I recently had the chance to A-B test a Mamo Motorsports LT4 V2 ported throttle body. This is Tony’s latest porting profile combined with a “shaft-mod” which reduces the profile of the shaft and associated hardware… allowing more airflow at wide-open-throttle. This throttle body is flow tested to 1100cfm, whereas a stock unit is 940cfm!

The rig-under-test is a 2018 GMC Sierra Denali 4×4. This beast of a truck has a stock L86 equipped with a Whipple 2.9 blower, ARH long tubes & high flow cats, 3” catback exhaust, Whipple intake tube, MBRP velocity stack, 3.875 upper pulley, LT4 fuel injectors, Lingenfelter Big Bore HPFP, DSX FlexFuel sensor, and 525LPH intank pump. We dialed the truck in to 571whp & 600wtq @ 8.5psi on 93 pump gas, followed up with 647whp & 670wtq @ 8.5psi on E50. This tuning was completed with the stock L86 throttle body. Once the tuning process was finished we installed a Mamo Motorsports LT4 V2 ported throttle body and made a pull… the results were great as the peak numbers jumped to 651whp & 676wtq @ 8.9psi!

The overlay below shows a consistent gain around 10whp and 10wtq throughout the whole pull, which is ~1.5% increase when making power and torque in the 650 range.

The overlay below shows the increase in boost seen in the intake manifold with the Mamo LT4 V2 throttle body. This indicates the blower was looking for more air than the stock L86 throttle body could provide. The boost increase was 1.3% to 1.5% through most of the pull; however, it did ramp  up after 5,700rpm with a peak increase of 4.8% at ~6,150rpm.

The overlay below shows the AFR measured with the two tests. The swap to the Mamo LT4 V2 yielded ~1.5% leaner air fuel ratio throughout the pull. This correlates well with the increase in boost we saw. Since the tune was not changed, the additional airflow leaned the mixture by a corresponding amount.

Some further data can be seen in the charts below. Without going into great written detail, you can observe the following:

• The critical data points (RPM, speed, temps, TPS) are nearly identical between the two runs.
• The MAF reading in front of the throttle body is 0.5% larger with the LT4 V2.
• The cylinder airmass calculation and total ignition timing is identical.
• The final dynamic airflow calculation is 0.003% higher with the LT4 V2.
• The injector duty cycle is 0.6% smaller with the LT4 V2.
• The manifold air pressure is 1.5% higher with the LT4 V2, which aligns to the dyno boost graph.

These data points support the increased airflow through the intake manifold (i.e. boost), and also confirm the power increase is only from swapping the Mamo Motorspots LT4 V2 throttle body.

Beyond the power increase, we can confirm an improvement in low throttle drivability. Tony’s smooth bore work really allows the airflow to travel through the throttle body in a more linear manner. This results in a significantly more natural “toe to throttle” feel, rather than the abruptness caused by a stock unit’s harsh edges.

All-in-all this is a great mod for someone looking for that extra airflow and improved drivability!