Fuel/ignition settings for best gas mileage??, up to 42° advance crazy?? Options

[Mueller]

I "borrowed" the quote below from aircooled.net

With the fuel prices going up and up, I figured that was the kick in the @ss I need to get my 914 up and running as a daily driver....since my fuel and ignition can be set however I want with my laptop, I figure I should optimize my little 1.8 for being as frugal with the petrol as it could be right now (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

QUOTE

It gets better! We give you the option of a vacuum advance on every unit except the basic model (single points are centrifugal only)! This means all you dual weber/dellorto guys can get another 4-5 mpg, AND the engine will pull harder off idle than ever before, and use less gas doing it (you can lessen the accellerator pump squirt, and idle jet size), while also running cooler! :-) The vacuum advance is FULLY ADJUSTABLE with a 3/32" allen key in the vacuum port to adjust the vacuum diaphragm, and you set it according to vacuum measurements you get from your carb(s). This means it doesn't matter what carb(s) you have, and it also doesn't matter what cam you are running! While other guys are running 32 degrees of full advance, you will be cruising around at 42 degrees on the highway, which optimizes mileage! It's important to know that the 32 degree setting is fine for full throttle, but at part throttle (cruise) you can use 42 degrees. If you are only running 32, your timing is retarded 10 degrees from optimal! Retarded timing creates MORE HEAT. This means you run cooler and use less gas if you have a properly working vacuum advance (VW put it on all their engines for a reason). All you need is a ported vacuum source ("ported" means the vacuum is coming from right above the throttle plate); do NOT run this to manifold or venturi vacuum!. Ported vacuum is 0 vacuum at idle, and 15-25" of vacuum at 3000 RPM and 1/8 - 1/2 throttle.