Long Rambly Part | Final Numbers

On Saturday, October 14, I got my car on the dyno for the first time. I had scheduled the dyno run with Byron Reynolds to finish tuning my computer after the installation of the Vortech Supercharger.

Byron had done a street tune (tuned in his driveway with as much information as he could get - along with his very sensitive ear) a couple of months prior to this. Tight schedules pushed the appointment out, so I was quite anxious to get it on the dyno. This would give us a chance to finalize the tune, as well as find out how much power this car was making.

I met him at Mustang Ranch along with Terry - the keeper of the dyno. I watched as they were finishing up a Saleen S351 with some major mods hit 480+rear wheel horsepower (rwhp) on the last run! Note to self - leave this guy alone at the stop light. I pulled my car on the ramps, and watched as Terry strapped the car down and connect the oxygen sensors.

The first run showed some issues with the street tune. Byron had gone off of the numbers supplied with the Pro-M 80mm MAF to do the initial calibrations, but they proved to be off quite a bit. They shut down the first run short, but if continued, it would have shown about 280rwhp or so. Byron pulled the computer and started his magic. He tweaked, we ran it.

Doing a run on the dyno was quite an experience. The dyno platform is about 4 feet in the air. The back wheels are on a drum, and the car is strapped to the platform. Various wires are hooked into the computer to moniter MPH, RPM, and air/fuel mixture. Each run, I would start the car and let it idle for about a minute, until the computer goes into "closed loop". Byron would then stick his ear into the engine compartment and Terry would tell me to get it going. I would then put the car into first, let out the clutch, and start "driving". I went through all of the gears up to forth, just as I would on a normal drive. Once I was in fourth and had it at about 2500rpm, Terry would give me the signal to mash the pedal. I watched as the tach and speedometer climbed, as well as boost and fuel. On most runs, the speed would get up to about 130mph! I also saw boost levels up to 11lbs.

At the end of the run - top RPM, a bit of detonation, or just enough data, Terry or Byron would give me the stop signal. I let off the gas and put in the clutch. Terry would then apply the brakes to the drum to get it to slow down. Total time in the car each time was just a couple of minutes - but a pretty stressful couple of minutes. Pressing the gas pedal to wide open throttle while being held in by a couple of straps was a bit unnerving, but Terry and Byron do a great job and the nerves calm after a couple of runs.

During the hour and a half of runs (8 total), I saw RWHP numbers in the range of 311 - 324. The biggest concern at the end was the amount of fuel getting to the engine. The Vortech kits shipped for the 99 and 00 Mustangs do not come with a new fuel pump. The instructions call for a modification to the existing in-tank fuel pump. Ends up that this modification is not quite enough once the engine reaches a certain point. This put a limit on how much power we could get out of the engine.

Another roadblock we saw was the Roush exhaust. The configuration of the muffler is thought to have taken my numbers down by as much as 20-25rwhp. The exhaust has to make too many turns to exit throught the side exhaust, thus causing a loss in horsepower.

Final Run

My final number are as follows:

Max Power - 315.9 rwhp Max Torque - 313.1 rwtq RPM - @5900 rpm Air/Fuel Ratio - fairly constant 12