Dyno Details - including Air/Fuel

[JMatt]

I got the raw data from my dyno runs. The first graph shows hp and torque. The second shows hp and air/fuel ratio. Test was run using 93 octane pump fuel from Shell. No other octane boosters or fuel additives were used.

[vvv90]

Hmmmm...Interesting. It's obvious you made more power on the "yellow" run because it was running leaner. I'm curious how you were able to do this?

Was the weather cooler? Was the engine warmer???

[JMatt]

Air temp was within 1 degree on each run. The highest result is on the last run, so I assume the engine was warmer. Beyond that, I don't know.

[vvv90]

Originally Posted by JMatt

Air temp was within 1 degree on each run. The highest result is on the last run, so I assume the engine was warmer. Beyond that, I don't know.

It would be interesting to know what your operating temps were throughout each of the runs. That would help determine optimal operating conditions. My theory is the car actually produces more power in the 195-200 degree range then 180-190.

Once the ECM gets hacked I can imagine even more power when we can adjust our own AFR's especially at lower temps.

[John Hennessey]

where did you place the o2 sensor for the af readings?

[JMatt]

Originally Posted by John Hennessey

where did you place the o2 sensor for the af readings?

About 200 miles away from me. Sorry guys, I wasn't there, so I can't give you a beter write-up about exactly how everything was performed.

[goddardzilla]

JMatt

In establishing the baseline you have done the best thing, the reading of this particular dyno may not be that significant. As you know, what matters is the gain in HP after modification, measured on the same dyno under the same atmospheric conditions.

I know it may not be easy to duplicate the same conditions exactly, when you dyno it after modifying. When I dyno mine I will try to duplicate temperature for air density, and also duplicate relative humidity. Correction factors will therefore be minimized. If the air is more humid, gaseous water displaces some of the gaseous air volume - including the oxygen, and the total volume of oxygen taken into the engine for combustion is reduced. Power is therefore reduced.

Some may feel that cooler, more humid weather, gives improved performance, that is due to increased air density, not the additional water vapour.

Definitely keep us informed.

[marlinspike]

Sheesh these things run seriously rich. I wonder how much upper end acceleration you could pick up simply by leaning things out.