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    • Dundon Motorsports builds a 4.2 liter 997.1 GT3 flat-6 which produces 550+ horsepower

      We all know the naturally aspirated Porsche flat-6 is reaching its last days. That does not mean it does not have more to offer. Dundon Motorsports built an impressive 4.2 liter 997.1 GT3 flat-6 which shows an impressive 462.9 wheel horsepower.


      They correct this to roughly 550 horsepower at the crank but what matters here is there is still room to gain in the flat-6.

      The motor is tuned on a Motec M1 and they are considering revisions to take it up past 500 rwhp.

      Notice the horsepower peak comes in at 7632 rpm:


      You might be saying to yourself, hold on, didnt Dundon Motorsports get 476.8 wheel horsepower out of a 991.2 GT3 4.0 with their headers? You would be correct. They made more power with the 991.2 GT3 4.0.

      They made less torque however as the 997.1 4.2 provides 341.56 lb-ft at 5162 rpm. The 991.2 GT3 4.0 with their headers managed 317.56 lb-ft at 4474 rpm whereas the stock 991.2 4.0 provided 271.41 lb-ft at 4428 rpm.

      The 4.2 is revving to a 8250 rpm redline and that really tells the story as its horsepower peak comes at 7632 rpm. The reason the 991.2 4.0 makes more power is is revving out further hitting its horsepower peak at 8377 rpm.

      Therein lies the give and take between torque down low and horsepower up top. With the 992 GT3 Porsche should be able to gain power by revving out further while also potentially going up to 4.2 liters for more torque. This means 550+ horsepower from the factory naturally aspirated flat-6 is well within reach if not more.

      This article was originally published in forum thread: Dundon Motorsports builds a 4.2 liter 997.1 GT3 flat-6 which produces 550+ horsepower started by Sticky View original post