[MAP]

Greetings Tony,

Interesting review - thanks very much. Since about six months ago, Mr. Vizard promised that this was coming, so I looked forward to it quite eagerly (see the "34:1 Afr?!" thread.) I'm looking for a cost-effective fuel delivery system for my 383 SBC, that I'm redesigning for a big improvement in economy, with a minimal loss of power.

This carburetor might work well, but I wonder whether the context of your evaluation holds much generality for other applications. Here's what I'm most concerned about: at 5-7-ish mpg, and with anything even remotely like a 14:1 AFR, you must be operating your carburetor with significant throttle opening, where the idle circuit might not be making a significant contribution to overall carburetor function.

I'm aiming for 25-ish mpg at 60mph on a flat surface with no surface wind, where I believe I'll be operating the carburetor mostly off of its idle circuit. It's this range of operation that concerns me, namely, the quality of fuel atomization here, and transient behavior based on the efficacy of the pump shot, in combination with an unusually lean steady-state off-idle AFR.

As such, to put it very crudely, I suspect you're using mostly 2/3 of the range of operation of your carburetor, whereas I'd be using 3/3, with an emphasis for economy on the 1/3 that you're not using. (Please correct me if I'm wrong about that, since I'm by no means trying to minimize your claims! You did, after all, begin the review with the qualification that it was preliminary.)

Do you have further insights in this regard?

Thank you,
Mark