Has anyone flow tested the coyote heads

[K4fxd]

Would like to know the flow numbers. I've seen anywhere from 280 to 390.

Some say they out flow a Yates D3 head but when I see published flow numbers they are much less than the Yates.
Here's the flow figures off of some of the first D3's

Int Valve: 2.180"
Exh Valve: 1.625"
Int volume: 280cc
Exh volume 150cc
Chamber: 48cc

Port Flow CFM @28"
.100" = 67/47
.200" = 154/101
.300" = 230/140
.400" = 301/206
.500" = 351/237
.600" = 381/253
.700" = 393/263

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[engineermike]

Interesting topic. I believe when that was stated they were actually referring to low and mid-lift flow. If you think about the flow area (skirt area) of a coyote head at, say, .300 lift, with a 38 mm valve you get 1.41 sq in. But since there are two you double it to 2.82 sq in. The 2.18” valve listed above has 2.05 sq in flow area at the same lift. The coyote has almost 40% more flow area at the most restricted part of the flow path! At max lift the port itself becomes the restriction so the huge Yates port does better with the valve out of the way. It took me years to realize that low/mid lift flow isn’t just for low/mid rpm; it actually helps the most at top end. The valve spends way more time at low and mid lift than it does at max lift.

 

[VictorH]

One other thing that tends to get overlooked is port velocity. In an ideal circumstance you want the best flow while maintaining the highest possible velocity. If you've ever driven a set of heads with huge ports, i.e. high flow numbers but lousy port velocity, their low and mid-range driveability is terrible. Sure you can get high HP numbers to some extent, but everything below WOT and high rpm suffers (a lot).

 

[Cobra Jet]

If you have not come across it, here's some reading materials regarding Coyote 5.0 cylinder head flow rates.

Some of it is repetitive based on who had the original source material and where it was distributed (or copied for other articles).

https://www.cjponyparts.com/media/images/install-pdf/install_bkfce-2.pdf

https://www.diyford.com/ford-coyote-engine-cylinder-head-performance-guide/

https://www.motortrend.com/how-to/mmfp-1209-ported-coyote-heads-dyno-test/

https://www.enginelabs.com/engine-t...esting-mpr-built-gen-3-coyote-cylinder-heads/

Also see this thread with quite a few Coyote reference PDFs in it which discuss the differences between the Gen1-Gen3 Coyotes.
https://www.mustang6g.com/forums/th...coyote-v8-engine-improvements-changes.138550/

This chart is courtesy of Power By The Hour and is on their website:

 

[K4fxd]

One other thing that tends to get overlooked is port velocity.

This is why the Cleveland sucked on the street. Same with the Chrysler 426 Hemi

In an ideal circumstance you want the best flow while maintaining the highest possible velocity.

To a point, you want to keep them below the speed of sound.

 

[Strokerswild]

This is why the Cleveland sucked on the street.

Yep. As a former devotee of the 4-barrel 351C, I concur. They make a great strip engine though.

 

[engineermike]

The CJPonyParts link has peak flow numbers for stock Gen1 heads and curves for various ported versions. Based on information provided, I believe the stock Gen3 heads probably flow similar to the ported TEA Gen1 heads. Note that the Gen3 valves are almost 1mm larger and the ports are 12 more cc volume than Gen1. The following shows a comparison of about what I think the Gen3 heads flow vs the Yates head:

However, I think it's also worth noting that flowbench flow isn't a great data point in determining how a head will perform. The dynamics, pressures, flows, and velocities are worlds different from a flowbench in an actual engine.

 

[Angrey]

From what I've read and researched (which can be difficult, because so many people fall victim for marketing gimmicks in reporting data) the older gen heads flowed about 280 and the new gen 3 heads flow close to unported GT350 heads (318-320).

Everything has to be taken with a grain of salt, because unless it's reported at .550" lift, it's not apples/apples.

Anyone (including bone stock OEM heads) can flow higher if you lift them past stock cam lift.

So it gets to be a bit nefarious with some of the aftermarket stuff.

 

[K4fxd]

The dynamics, pressures, flows, and velocities are worlds different from a flowbench in an actual engine.

I agree 100% but I need accurate data for my sim program. So far using the Yates flow rates I get pretty close to actual dyno numbers.

 

[Unas2k5]

If you have not come across it, here's some reading materials regarding Coyote 5.0 cylinder head flow rates.

Some of it is repetitive based on who had the original source material and where it was distributed (or copied for other articles).

https://www.cjponyparts.com/media/images/install-pdf/install_bkfce-2.pdf

https://www.diyford.com/ford-coyote-engine-cylinder-head-performance-guide/

https://www.motortrend.com/how-to/mmfp-1209-ported-coyote-heads-dyno-test/

https://www.enginelabs.com/engine-t...esting-mpr-built-gen-3-coyote-cylinder-heads/

Also see this thread with quite a few Coyote reference PDFs in it which discuss the differences between the Gen1-Gen3 Coyotes.
https://www.mustang6g.com/forums/th...coyote-v8-engine-improvements-changes.138550/

This chart is courtesy of Power By The Hour and is on their website:

Are the gen 1 Mustang heads any different than the truck heads ? Do you know ?

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