Plenum

[Antwon]

Hey guys lookin at doin a few more go fast mods to my car. My question is will a plenum make a difference chasing NA power on a SOHC ticky motor? It will obviously have a little head work, fuel system, tune etc as well.

[BAGT514]

Originally Posted by Antwon

Hey guys lookin at doin a few more go fast mods to my car. My question is will a plenum make a difference chasing NA power on a SOHC ticky motor? It will obviously have a little head work, fuel system, tune etc as well.

Any NA motor will appreciate a little massaging anywhere that the air changes direction. Making the radiuses as smooth as posible and removing casting flashes & join lines will make the airflow much smoother and yeild small increases in power. Combine that with the other mods you are planning and you will end up with a very efficient motor. If you have some spare time on your hand and a spare intake (cheap from most wrecking yards) - jump in and do it yourself. Don't hog crazy amounts of material out - just clean up what is there

Good luck

[Antwon]

Yeah ive already got a spare BBM, so your saying a mucked around with BBM will be just as good as a plenum?

[JC]

Do you mean like a turbo plenum? The stock plenum is the shape it is for NA applications - it changes runner length depending on engine speed/vacuum etc to make the most of torque and power through the rev range. Replace that with a box style plenum, and you may gain in the high rev range, but lose heaps down low, or vice versa. Depends what you want.

In a turbo application where power is everywhere, intake runner length etc is less important as the air is forced in everywhere, meaning the design can bet different without much noticeable loss at a particular rev point or throttle position.

[dansedgli]

A cooler piping blew off last week and it felt pretty good. It didn't feel like it lost a heap of low down power compared it an na one.

You should make more power like the na dohc's do but I havent seen it done on a sohc engine.