Newly ported Plenum

[Jetson8294]

I was wondering since i just got done porting my plenum, how much power increase is average for that? i have a 52 TB, HUGE(6" diameter, 10" long) air filter. and a 2" straight pipe. oh and its a 5spd as well.

[92lebaronGTC]

I've heard of gains of 5-10hp in higher rpms depending how much you gutted out of the plenum. It's a definate noticable increase.

[Jetson8294]

everything is gutted and smooth enough where it feels like polished aluminum

[3rdGen3.0]

polished? bye bye turbulence...

may want to roughen it up some... some turbulence is good... or is that only in the valves?

[Boogieman142]

some turbulence is good, thats why ppl losesome bottom end when they port out.

[Tim_K]

I don't see how having turbulence in a dry intake manifold would make any difference. Moving air is moving air, there's no fuel to keep mixed up in it.

I've got my intake machined and the corners rounded out with carbide cutters and sanding drums, and the 52 mm throttle body is on also. After I get some totally stock 1/4 mile numbers in my '93 Shadow ES V6 / 604, I'll start "improving" it!

[3rdGen3.0]

Quote:

Originally Posted by Boogieman142 some turbulence is good, thats why ppl losesome bottom end when they port out.

I think that has more to do with changine VE...

When you make less restrictions in the intake, the air comes in with less resistance, but the air is also less dense at the same rpm of the unported plenum... this lowers VE, which lowers torque... but you gain VE up higher in the rev band, which increases torque (which increases hp) up high...

[Ntrain2k]

Quote:

Originally Posted by 3rdGen3.0 polished? bye bye turbulence... may want to roughen it up some... some turbulence is good... or is that only in the valves?

You only need a minor bit of turbulence in the intake port of the head.

[Ntrain2k]

Quote:

Originally Posted by Boogieman142 some turbulence is good, thats why ppl losesome bottom end when they port out.

It's not that you lose bottom end, it shifts the whole power band up a bit higher. We have a load of bottom end stock as it is. I gladly traded off some of that bottom end for the extra power up top.

[Ondonti]

Quote:

Originally Posted by 3rdGen3.0 I think that has more to do with changine VE... When you make less restrictions in the intake, the air comes in with less resistance, but the air is also less dense at the same rpm of the unported plenum... this lowers VE, which lowers torque... but you gain VE up higher in the rev band, which increases torque (which increases hp) up high...

That made no sense.

[DKKNE]

Yep that made no sense at all