I've been thinking about this for awhile now so Im going to try and explain and see what you guys think. I'm not sure exactly how to explain it, so I'll do my best and you follow along . It all comes down to, if you left your car idle for a solid hour, how much fuel would you consume?
Im going to use my Metro as an example. Would it be safe to say that a 1 hour idle burns 1 gallon? If that is so, imagine drifting down an infinitly long hill at a constant 30mph. Even though you are drifting, a very good FE technique, after 1 hours drive you would only net 30mpg. Thats horrible for my car.
So, in theory, to get up to my average 60mpg in the summer months, you have 2 options. Either the 1gallon per hour estimate is clearly incorrect and it is closer to 1/2gallon per hour (thats alittle hard to believe), or you would need to increase your speed to net a higher mpg. So, at some point, accelerating would be more effecient than drifting.
Of course, that makes sense. To take it to the extreme, if you only drifted at 1mph, you would only go a few miles on an entire tank. At 15mph, you would increase FE by going further before your tank ran out. So, where is this "sweet spot" on the entire spectrum where drifting is not hindering your FE but excessive accelerating is not hindering you either?
Got that? I know there are tons of veriables, but work with me here . My car is a `95 1L 5speed btw...
Our 6cyl 250hp Honda Odyssey uses .4gph at idle. If your Geo uses half that (not unreasonable) in the scenario you provided, that would would put your 30mph coast at 150 mpg which is probably not too far off.
Also the term 'drift' is usually used for tire smokin' sideways drivin' fun. Usually done with a rear wheel drive car with lots of full throttle use. Please 'coast' or 'glide' instead so you don't get misunderstood.
"Drifting" has the connotation of driving sideways with rear drive wheels spinning and front brakes applied. <beatr beat me!>
If 'coasting' is a better description, then there are two versions:
Coasting in gear, engine at faster than idle speed, or
Coasting in neutral, engine at idle.
In neutral (clutch pedal down or lever out of gear) means the engine is using some fuel to maintain its minimum rotation speed.
Coasting in gear means the car is driving the engine faster than the idle speed. Most electronic fuel injected engines completely shut off the fuel under these conditions and resume the idle fuel volume when the rpm drops that far. But this is engine braking and reduces the distance that can be covered while coasting.
To completely oversimplify:
Coast in gear, foot off the accelerator, if the hill is steep enough that you'd need brakes to prevent going faster than you'd like.
Coast in neutral, foot off the accelerator, if you'd otherwise need some amount of gas to keep from ending up going slower than you'd like.
You're either talking about drafting or gliding (EOC), drifting is a stunt driving maneuver and is done with complete disregard towards fuel economy (or anything else for that matter, drifting in the sense of the word is absolutely not economical).
A FE gauge should be standard equipment in every vehicle.
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ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
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Thanks for the information guys! I never expected my fuel consumption at idle to be so low. It sounds like my gph is closer to .2-.3. That makes a world of difference in calculations.
LOL, you guys beating me for using the term "drift". Can you imagine a metro "drifting"??? I've always used that term, but I'll keep that in mind now that the japanese culture has overthrown our own...
Or you could use the most efficient method ever... and just coast with your engine off.
Yes, EOC'ing is where I make alot of FE gains. Currently though, with this freezing weather, it has gotten my spirits down and I just get from point A to point B ASAP. Not only mentally, but it physically hurts my FE becuase all my driving is short trips so about 80% of my driving is with a cold engine. I am still averaging 45mpg, but in the summer its easy for me to get in the 60's. My record is 78!