..low 10psi and hi 14psi) i thought having the bigger turbo on a car that wont push it as hard could run a lil bit more than they do on the r33s???? i no they are still ceramic internals.

_Ryan_ Grand Master

_Ryan_

Posted
Posted
o so run less than a rb20 turbo? i have my setting now ( ..low 10psi and hi 14psi) i thought having the bigger turbo on a car that wont push it as hard could run a lil bit more than they do on the r33s???? i no they are still ceramic internals.

I would not run 14psi.

Do a search on ceramic+stock turbo.

Rekin Grand Master

Rekin

Posted
Posted
o so run less than a rb20 turbo? i have my setting now ( ..low 10psi and hi 14psi) i thought having the bigger turbo on a car that wont push it as hard could run a lil bit more than they do on the r33s???? i no they are still ceramic internals.

ive heard this before but I cant remember the logic used to get to this reasoning. Something regarding that the rb20 with 14psi it doesnt create the same load as a rb25 running 14psi due to the size difference and hence the rb25 turbo can push more on a rb20.

Someone smart should be able to confirm/deny this. Cbf working it out

The Dan Grand Master

The Dan

Posted
Posted

It has to do with shaft speed. The bigger turbo flows more air. Boost is only a biproduct of the restriction present in your engine. Considering the restriction doesn't change, the larger turbo has a slower shaft speed to generate the same airflow that the previous turbo did, therefore, there is less load on the bigger turbo

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

rb20s generally flow less than rb25s. so at the same boost the rb25 is flowing more air and therefore the turbo is spinning faster. 12psi is considered fine on a 25, 14-15psi would be about the same on a 20

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