arghx7
Well-Known Member
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I posted this in another thread, but I want to make a dedicated thread.
TLDR; Those valves in the intake manifold are restrictions added for fuel efficiency and emissions, not to improve the torque and power curve.
I watched a Youtube video recently and have seen it posted a few places saying that the 2015-2017 Coyote has Intake Manifold Runner Control Valves, like certain older Ford engines. The Coyote actually has Charge Motion Control Valves, which may look similar but have a very different purpose.
If you open the Ford Performance document, "2015-16 Coyote 5.0 Improvements" available on their website (current link: https://performanceparts.ford.com/download/PDFS/FPP_Gen_2_Coyote_Technical_Reference_2-16.pdf ) you get a partial explanation. Here is a diagram showing these valves:
And here are the relevant passages:
[Gen V GM small block head showing charge motion axes)
Charge motion control valve is a restrictive device meant to increases tumble and swirl in the combustion chamber for fuel economy, emissions, faster burn, and reduction of knock in cruising conditions. In this case, they work together with the intermediate lock VCT for Atkinson Cycle operation in order to improve fuel economy and emissions.
Ford's also used charge motion control valves in the past on various engines in one form or another; for example, the 3.8L V6 in the past would block off one of the intake ports when the valve was closed, to induce higher swirl:
Source: SAE 961151 "Development and Application of Ford Split Port Induction Concept"
Other manufacturers call them different things, like Tumble Control Valves, Tumble Generating Valves, Swirl Control Valves, etc but the basic purpose is the same: to improve mixing in the combustion chamber and promote faster, more stable burning.
So what is an Intake Manifold Runner Control Valve?
An intake manifold runner control valve changes the lengths of the runner for volumetric efficiency gains in particular rpm ranges. They've been used by Ford in the past and are common on a lot of high revving n/a engines (various Porsche engines for example, Rx-8's, etc). It may have some restriction, but that's judged to be outweighed by the tuning effect to improve the torque curve. For example, the non turbo Supra 2JZ-GE engine used a form of intake manifold runner control:
The current 5.0 Coyote makes more top end power because they used a higher flow intake port and larger valves, and made up the part throttle emissions using the charge motion control valve. A charge motion control valve is inherently restrictive, but in this case a straighter intake port and larger valves makes up for it (along with more valve lift).
Deleting the charge motion control valve should have a small improvement in head flow and peak power but might require a retuning of part load VCT due to slower burn. I don't have any numbers, but it's a known flow improvement on other engines, which often requires some part throttle load tuning in terms of spark timing and VCT tuning change. Ford Performance sort of implies this, but they aren't going to go ahead and tell you to delete something that affects emissions and could require part throttle tuning.
The power gains on the Gen 2 Coyote are despite the Charge Motion Control Valve, not because of it.
TLDR; Those valves in the intake manifold are restrictions added for fuel efficiency and emissions, not to improve the torque and power curve.
I watched a Youtube video recently and have seen it posted a few places saying that the 2015-2017 Coyote has Intake Manifold Runner Control Valves, like certain older Ford engines. The Coyote actually has Charge Motion Control Valves, which may look similar but have a very different purpose.
If you open the Ford Performance document, "2015-16 Coyote 5.0 Improvements" available on their website (current link: https://performanceparts.ford.com/download/PDFS/FPP_Gen_2_Coyote_Technical_Reference_2-16.pdf ) you get a partial explanation. Here is a diagram showing these valves:
And here are the relevant passages:
So what is a Charge Motion Control Valve?Ford Performance said:
[Gen V GM small block head showing charge motion axes)
Charge motion control valve is a restrictive device meant to increases tumble and swirl in the combustion chamber for fuel economy, emissions, faster burn, and reduction of knock in cruising conditions. In this case, they work together with the intermediate lock VCT for Atkinson Cycle operation in order to improve fuel economy and emissions.
Ford's also used charge motion control valves in the past on various engines in one form or another; for example, the 3.8L V6 in the past would block off one of the intake ports when the valve was closed, to induce higher swirl:
Source: SAE 961151 "Development and Application of Ford Split Port Induction Concept"
Other manufacturers call them different things, like Tumble Control Valves, Tumble Generating Valves, Swirl Control Valves, etc but the basic purpose is the same: to improve mixing in the combustion chamber and promote faster, more stable burning.
So what is an Intake Manifold Runner Control Valve?
An intake manifold runner control valve changes the lengths of the runner for volumetric efficiency gains in particular rpm ranges. They've been used by Ford in the past and are common on a lot of high revving n/a engines (various Porsche engines for example, Rx-8's, etc). It may have some restriction, but that's judged to be outweighed by the tuning effect to improve the torque curve. For example, the non turbo Supra 2JZ-GE engine used a form of intake manifold runner control:
The current 5.0 Coyote makes more top end power because they used a higher flow intake port and larger valves, and made up the part throttle emissions using the charge motion control valve. A charge motion control valve is inherently restrictive, but in this case a straighter intake port and larger valves makes up for it (along with more valve lift).
Basically, for the Gen 2 they had a bigger budget to handle the trade off in head design between part load efficiency and peak power, whereas on the older Coyotes they had to use a "one size fits all" design.Ford Performance said:
Deleting the charge motion control valve should have a small improvement in head flow and peak power but might require a retuning of part load VCT due to slower burn. I don't have any numbers, but it's a known flow improvement on other engines, which often requires some part throttle load tuning in terms of spark timing and VCT tuning change. Ford Performance sort of implies this, but they aren't going to go ahead and tell you to delete something that affects emissions and could require part throttle tuning.
So just to sum it all up, the Gen 2 Coyote did not add a valve to improve runner length tuning and get a wider torque curve (IMRC). They added an at least somewhat restrictive valve (CMCV) to improve fuel economy and emissions, but at the same time they used a better flowing head to still make more power.Ford Performance said:
The power gains on the Gen 2 Coyote are despite the Charge Motion Control Valve, not because of it.
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