Max Flow In Cfm Of Std Turbo (rb20/rb25 T3)

[Justlikemusic]

Anyone know what the maximum flow in CFM the standard turbo (RB20/RB25 T3) is?

[Justlikemusic]

I think I might have worked it out myself... the smaller turbo on a larger motor will just have to work harder to produce X amount of boost for that engine. And the turbo is rated on HP. So in theory with a large enough wastegate it shouldn't be an exhaust restriction running a smaller turbo, and running 4psi boost should be safe... but then at higher revs out of the map, the boost will go down? ugh, wanting to put an RB20 turbo onto a falcon 4L since it's T3 flanged and $100. Will upgrade it later after I spend the rest of the money getting the rest of the kit.

[paulr33]

the rb20 turbo is too small for the 4L

the housing will choke the car and probably make it run like ass

the XR6T barra engine has a GT35R turbocharger on it and the housing is massive 1.06a/r

putting a tiny GT25 with a 0.50a/r will just choke up the engine and youll see instane EGTs when its on boost

exhaust pressure will be off the planet as well

[Justlikemusic]

I think the reason for wanting to go that way was quick spool and I make more use of the falcon's low down torque than I do revs. Also it has a T3 flange so after I spent the time making the manifold and running IC piping and such I could upgrade to a larger one. Wouldn't the wastegate correctly sized vent that exhaust pressure away from the turbo though?

That's why I asked the question in regards to the compressor housing and how it relates to cfm/intake amount. Cheapest turbo I could find for this sucker would be about $500 used for a Garrett or cheap China.

[Adriano]

It will make great boost from about 1000-1500 rpm, then the motor will ose over and end up making almost no power at about 3500

[paulr33]

adriano is spot on

wastegate internal, external, twin whatever you like

the housing is too small

you are trying to basically run fire hose pressure through a std garden hose

it wont work and will just crap itself

[Justlikemusic]

Thanks for the help. Might just leave it until I can afford a larger turbo. I pretty much have 10% more than the amount for everything I need including pricing on a cheap used turbo, but a $1000 new one is out of my range right at the moment. I really don't want to go with a chinese turbo for $500 because I have read many hours on the net of them being crap and falling apart. However at the same time have seen so many setups with the Monsta turbos which are chinese too, all the same I guess. I know the Chinese have different metal gradings, and standards etc, but in subwoofers that doesn't matter as much as it does with a turbo bolted to my precious engine!

[Adriano]

Exactly, i would be looking for an sleeve bearing 3076 with a .82 or 1.06 exhaust housing, should eb able to get a good one for $500

[89CAL]

if you cant afford to do it right then dont do it at all

save your money and get a proper turbo for it....