fuel warmer test results are in !!

[ELF]

I have been testing a fuel warmer off and on for about 7 months.

summer testing was four 100 mile round trips. 2 trips with the warmer on and two with warmer off. trips were done on 4 different days but temps were 80f to 85f. trips were early morning with very little wind.60mph cruise control.
trip no. 1 with FW. 31.9 mpg
trip no. 2 no FW. 33.9 mpg
trip no. 3 with FW 32.1 mpg
trip no. 4 no FW 34.1 mpg
my conclusion about 2mpg loss in warm weather.

one test at 24f did 20 mile test flat ground 10 west/10east. 55mph cruise.
west with FW 34.9 mpg
east with FW 35.3 mpg
west no FW 34.7 mpg
east no FW 35.5 mpg
my conclusion no change in mpg.

I did 4 test runs today 20 mile flat ground 10 west/ 10 east 55 mph cruise intake temp -8f
west no FW 29.7 mpg
east no FW 36.5 mpg
west with FW 29.5 mpg
east With FW 36.4 mpg
west no FW 28.5 mpg
east no FW 37.1 mpg
west FW 30.5 mpg
east FW 35.5 mpg

There was some gusty winds out of the NW today thats why big difference from west to east.
My conclusion no change in mpg.
One interesting note, when I took the FW off the radiator hose the FW was cold to the touch, I don't think it was warming the fuel too much. When I tested in summer It was hot to the touch.

I have some pictures but don't know how to post them, I uploaded them to my garage but how do I get the url to post them?

[Red]

Nice findings :) Wonder if anyone has tried this on a carb'ed car to see if there is a difference based on fuel deliver systems

Right click on the image, select properties and url should be somewhere on that screen depending on your browser. Copy that and paste that between "" tags

[ELF]

A couple of pics the one with the rope was how I tied it up off the hose for testing, the other one just shows the warmer.
BTW when I had the warmer on the hose for testing it was wrapped with insulation to keep the heat in.http://www.gassavers.org/garage_images/isn5ty871083gc8omuul.jpghttp://www.gassavers.org/garage_images/2orypsg3qg9mehdbft23.jpg

[diamondlarry]

If that is the fuel warmer I think it is, you are supposed to wrap it in several layers of insulation to hold the heat in. In the temps you have now, it's probably acting more like a cooler than a warmer without being insulated. I have one of these laying on my couch but it's too cold to mess with.

[ELF]

BTW when I had the warmer on the hose for testing it was wrapped with insulation to keep the heat in.

I did.

[diamondlarry]

OOPS! I missed that. My apologies.:o

[zpiloto]

On my 626 I got a 3% increase. Mine was 3/8 copper tubing laided across the radiator and wrapped in foil. My computer crashed and I lost most of my data for my cars :mad:. so take it with a grain of salt. YMMV.

[beatr911]

[QUOTE=ELF;39619]I have been testing a fuel warmer off and on for about 7 months.

summer testing was four 100 mile round trips. 2 trips with the warmer on and two with warmer off. trips were done on 4 different days but temps were 80f to 85f. trips were early morning with very little wind.60mph cruise control.
trip no. 1 with FW. 31.9 mpg
trip no. 2 no FW. 33.9 mpg
trip no. 3 with FW 32.1 mpg
trip no. 4 no FW 34.1 mpg
my conclusion about 2mpg loss in warm weather.

one test at 24f did 20 mile test flat ground 10 west/10east. 55mph cruise.
west with FW 34.9 mpg
east with FW 35.3 mpg
west no FW 34.7 mpg
east no FW 35.5 mpg
my conclusion no change in mpg.

I did 4 test runs today 20 mile flat ground 10 west/ 10 east 55 mph cruise intake temp -8f
west no FW 29.7 mpg
east no FW 36.5 mpg
west with FW 29.5 mpg
east With FW 36.4 mpg
west no FW 28.5 mpg
east no FW 37.1 mpg
west FW 30.5 mpg
east FW 35.5 mpg

There was some gusty winds out of the NW today thats why big difference from west to east.
My conclusion no change in mpg.
One interesting note, when I took the FW off the radiator hose the FW was cold to the touch, I don't think it was warming the fuel too much. When I tested in summer It was hot to the touch.

QUOTE]


ELF, do you have any data on the temperature of the fuel? With WAI people are finding that about 100F is the best temp, wonder if there is a similar optimum temperature.

[ELF]

No I don't have any data on fuel temp. But my testing in warm weather shows that too much heat is bad for FE.

I think WAI is a more logical route since heating the gas is not going to make enough of a temp change to overcome all that cold air.

[70 mpg jetta]

senior enginer @ Champion Spark plug booth @ SEMA show
(early 90's) claimed that 90 f is ideal temp for max pump gas
combustion!
keep im mind not to confuse max combustion due to hi fuel temp and loss of potential power extracted for each combustion chamber filling (volumetric efficiency)
also an M.A.F. is pretty good at metering air and compensating for density due to temperature variations, there is no equivalent device for measuring the density of fuel delivered to the engine - or is there? anyone, anyone?

[ELF]

I don't know about the density of the fuel but, my car has 2 fuel temp sensors.
One is located on the fuel rail, the other is back toward the tank. I would imagine that with the temp of the gas you could get a pretty good indication of the fuel density.

[tulsa_97sr5]

Not exactly sure if this info help, but Toyota is infamous for mounting their fuel filters right on the engine block. Makes them a real PITA to change (Toyota says they are a lifetime part) . I've always thought the reason was to warn the fuel shortly before it hits the injectors. Can't think of another reason they'd do it this way.

Because of mounting it there they have to use a rather beefy filter which costs 3 or 4 times as much as others I've changed. Metal case, much larger than the little plastic one my mazda 323 had.

[JanGeo]

Filter is under pressure too so metal is a good idea. Makes me wonder where mine is - had some people have engine problems and were going to change it to see if it helped. They had start and stall problems.

[ELF]

I learned something new after reading through a repair manual for my car, I was reading the part about fuses and relays, and It said something about a fuel warmer relay, so maybe there is already something already on there. I wasn't to sure because the manual covered many years and 2 different engines.

[Freedom_man]

I build a fuel heater for a FI car it was a 1990 ford probe and I got an average of about 2 more mpg.

It was a copper tubbing sized so the fuel hose would seal on the ends of it. I did about one and a half wraps around the exhaust manifold.

Did the same thing on my 68 bug with steel brake line on the stock exhaust manifold improvements were small but the fuel did heat up I could see it bubbling in my clear glass fuel filter.

[2TonJellyBean]

It was a copper tubing sized so the fuel hose would seal on the ends of it. I did about one and a half wraps around the exhaust manifold.

Is that even safe?

[cfg83]

2TonJellyBean -

Is that even safe?

I think it has to be strong enough to handle the gas line's PSI. I have a fuel heater for my hydrogen-booster system, but my mechanic didn't want to install it because of safety issues. From what I have read, the real problem is "vapor lock". I *think* the best fuel heater is one where you can somehow control the temperature :

Vapor Lock
http://autorepair.about.com/cs/generalinfo/l/bldef_856.htm
Definition: When gasoline overheats and boils inside the carburetor bowl or fuel pump of a hot engine, it ceases to flow. This can cause stalling or hard starting. This is called vapor lock, and it usually happens during hot weather. If a hot engine won't start, all you can do is let it sit and cool off. You should check the cooling system to see if anything is causing the engine to run unusually hot (a bad thermostat or cooling fan, for example). Switching brands of gasoline may also help.

Fuel heaters are common for diesels in the northern climes :

IN-LINE FUEL WARMERS
http://www.arctic-fox.com/sitepages/pid43.php
* Stainless Steel Construction
* No Moving Parts
* Maintenance Free
* A Model for Every Application
* Easy Installation
* Thermostat Optional
* 5 year, 600,000 mile Warranty

I am sure that these fuel warmers would be "butch" enough to handle the fuel line pressure, but they wouldn't prevent vapor lock. You would need a "shut-off thermostat" for that :

Shut-Off Thermostats
http://www.arctic-fox.com/sitepages/pid63.php
FEATURES AND BENEFITS:

* The Arctic Fox "Series 400" shut-off thermostat stops the coolant flow when the fuel flowing through it reaches approximately 78° F/ 25° C to 95° F/35° C.
* The "Series 440" shut-off thermostat operates at a range of approximately 104° F/40° C to 125° F/52° C.
* Helps keep the fuel within the recommended temperature limits for maximum horsepower as suggested by engine manufacturers.
* With the shut-off thermostat you can convert your existing or any coolant type warmer into a thermostatically controlled fuel warmer.
* Utilizes proven sensor module technology used in engine coolant applications.

The problem with these is that you can't program the shutoff temperature, :( . For GasSaver purposes, we would want to control this.

CarloSW2

[ZugyNA]

No I don't have any data on fuel temp. But my testing in warm weather shows that too much heat is bad for FE.

I think WAI is a more logical route since heating the gas is not going to make enough of a temp change to overcome all that cold air.

I tested a fuel heater on a carbed 1.5 L using copper coiled around the upper rad hose. Usual measured fuel heat right before the carb without the heater was 110F in summer.

With the heater it ran around 125-135F at cruise in summer. Got as high as 156F or more in summer in traffic. Once had the engine start to run like a diesel at idle in summer.

Despite using a rad block...I could get no mpg gains in winter.

Gains were around 8% in summer. Had no issues with vapor lock until around 150F when the engine might stumble some...never stopped though.

I've heard that the temp to shoot for with EFI is around 150F.

[Danronian]

On my '75 Malibu, i had vapor lock with the factory routing of the fuel lines...

On that car, the fuel pump is mechanical off the motor, then the fuel line goes against the motor to the carb. For me, the only time it was a problem was when I went to start it on very hot days, after it was already warmed-up. When there is no air flowing in the engine bay is when it locked itself most often. It would just take a lot of pumping of the gas pedal and lots of turns of the started to get it started again. Not really a safety issue, just annoying.

[cfg83]

ZugyNA -

I tested a fuel heater on a carbed 1.5 L using copper coiled around the upper rad hose. Usual measured fuel heat right before the carb without the heater was 110F in summer.

With the heater it ran around 125-135F at cruise in summer. Got as high as 156F or more in summer in traffic. Once had the engine start to run like a diesel at idle in summer.

Despite using a rad block...I could get no mpg gains in winter.

Gains were around 8% in summer. Had no issues with vapor lock until around 150F when the engine might stumble some...never stopped though.

I've heard that the temp to shoot for with EFI is around 150F.

Ok, then if that's the case, then the "Series 440" shut-off thermostat (104° F/40° C to 125° F/52° C) would be a workable if not optimum fit. I think I will e-mail them and ask them. I wonder what they'll think if I ask if I can use it for non-diesel applications? Gotta do some homework.

CarloSW2

[ZugyNA]

ZugyNA - Ok, then if that's the case, then the "Series 440" shut-off thermostat (104° F/40° C to 125° F/52° C) would be a workable if not optimum fit. I think I will e-mail them and ask them. I wonder what they'll think if I ask if I can use it for non-diesel applications? Gotta do some homework. CarloSW2

On the other hand...LaPointe says his fuel heaters using the top rad hose heat the fuel to coolant temp summer and winter....due to their high efficiency. In an email.

You might also try using a regular coolant thermostat (160F?) to control the fuel heat by controlling the coolant heat where it circulates thru the heater? Or just a shutoff valve adjusted according to summer or winter.

I'm going to try making one this winter using hardware store parts and using the heater lines for use in winter.

http://www.mpgresearch.com/viewtopic.php?t=1702&highlight=fuel+heat

Can't say much for the mpg testing, but the heater design looks to be OK. Need to run the coolant and fuel in opposite directions for efficiency...there is an earlier discussion with more info.

[BMac]

I don't know where people get this idea of putting a fuel heater in/on/around the rad hose. That's no good! That temp varies too much. You have to put it where it feels the coolant under the thermostat and is kept at a constant working temp. That doesn't happen after the thermostat. That coolant is only warm after the engine feels too much heat. Keep the fuel heater at the working temp of the engine.

[cfg83]

BMac -

I don't know where people get this idea of putting a fuel heater in/on/around the rad hose. That's no good! That temp varies too much. You have to put it where it feels the coolant under the thermostat and is kept at a constant working temp. That doesn't happen after the thermostat. That coolant is only warm after the engine feels too much heat. Keep the fuel heater at the working temp of the engine.

I think the idea is to reclaim the waste heat from the coolant (i.e. get it for free).

Maybe this is more of what you think would work :

Hotline Electric In-Line Fuel Heater
http://www.arctic-fox.com/sitepages/pid20.php
1015
Fuel warmer with internal heat tape in the fuel hose. Before starting, thaw frozen diesel fuel in just 3 to 5 minutes.

Call Arctic Fox for information on how the Hotline can work in conjunction with coolant heaters for complete fuel system protection.

* Available in 12 or 24 Volt applications.
* Controlled by a switch on the dash.
* Optional thermostat control available.

Assuming the current draw is low, then this could be a way to discreetly control the fuel temperature. But, the fact that it's in contact with the fuel (it's intended for diesel, not gasoline) seems too dangerous to me.

CarloSW2

[BMac]

BMac -



I think the idea is to reclaim the waste heat from the coolant (i.e. get it for free).

Maybe this is more of what you think would work :

Hotline Electric In-Line Fuel Heater
http://www.arctic-fox.com/sitepages/pid20.php
1015


Assuming the current draw is low, then this could be a way to discreetly control the fuel temperature. But, the fact that it's in contact with the fuel (it's intended for diesel, not gasoline) seems too dangerous to me.

CarloSW2

No! The idea is to heat the fuel for mpg gains. Keeping it at a constant temp will work better than having it vary all the time.

As for the electric current in the fuel line, like Charles Nelson Pogue said when asked if his carburetor was dangerous because it heated the fuel, "THAT'S NONSENSE, IT'S NOT DANGEROUS UNTIL THE GASOLINE COMES IN CONTACT WITH OXYGEN!"

[Daox]

As several people have mentioned, the temperature of the fuel must be kept consistant to see at what temperature you attain maximum effeciency. This will be different for every engine. I had designed a system for my Matrix shortly after I had bought it. The system included provisions to monitor and control temperature at will. Little did I know that the fuel rail was already heated. If anyone is interested, I laid out my plans pretty well in the thread below. So, feel free to duplicate my work and give it a try.

fuel heater (http://www.mpgresearch.com/viewtopic.php?t=1548&postdays=0&postorder=asc&&start=0)

[Erik]

Daox- I couldn't get the above link to work.

How about circulating gas through the radiator's transmission cooler lines?

I recently replaced my radiator. It was a generic model which includes the transmission cooler line in the lower tank. These lines are unused and still capped since I have a manual transmission. My engine has a carb, so my fuel pressure should only be about 5-7 lbs.


My intake manifold has coolant circulating through it and gets hot, so I wonder if the carb/gas gets hot enough as it is now.

[cfg83]

BMac -

No! The idea is to heat the fuel for mpg gains. Keeping it at a constant temp will work better than having it vary all the tim

I didn't make myself clear. I think the original *idea* went like this :

1 - Diesels "warm up" cold diesel fuel using engine coolant-based heat exchangers.
2 - Why can't we use this pre-existing method to heat gasoline for MPG gains?

If this could work for gasoline, then it would be "for free" in the sense that it wouldn't add load to the engine.

But, as you say, a variable heat source is a "bad design" to begin with.

As for the electric current in the fuel line, like Charles Nelson Pogue said when asked if his carburetor was dangerous because it heated the fuel, "THAT'S NONSENSE, IT'S NOT DANGEROUS UNTIL THE GASOLINE COMES IN CONTACT WITH OXYGEN!"

Thanks for the answer. That's what I was hoping to hear.

Correct me on this. There are never any "air bubbles" in the line? But maybe it's even safer than I think. Would gasoline even ignite between 125 degrees F and 150 degrees F?

CarloSW2

[Daox]

Daox- I couldn't get the above link to work.

Try again, it is finicky sometimes. If that still doesn't work I'll work some copy/paste magic.

[Snax]

I don't know where people get this idea of putting a fuel heater in/on/around the rad hose. That's no good! That temp varies too much. You have to put it where it feels the coolant under the thermostat and is kept at a constant working temp. That doesn't happen after the thermostat. That coolant is only warm after the engine feels too much heat. Keep the fuel heater at the working temp of the engine.
Many motors have a throttle body/carb coolant loop which may be tapped off of the block coolant circuit. Seems like that would be the ideal source to tap into.

Edit: Oops, I guess Erik sortof already mentioned that possibility. Regardless, my understanding is that this coolant loop is more of a safety feature to prevent freezing the butterfly rather than to heat fuel - which I suppose raises the question: If you tap into it to heat the fuel, would enough heat remain to keep the throttle plate from freezing open?!?!

[ZugyNA]

Many motors have a throttle body/carb coolant loop which may be tapped off of the block coolant circuit. Seems like that would be the ideal source to tap into.

With a V6 I owned there was a fairly substantial TB coolant hose, but with a current 4 cyl the hose is way too small.

I'm going to attempt to use the heater hose...where I will try to setup a bypass so that the flow is split between the heater and the fuel heater...probably just using a larger water shutoff valve as used with home water systems. (have used a small toilet shutoff valve with no problems)

This assumes the coolant will flow thru the heater core easier than the fuel heater....blocking the flow to the core...forces it thru the fuel heater.

This would allow regulating the coolant flow thru the fuel heater...and could even be used in summer by allowing the heater core to remain set on HOT (valve open). The fuel heater itself would need to be over designed for a high temp exchange....espec for winter. Hoping enough heat is left over for the inside heater.

Using elect power to heat the fuel is self defeating...espec when there is waste heat from coolant in summer at least.

[8307c4]

Now that's funny, heating fuel :p

All you had to do was set out a 5 gallon red fuel container in the sun, right about when its 90 degrees outside, let it sit for a couple of hours.

Then remove the cap and take a look inside, you should see bubbles.
That would be the fuel boiling, do you know what happens when fuel boils?
It loses octane.
That could be why they keep the stuff underground at fuel stations.

I'm surprised you didn't see a decrease in mpg.
I'd have to guess it didn't get hot enough...

Now cooling it, that might do something.
But by then you're as well off cooling the intake air.