DB has this on his Facetweetagramtrist page from an event he went to over the weekend in AZ. 2 GP2s were dynoed 1 stock, 1 with the NM Engineering tune. Stock was 204HP/204torque. Tuned was 224/207. [ame=http://www.youtube.com/watch?v=tVPm_jTKIbs]GP2s on the Dyno - YouTube[/ame]
Your mate's readings are in BHP, different than the US SAE Corrected standard. Your mate's reading are also at the flywheel with the no accessories. These readings are at the wheel, and include all the loses from accessories and drivetrain. Also, it depends on calibration of the dyno on the day the readings are taken. These numbers are more for seeing the differences on the same car after mods have been added. If these cars were to get on a different dyno the numbers would probably be different. You really can't directly compare the standard BHP UK figures with those in this test.
Even on a Mustang, I would have thought the tuned GP2 would have pulled a better torque increase. From what I saw on FB, the tuned GP2 had a larger IC and high flow air filter. 20HP is not bad, I suspect the NM tune is mild. Don
Yes. Except in the temps during the pull, the IC wouldn't have made much of an impact. The K&N was probably good for 2-3HP. These guys are trying to make a little more power as reliably as possible. The main use for both of these GPs is track days.