I had to retune my car today due and since I've installed a cutout since last time I tuned it, I decided to run it with the cutout open.

Result, lost 2 RWHP and 17 RWTQ over closed cutout. (I have a DMH, not that it would matter) This is on a cam/LT/catback car.
On the last dyno day I had, on a head/cam car, an open borla did not yield any HP over a closed one.

Neither of the cars were getting any knock retard.

I guess that makes my cutout pretty much useless other than scaring people off.

 

I gained 8rwhp by going to an open Borla vs full block off plate - cam/bolton car.

Its worth mentioning that the open setup raised (leaned) the A:F out by .2 points.

Ryan