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Head flow work makes more HP

3K views 26 replies 12 participants last post by  mattr66 
#1 ·
So it looks like doing flow work to the heads gives more HP by lowering drive pressures. At least in Treys case with the 38r. I would like to hear more about head flow work, and how much more can be done/gained beyond what Trey did.
 
#2 ·
Head porting will never cause power to drop if done correctly. ;)

Also if the common rail from Swamps uses a much smaller injector, more flow could be had by increasing the port cross section at the injector sleeve.
 
#4 ·
Yes he had them on the pumpkin when testing out some b codes and nos. But these are not the ones that had all kinds of wicked porting done. They just have some very mild porting.
 
#15 ·
Find a set of cracked 1's 1st and grind 1 port at a time then test. If you don't have access to a flow bench start by seeing how much you can change w/out increasing volume.

Or you could make a custom set of door props, I had a matched set of SB2.2's for awhile that held doors open nicely!
 
#25 ·
I know who did the heads on the orange pumpkin. I think they are currently planning on setting up a program for the 5 axis Hass.

In a conversation with the head man the other day, they are very careful to not mess with the swirl that is built into the head. You can get more flow and power by screwing with the swirl, but you will smoke like a freight train if you do.

I leave my head work to the real experts because they have so much experience and so many little tricks. Plus I hate the taste of metal dust.

JonFord
 
#26 ·
Maybe I missed the thread but I don't see how porting 7.3 heads would really lower overall drive pressures. All the work on a 7.3 head needs to be done on the intake side since the injector sleeve just blocks the entire intake runner where-as the exhaust has a straight shot right out of the motor.

This would indicate to me that boost would be lowered from porting all the while getting the same or more air but drive pressures would not really be effected.

Anyone care to educate me on why my reasoning is flawed?

I've always suspected that my significant head porting plays a serious role in my years of dealing w/ smoke and slow spool-up although I've mostly got that handled now. We did take care to maintain swirl when we ported my heads but we removed so much metal that velocity and restriction had to be effected in a HUGE way.
 
#27 ·
Don't think of it as a boost to backpressure ratio. Think of it as intake flow vs backpressure. Anytime you are cramming more CFMs into the engine while keeping the backpressure the same you have done the same thing as decreasing the backpressure.

One other thing to consider is port reversion on the exhaust side. I'd imagine that a constrained exhaust port such as a turbo motor would need different analysys on a flowbench vs somehting that is supposed to open to atmosphere as soon as possible.
 
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