Fuel Analysis

[CarloL]

Hi

I have an M130 , I would like to do some fuel analysis on two different types of fuel in terms of performance benefits to the car , detonation , AFR's

I have log files for both Fuels , what is the best way to approach this?

thanks

[David Ferguson]

With a dyno. You can only realize the benefits of a different fuel if you change the tune on the ECU to accommodate the properties of the fuel.

Late-model factory ECUs often do some level of ignition tuning based on the knock sensing, but only with a dyno will you be able to document the performance change -- on the road there are too many variables (like wind speed and direction) that make comparisons of small difference difficult to determine.

If you want to try -- then start with overlaying two runs over the same road and look for differences in speed (or G Force Long). Make sure the initial speed and RPM are identical, and move data to get it to line up at the starting point.

[CarloL]

thanks David!

You do not happen to know if the M1 does some ignition adjustment based on knock sensing; I think I seen a Trim section you can setup

[David Ferguson]

I have setup and successfully used Knock Control on the M1. What it allows you to do is have the ignition retard on an individual cylinder basis as knock is detected. This is a safety and reliability feature that avoids the engine running continuously in a knock condition which can be very bad particularly for an engine with forced induction.

However, only if the engine is knock limited in it's ignition timing does this result in maximum performance. You will obtain the true maximum performance by using a fuel with adequate octane to avoid knock when the ignition timing is tuned for maximum best torque.

I run a stock Mazda 2L engine in my sports racer. It can run with out knock on 91 octance pump fuel (ie, relatively inexpensive compared to race fuels), however there are certain situations (end of a long straight, 25+sec at WOT, where the combustion temps have started to rise) when knock will be detected and the M1 will pull 2 - 4 degrees of timing from a couple of cylinders. I'm pretty sure I'm maximizing performance per dollar for my car!