Intake Manifolds - My Big Fat Obnoxious Torque Curve

Here we have the shock plates installed in the car and strapped to the dyno. This was a fairly simple modification to make that sure made it easy to hold the car in place. Having a car come loose on a chassis dyno is a good way to ruin your day.

You're going to need a tall hood or else a hole in it to run this combination. The Victor 383 is a tall manifold and when you add a two-inch spacer plus a full-height air cleaner you have 16 inches of height to deal with.

A handheld infrared thermometer is a great addition to any tool box. It is a super simple way to check the temperature of the manifold or the radiator. Sure beats the old method of measuring how big the blister on your thumb is after touching the manifold! This unit is a Sears Craftsman but they are available in many locations.

The star performer of the day was our new handheld wideband O2 air-fuel ratio meter from Innovate Motorsports. This little guy was dead nuts on when compared to the O2 sensor which the DynoJet uses. We're going to install one of these into our car on a permanent basis so we can keep an eye on the air-fuel ratio changes after every modification we make.

We couldn't leave well enough alone so we ran a carbide burr over some of the rough edges inside the Performer RPM manifold. We're not sure if this helped or hurt the airflow, we just enjoy grinding on things.

Performer RPM with Different Spacers
This graph show three dyno tests; a one inch open spacer (shaded line), a one-inch four-hole spacer (solid line) and a two-inch tapered spacer (broken line). The Performer RPM wasn't super sensitive to spacers in our application. It did like the two-inch tall tapered spacer the best, but the one-inch tall one was very close. No spacer also worked fairly well so if you don't have the hood clearance to run a spacer, don't worry about it.

Performer RPM vs. Victor 383
The Performer RPM makes more torque and horsepower throughout the entire dyno pull. It only begins to give up the lead once the engine is past the power peak. This is one tough manifold!