Story continues below this advertisement
When Pennsylvania College of Technology designed the Aftermarket Performance Specialist credential in 2012 it was decided that two of the four classes in the credential would be focused upon bolt-on aftermarket parts and chassis dynamometer testing of the parts. The two classes would involve the students with installing, chassis dyno testing, and evaluating the aftermarket parts for ease of installation, requirements for modifications, and performance. With that in mind the college was able to acquire a Hamburger’s Performance Products throttle body spacer for the college’s 2006 5.7L Hemi Dodge Charger.
The Charger is a 47K mile original all stock vehicle. It was a totaled vehicle that was repaired by a body shop with the hopes of selling the Charger off their used car lot for a nice profit. After sitting on the lot for months with no interest from the general public the college arranged to acquire the Charger. There were several areas of the car that needed attention but now it is a reliable part of the dyno fleet.
A minimum of three dyno runs are performed at each stage of the dyno testing and it is a requirement that the three dyno runs be within 1% of each other to establish a creditable test. All results will reflect the torque and horsepower at the drive wheels, in the case of the Charger, the rear wheels. Also, all the testing is done in the ABA format; this means that a baseline is established and then a component is installed and tested, after the part is tested it is removed and the baseline is tested again. Provided the baseline numbers of the pre- and post-testing of the component are the same the test is considered valid. If the pre- and post-test results are different something has changed and the component testing cannot be verified as valid due to the change (vehicle/engine damage, different driver, incorrect weather correction factor, etc.). Once the reason for the pre- and post-test difference is corrected the testing can start over.
The Charger was strapped to the Mustang chassis dyno to establish a baseline before the throttle body spacer would be bolted on to the Charger. With the Charger’s drivetrain and engine warmed up and all the safety checks completed the engine was run at WOT from 2800 rpm to 5500 rpm. The Charger made three very nice runs through the rpm sweep. The Hemi produced 296.8 lb/ft of torque at 4400 rpm and 275.0 horsepower at 5200 rpm. Over the rpm sweep the average torque was 280.0 lb/ft and an average of 223.3 horsepower. A solid baseline was established, now it was time to install the Hamburger Performance Products throttle body spacer.
Testing a throttle body spacer would be a fairly easy test to set up. The expectation of throttle body spacers is to give your vehicle’s engine significant torque gains, increased throttle response, and increased fuel mileage. These claims are based upon the slight increase in plenum volume and the taper of the throttle body spacer providing an increase in velocity and swirl of the incoming air stream. The dyno test would evaluate the Hamburger’s Performance Products Torque-Curve MPFI Spacer Kit (part no. 3260) that was designed for various Dodge/Chrysler products with the 5.7L or 6.1L engine, view www.hamburgersperformance.com for your particular application. The throttle body kit included a CNC machined throttle body spacer made of 6061-T6 billet aluminum, an O-ring, and mounting hardware. The installation started with disconnecting the battery negative cable. With the battery cable disconnected, the Intake Air Temperature sensor (IAT) was disconnected from the air tube, the hose clamps on the air tube were loosened at the air cleaner box and the throttle body, and the air tube was removed. The four bolts on the throttle body were removed and the throttle body was carefully moved out of the way, taking care not to damage the factory O-ring on the intake manifold. The O-ring from the kit was installed on the throttle body spacer and the spacer was located on the alignment pin on the intake manifold. Depending upon the build date of your vehicle there are two different bolt lengths that must be selected to reinstall the throttle body to the intake manifold with the spacer sandwiched in between. The four bolts needed will be 6mm X 55mm bolts or 6mm X 70mm bolts; you will use all four bolts of one size or the other. All the bolts are included in the kit. The throttle body bolts with washers were installed and were torqued to 105 in-lbs. The air tube was reattached to the throttle body and the air cleaner box, the clamps tightened, and the IAT was reconnected. The battery’s negative cable was reconnected and the engine started to verify there were no leaks and no “check engine” lights illuminated. Expect the installation time to be less than 15 minutes with the use of basic hand tools.
With the TB spacer installed the Charger was backed onto the dyno. The Charger was warmed up and then three runs were made to evaluate the performance of the TB spacer. The same rpm sweep that was used with the baseline was employed with this test. The Hemi posted a maximum torque of 297.4 lb/ft at 4400 rpm and 275.5 horsepower at 5400 rpm. The torque was up 0.6 lb/ft and the horsepower was up 0.5 horsepower over the baseline. The peak horsepower was 200 rpm higher than the baseline. The average torque was 280.1 lb/ft and the average horsepower was 223.4 horsepower an increase over the baseline of 0.1 lb/ft of torque and 0.2 horsepower. After the TB spacer runs, the spacer was removed and the Charger was re-run in the baseline tune. The results were the same as the previous baseline; therefore, there were no major changes between the pre- and post-tests. The TB spacer tests results were considered valid.
With all the runs completed and the numbers crunched it was a positive test. The installation of the TB spacer provided a WOT increase in torque and horsepower at the drive wheels. There was no evaluation of the increase in fuel economy the TB spacer may have provided due to all the tests being performed at WOT. While the increases in torque and horsepower were not huge, the numbers provide a real world usage; your application and results may differ. As one of my instructors told me years ago, “judge slowly”, other changes may result in larger torque and horsepower increases from the TB spacer. Headers, full aftermarket exhaust, software tuning, a different air box, air tube, or air filter may provide an increase in the TB Spacer’s performance numbers. Every time a change is made other changes must be made to improve the engine’s performance, eventually you will hit on a combination where all the parts work extremely well together and the performance at that time will be its peak until your next change, then the process will begin again. Next month look for exhaustive testing to help increase the TB spacer’s performance. - The Professor