Fluid temp vs MPG

[NancysToy]

MikeinGA -
Water will merely vaporize in the combustion chamber (or any other type of fire). It does not dissociate readily, so the oxygen and hydrogen cannot form gasses that can be used in combustion. Water is a stable chemical compound, that is very difficult to break into its component parts.

HDXBones -
The air density I am talking about is that measured on an air density gauge. Moderately humid air is denser by the meter. I know what you are saying, and I was trying to explain much the same thing. Basically there is less available air in humid air than in dry air, so there is less fuel required to maintain the same A/F ratio.

 

[BajaRon]

I can understand why this post has pretty much become a private discussion. To add to the muddy water, there really is more oxygen in humid air (by volume) than there is in dry air. But of course, Scotty is right (and problaby HDX has said this too but I didn't have it in me to read back through all the posts). The O2 in water, be it liquid or vapor, is just not available for combustion.

The volume of H2O in the air displaces the O2 that is available for combustion thus lowering the actual, usable O2 in your fuel/air mix resulting in less power and thus, less MPG for the same volume of combustible mix in your cylinder.

Wow! It almost sounds like I know what I'm talking about! Good enough to fool my wife anyway! :thumbup:

 

[BajaRon]

.......now that we're up to speed on air density and the effects of altitude and humidity, who wants to discuss Bernoulli's principle and carburetor icing?.......:chat:

Wow! And I thought I was getting a headache before!

Since we are injected and not carbureted (Spyderwise that is) I think I can afford to skip this one...

 

[SteveMac]

WHEW! :shocked::hun:

I just turn the key, hit "mode" and off I go. Glad you guys have all this figured out. :thumbup:

 

[BajaRon]

WHEW! :shocked::hun:

I just turn the key, hit "mode" and off I go. Glad you guys have all this figured out. :thumbup:

You are so much better off for it too! hyea:

 

[billybovine]

I've been noticing lately that the colder my water temp is the more fuel is being consumed. And of course when it is warm the less. I know on cars there is a sensor to richen the fuel mixture so to warm up the vehicle quicker. Is it the same on the Spyder? Yesterday, I went on a PG mission "down the hill" which has been enjoying 80 degree temps lately. My temp gauge on my RT showed rough half way. I drove about 120 mi and got about 35 mpg. Coming home in the desert the outside temp was in the 60's, my water gauge showed about 1/4 up (analog), and I got about 28. Why? Also, last summer I added a little "Engine Ice" to my fluid because of the high temps out here in the desert. But in the winters, when the temps drop below freezing and stay in the 50's during the day, my fluid temp may barely show any rise at all when cruising on the freeway. And of course the mpg drops. So whats going on here? I'm sure there are many owners out here who may be in the same "boat".

OK guys now that it is settled that colder air and fuel would likely improve gas mileage, water does not burn and before someone sugests that the Rotax mill in our spyders is capable of cold fusion lets get back to Desert Spyder's original observation. In cooler temperatures his enige runs cooler and his gas mileage suffers. Maybe he has a cooling system problem, thermostat perhaps? I have heard of them starting to fail and not fully closing when cold. Could it be just in the nature of the beast to run cold in cold temps?

 

[BajaRon]

OK guys now that it is settled that colder air and fuel would likely improve gas mileage, water does not burn and before someone sugests that the Rotax mill in our spyders is capable of cold fusion lets get back to Desert Spyder's original observation. In cooler temperatures his enige runs cooler and his gas mileage suffers. Maybe he has a cooling system problem, thermostat perhaps? I have heard of them starting to fail and not fully closing when cold. Could it be just in the nature of the beast to run cold in cold temps?

Wow! Really!? We get to talk about the original subject again! Oh My! (You can insert 'Lyons and Tigers and Bears' if you like).

The fuel management system does richen the mixture at below operating temperatures. I suppose it is possible that if this minimum temp is not being maintained (or, if the ECU thinks the coolant temperature is too low) fuel mileage could suffer. I don't think anyone is saying it isn't possible, just unlikely if everything is operating correctly.

I believe additional fuel may also be added if the incoming air is quite cold. But this is simply to compensate for the denser air to keep fuel ratios adequate and should not cause MPG to suffer.

And I don't think anyone is saying that water burns, at least I hope not! :yikes: I thought we were having fun with the concept, but I could be wrong in that.

I think the intent was to convey that water can increase performance (fuel mileage, etc.). There are ways other than combustion to produce energy. It is true that under certain ideal circumstances, introducing water into the combustion process at just the right time and in carefully metered amounts can be advantageous in some engines.

This is quite different than oxygen robbing humidity in the air mass being used to charge the combustion chamber.

Now, about the subject of Cold Fusion! :roflblack:

 

[Pandy]

Well as for me,

This thread is most timely, yesterday, we rode from Charleston to Macon GA and back. ( So where were all the GA Spyder riders) This was to accomplish two things, lunch at Nu-Way Weiners and a trip to what has to be the best Bass Pro yet. (no, we haven't been to Springfield) Now, to my point; ambient temp by the trike's indicator was never above 51F. Nighttime was down to 31F at one point. My fuel economy was down by 15 to 25%. Now, this could also be air filter, worn plugs, the machine turned over 17K miles in I-16. So, maybe there is something to the decrease in ambient temp and fuel economy. No, not what I would expect from a closed loop system, but who expects anything normal from Spyders? And they are Canadian yet!Cold shouldnt faze them! Not to hijack the thread but a great time was had by all, eh?
Patrick