Sickness91Z28

iTrader: (1)

Hey guys....

I'm going to be installed an adjustable fuel pressure regulator and a fuel pressure guage to my engine....soooo..I'm going to have to remove the plenum. My question is....would it be a good idea to go ahead and port/polish it? I currently have a full catback Flowmater Exhaust, Edelbrock TES headers, 52MM Edelbrock/BBK Throttle Body, and Ram air Boxes. Would I be getting way to much air if I port my plenum? I don't want to lose power by doing something like this. Any thoughts or suggestions would be great. Thanks

rezinn

No such thing as too much air. You only use what you need. Too much fuel, on the other hand, can be bad. Don't turn that regulator up too high

bigals87z28

there is such thing as too much air. Thats why people dont put 1000cfm carbs/tb's on there 305.

porting the plenum is a great mod to do that can be done easily. Removng the EGR walls will help air flow better into the plenum. Also, port matching the runner openings to gaskets is a good idea. I have some crappy pics and I hope that when I do it again, I can snap some good ones.

Johnny Blaze

iTrader: (15)

A lot of work can be done on the TB side. Match up the TB gasket.

rezinn

Let me clarify. We're talking about porting here, not throttle bodies. If you want to make power on tpi, there is no such thing as too much air VOLUME in the plenum. Volume makes revs, people don't put a 1000cfm throttle body on their cars because it kills throttle response and probably reduces air velocity so much that it hurts low end power. Cutting some edges out of your plenum will not have the same effect.

305sbc

iTrader: (3)

Exactly right.
The CFM (volume) of air going into your chambers will remain fairly constant and directly linked to the volumetric efficiency of the entire system including the exhaust. Gains from bigger throttlebodies and porting come from the increase in air density inside the intake tract.

Almost any porting you do to a TPI will increase density in the intake. When the density starts going up significantly you will then need to adjust the fuel delivery with a DIY PROM.