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?

 

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

 

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

 

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.

 

Also depends om turbo size.

 

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.

 

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

 

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.

 

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.

 

Thats why you go with a bigger port.

 

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