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With due respect to Cobb, it might have something to do with Porsche purposefully stifling the output of this engine to keep its place in the brand hierarchy.
If Porsche has intentionally limited the torque output (which I believe they have), this is more likely due to the fact that the manual transmission is torque limited to 310 ft-lbs and they cannot exceed this figure if they want the gearbox supplier to replace failed units under warranty.
This is the reason that both the 3.8L and 4.0L GT4 make this amount of torque, when even the 3.8L should be making 325 ft-lbs (like the Carrera with the same engine).
If Porsche has intentionally limited the torque output (which I believe they have), this is more likely due to the fact that the manual transmission is torque limited to 310 ft-lbs and they cannot exceed this figure if they want the gearbox supplier to replace failed units under warranty.
This is the reason that both the 3.8L and 4.0L GT4 make this amount of torque, when even the 3.8L should be making 325 ft-lbs (like the Carrera with the same engine).
Do you have more info to share on the torque limitation on the transmission? I have no reason at all to doubt you are wrong, just want to read up more on it myself too. Also, that seems like a close margin to come out with a car that is 4 ft-lbs from a drivetrain component’s limit, especially given the variations in actual power numbers of cars being built and the aftermarket appetite of the customer base (though the latter would admittedly be less of a concern/reason for Porsche to do something).
The Cobb AccessPort combined with a pro-tune (once you have supporting modes to justify it) is no joke. I've been running with a Dundon Pro-Tune on my car that has their headers and OAPs installed and the gains over the base map are very real. Using the AccessPorts data logging and virtual DynoJet software I was able to compare relative HP numbers. The graph below shows the results - keep in mind that the absolute numbers here are not calibrated (this is a virtual dyno after all)... if you consider that the header/OAPs on their own likely result in 20-30HP increase, and that the pro-tune results in an additional 20-30HP increase then the overall increase is in the 40-60WHP range, and I tend to think that number is closer to 60WHP than 40WHP.
With due respect to Cobb, it might have something to do with Porsche purposefully stifling the output of this engine to keep its place in the brand hierarchy.
They were able to extract a lot more out of the 4.0 in the GT3 also.
01-02-2024, 10:12 AM
