Pressure Tested

How Two Edelbrock Intake Manifolds Perform Under 30 PSI of Boost

- Jeff Huneycutt

If you are any kind of gear head or have worked with engines for even a little while, then you are likely familiar with the rules of thumb when it comes to intake manifolds and horsepower. The main rules goes like this: Longer intake runners lend themselves to making torque in the low-rpm range, while shorter runners hurt torque on the low end but are much better and making high-rpm horsepower. Another useful rule is that a straight path for the air and fuel to follow from the intake into the port will produce better high-rpm power than a path beset by curves or other obstructions.

Of course, those rules are all about making it easier for an engine to pull air and fuel through the intake manifold and into the combustion chambers. In other words, a naturally aspirated engine. But what happens when we turn that paradigm on its head by adding just a touch of boost? And by “a touch” we mean 30 psi, which is approximately two full atmospheres, from a pair of turbos. Yeah, go big or go home.

When you go from a naturally aspirated to a boosted application, the conventional thinking says that the intake manifold becomes less important. After all, when the intake valve opens, the boost pressure has all the air you could need sitting right there ready to jump into combustion chamber, so the intake manifold configuration doesn’t really matter.