I was thinking.... what affect does a set of ported heads have and are they really worth it on a FI motor. I thinking this because your already forcing air into the cylinder. N/A motors are dependent on the lift and flow of the heads because the cylinder has to draw its own air and the smoother larger runner helps. Is this the same concept on a FI car?

 

We are exploring things as well.... My thoughts are to get a set of LQ9 heads and port them to the water jackets and go from there... more volume the better right..????? Somebody correct me if I am wrong about this..

 

A freind did a ported head swap and with no other changes it made the same power just at a lower boost.

 

Ive heard this is the only reason for doing it. The gains are reached by increasing efficiency allowing for more boost and better flow. Its debatable if it is cost effective or not.
I would think that with a good set of heads you may be able to net more power per pound of boost than was previously attained. Im no expert. Just throwing some things out there.

 

Interesting post. What do some other guys making big power think? I would think that more power at lower boost would be better if one plans to run more boost.

 

I am looking as well from MM, PSJ, or Harlan as well or anybody else with alot of experience with F/I..

 

you will certainly get efficiency gains, but those gains per $ will be negligable to the gains you get per psi increase in boost.

this goes out the window if you are building for max effort

 

The more the heads flow the less restrictive they are.

If I could slap on a set of ported heads that flowed 50 more cfm than my current heads I would do it, realizing that the engine hp will go up.

 

That's what I was thinking...AFR's may be going on this summer.

 

Volume of air is much more impotant than velocity like a N/A setup though correct..????????

 

I run some 6.0 heads now that flow like 300/225 at .600, so they are pretty average but are quality work.

It really comes down to HP goals and the fuel you will use. Some combos use pump gas and some require 110, 112, C16.

 

i think it will give more hp but wouldn't spend the money unless you had everything else done...especially suspension.

 

Well I am going to home port the LQ9 heads and match them to my LS2 intake that has been cleaned up already. Then from there I will port the ports as much as possible...

 

When I had my powerdyne I picked up 60 rwhp (from 390 to 350) with mildly ported heads, macs, and a really mild cam (LPE GT2-3). The car sounded the exact same, and the boost didn't change either. The headers were good for 15 or 20, but the rest I attributed the other 40 to the extra lift of the cam and better flow at lift of the heads.

The car was a blast except for the damn belt slipping all the time.

-Geoff

 

TURBO.....

 

This is what Im wondering also. In a N/A setup, velocity is VERY important, but whats the most important factor with a FI setup... volume or velocity? Heads like the AFRs may not be worth all the extra money over a ported set of stockers if we are looking for volume. AFRs are made around velocity with the small runners and are much more expensive.

 

Thus the reason Im going boost with no belt

 

I assuming you mean gaining hp by doing a pulley swap to compensate for the loweer boost your going to see after you put on a set of free flowing heads?. From what I understand is that your not going to see any hp gains on a FI application but just gain effciency right?.

 

You'll probably see a bit of a gain even without changing blower speed. But much of that could be from the better exhaust ports.
I think it boils down to budget. A set of nice flowing heads is always a good thing if you have the cash.
But you can force the air through a set of lesser heads with no problem or even with fewer cyls and ports and make big power .
After all there are max effort 4 bangers making 1000hp with a whole lot of boost- just to illustrate the point.
Steve

 

They must help some, cause with only 5# of boost and the Stage II 5.3L heads and cam. I made over 500 rwhp.