The Dyno Session at Cordes Performance Racing
We took the car to Aces Auto Elite for an oil and filter change along with a brake fluid flush to address the fluid that was never changed as part of the 2 year service. I handled the air and cabin filter maintenance myself. Those who read our project introduction will remember the PPI caught brake fluid with elevated water content despite a service record showing it had been changed. When I pulled the old air filters, the date stamps suggested they were original to the car rather than the recently replaced units the records indicated. Reaching the air filters in a Cayman requires removing the rear trunk panels to access the engine compartment. What actually happened is not a difficult conclusion to arrive at, and it is a shame this occurs at any dealership, let alone one servicing vehicles at this price point.
With the car in known condition, we took the Cayman to Cordes Performance Racing (CPR) in Arizona. CPR is one of the premier performance shops in the state, known for building 1,000+ horsepower Corvettes and Vipers and their dyno cell is first-rate.
Our “Artificial” Baseline
Walking in, our car wasn’t stock. Two modifications already changed the picture:
Soul Over-Axle Pipes (OAPs): The factory over-axle pipes contain 700-cell silencers that, while unmonitored by the ECU on US-spec cars, are significantly restrictive. The Soul OAPs remove that restriction. They also give the car what we assume is the sound Porsche wanted from the factory.
Disconnected Exhaust Valves: With the factory PSE valve logic not yet tuned, we’d disconnected the valves so they remained permanently open, ensuring no sound dip prior to the ECU tune.
This means our baseline dyno number already reflects a partially uncorked car. That’s important context when reading the results.
The Baseline Pull
Mitch ran a Stage 0 logging map first for pure data collection with no calibration changes, designed to capture the full picture of what the factory ECU was doing. We ran in 4th gear.
The data confirmed what the reverse-engineering work predicted. The ECU was pulling timing on AZ pump gas. Porsches hate ACN91 and the throttle tapering above 5,000 RPM was clearly visible in the logs. The factory also has a self-defense mode: if the ECU detects enough knock events, it enters a low-power protection mode to safeguard the engine.
Intake air temperatures were also climbing fast on the dyno, reaching 67°C. These cars need airflow to stay cool, and a shop dyno with limited air movement is a tough environment. We were limited to approximately three pulls before the IAT climbed high enough to require a cooldown. That constraint shaped our testing approach for the day.
Stock baseline: 341 whp at peak (Run 1)
3 comments
Man, the car is making good power. I figure Project Cayman T is around 320whp on 91 octane with all the stuff I’ve done to it. That’s probably around what your car would put down stock, before the OAPs. So you’re up around 65-70whp on me, give or take. With some planned mods somewhere in the future, I think I can gain 20-30whp while staying on 91 oct and stock cat, but I’m not going to get close to where you already are.
Definitely have to get you to drive it to see what your thoughts are. As you’ve said it’s a heck of an engine. I bet your car’s torque curve is pretty sweet at low RPM’s especially. Lot’s of different flavors of ice cream in the Porsche lineup.
Oh yeah, thank goodness you can eliminate the pops and bangs.