I've used a set of thermistors mounted in headers to monitor exhaust port temperature during a dyno run. 2,000 degrees F. at full throttle is considered to be ideal for a race engine. That's usually about a 12.5:1 air/fuel ratio, far too rich for good fuel economy. For a road test, something similar might be possible, but I don't really see the advantage over just installing a clean set of plugs and doing a 50-mile test run. With a pre-planned route involving some hills to climb, city and highway driving, etc., then pulling the plugs and looking at the color of the insulators should give a much better indication of correct mixture.
Jerry
Last edited by Hotrod Lincoln; 07/15/2010 5:35 PM.
