I just like knowing stuff, so I went to above-average lengths to understand the gains made by ECU tuning with the Cobb Accessport on my Cayman GTS PDK after fitting Fabspeed race headers to the otherwise stock car. Independent testing is always more fun than taking salesmen at their word.
About those headers, to say that they wake up the car is an understatement. And not just the car, the rest of your neighbourhood too. Louder and a tiny bit dronier with the valves closed, but manageable and I got used to it pretty quick.My other half did not notice the difference with the valves closed even.
It's sufficiently civilized for me. Valves open increases sound and drama to a huge degree. The difference is an order of magnitude different than with stock headers. Closed = pretty calm but open = all hell breaks loose. I imagine that this is a feature of all catless headers, I just happen to have Fabspeed as I picked them up on Panjo for half price.
An increase in midrange power is very noticeable. At high revs you can't really tell, the only real difference is that your car is making a sound usually reserved for race cars or lrare Italian stuff three times the price. My car being a CGTS, the gains are going to be smaller than those seen by an S model since my car already keeps the throttle fully open to redline to get to that 340 rated crank HP. So the average Cayman S should get 10-15whp higher gains than what I got, in theory anyway.
Unfortunately I do not have any representative data for the car pre-headers. I have logs from the Cobb accessport with stage 1 but the car was on summer tires and temperatures were 10 to 15 degrees C warmer. In any case, I wasn't that interested on what the difference would be like on OTP maps stage 1 versus stage 2. What I wanted to know is how big the difference with the stock map was, and how much the Cobb OTS left on the table.
I used Fabspeed's protuner, Steve. A man of not that many words but lightning quick responses at times when you'd think he would be asleep (middle of the day in Europe). Sometimes I got an updates map less than 10 minutes after sending him a log. In total he sent me 4 maps, the baseline was only a little different to the OTS stage 2, but the maps got more aggressive with each revision.
Logging the ignition timing told the biggest story. The car was running in pretty cold air, and each of these 3 runs on different maps showed no per-cylinder corrections at all. So all cylinders ran the this level of timing throughout the run.
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This resulted in the following difference in acceleration between the Cobb Stage 2 and the pro tuned map from Fabspeed, datalogged with the Cobb AP:
![Image]()
At this point I started calculating and extrapolating and figured that power had increased something in the neighborhood of 20 horsepower from stock. But there were some assumptions to be made and eventually I set F it and went to a dyno nearby.
Each map was flashed in right before the runs were done. None of the maps had any adaption time.
Red= stock map
Blue= Cobb stage 2 OTS
Green= Fabspeed protune
![Image]()
A few things to note:
Keeping all that in mind, the stock 340 HP car gained roughly 25 whp over fully standard by adding headers and a pro tune. To get a bump to 365-ish BHP strikes me as good value for these mods, and I see no reason to add an IPD Plenum. In fact the tuner advises against it for these motors. The only thing I might still add is Fabspeed or Bcvelocity exhaust tips.
If Porsche rates their cars semi accurately, a Boxster/Cayman S could gain 40whp where I only got 25 due to the higher starting point.
GPS logs confirm the gains as well. I use a 10 Hz bluetooth GPS logged and Circuit tools software to verify.
I found some numbers of a German car magazine who do independent testing. In their testing, a Cayman GTS PDK did 100 to 160 km/h in 5.8 seconds. My car did it in 5.82s on summer tires fully stock. So my car performed normally. The crappy weather cut short testing before I ran the final map, but the penultimate map from the protuner did 100-160 clicks in 5.43 seconds. Winter tires do seem to slow the car down by 0.1s in this test so the new time is on the slower side of the curve.
For comparison, a GT4 does it in 5 seconds dead in the same German magazine's testing, so the upgrades have put me in the middle between a stock GTS and a GT4. Possibly a bit closer to the GT4 than to stock.
Finally, a video on the dyno itself. Obviously the sound gets normalized by the phone, you couldn't stand close to it without covering your ears.
The bottom line: If you want more power out of your car, these mods are the most value you're going to get for the money. A protune is a must as it's relatively inexpensive and makes most of the difference at the end of the day. Fabspeed's guy is great. Making logs on the road may not be ideal, but I do believe it's the best environment to tune a car in principle due to totally realistic loads and airflow. It works. I wanted to test on a MAHA LPS3000 dyno to get a better idea of the crank figures but it turns out there's only one of them in this city and it's owned and operated by a Mercedes dealership.
About those headers, to say that they wake up the car is an understatement. And not just the car, the rest of your neighbourhood too. Louder and a tiny bit dronier with the valves closed, but manageable and I got used to it pretty quick.My other half did not notice the difference with the valves closed even.
It's sufficiently civilized for me. Valves open increases sound and drama to a huge degree. The difference is an order of magnitude different than with stock headers. Closed = pretty calm but open = all hell breaks loose. I imagine that this is a feature of all catless headers, I just happen to have Fabspeed as I picked them up on Panjo for half price.
An increase in midrange power is very noticeable. At high revs you can't really tell, the only real difference is that your car is making a sound usually reserved for race cars or lrare Italian stuff three times the price. My car being a CGTS, the gains are going to be smaller than those seen by an S model since my car already keeps the throttle fully open to redline to get to that 340 rated crank HP. So the average Cayman S should get 10-15whp higher gains than what I got, in theory anyway.
Unfortunately I do not have any representative data for the car pre-headers. I have logs from the Cobb accessport with stage 1 but the car was on summer tires and temperatures were 10 to 15 degrees C warmer. In any case, I wasn't that interested on what the difference would be like on OTP maps stage 1 versus stage 2. What I wanted to know is how big the difference with the stock map was, and how much the Cobb OTS left on the table.
I used Fabspeed's protuner, Steve. A man of not that many words but lightning quick responses at times when you'd think he would be asleep (middle of the day in Europe). Sometimes I got an updates map less than 10 minutes after sending him a log. In total he sent me 4 maps, the baseline was only a little different to the OTS stage 2, but the maps got more aggressive with each revision.
Logging the ignition timing told the biggest story. The car was running in pretty cold air, and each of these 3 runs on different maps showed no per-cylinder corrections at all. So all cylinders ran the this level of timing throughout the run.
This resulted in the following difference in acceleration between the Cobb Stage 2 and the pro tuned map from Fabspeed, datalogged with the Cobb AP:
At this point I started calculating and extrapolating and figured that power had increased something in the neighborhood of 20 horsepower from stock. But there were some assumptions to be made and eventually I set F it and went to a dyno nearby.
Each map was flashed in right before the runs were done. None of the maps had any adaption time.
Red= stock map
Blue= Cobb stage 2 OTS
Green= Fabspeed protune
A few things to note:
- The protune gains are bigger relative to OTS maps than OTS to stock.
- The stock map does already get some benefit from the catless headers. How much we don't know. Anywhere from 2 to 5 peak HP if I had to guess.
- The peak number for the stock map seems a tad inflated (2 to 4hp) from the unnatural little spike it made at 7100 RPM. There may have been some traction loss (a bit slippery the first 2 runs we did due to melting snow from the tires)
- The winter tires (275/35 R20 rear) most likely do lower the wheel power measurement by as much as 10-20hp. But we only care about the delta anyway.
Keeping all that in mind, the stock 340 HP car gained roughly 25 whp over fully standard by adding headers and a pro tune. To get a bump to 365-ish BHP strikes me as good value for these mods, and I see no reason to add an IPD Plenum. In fact the tuner advises against it for these motors. The only thing I might still add is Fabspeed or Bcvelocity exhaust tips.
If Porsche rates their cars semi accurately, a Boxster/Cayman S could gain 40whp where I only got 25 due to the higher starting point.
GPS logs confirm the gains as well. I use a 10 Hz bluetooth GPS logged and Circuit tools software to verify.
I found some numbers of a German car magazine who do independent testing. In their testing, a Cayman GTS PDK did 100 to 160 km/h in 5.8 seconds. My car did it in 5.82s on summer tires fully stock. So my car performed normally. The crappy weather cut short testing before I ran the final map, but the penultimate map from the protuner did 100-160 clicks in 5.43 seconds. Winter tires do seem to slow the car down by 0.1s in this test so the new time is on the slower side of the curve.
For comparison, a GT4 does it in 5 seconds dead in the same German magazine's testing, so the upgrades have put me in the middle between a stock GTS and a GT4. Possibly a bit closer to the GT4 than to stock.
Finally, a video on the dyno itself. Obviously the sound gets normalized by the phone, you couldn't stand close to it without covering your ears.
The bottom line: If you want more power out of your car, these mods are the most value you're going to get for the money. A protune is a must as it's relatively inexpensive and makes most of the difference at the end of the day. Fabspeed's guy is great. Making logs on the road may not be ideal, but I do believe it's the best environment to tune a car in principle due to totally realistic loads and airflow. It works. I wanted to test on a MAHA LPS3000 dyno to get a better idea of the crank figures but it turns out there's only one of them in this city and it's owned and operated by a Mercedes dealership.
