Hypermiling!

[Neouka]

Well, almost. I've attempted to pseudo-hypermile my car. I don't do some of the crazy things the true hypermilers do.My commute is a 95% urban freeway - 70km one way, so some of the time it's a lot of stop-and-go. Since gas is so ridiculously expensive, I changed my driving habits, unlike everyone else on the road. Well, I guess they enjoy being raped at the pump with their V8 SUV.Basically I try to maximize my kinetic energy, and not touch my brakes unless I absolutely have to. I leave a rather big buffer space between myself and the car in front of me, so if he touches the brakes, I can entirely use engine braking (afaik you use 0 fuel coasting IN GEAR, not in neutral and idle, so long as you are above the fuel cut-in, which is about 1000 rpm) and my gears to adjust my speed to match. Then, when accelerating, do it very slowly and in the highest gear possible - since you'll probably just end up having to slow down soon anyway.Anyway, I just filled up:42.725 liters (11.3 gallons)and I managed an impressive 780 km (488 miles) from that tank due to my driving habits. 43.18 mpg for that tank +/- 1 mpg for volume inconsistencies that gas pumps have.I'm impressed

[Eloi]

Impressive indeed. It's the 1.8L?

[Neouka]

It's an '03, so all you could get is 1.8L But yes, it's the base 1.8L engine, 5 sp manual.

[aradlaw]

That is impressive ...that's 5.47 L / 100 km in Canadian Must be frustrating having all the drivers cut into your 'rather big buffer space'

[Neouka]

yeah it is a little, but since my job involves driving a coachbus, I try to not let the highway get to me, since I don't want to get burned out.So if people want to take the big space in front of me, they can... and I just adjust accordingly. I try to not impede traffic too much though, cause then it's just crazy. Yet, people still get pissed at me, but like I said before, if they enjoy getting horrible fuel economy because they have poor driving habits... that's their choice.

[jwalcik]

That's impressive. It sounds a bit like that guy in Seattle that improved his gas mileage by just driving at a steady pace. It was slower than the top speed of the herky jerk of rush hour, but he avoided the brakes as much as possible and just eased along as well.

[ColonelPanic]

As much as it would be cool to get some of the numbers that the true hypermilers get, there's no way I would do it.. Don't feel like shutting off my car while I'm going down the highway to do a pulse and glide. I want to drive for more efficiency but do it safely and not cause excessive wear and tear on the drivetrain.It's amazing how much of a difference it makes when you drive like you posted, Neouka. I'm currently playing around with some different driving techniques, trying to figure out how to squeeze as much FE out of my little car that I can. People around me are getting pissed too.

[bull77]

Quote, originally posted by Neouka »and I managed an impressive 780 km (488 miles) from that tank due to my driving habits.impressive to say the least --- i haven't surpassed 600 on 1 tank yet

[WD0AFQ]

Have you got a ScanGauge? You may improve your mileage with one, I kinda doubt it tho with those numbers. I use one in my 03 GT and have gotten right at 37 mpg from a tank. I have consistantly improved the normal mileage from 29-30 mpg to 32.5 using the gauge. That was not really by slowing down either. It has several features that will assist one in saving fuel. Well worth the cost, especially for a stick shift Vibe.Dan

[zionzr2]

I tend to use these "big buffer" techniques in traffic as well.My only issues with traffic is that if people are going to much over or under the flow of traffic. Plus or minus 15 mph of the flow of traffic is unsafe reguardless of the speed limit.I use nutral coasting to help "hypermile" with an automatic and the use of scanguage i can see it read 300+ instant mpg.I also have the scanguage show the GPH. and try to keep the lead out of my foot to keep the GPH reading as low as possible.

[Neouka]

no, I don't have a scanguage... but by the sounds of things I don't really need one But it would be neat to watch some numbers as I go. I think they run about 200 bucks here though.Instantaneous gas mileage is kinda a useless figure in the grand scheme of things =p You need a pretty large average, ie, per tank of fuel..I'm not entirely sure how automatic transmissions work, but my understanding of manual transmissions and fuel delivery is, if you leave it in gear and have your foot entirely off the gas pedal... zero fuel is going in to the cylinders, so long as your RPMs are above the fuel cut-in point, which is about 900 or 1000 RPM after the engine is warmed up. If you coast in neutral, you are using fuel as it needs to keep the engine idling. I try to maximize that gear-coasting time to save fuel in the long run. Maybe I'll get a diesel smart car for my next ride

[jwalcik]

Quote, originally posted by Neouka »I'm not entirely sure how automatic transmissions work, but my understanding of manual transmissions and fuel delivery is, if you leave it in gear and have your foot entirely off the gas pedal... zero fuel is going in to the cylinders, so long as your RPMs are above the fuel cut-in point, which is about 900 or 1000 RPM after the engine is warmed up. If you coast in neutral, you are using fuel as it needs to keep the engine idling. I try to maximize that gear-coasting time to save fuel in the long run. As long as the engine is running at least *some* fuel is being used. That's where the whole "internal combustion" bit comes in. The gas is what does the combusting . idling in gear doesn't use any more or less fuel than idling in neutral.

[wyatt89]

Jwalcik, are you sure that the engine uses fuel when you are totally off the gas coming down from speed? I thought the engine was just releasing compression with no fuel delivery in that situation, I could be wrong but thats what I thought...

[kunkstyle]

It's using gas, even when not on the throttle. Hence the idea of hybrids. The engine is shut off completely when off the gas, and uses electric power to start back up.

[Neouka]

The Prius is a little different, but I thought in the Insight, after you're up to speed, the gas engine turns off only after you come to a complete stop..? The Insight will not run on electric-only.I know with the Prius, when accelerating normally, the car will run electrically up to 30 mph, then the gas engine is turned on. I don't think the gas engine will shut off at highway speeds just because you took your foot off the gas pedal... I think we need an automotive engineer in here to sort out some unknowns for us

[prathman]

Quote, originally posted by kunkstyle »It's using gas, even when not on the throttle.I'm not entirely sure on the Vibe, but I'd be surprised if a modern fuel-injection system wouldn't shut off the gas completely when coasting down a hill where the car's motion is enough to keep the engine above normal idling speed.I do know that this was the case even in our '83 Stanza which still had a carburetor. There was a special relay built into it that would cut off the gas supply if your foot was off the gas pedal and the engine rpms were above 1300. In that car I could feel the effect on the engine when the gas was restarted on dropping to the threshold rpm and checked out the cause in the factory manuals.

[ColonelPanic]

I'm thinking there probably is some sort of fuel cutoff. I find the technique that's helping my lil' Hyundai the most is getting up to speed then letting off the gas and coasting in gear whenever possible. It's really noticeable when observing the ScanGauge. By working the throttle lightly when I needed to use it and doing a shload of coasting the other night, I ended up with 40.7 MPG for my commute home per the SG's 'current trip' function. Now, each little hill I see, I let off the gas a little and take advantage of it. Seems to help.

[Neouka]

Exactly.. I don't see why it wouldn't cut fuel completely if you're using kinetic energy to propel the car instead of the engine.That's why we have EFI - Electronic Fuel Injection, right? Some cars with bigger engines even have Displacement on Demand, where the computer will shut off fuel delivery to a certain number of cylinders at certain times to save fuel. Computers r smrt!! .. well, with the exception of the Cadillac V8-6-4

[engineertwin2]

Sorry to disappoint the masses here, but fuel IS being burned while the engine is on, regardless of whether you are using your momentum.The drag of the piston in the cylinder without any of them being fired would slow down the motor to below the fuel cutout limt rather quick. A good way to know this is to run out of fuel. The engine halts pretty quick.I will say that it doesn't consume much fuel and that's why you see an improvement in fuel economy, but it does consume fuel.The Displacement On Demand gurus try to cut down on fuel consumption by shutting off cylinders, but they never shut them all off. Only the hybrids, with electric drive offer that capability.

[Daox]

Glad to see some more people driving for fuel economy. I don't drive my Matrix much (its the wife's car) but I do drive a 1997 Paseo and I do do the engine off pulse and glide. The car is rated for 34 highway mpg and I am now averaging 50 mpg and still waiting for summer gas and warmer weather. You can do amazing things with driving technique. I believe my best tank in the Matrix is 43 as well with engine on coasting and some not so nice traffic and weather situations. Even with engine on coasting you can get some amazing numbers as you have shown Neouka. If more people were like you gas wouldn't be so insanely priced as we just wouldn't use as much. Good job. I am of the understanding (and my scangauge backs me up on this) that fuel cutoff does occur while coasting in gear with no throttle input. This is the case at least in manual transmission vehicles. I'm not sure about automatics. This is why you do get the engine braking effect while in gear. This has been standard for years now as emissions have been tightened.

[NewNeptune]

This was thoroughly discussed on Edmunds, I just wish I had a link to the thread. Basically, someone with connections to GM engineering confirmed that on some GM vehicles, the fuel and spark is cut when coasting downhill.

[zionzr2]

if there were periods of time where there was zero fuel going into my engine then the GPH (Gallons Per Hour) guage on the ScanguageII i have would read zero durring those times. It never reads less than 0.2 GPH.

[engineertwin2]

I never suggested that you couldn't get amazing gas mileage while coasting - I only said you are still using gas to idle the vehicle.

[prathman]

Quote, originally posted by engineertwin2 »Sorry to disappoint the masses here, but fuel IS being burned while the engine is on, regardless of whether you are using your momentum.The drag of the piston in the cylinder without any of them being fired would slow down the motor to below the fuel cutout limt rather quick. A good way to know this is to run out of fuel. The engine halts pretty quick. Only if I put the car into neutral or disengage the clutch. Otherwise the engine will keep turning at a speed proportional to the vehicle speed whether or not any fuel is being injected to the cylinders. Of course the car will slow down faster than if the transmission were in neutral, but it can still coast for quite a distance, especially if there's a downhill.With an automatic the coupling isn't as direct, but even there the engine will tend to keep turning due to the car's motion if not in neutral.

[Daox]

Quote, originally posted by zionzr2 »if there were periods of time where there was zero fuel going into my engine then the GPH (Gallons Per Hour) guage on the ScanguageII i have would read zero durring those times. It never reads less than 0.2 GPH. Do you have the updated scangauge with xgauge features? Mine didn't do this either until I sent it in to be updated.

[vibolista]

Great to see some of the Vibers trying out ways to get the most fuel mileage out of their cars. I guess I've been doing that for a long time, not just lately. One thing that I've frequently noticed on the road now, even with the price of gasoline pegged over 3.50 a gallon... the use of brakes going down a moderate hill and then accelerating up the next hill. This kills the free energy gained going down a hill by slowing before the bottom and then using the accelerator to speed up as they climb the next rise. Am I the only one that sees this behavior? I understand the dilemma of keeping speed below a rational level in case law enforcement is near. To slow below the speed limit on the way down and then actually push above the posted limit on the way up, has to be rate as one very expensive driving plan... but I see it done almost every day around here. We have a lot of rolling terrain in this region. Keep up the good work !! If you find something that helps improve mileage, we need to learn about it. Planning ahead while driving, to avoid using the brakes when it's safe to do so, is one of the best ways to save fuel. Steady and gentle application of the go pedal has its obvious advantages.

[bodhi_tree777]

Hello, all. I've been lurking on this forum for a while now but finally decided to post. My name is James, I have an 03 GT and I've found myself lately trying to maximize the FE i can get out of this thing. I live in WV so lots of hilly terrain to deal with, but with just a few modifications in my driving technique I'm averaging what you see below. Still like to get it a little higher, but its a shared car and my wife is less interested in hypermiling than i am . So aside from the basics (coasting in neutral, properly inflated tires, clean air filter etc) what am i missing? is there anything specific to our cars that i can be doing that would help out? I've even started killing the engine at long lights (10-15 seconds or more), but I'm not really keen on EOC'ing on the highway (I don't like losing my power steering and I'm not very good at bump starting & rev-matching), not really into drafting semis (a little risky when I have a 20-month old in the car) or doing anything else stupid or dangerous. It's a little warm for this, but has anyone tried a grill block or a WAI? any luck?Forgot to mention, I'll also be removing the roof rack next week to cut down on drag (thanks to the how-to on this forum!), any other ideas for aerodynamic improvements? Wings, maybe? I'll be getting a scanguage in the next week or so, hoping that the visual indicators will help me and encourage the wife as well. Any ideas would be great, & thanks in advance.James / Bodhi Tree Studio / Tattoos & Illustration--2003 Vibe GT (standard save for the DIY cargo mat --

[Neouka]

nono, don't coast in neutral. Coast in gear. You have a manual, take advantage of it. 0 Fuel used (above 1000 rpm) and you get engine braking.Aside from that.... trade your Vibe GT in for a base one, and you'll get much better mileage

[bodhi_tree777]

Quote, originally posted by Neouka »nono, don't coast in neutral. Coast in gear. You have a manual, take advantage of it. 0 Fuel used (above 1000 rpm) and you get engine braking.Aside from that.... trade your Vibe GT in for a base one, and you'll get much better mileage don't i wish .. as far as the coasting thing, i wasn't sure after reading this thread. So basically, coasting in gear will slow you down somewhat faster (depending on the hill) but will use less fuel (or no fuel)? Does that strain the clutch or trannie at all? Sorry for any dumb questions, but my experience working on or understanding cars was basically nil before about a year ago, and any knowledge i've garnered is usually the result of something going wrong with my car . Trying to be a little more proactive with this one. James / Bodhi Tree Studio / Tattoos & Illustration---

[WaveAction]

im getting roughly 30-33 mpg in my vibe..only cause 1..i got abit of a heavy foot..specially with my new SRI..love the growl so gotta hear it..and 2) coming home from work it's all up a mountain so that takes a toll on it aswell

[Neouka]

when you take your foot off the gas pedal and coast in gear, the ECU cuts fuel delivery, and compression will cause engine braking (ie, you slow down), so theoretically you can make your brakes last longer too. It won't strain the clutch unless you're riding it, which you shouldn't be doing anyway. No extra wear on the transmission either.

[ColonelPanic]

Heh, found a Vibe GT owner who is trying to start this hypermiling thing.. link