I like bullet lists.
-Went to Haddad Motorsports for dyno time/tuning
-Made about 350 whp/340 wtq (I was expecting anywhere from 350-400 whp, true test will be on the drag strip/track)
-I let their pro work the tune with a Dynapack chassis dyno (you have to remove the wheels to bolt up the hubs)
-When I rolled in, WOT runs were not sorted out
-He reworked the open loop speed density & MAF tunes over pretty much the entire fuel/timing/etc. maps
-They can program the dynapack with varying loads, it's pretty sweet
-I had a strange whistle/supercharger sound coming from the engine/ehxuast and wanted to get them to help me figure out what the hell it was before really beating on it
-First couple of pulls, they noticed the sound, the shop owner Mike Haddad thought it may be an exhaust restriction/backpressure problem (read: stock cats & fbody manifolds & too thin piping & bad bends, etc.)
-They plugged in a pressure sensor before the cats
-Made some 4th gear pulls, measured backpressure vs. rpm
-See plots in pics. The tuner said an old rule of thumb is that more than 1-2 psi of backpressure on a car that is going to be beaten on is generally not good for performance (and it keeps more heat in the exhaust track... that's bad for exhaust valves and pistons, etc.)
-They said my exhaust sucks
Yeah I already know that :P I want to keep stock manis/cats for emissions
-At the end of the day, the car feels great. Having 300+ ft-lb torque to use for most of the rpm range makes me smile :gruffy:
-They think I could make another 30-50 hp if I redid the exhaust (long tubes, bigger piping, high flow cats, 4" rear muffler)
-I'm broke so that's not going to happen soon :wave:
-The tuner, shop owner, and techs were super cool. Great guys to deal with.
Anyway, car runs great, it really feels good. I ripped on it the whole way home. I love torque. This car weighs 2900 lbs+passengers, and has 4:10 rear gears :chug:
