[canaglia]

Originally Posted by RedSquirrel

After seeing the BoP tables for the Nürbugring at the weekend, I've been wondering just what is so special about GTE engines. The Porsche GT3R and RSR both have a four litre flat six and make similar power after the air restrictors have been fitted. Yet the GT3R has 2x41.5mm restrictors (FIA spec) or 2x36mm restrictors (Nürburgring spec) while the RSR has 2x30.9mm (as of the race at Spa). I was hoping some of the more technically-minded people on here might know.
Sources:
https://24h-information.de/wp-conten...12.05.2018.pdf
https://www.fia.com/fia-gt-committee
https://www.fia.com/events/world-end...ance-committee (Decision 18)

Difference is that 911 gt3r engine is basically street engine slighlty modified and tuned for racing trim; 911 RSR engine is the same old gt3 rsr motor, that however got much more racing parts in its build.
Both have similiar power and torque output, revving up over 9000rpm, but the latter being a better tuned engine needs smaller restrictors to achieve same performances.

In early days of this year, I discussed here about how could AMG GT3 and 2017 cadillac dpi have a 100hp different power output despite same displacement, layout and similiar restrictor sizes. The answer is the same.