Ok who has ever heard of this? I got a 99 cobra with a 01 eng. Put on a bassani cat-less X-pipe,mac fenderwell cold air pipe and dyno'ed it. The numbers were 287 rwhp. After that i did 4:10's steeda underdrive pullies and a magnaflow catback. Re-dyno'ed it at 282 rwhp. WTF:cuss: The air fuel curve changed by 2 points first dyno run was a 12:1 then after the other mods it went lean to a 14:1 ratio. The guys at the dyno were at a loss of words. Anyone got an idea what happened?:cryying: