Scratching my head on this one. Car was noticeably down on power last year. Checked ignition timing and found that it was way out. Suspected CAS. Changed it and didn't fix anything, so just reset timing and continued. Car was better but still down on power. Eventually found that the timing belt had slipped on the crank. So fixed that and thought all was fixed.
At the last race weekend the car still seemed slow compared to the rest of the field. Threw it on the dyno this weekend and found it down almost 17 HP from last time (2 years ago... about 5 weekends of racing).
My baseline 2 years ago (with tweaked AFR) was 38.5 psi and 13 degrees of timing.
Things that have been checked:
-new plugs, wires
-tried different fuel pressures from 35 to 46 psi; verified it's steady during a pull
-verified TDC with dial indicator
-exhaust is straight through and loud
Leakdown is maybe 15% right at TDC but immediately jumps to 5-10% on either side. Some noise past rings on two holes. Not the freshest of motors but IMO power is way down compared to leakdown numbers.
I didn't verify the correction factor being used by the Dynojet, just in case it's reading wonky.
AEM digital AFR guage reading and its analog voltage output agreed at idle, but when revved the output voltage (as measure with DVOM and Dynojet) deviated a bunch from the gauge digital readout. Not sure what's up with that.
Only other thing that comes to mind is last time I think I dynoed with a second fan blowing at a 45 angle right into the engine compartment. So maybe it's a bit low with just 1 large fan, but I can't see it being that much of a difference. Plus the car seems down on power compared to the field.
What else is there to try? ECU?? Injectors? (idle is fine) Temp sensor??