Quote:
Originally Posted by gumby79
Any progress or is this project one for the bad idea pile. I hope progress.
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The Karen-Mobile has been running very strong for the past several years with this warm-air intake. I modified the WAI a little at the tail end of 2014, by fabricating a block-off plate from coroplast, that effectively forced all the intake air through the installed heater core itself. Earlier this summer, I re-arranged the inlet plumbing by using black pipe that is routed out of the existing coolant temperature sensor hole, which replaced the plastic tee in the radiator inlet hose that I had misgivings about. There's a tee in the black pipe where the coolant temperature sensor sits in now.
These past several days have seen remarkably warm outside temperatures, with daytime temperatures reaching 60 F (~15 C). As a result, the Karen-Mobile has been seeing some truly awesome gas mileage figures. Right now, the Karen-Mobile's MPGuino shows a tank fuel economy reading of about 29 MPG over a stretch of about 50 miles since last fill-up, which is the highest it's ever been. Instantaneous fuel economies have been observed to reach 50 MPG in areas where I'd normally see about 32-35 MPG.
From reading the multi-page thread about vapor carbs, I have hypothesized that the main benefit from the WAI is its ability to cause the gasoline to vaporize more readily. The gasoline vaporizes when its vapor pressure reaches that of the surrounding air, and the vapor pressure is of course dependent on the gasoline temperature. Now, when you spray a mist of gasoline into a mass of warm air, its temperature will quickly rise to that of the surrounding air, and as it does, the gasoline's vapor pressure will also rise to the point where it will vaporize. This raises the pressure of all of what's actually being sucked into each cylinder, causing the engine to work a bit less at drawing in the air/fuel mixture than it would otherwise.
Now, I know that what we consider to be gasoline is actually a mixture of many different chemicals that have differing vapor points, but for purposes of tracking what happens from the brief amount of time when the gasoline is sprayed into the intake port as a fine mist to begin with, to where the more volatile components actually change into gaseous form, to where it gets sucked into the cylinder, I'm going to consider this process to be where the gasoline is effectively turned into a vapor.
I am going to figure out how to add a secondary heater core, placed before the air filter. It should be fairly easy to do. Ideally, I'd like to be able to heat the air to about 110 F (43 C) wintertime/140 F (60 C) summertime. I figure that between summertime and wintertime gasoline blends, I should see this vaporization occur more reliably than now.