hot fuel vs. cold air
 

ive been thinking about this. you can have a hot air intake to heat the fuel up so the gas burns better or cold air because its more dense then hot air.
but the i found out for every 25 dreases you heat the fuel up is one mpg and for cold air its every 11 dreases colder its one mpg if i remember right

so my q is this has anyone tested this?::D

Yes, many ecomodders have tested cold vs hot air intakes and almost all found that the latter is better for fuel economy. CAI gives more power, but at the cost of more fuel*. There are scores of threads about CAI vs WAI. There are also lots of threads on preheating fuel, so no reason to repeat all of their info here.

*) This is true only for gassers. Diesels like cold intakes for both power and FE.

I have found that heating gasoline to 180 deg. F yields about a 10% return improvement in fuel economy. Detonation threshold seems about the same for a given octane value. Greater tendency to vapor lock during hot restart. Most OBII ecu s have the ability to recognize this condition and will keep injectors closed until engine restarts. May take 2 or 3 tries but it will fire up. Heating intake air also improves fuel economy but I have found a greater tendency to go into detonation especially when ambient temps. go above 60 deg F. If you run a dedicated water or water/methanol system you can effectively supress detonation with even the lowest octane fuel.

Diesel or gas?

10% cool :D is there any way that can hurt my truck??? if not sounds like im going to be heating some gas do you use the coolant? to heat it

gas

probably not
 

all systems run most of the time at an
Air to Fuel ratio of 14.64 to 1
1 part fuel
14.64 parts air
by weight

so
1 part of fuel will have much less influence on the temperature of the complete mass entering the combustion chamber than the 14.64 parts of air

and
on systems that have a return line
that extra unused very heated fuel goes back to the fuel tank , heating the fuel in the tank
which causes heavy duty evaporation and pressure build up in the fuel tank much of that pressure and HC
can
be vented
to atmosphere
because most systems are not designed to handle that scenario
fuel vented to atmosphere does not increase FE as it is
wasted

10% improvement .... not very likely

your right!!!!!!!!! but what if we bypass the return line?

That would be bad. Systems with return lines need the flow for cooling and fuel pressure regulating purposes (I think). It probably would not run if you blocked it off, or it would run poorly. New cars do not have return lines, so maybe something could be done there. But I wonder what hot fuel will do to the life of a fuel injector.

I would listen to mwebb - heating fuel will probably have little effect on anything.

Well dang, I never knew that! And here I went to all the trouble of making a hot air intake for MAX (Kubota-powered sports car) thinking that temperature was more significant than density on a compression-fired engine (and that reducing density would be beneficial too, because it reduces pumping effort). Why does cold air intake improve mileage on a diesel?

PS--mine's turbocharged--would that make a difference in optimum air temp for FE?

the only thing you could do is move the pressure regulator to the tank, where the pump is (if it is there) . this way you would have one line to fuel rail, dead ended . this still has return line but it is real short, just going into tank .
This is what Honda does in later models . the pump, regulator are all one unit with sender in it .
This would or could have a tendency to vapor lock more than with regulator at rail .

new er cars control fuel pressure other ways
 

Unfortunately, the radiator temp varies wildly even when the engine coolant temp is steady, depending on engine load, ambient temp and vehicle speed. The thermostat regulates engine coolant temp by regulating the flow of coolant through the radiator to maintain engine coolant temp, say 195F. Only during high load and/or slow vehicle speeds will the radiator temp equal engine coolant temp. At this point, the thermostat is 100% open and the coolant bypass is 0% open. During most situations when the engine coolant temp is "warmed up" at, say, 195F and the engine load is relatively light and air flow sufficient, the thermostat is a tiny bit open and the bypass is mostly open, as engine heat rejection is low relative to airflow. Common exceptions are stop and go traffic and higher engine load situations when there is insufficient airflow through the radiator and/or relatively high engine heat rejection. In this situation, once the radiator temp rises to where the radiator and engine coolant temps are equal and the thermostat is 100% open, both temps will continue to rise up to fan on temp, say 210F, when the fan will turn on to cool the entire cooling system down. Once airflow increases because of sufficient vehicle movement and/or engine load is reduced and radiator temp falls below 195F, the thermostat will once again be partly open, regulating coolant flow through the radiator to regulate engine coolant temp at, say, 195F.

I would pull air from the exhaust manifold heat shield for a HAI. Use tin foil to channel as much air around hot things as possible. Much hotter and steadier temps than the radiator shroud.

800f is too hot
 

Is there an optimal IAT for best BSFC?

darn im just trying to thank out side of the box

Q what is the best mod you have ever done?

I did a little Excel heat energy calculation, using a specific heat of 1 kJ/(kg K) for air, and 2 kJ/(kg K) for gasoline. The air was assumed to be at 30 C (86 F), and the gasoline was assumed to be heated up to 90 C (194 F, and presumably heated up by engine coolant). A 14.7:1 mass ratio was assumed, too.

(1 kJ/(kg K)) * (14.7 parts air) * (30 C + 273.15 C) + (2 kJ/(kg K)) * (1 part gasoline) * (90 C + 273.15 C) =

(1 kJ/(kg K)) * (14.7 parts air) * (303.15 K) + (2 kJ/(kg K)) * (1 part gasoline) * (363.15 K) =

4456.305 kJ/kg + 726.3 kJ/kg =

5182.605 kJ/kg

Now, to find the final temperature of this mixture:

5182.605 kJ/kg / (1 kJ/(kg K)) * (14.7 parts air) + (2 kJ/(kg K)) * (1 part gasoline)) =

5182.605 kJ/kg / (16.7 kJ/(kg K)) =

310.3 K

or

37.2 C (98.9 F). This is a 12.9 F difference between the initial and final temperatures.

Given that my documented HAI gain of around 5% is done with an intake air difference of about 45 F, I would have to agree that 10% improvement with fuel heating seems rather unlikely.

That's a good thing. Most great ideas have come from this type of thinking. But I have found for myself that a lot of outside the box thinking leads to disappointment. But thanks to this forum we have some guidance - what should work and what definitely will not. If my "tone" has implied that I think I am an expert here and my word is that last word, I apologize, because I am definitely not an expert. I will be the first to set that one straight.

Nothing of substance. Unfortunately, my wife and I share the car that gets driven the most, so any mod that requires any extra driver input is out of the question because she is NOT interested. This is also the reason our car is an automatic instead of a manual. BUT...I am on the verge of doing a mega-eco-mod: converting my lowly MX3 to an EV. All the parts are in the garage and I only have a living room wall unit to complete before I rip and tear!

i thank you for the guidance

a EV cool how may deep cycle battery's are you going to use?:thumbup:

Probably 12. Here's the thread:
http://ecomodder.com/forum/showthrea...gun-19957.html

Also on modern FI with return lines the fuel temp is far above ambient temps , my guess somewhere around 100 -140F range . the injectors get even hotter .
I would also wonder how heating fuel to 200F or so would affect long term reliability of injectors and even fuel pump as the fuel is used as a coolant .