DYNO RESULTS: 718 GT4 SOUL Race Exhaust System

Our customer, Johnny, opted to dyno test his 718 GT4 along the way of his mod path – starting with a SOUL Race Exhaust System. Baseline runs and post exhaust results were generated by HPA Performance with their state of the art Superflow dyno.

Superflow’s Autodyn 30 is known for unmatched repeatability with dyno runs. “SuperFlow® does not use complicated belt systems that stretch and break or inconsistent electronically synced systems that allow the front and rear rollers to spin at different speeds, causing driveline windup and damaging driveline components. Differentials and driveshafts allow SuperFlow® to measure and compensate for the parasitic losses of every dyno produced so that each one leaves the factory calibrated with its own inertia and parasitic data. The end result is the most accurate torque and power measurement available. Further, torque is measured using two temperature-compensated load cells, one at each roll set, so you can see total torque across the rpm range, but also the torque split between the front and rear axles. ”

A system befitting of a GT car: We redesigned the entire exhaust aft of the headers for maximum flow. The factory dual exit/entry flanges connecting the over axle pipes to the PSE muffler limits the piping diameter to 2.25”. The SOUL Race Exhaust System is optimized into a single 2.5″ flow path on either side with accommodations to mount factory style tips. Great care was made to mind clearances for hard use on and off the track, expect no issues with our mandrel bent piping. The longer piping routing also helps noticeably smooth out the exhaust sound while the slight blending of the X gives the car a higher pitched sound more akin to the previous 981 generation we’ve come to know and love. Durable race resonators add a more refined note to the aggressive exhaust note while slightly reducing drone. A non-resonated version is option for those looking for maximum weight reduction and sound.

Airflow is provided by a Nascar wind machine that simulates true driving conditions. A fan exhausting above the engine at 42,000cfm can pull 98,000 BTUs of heat.

This car has no other modifications, stock ECU tune, and is running 91 octane gas (Canadian).

Base peak numbers: 373 whp / 293 ft-lbs.

Final peak numbers: 391 whp / 302 ft-lbs.

Peak gains: 18 whp / 9 ft-lbs

Our larger diameter, single flow path piping makes for great gains in the higher RPM’s to boost on-track performance! We’d expect to see greater gains with 93 octane gas and an more aggressive curve with an ECU tune.


SOUL 718 GT4 / Spyder / GTS 4.0L Race Exhaust System  |  HPA Motorsports website

Questions? Comments? Let us know!

– Mike Spock / Marketing Manager