I'm having a shop custom port my AFR 180 heads and they already said they would flow better than AFR competition CNC'd 195's when they are done so that right there made me happy, especially since they are charging less than what AFR would.

My question is, how much head flow should I ask for? Is there a point where they flow too much and it hurts velocity? I want them to be as good as they possibly can be so there is no question in my mind about how well done they were, but I don't want it to be too much if there is such a thing. They are going to also be giving me the flow chart.

They are going to have 1.94 intake valves and 1.60 exhaust. My cam has a max 232 duration and a 530 lift, and I'll be running forced induction. I know I want my exhaust flow to be wicked sick for running boost and for a better TQ curve.

Anyway, is there such a thing as too much intake flow? If so would it matter if running boost? If yes then how much flow would you want, 300cfm or what? Also, what's a good exhaust flow in relation to intake flow for a forced induction motor, like 65% of what the intake flow is?

The other thing to factor in I guess would be my intake. Ported Accel Base with ported SLP runners and a ported stock plenum, 52mm TB too.

Thanks!

 

Well you've asked a couple good questions there. Let's see

1. Yes you can hurt an engine by going with too much "flow" reduces velocity.How much is dependent on CID, compression, cam, intake, how quick your boost comes in,etc. Also I would be very leery of a shop claiming that they'll get your 180's to flow more than the CNC 195's. AFR does very good work and keeps velocity up. Sure you can get higher flow numbers, but you may sacrifice velocity.

2. On a good note, blown motors like runner volume and help make up for lost velocity. How much is too much is dependent on the stat's of your supercharger, it'll need to be able to fill that volume and make boost.

3. On a NA motor I like to see exhaust flow be between 70 and 80% of intake. On a blown motor I like to see between 77 to 85 %, though you can compensate for this by running a dual pattern cam.

The only thing i'd really worry about with your combo is the idle quality. The blower won't help you there, and that's a pretty good sized cam. If you haven't bought the cam yet I'd look at a blower specific grind from any of the major manufacturers.

 

Thanks for all the info, it comfirms what I thought.

The blower is going to be a ProCharger F1 and the cam that I already have is a custom grind that is already designed for boost.

So how much flow on the intake side should I ask for at .550" lift? 300cfm? The Comp CNC'd 195's flow 280cfm at this lift...