Why would you want to use hot air? Why do you think hot air would lean out the mixture?
Originally Posted by rh77
First, welcome to the forum. Conceivably, a hair dryer could add that extra hot air, lean out the mix, and the inverter power draw might be negligible. Something to think about. Any thoughts out there? I think it's worth a try...
But, my plan is to introduce a hairdryer to the air-intake. I'd like to get the biggest hairdryer I can, plug it into the beefiest inverter I can, and hope the alternator is as strong as I think it is.
And just have the hairdryer set to "high" and blowing into the air-intake piped in somewhere close to where the filterbox is under the hood.
Any thoughts on how or if this could work?
Thinking outside the box, is good. So I want to congratulate you for thinking about this.
However, as another poster mentioned, the electrical power for this would kill you, even if everything else about this plan worked. The thing most people forget, is that virtually all electrical power from a car, ultimately comes from the ALTERNATOR. And where does the alternator get it's power from? You guessed it, the alternator gets its (mechanical) power from drag on the gas engine (i.e. lower fuel economy)!
NOTE: This isn't just theory. You can actually measure (or even "feel", if the wattage is high enough) the extra drag on the engine, due to using more electricity in a car! And in fact, I've actually been able to usefully increase my FE (in my CRX) just by lowering my electrical power usage (by such means as replacing the standard car bulbs with energy efficient LED modules, running power using fans less, etc).
So what do the numbers say? Well, the "rule of thumb" I seem to remember, is that 1 horse power of drag is approximately equal to 700 watts of electricity _IF_ your generator was 100% efficient (and car alternators are not even close to 100% efficient, nor are "power inverters" for that matter). So assuming your hair drier used approximately 1400 watts to run (and a lot of hair driers use more than that on high), you are talking 2HP+ minimum drag (likely AT LEAST 3HP in practice, due to less than 100% efficiency).
And this is drag OVER AND ABOVE any power the engine generates to move the car forward! This drag is just to power the hair drier, nothing else! And this is what the laws of physics say HAS TO HAPPEN, it's not just a matter of engineering this well, it's the physical limits of what you are trying to do (i.e. the electrical energy for that hair dryer has to come from somewhere, it's not magically created, and in a traditional car it comes from extra mechanical drag on the gas engine). So there is no way to "engineer around this", unless you had a totally different source of electrical power (a big plug-in battery pack, perhaps?), in which case you are really just making a weird sort of electrical-gas hybrid car. Otherwise, you are pretty much stuck with these numbers.
So the bottom line, is that you will pay a 3HP+ loss of power (possibly 6HP or more, depending upon the efficiency of your components), just to run the hair dryer constantly. And this loss of power will hurt your FE a fair amount (the effect on the car will be similar to what would happen if you had your brakes partially engaged all the time). And this loss of FE is almost certainly going to be greater than any FE gains you could get by warming your car intake air. So you would essentially lose FE overall, not gain it.
OTOH you might be able to boost FE, if you were to find a source of heat that doesn't require nearly so much energy to tap into. For example, using some of your "waste heat" (from the car's exhaust system), via a "heat exchanger", to heat your car's intake air. I'm not saying even this would gain you FE in your car (it may or may not, depending upon how your car responds to warm air intake), but at least an approach using "waste heat" avoids the huge power losses associated with generating heat from electricity in a car (so it actually has a chance of helping overall, unlike the hair dryer, which would use too much power to make it practical)...
Try the WAI like others on this site using a dryer vent hose. I think Draco is right. You are talking about a huge electrical load. You have plenty heat under there esp. if you seal the engine bay well. Maybe too much.
A guy named Richard Reece used a hair dryer to make a WAI for his Insight and saw drastically increased FE in colder months and on cold starts. I don't think that the forced air action helped, but rather the warming of the air.
Maybe the hair dryer heating element alone would create a warm air effect, but the fan would have no effect at all. Look around for people using leaf blowers as superchargers and you'll find that even they only produce around 1psi. IIRC a leaf blower moves a lot more air a lot faster than a hair dryer.
The fan was rated at 5 Amps, which I think is similar to the draw of my now disabled DRLs. The problem was that most of the fan components were plastic, so it was only rated up to 160 degrees F. At about 150 degrees F, it started to deform the bilge blower housing. I think that a metal "turbo/snail" shaped fan would work better. I didn't go that route because I wanted an inline fan for easier installation.
Also, even though it pulled in hot air, the *volume* of air that it pulled in seemed to increase the mix of cold air coming in. I think that going with a straight WAI is better.
Idea : Why not use the hair dryer concept for engine warm-up only? Assuming the 1800 watt load wouldn't lower the already bad FE too much, the faster engine warm-up time might be a pay-off. Also, the shorter time span for keeping the hair dryer on should increase it's life span. However, most hair dryers suck, so you would probably need a really high quality one.
Don't forget that a hair hair dryer that was not intended to be used in such a harsh environment. Temperature/vibration/exposure to moisture, and being "on" for potentially longer periods of time then the average beehive takes to dry, all could cause a failure which could either cause an electrical fire in your engine, or suck hairdryer parts into your intake.