331 Dyno #'s Dead @ 5100 RPM (Long)

Originally Posted by Dark_5.0

Cars running the cobra ecu almost never dyno well.

I would expect to put out over 350RWHP with my top end on a 331.

What was your AFR.

I'm guessing one of your problems...and probably the main one...is the stock Cobra computer. From what I have heard...they suck! Do the conversion to the regular Mass-Air 5.0 computer. I may be wrong but I believe it's the A9L. A guy on another board I'm on did the computer conversion and picked up a TON of power. You should seriously look into this Fox-4-Cobra.

[andy669]

The tuner should be able to get around the limitations of the stock computer with no problems. Heres the picture of the printout that Fox-4-Cobra emailed me. The place he dynoed at wouldnt send him the whole file.

The only thing that stands out to me is that the numbers are low. It looks like its holding the power pretty decent before he stopped the pull. You cant tell exactly what the air-fuel is, but it looks like its in the 13.5 range.

With flat-tops and 93 octane, 28 degrees is about all those chambers want for timing. I dont think thats the problem.

I'd really like to know exactly what the injectors were doing. From there I'd look at valvetrain geometry. Also, what spark plugs are you running? The next time you go back to the dyno, take a 3.5" floppy and tell them you want the files saved to it, otherwise you will go elsewhere.

Andy