Stingy Dyno?

[SleeperGT]

Looking for some input on two dyno experiences, on two different dyno's. After I had the base Vortech kit installed on my car I had it dyno on I believe was a DynoJet and I had it at the track. Car dyno'd at 313 rwhp and the car ran a 105 mph quarter mile at about 13.5 (street tires and very bad 60' time). This hp # matched practically spot on with the Analyzer. Since then I have done upgrades which have led to better track #'s. The odd thing is my most recent upgrade was a Dyno Tune, 90 mm MAS and 42 pound injectors. This was done on a Mustang Dyno and the numbers were dramatically lower than I expected. Car dyno'ed at 323 wrhp, 327 rwtrq. Just a tiny bit over the stock Vortech install (and much lower torque #). However I took the car to the track and it ran about what I expected with the upgrades, 12.7@110 mph. I was told that the Mustang Dyno typically generates more conservative #'s. When I plug my #'s into the analyzer I come up with 400 hp (car has a track weight of 3825 with my big behind in it). Has anyone experienced something like this before or any comments on a Mustang Dyno?

1. "Stock" Vortech: 105 mph@13.5, DynoJet at 313 rwhp, 369 rwtrq.

2. Diablo Custom Chip & PowerPipe: 108 mph@13.0, no dyno #'s.

3. Dyno tune, 90 mm MAS & 42 pound injectors: 110 mph@12.7, Mustang Dyno 323 rwhp, 327 rwtrq