A Corvette engineer once told us that engines are just big air pumps. They draw air in and exhaust air out. Callaway Cars and MTI Racing have devoted a lot of time finding ways to increase an engine's air pumping capability. They both offer products that increase an engine's air pumping capacity. Our plan was to replace a stock LS1 throttle body and mass air flow sensor with replacement units from both companies to validate the concept.
We visited MTI Racing in Marietta, Georgia, because they have their own in-house Dynojet chassis dyno. The chassis dyno is perfect for these kinds of product validations. Owner Reese Cox is a former Corvette SpeedVision GT race driver who knows how to make Corvettes go fast and is an expert with his dyno.
Callaway's Billitt Throttle...
Callaway's Billitt Throttle Body is blue anodized with the Callaway name machined into the top.
Our test car is a '00 FRC LS1 with a head and cam package. It has a Callaway "Honker" air intake, a high-performance cat-back exhaust system, and long-tube headers. The only part of our air pump LS1 that remained stock was the throttle body (TB) and mass airflow sensor (MAFS). Callaway Cars sent us one of their CNC-machined, blue-anodized 6061 aluminum TB units. Their Billet throttle body is PN 203.50.2650 and retails for $645. MTI Racing also provided us with one of their poly high-flow MAFS. The MTI MAFS part number is 89873255332 and retails for $299.
With our new parts in hand, the car was placed on the dyno for a base run. The car pulled 419.2 hp and 393.3 lb-ft of torque. The MTI team then installed the Callaway TB, and in a flash it was finished. When we compared the original unit to the Callaway TB, it was obvious why the new design maximized airflow. The unit has a 78mm throttle plate that matches the intake manifolds inlet opening. It also features a "bell-mouth" machined inlet shape and is CAD engineered for maximum airflow. All parts are new OEM style and come ready to plug and play. We elected not to hook up the TB coolant lines because this car lives in a warm climate. After the installation, the car started up immediately, and it did not have any drivability problems. Back on the dyno, the car pulled 424.2 hp and 402.2 lb-ft of torque! Now we're talking, even though the car delivered good horsepower before, it was a little short on torque. The torque gained by adding the Callaway TB helped make the car easier to drive in stop-and-go traffic. Torque is king!
Next MTI removed the stock MAFS. The MAFS comes in three pieces. Removing the four Torx screws allowed the MASF to come apart easily. The middle part of the stock MAFS fits into the two halves of the MTI Racing MAFS. After tightening the four Torx screws, the unit was ready for installation. Again, we experienced no starting or drivability problems. Back on the dyno, we recorded 429.1 hp and 408.4 lb-ft of torque. Out on the road, the car felt much more responsive at lower rpm. Adding these two components netted us a 9.90 hp and 15.10 lb-ft of torque improvement. We highly recommend these products to help your C5 move more air!
1 MTI used a 10mm extension...
1 MTI used a 10mm extension to loosen the two bellows clamps.
2 Once the clamps are loose,...
2 Once the clamps are loose, the bellows between the stock throttle body and the stock mass airflow sensor are removed.
3 MTI used a radiator hose...
3 MTI used a radiator hose tool to remove the throttle actuator connector on the left side of the throttle body. They also removed the PCV hose and the throttle position sensor connector on the right side of the unit.
4 the two throttle coolant...
4 the two throttle coolant hoses from under the throttle body were removed and plugged. (You might experience a small loss of coolant.) We removed the three 10mm bolts from the throttle body and lifted the unit from the car.
5 This car lives in a warm...
5 This car lives in a warm climate, so we elected to bypass the throttle coolant lines as shown in this photo. We do not recommend this procedure in cold climates.
6 We reversed the removal...
6 We reversed the removal procedure to install the new Callaway unit.
7 We dynoed the car after...
7 We dynoed the car after installation and measured a 5 hp and 8.90 lb-ft increase in torque.
8 This dyno chart plots the...
8 This dyno chart plots the engine performance improvement after the Callaway throttle body was installed.
9 MTI offers a lightweight...
9 MTI offers a lightweight composite Mass Air Flow Sensor that greatly reduces air restriction. Four Torx screws hold this unit together. We simply inserted the center section from the factory unit into the MTI part and reassembled it with the four original screws.
10 To remove the factory...
10 To remove the factory MAFS, we unplugged the air temperature sensor and mass airflow connectors. Reinstall the MTI unit by reversing the removal procedure.
11 When MAFS installation...
11 When MAFS installation was complete, we dynoed the car again and saw a 4.9 hp and 6.20 lb-ft of torque improvement. These two additions netted us a 9.90 hp and 15.10 lb-ft of torque increase over the stock units.