I learned to Pulse and Glide on my V8 Lexus LS400 98', and achieved on average 27 mpg half local half highway. Typically on highway I pulse to 65 mph and glide in Neutral to 45 mph and repeat, when traffic allows. The car's spec for mpg is 25/18. My only concern is, when on neutral, does the engine still charge 12V battery? The A/C definitely works less when on neutral. The car had difficulty starting up at one point, but after I bought battery charger and fully charged battery overnight, the problem went away. Maybe that was due to the short trips of less than 10 miles most of time, that 12V battery never got enough time to charge. Thanks!
60s era cars and 70s era motorcycles often did not charge at all at idle. More modern vehicles have only greatly reduced charging at idle, similar to the greatly reduced A/C.
Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com is a good site for improving mpg of non-hybrid cars... One of the techniques they do over there that you might be interested in is removing the alternator to save gas mileage and recharging your 12 volt when you get home. This kinda of alternator deletion can earn you several more miles per gallon but has a limited range.
If the belt is spinning the alternator then it is charging the battery. If you increase the rpm (ie when driving) it will charge faster than when it is idling. Putting the car in neutral does not disengage the alternator.
