Project 5.0 Mustang: Improving the Breathing With Ford Racing and Cooling with CSF

Project 5.0 Mustang: Improving the Breathing With Ford Racing and Cooling with CSF

by Mike Kojima

In previous installments of our Project Mustang we had installed most of the common bolt ons for our 5 liter Coyote engine.  We had gotten a pretty decent boost in power but we had noted that our power would really fall off at higher RPM, more that what we thought a free breathing 4 valve motor should.

What we did notice is that Ford produces a few different OEM intake manifold designs for the Coyote. The two options that interested us were the Boss 302 and the Cobra Jet.  The Boss 302 intake manifold is what came on the Boss 302 model obviously. It has much shorter runners than the stock intake manifold and a larger plenum using the stock throttle body.  When checking out dynocharts online the Boss 302 seemed to definitely give a top end boost at the expense of a little loss on the bottom end.

We also checked out the Cobra Jet intake manifold from Ford Racing.  This was the intake manifold that Ford created for the naturally aspirated Cobra Jet drag car.  The Cobra jet manifold needs a really big Ford Racing oval throttle body and a specially designed Ford Racing cold air intake to mate with the throttle body.

When looking at other peoples results online, this seemed like the manifold to get for a stock Coyote with long tube headers. The Cobra Jet intake manifold seemed to have the same slight bottom end loss as the Boss 302 intake manifold but a definite gain over the Boss 302 on top end.  So the Cobra Jet it was.

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The Cobra Jet manifold has inlet runners considerably shorter than stock.  This contributes to top end power. The runners are about the same length as the ones on the Boss 302 intake.  The Cobra Jet intake is molded from thermoplastic, the plastic does not conduct heat too well which helps keep the intake charge cool.  The smooth interior of the runners should contribute to good for flow as well. O-rings around the runners ensure a positive seal to the cylinder heads.
The Cobra Jet intake has a huge opening for a really large oval throttle body.  The oval shape means you have to stick to Ford Racing’s offerings but the size is large enough to accommodate just about any power level that the engine is capable of.  The manifold features a nice O-ring seal for the throttle body.  You can see how large the plenum of the manifold is as well.
The Ford Racing throttle body is one of the largest we have ever seen.  Its oval shape probably makes it less sensitive to idle control issues which is critical for drive by wire applications. The throttle is a complete drop in unit with all the drive by wire stuff pre installed.
The highly polished throttle body comes with a throttle position sensor.  The part is high quality, much better than your typical aftermarket fare. Everything is set to drop in with nothing to mess up.

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