has anyone tried making an intake heater?
 

I tried searching the forum but didn't see anything.

My idea is to put something like this into a metal intake tube to heat the air going into the intake. Similar to a diesel setup.

Ford Thermostart Intake Manifold Heater 2000 3000 4000 5000 7000-7710 C5NE9A436A | eBay

In this cold climate of mn I think it might help in the winter time for mileage.

What do you think?

Might be nice for pre-heat but I wouldn't plan on driving with it.

Been there done that on my diesel.
Glow coils - Diesel Place : Chevrolet and GMC Diesel Truck Forums

I realize that diesels have been doing it for years, has anyone done it on a gas car?

I've not seen anyone try this on a gas engine. I don't expect it would help fuel economy. You'd end up burning more gas to keep the heater running than you'd save with warmer intake temperatures. Many people here have used "warm air intakes," which scavenge waste exhaust heat. A search for that phrase on the forum should turn up a number of results.

Correct me if I'm wrong, but with gasoline engines the idea is to preheat the fuel for easier ignition, and to chill the air to make it more dense.

What I posted back on a similar topic.

http://ecomodder.com/forum/showthrea...cus-18020.html
Ford has a patent using the A/C system to pre-chill the intake air.

In a gas engine you have the EGR, and you want to keep it so why bother with an electric heater?
(in a diesel one of the best things you can do is block or delete the EGR)

Thats the idea for more power but we are after more MPG. Cold, dense are will make the ECU use more fuel, resulting in more power. In our world we want the opposite. Warmer air would require less fuel to burn, making less power but more MPG.

Maybe I'm faulty in my logic, but if you make more power, aren't we talking about efficiency?

A more efficient engine gets better MPG, right?

I know that there are always exceptions to the rule, just talking comparables here.

Yes, but it's less thermally efficient to pre-heat the intake air (or petrol/gas).

However, prior to directly-injected/near-TDC injection engines the ambient air temp is a measurable influence on capability of the petrol to mix completely with the air. - This is why heating the charge is good, ie. the -ideal- thermal efficiency drops a little but it's negative effect is far outweighed by the gains of better fuel evaporation.

I have been shown (back-of-the-envelope) that trying to get this effect by heating fuel is a no go. Petrol just has too little heat capacity (ie. the very fact that it evaporates so easily is the problem). So if the petrol is the medium that's carrying the heat it will be totally swamped when it meets the coldness of the air.
<though I'm still not 100% convinced I must say!>