I recently changed my exaust setup from true duals, (no cats), dynomax turbos dumped at the rear, to an x pipe, no cats, thru dynomax bullets and was curious if i picked up and hp/tq. Last year i put down 406rwhp and 403tq on may 5 at 76 degrees and low humidity with the old exaust, and a few days ago with the new exaust I had 4 pulls done with only a best of 389rwhp and 383tq in 90 degree with a heat index of 110.
How much would the heat be affecting these numbers? My air filter was dirty as hell, and my left bank was running a little lean too. Last time i had ngk plugs instead of the autolite plats i have...*sigh* The first pull is what really scared me though cuz it only did like 376. Could this more free flowing exaust actually have hurt me? the motor wasn't changed at all except for all new bearings due to a oil pump drive gear fubar. Thoughts?