My next experiment (possibly insanity)

[repete86]

Okay, so I've come to the conclusion that apart from a few things that I haven't done yet to the Green Machine, there is little left of the things I've been researching to improve efficiency without doing more work than I feel like doing, so I'm now looking at things in the engine and trying to figure out if there's something easy that I can do and I think that I found it.

The combustion point of gasoline is 470 degrees fahrenheit. I keep seeing various figures about what the bp is of gasoline. Judging by what I'm reading, it's somewhere between 100 and 437 degrees. The most common figure that I'm seeing is around 250 degrees.

There are a few pipes and hoses running from the engine to the back of the car. Conveniently, the gas line and exhaust are pretty close at times. I intend to measure the operating temperatures of various parts of the engine over the next few days to see if there's a nice spot where it's consistently around 300 degrees and that is close to the fuel rail. When I find this I intend to wrap the gas line around it in order to vaporize the gasoline, therefor expanding it in order to put a smaller yet faster burning bit of fuel into the engine for cleaner combustion.

Is this going to propel my mileage to new heights or make he Green Machine a time bomb?

[skewbe]

Originally Posted by repete86

Is this going to propel my mileage to new heights or make he Green Machine a time bomb?

I... uhhh... err... umm...

I'm sure my exhaust temperature varies wildly, especially when codfishing. I saw a fuel heater on a buddys biodiesel and it used engine coolant and a heat exchanger, that would probably be safer and more consistant.

[lunarhighway]

Originally Posted by repete86

Is this going to propel my mileage to new heights or make he Green Machine a time bomb?

sounds like something that might propel yourself to new heights.

[zpiloto]

There was a guy that did testing with this I think it might have been the Hydrogen Boost guy. He took a 1/4" copper tubing and wrapped it around the exhaust. His magic number was 220 degrees before he had drivability issues and vapor lock. Most aftermarket heater use the radiator hose for heating which I think is to keep the temerature around 190 degress which is probably the number you want to shoot for. It does recirculate the fuel so you will be warming the tank.

On my 626 I used 3/8" copper tubing across the radiator wrapped in foil and saw a 3% increase. Might do a search this has been covered before. There was some problem with using cooper because of the way gasoline reacts with it over time. All in all it kind of a risky proposition and I won't be doing it on my current ride because the risk don't exceed the gain IMO. The fire bottle on the passenger floor is all ways a good converstaion piece though.

Looking at your garage You best best might be to finish off th aero mods. With as much highway traveling that you do aero is going to give you the best bang for the buck after driving techniques.

[bones33]

Heating fuel seems like a really good idea, one that I thought would be really beneficial for some time now but just don't have the time to actually do on my present ride. Heated fuel theoretically should aid vaporization as the pressure drops from the nominal 40psi of the FI system to a vacuum after the injection pulse. Heating until just below the temperature at which the fuel system pressure keeps the fuel as a liquid and not flashing off (boiling) ought to give the most benefit.

A smaller flat plate heat exchanger has the ability to transfer a good amount of heat to the fuel, I saw some good candidates on ebay a few months ago. An alternative is Mercedes Bens part # 900 500 00 99 diesel fuel heater, or Arctic Fox 1-704B and there are others. All the heat exchangers are much more expensive than fuel line wrapped around a heater hose, but you'll have a much better chance of approaching coolant temperatures, my guess is maybe you'll realistically get to 170F or so. To minimize heat loss to the fuel tank in a loop fuel system, install another heat exchanger to transfer the heat from the fuel going to the tank to the fuel going to the fuel rail. This will boost your system performance by preheating your fuel before reaching the exchanger with the engine coolant. Returnless systems on newer cars wouldn't have that problem, but most of us drive older cars.

If you want to go cheap (as most of us do to make it worthwhile) you might try completely wrapping your radiator hoses in fuel line, maximum surface area for heat transfer is essential. Have the cool fuel wrap the lower (cooler) hose first and then proceed to the upper hose (warmer), then to the fuel rail.

For fuel line re-routing, use straight stock steel fuel line available at auto parts stores for making custom fuel lines, and bend it yourself. Brass is another alternative as it doesn't crack like copper will. Be sure to use barbed ends so the rubber fuel lines won't work thier way off under pressure.

If you do go down this path, please record your actual fuel temperature at the fuel rail. I've seen some experimentors that say they have heated fuel where the fuel line touches the radiator hose for a few inches. With the flow rate of your fuel system there is very little heat gain to the fuel.

It really should be safe to do provided you don't start messing with exhaust heat (fluctuating and scary) and your connections are solid. I'll be really interested to hear your results! Good luck!

[cfg83]

zpiloto -

Originally Posted by zpiloto

There was a guy that did testing with this I think it might have been the Hydrogen Boost guy. He took a 1/4" copper tubing and wrapped it around the exhaust. His magic number was 220 degrees before he had drivability issues and vapor lock.

You're right that he did experiments, but I can't find specific references on his website. From what I know, using the exhaust worked for him, but he didn't consider it viable for a long term installation because it was vulnerable to breaking and leaking fuel .

Most aftermarket heater use the radiator hose for heating which I think is to keep the temerature around 190 degress which is probably the number you want to shoot for. It does recirculate the fuel so you will be warming the tank.

On my 626 I used 3/8" copper tubing across the radiator wrapped in foil and saw a 3% increase. Might do a search this has been covered before. There was some problem with using cooper because of the way gasoline reacts with it over time. All in all it kind of a risky proposition and I won't be doing it on my current ride because the risk don't exceed the gain IMO. The fire bottle on the passenger floor is all ways a good converstaion piece though.

Looking at your garage You best best might be to finish off th aero mods. With as much highway traveling that you do aero is going to give you the best bang for the buck after driving techniques.

My hydrogen-boost comes with a fuel heater that uses the radiator coolant :



It's basically just a spiral of copper pipe that you run the radiator hose through. The fuel goes into the spiral of copper tubing (one of the little "antenna" in the picture), is warmed up by the hot radiator hose, and comes out the other end (the other "antenna"). I would guess that the number of spirals would control the average temperature increase of the fuel.

My mechanic won't install it because he fears that it can't take the fuel PSI, but I think he is being smart (protecting himself from liability).

Artic fox makes fuel heaters for Diesel fuel, but I think that some of them can be adapted for gasoline :

Biodiesel Fuel Warmers & Accessories
http://www.arctic-fox.com/sitepages/pid74.php

I think in all cases it comes down to controlling the maximum temperature increase of the fuel (vapor lock?), right?

CarloSW2

[repete86]

If you do go down this path, please record your actual fuel temperature at the fuel rail.

How do you recommend doing this? My ability to work on my engine is pretty limited and decided on this experiment because it seems easy enough for me to perform on my own. My car is OBDI, so I can't get a scanguage into it. I've been meaning to buy a SuperMID, but can't afford it and would need to pay someone to install it for me. Would my mechanic be able to print a readout of this data from his diagnostic computer next time I get my oil changed?

[bones33]

How do you recommend doing this? My ability to work on my engine is pretty limited and decided on this experiment because it seems easy enough for me to perform on my own.

You can get a cheap mechanical water temperature gauge (about 17 bucks or less) and gently hose clamp it to your fuel rail and wrap it with foil or some other insulating material to keep air currents from throwing it off. It'll give you a pretty good indication.

[repete86]

Thanks. If I get around to trying this, I'll definitely try to make that happen.

[cfg83]

repete86 -

Originally Posted by repete86

How do you recommend doing this? My ability to work on my engine is pretty limited and decided on this experiment because it seems easy enough for me to perform on my own. My car is OBDI, so I can't get a scanguage into it. I've been meaning to buy a SuperMID, but can't afford it and would need to pay someone to install it for me. Would my mechanic be able to print a readout of this data from his diagnostic computer next time I get my oil changed?

I think you would have to get some kind of high temperature sensor that is independent of the drivetrain "on the inside" of the fuel rail in some manner.

I got this :

High Range Adjustable Temperature Switch with LCD
http://www.jaycar.com.au/productView.asp?ID=KC5376


I got the high temperature one because it has an LCD and I want to be able to analyze engine or exhaust temps for when I attempt lean-burn scenarios.

The one I got might be overkill for what you need, but it is the same kind of thing. Mine came with a really big temperature probe, so I don't think it would work inside a fuel rail.

You need something with a readout and the ability to read temperatures up to "temperature X". Do you have an electronics shop nearby like "Marvac" or something that has kits that you could assemble?

CarloSW2