Head Porting for Fuel Milage

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Re: Head Porting for Fuel Milage

Post by Tom68 »

GARY C wrote: Fri Mar 24, 2023 11:47 pm Has anyone ever increased air inlet via cam and head flow and used less fuel?
Long duration late closing inlet valve reduces pumping loss (throttled operation, increased flow not utilised) at cruise etc, so better economy, then helps cylinder fill at high engine speeds, power.

Of course if you were changing from something like this it wouldn't be hard to make improvements.

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Re: Head Porting for Fuel Milage

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Tom68 wrote: Sat Mar 25, 2023 2:47 am
GARY C wrote: Fri Mar 24, 2023 11:47 pm Has anyone ever increased air inlet via cam and head flow and used less fuel?
Long duration late closing inlet valve reduces pumping loss (throttled operation, increased flow not utilised) at cruise etc, so better economy, then helps cylinder fill at high engine speeds, power.

Of course if you were changing from something like this it wouldn't be hard to make improvements.


253 184.jpg
Maybe I should have been more specific, the OP already has a fuel efficient engine so can one expect to make more fuel efficient by increasing air flow and cam?

Forgive my ignorance but when I see "Fuel Milage" I add an e and then assume one is looking to reduce Fuel Mileage.

But joking aside, most porting smooths out sharp edges which I would think hurts fuel shear not helps. Porting increases air into the cylinder which has to be offset with fuel for burn so it seems unporting would be more beneficial.
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Re: Head Porting for Fuel Milage

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BobbyB wrote: Thu Jan 26, 2023 11:00 am Currently rebuilding a 2.8 ford V6 for an 83 ranger 4x4 truck with 4 speed manual transmission.

What modifications to the heads will help with fuel milage and low speed torque? I am not concerned with peak horsepower.

I expect to have Mike regrind a cam. I have access to a flowbench.
One thing I have always thought of was cutting the throat like a step booster in the carburetor to sheer fuel... Everyone I have talked to about this made a big deal about how it would hurt flow numbers.

If you have access to a bench and a velocity probe the I would look at filling in and speeding up any slow areas as well as making all areas somewhat rough are textured to prevent wet fuel flow.
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Re: Head Porting for Fuel Milage

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GARY C wrote: Sat Mar 25, 2023 3:35 am
Tom68 wrote: Sat Mar 25, 2023 2:47 am
GARY C wrote: Fri Mar 24, 2023 11:47 pm Has anyone ever increased air inlet via cam and head flow and used less fuel?
Long duration late closing inlet valve reduces pumping loss (throttled operation, increased flow not utilised) at cruise etc, so better economy, then helps cylinder fill at high engine speeds, power.

Of course if you were changing from something like this it wouldn't be hard to make improvements.


253 184.jpg
Maybe I should have been more specific, the OP already has a fuel efficient engine so can one expect to make more fuel efficient by increasing air flow and cam?

Forgive my ignorance but when I see "Fuel Milage" I add an e and then assume one is looking to reduce Fuel Mileage.

But joking aside, most porting smooths out sharp edges which I would think hurts fuel shear not helps. Porting increases air into the cylinder which has to be offset with fuel for burn so it seems unporting would be more beneficial.
Not sure the 2.8 is very fuel efficient….I hope Mike can grind a cam that helps instead of hurts the mileage and low speed torque.
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Re: Head Porting for Fuel Milage

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GARY C wrote: Sat Mar 25, 2023 3:44 am
BobbyB wrote: Thu Jan 26, 2023 11:00 am Currently rebuilding a 2.8 ford V6 for an 83 ranger 4x4 truck with 4 speed manual transmission.

What modifications to the heads will help with fuel milage and low speed torque? I am not concerned with peak horsepower.

I expect to have Mike regrind a cam. I have access to a flowbench.
One thing I have always thought of was cutting the throat like a step booster in the carburetor to sheer fuel... Everyone I have talked to about this made a big deal about how it would hurt flow numbers.

If you have access to a bench and a velocity probe the I would look at filling in and speeding up any slow areas as well as making all areas somewhat rough are textured to prevent wet fuel flow.
Yes, kind of my thought… sharp edge to keep fuel and air well mixed… what about a 75 degree cut before the 45 seat rather than a 60… does it seem like it would help? This seems like uncharted water…mostly.
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Re: Head Porting for Fuel Milage

Post by Bigchief632 »

GARY C wrote: Sat Mar 25, 2023 3:44 am
BobbyB wrote: Thu Jan 26, 2023 11:00 am Currently rebuilding a 2.8 ford V6 for an 83 ranger 4x4 truck with 4 speed manual transmission.

What modifications to the heads will help with fuel milage and low speed torque? I am not concerned with peak horsepower.

I expect to have Mike regrind a cam. I have access to a flowbench.
One thing I have always thought of was cutting the throat like a step booster in the carburetor to sheer fuel... Everyone I have talked to about this made a big deal about how it would hurt flow numbers.

If you have access to a bench and a velocity probe the I would look at filling in and speeding up any slow areas as well as making all areas somewhat rough are textured to prevent wet fuel flow.
A lot of Ford heads had something like that, Cleveland and M heads, Boss 302 heads, 429/460 heads and some others, a big ridge cut under the bottom angle of the seat. My guess it it's there for fuel sheer, as there's probably puddled fuel running down the port, especially the Boss 302 heads which are essentially 4v Cleveland heads on a Windsor 302, it was a band aid to help combustion, and they hadn't quite figured out port sizing and air flow relationships at that point. As far as in the carb, it's waaay to far up the channel to have an effect by the time it reaches the valve.
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Re: Head Porting for Fuel Milage

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GARY C wrote: Fri Mar 24, 2023 11:47 pm Has anyone ever increased air inlet via cam and head flow and used less fuel?
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Re: Head Porting for Fuel Milage

Post by GARY C »

BobbyB wrote: Sat Mar 25, 2023 10:13 am
GARY C wrote: Sat Mar 25, 2023 3:44 am
BobbyB wrote: Thu Jan 26, 2023 11:00 am Currently rebuilding a 2.8 ford V6 for an 83 ranger 4x4 truck with 4 speed manual transmission.

What modifications to the heads will help with fuel milage and low speed torque? I am not concerned with peak horsepower.

I expect to have Mike regrind a cam. I have access to a flowbench.
One thing I have always thought of was cutting the throat like a step booster in the carburetor to sheer fuel... Everyone I have talked to about this made a big deal about how it would hurt flow numbers.

If you have access to a bench and a velocity probe the I would look at filling in and speeding up any slow areas as well as making all areas somewhat rough are textured to prevent wet fuel flow.
Yes, kind of my thought… sharp edge to keep fuel and air well mixed… what about a 75 degree cut before the 45 seat rather than a 60… does it seem like it would help? This seems like uncharted water…mostly.
It would be hard to say without doing a back to back test thats why I never pursued it, my build were performance oriented so I stuck with what I knew.
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Re: Head Porting for Fuel Milage

Post by Bob Hollinshead »

I've always wondered if steep intake seat angle with a minimal top cut to kill low lift and reversion flow might help fuel economy? Size the port properly for better filling at the cruise rpm. Cam it for less overlap.
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Re: Head Porting for Fuel Milage

Post by juuhanaa »

Bob check this,

https://youtu.be/QzHoC7nFBJ8



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Re: Head Porting for Fuel Milage

Post by mag2555 »

In thinking about reworking anything with the heads once again to achieve your goals and in thinking about other heads that already contribute to overall fuel efficiency I say this.
You want the minimum port area to both attain the rpm you need and the level of Hp for your needs and this hopefully will cause you to shrink the port and valve bowl some in conjunction with running as big a intake valve as you can above what you have now.

The effect you want is that between like .200” and .400” is to the small bowl throat and big valve spread the mixture as best as possible 360 degrees around the chamber.
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Re: Head Porting for Fuel Milage

Post by Tom68 »

Maybe port the heads to suit a lean AFR, lot's of swirl and run it hot to reduce misfires.
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