BlaCkPlaGUE

We all know that increasing the RPM above factory for an NA engine is COMPLETLEY useless unless the engine has been ported.

How about turbo/supercharged setups? Since air is being forced in, instead of sucked, do the same rules still apply?

RX7WEEE

iTrader: (16)

No because you cant get all the air out of the engine fast enough.

BlaCkPlaGUE

So in other words, increasing the RPM on an engine with forced induction would be worth it?

SideWindeRx7

no. Most turbo rx7's will stop making more power around 7.5-8.5k rpms ..
unless you have a pport turbo setup or big bridge, I dont see a gain. Just more wear and tear on your engine.

Klar

Also depends om turbo size.

BlaCkPlaGUE

Ok, this is what im trying to find out, we got two different answers so far. One guy is saying it makes no difference, and another is saying that it will depending on the turbo size.

z8cw

There is no difference...turbo or not. The ports determine the characteristic of the engine, expressed in VE = volumetric efficency. With the stock ports VE falls of after 6k rpm. Engine volume, rpms and VE give you the HPs. The pounds of boost you force into the engine are just a straight multiplier; ie 1 atmospheric pressure, 2 atmospheric pressure and so on.

CW

BlaCkPlaGUE

Alright, I still don't understand what the hell that means except I do know what volumetric efficiency is. But I got it, thank you.

z8cw

Sorry, didn't answer your original question. Since VE falls of so dramatically at higher RPMS you stop making more power even with increasing rpms.

Klar

Thats why you go with a bigger port.

Kahren

iTrader: (13)

go to the dyno, see the power curve and find out