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Warm fuel = better atomization?
Posted: December 19th, 2008, 3:55 pm
by fowljesse
I've read about this over the years, but warming the fuel is generally done to lean out the AFR. I'm wondering if I could warm up the fuel for better atomization, and adjust the amount needed with Megasquirt. My concern would be detonation, if it atomized to efficiently, or raised the combustion chamber temp. I'm going to have relatively cold air (Ram air). I wonder, also, if heating the fuel would help to keep it from clinging to the valves, and runners before the combustion chamber.
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 4:13 pm
by onlytrueromeo
Warm is relative - a bet a few degrees won't do anything, but gasoline when heated (like most other liquids) to a certain point will begin to evaporate faster. This means its no longer a liquid and would definitely atomize faster. Injectors cannot pump gasses but if you keep it pressurized it won't become a gas anyway, then once it leaves will have room to expand.
I don't have any of my thermo books with me or I could look up the vaporization points and give you a degree range when this is possible...my guess is that you'd have to significantly heat the gasoline (via a line by the exaust).
If some of the gasoline is going into the cylinder already as a gas, it will burn faster and hotter than normal, I would think it would also make more power. Timing would have to be adjusted because of the faster burn.
Anyone else agree with this? Or am I off?
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 4:47 pm
by SuperK
Some companies make wierd things to reroute the fuel line to/through the cat... Well, not INSIDE the cat, but yeah, whatever, you know what I mean. Maybe. Maybe you don't know. Maybe you want to know, but you're afraid.
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 4:54 pm
by shameem
You may be better of going with additives that reduce surface tension. Heating pressurized gasoline is not a good idea.....
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 6:10 pm
by fowljesse
Yeah, I didn't want it to turn to gas.. I just thought that if it were warmer, well, you know..
Ideally, I'd like to heat it to just before it would turn to gas, but regulating that would be difficult, since the headers wouldn't be at a constant temp, and fuel flow would be a variable, too.. I think the heat increase should be proportionate to the flow.
I'll find out what temp the Gasoline turns to a gas, and take temp readings at the rear header. If it's not more, I'll test the possibility of putting the fuel filter there.
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 6:29 pm
by onlytrueromeo
Well heres the thing - for most liquids (basing this off water) energy is much greater during phase changes than just through warming. What you COULD do is get it just before vaporization, but minor fluctuations would mean that some would still turn into gas.
I don't think its worth it unless youre trying to build a setup to inject gasoline as a GAS into the cylinders. (This would work MUCH better with diesel as the diesel is injected at the perfect time, whereas gasoline engines work less efficiently.)
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 6:37 pm
by fowljesse
Yeah, ideally, I'd like it to be a few degrees below that point at the injectors.
Hmm.. there's also the fact that some of the gasoline gets shot onto the tops of the valves while they're closed.
Re: Warm fuel = better atomization?
Posted: December 19th, 2008, 11:50 pm
by mitmaks
heating gasoline? Have you guys heard about vapor lock, its a bad thing. Of course you guys never drove big car with a big block like i do (charger 440) You can cook a breakfast on it in a matter of minutes, it's very easy to warm up fuel line in the engine bay of a big block car to a point it's in vapor state.
Re: Warm fuel = better atomization?
Posted: December 20th, 2008, 12:33 am
by fowljesse
Oh, yes. My RV has a 454 4Bbl. I used to build and drive hotrods. Vapor lock, and me are old pals. I thought about it, and looked into it. With our open loop fuel system, and fuel pump at the tank, I don't think it would happen, and i would heat the fuel just before the rails.
Re: Warm fuel = better atomization?
Posted: December 20th, 2008, 6:46 pm
by mitmaks
sometimes it would get so hot (fuel vapors) that when I tried to start it it would backfire through carb. Whatever fuel was left in fuel bowls it would just explode. Good remedies are intake to heads gasket that has heat crossover passage blocked off and then thermal spacer between carb and intake. On my car there's originally supposed to be a fuel vapor separator. They don't do that on newer cars.
Re: Warm fuel = better atomization?
Posted: December 20th, 2008, 9:12 pm
by fowljesse
Yeah. That's how I built my 350s, and wrapped headers.
Re: Warm fuel = better atomization?
Posted: December 20th, 2008, 9:22 pm
by mitmaks
wrapping headers looks tacky and it will trap all the moisture on the headers and they will rust out. Ceramic coating is best thing imo.
Re: Warm fuel = better atomization?
Posted: December 21st, 2008, 4:40 pm
by fowljesse
True, but I leave on simple means..
I'm poor.
Re: Warm fuel = better atomization?
Posted: December 26th, 2008, 10:48 am
by projectzemx3
fowljesse wrote:True, but I leave on simple means..
I'm poor.
lol i hear that. header wrap cant be that bad, dont drive in the winter. ill probably be using header wrap
Re: Warm fuel = better atomization?
Posted: January 10th, 2009, 12:16 pm
by Nd4SpdSe
Hey Jesse, was just reading PASMAG and they have a product listed in there as a fuel chiller. It's called the SMAX Cool Can and for what they say, the fuel drops in temperature and becomes more condenced. Cooler fuel means more fuel, which means more power.
http://www.speedmaxperformance.com/" onclick="window.open(this.href);return false;
I don't know if it's what you're looking for, especially since your looking at being more efficient rather than make more power, but just to point it out, people out there are doing the opposite of what you inquired about.