Hypermiling

[Danoff]

No, it isn't.

If you feel the need to dart around someone when you see a traffic light ahead is red, but you want to tailgate the driver in front regardless, it's you who is driving without respecting a safe distance towards another driver. Therefore, it is you who is a potential traffic hazard, and not the driver you are following.

I guess then you're claiming that it is not posing a danger to anyone to drive in a manner that is inconsistent with most of the other cars on the road. I don't agree. Take, for example, the guy who slavishly does 55 mph despite traffic flowing at 70 mph. He could claim that since he's moving slower, he's safer, and it's everyone else who is breaking the law that is the traffic hazard, and it's on them to be more responsible. The reality is that he's a roadblock in the flow of traffic and is creating a nuisance.

I see the point, but I also see it as a debatable one. Regardless of the law, regardless of how many miles per gallon you get, regardless of quite a few other factors, you have to flow consistently or you're a disruption.

It's so circumstantial though, there are plenty of times when flowing will result in a 20-car accident. People can be very stupid.

 

[Wolfe]

Being one of the first cars to stop at a red light when you could have coasted to catch the green also makes you a disruption to the flow of traffic, forcing cars behind you to slow or stop until you get going again.

I don't hypermile but I slow down early for red lights because it's rational and convenient. I think in the right conditions it improves the flow of traffic since anyone who remains behind you doesn't have to stop either, even if they think you're a slowpoke or an idiot. I try to do my part to combat traffic waves.

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I have a question for the hypermilers, since the subject is fresh in my mind from an "oops!" moment running the Forester down to less than two gallons -- does anyone opt against playing the "get the most miles out of a whole tank" game in order to be nicer to your fuel pump? The fuel is usually what cools the pump. It is said a quarter of a tank will do.

The Legacy actually holds a quarter of a tank when the needle points directly at 'E', but the Forester doesn't, so I guess that's how it slipped my mind.

 

[niky]

Now, are you increasing danger to anyone? That's much more debatable. There are lots of arguments that driving as described above may be safer. But predictably? not really.

You are slow but predictably slow. Deceleration is gentle enough that they can either coast behind you or pull out and overtake.

It's a bit of a slippery slope to demand more. Should everyone who's slower than the fastest person on the road drive like their throttle is stuck open and their brakes are binary on/off switches? I used to think that way, but after learning more... much more about automotive safety, I'm content to hang back from the guy in front. Even when I'm actually in a hurry... because it's much easier to overtake them if you create a safe space between you.

in America, where people generally cruise at 80, actually following the speed limit can be considered anti-social.

But this country is a bit different. We have our share of impatient jackrabbits, but most of the traffic goes under the limit or just above the posted minimum. Because when you're making just $1,000 a month (minimum salary at which you qualify for a car loan...) and gas is nearly $4 a gallon (about 80c a liter here), you generally don't want to spend more at the pumps than absolutely necessary.

About the coasting in neutral thing: I was always told coasting in neutral could potentially cause harm to the engine / transmission. I generally just rev-match and use engine-braking to slow me down instead.

Yeah, been told that, too. But some modern automatics go into neutral when cruising, already. I do it as a matter of course in my manuals. You get to go further... all things considered. Even with DFCO (deceleration fuel cut off) on modern engines, the momentum lost is a bigger contributor to consumption than what you lose idling in coasting.

I have a question for the hypermilers, since the subject is fresh in my mind from an "oops!" moment running the Forester down to less than two gallons -- does anyone opt against playing the "get the most miles out of a whole tank" game in order to be nicer to your fuel pump? The fuel is usually what cools the pump. It is said a quarter of a tank will do.

Two gallons isn't that bad. Down to a gallon or less is dangerous for the pump. But yeah, no need to drain the tank completely every time.

 

[Wolfe]

Two gallons isn't that bad. Down to a gallon or less is dangerous for the pump. But yeah, no need to drain the tank completely every time.

Yeah, it would have been down to a gallon or less if we had continued the rest of the way home. Until we stopped I couldn't be sure how much we had because I'm not as familiar with the Forester's gauge. The tripometer could have indicated a very empty tank if we had been down two miles per gallon, but it's been steady around 25.5mpg.

 

[mustafur]

If it's a 1 lane road, gentle slowing will improve the traffic flow.

 

[20832]

Drove to Amsterdam with @NP the other day in my '11 Swift (94hp).

Including the trips from and to work and with the trip made to Amsterdam I drove 503km and still have just a hair under half a tank left. That would mean that I'm currently driving my car with a fuel consumption of ~4,3l/100km (54.7mpg) which is 0.7l beneath the fuel consumption stated by Suzuki. Gotta say that I'm quite pleased with that.

 

[homeforsummer]

I have a question for the hypermilers, since the subject is fresh in my mind from an "oops!" moment running the Forester down to less than two gallons -- does anyone opt against playing the "get the most miles out of a whole tank" game in order to be nicer to your fuel pump? The fuel is usually what cools the pump. It is said a quarter of a tank will do.

I've gone down pretty low accidentally before, but try not to most of the time. I'll usually let it dip below 1/4 of a tank though, unless I'm on a longer trip and can't guarantee a fuel station will appear in a short enough distance.

 

[CodeRedR51]

I usually try to fill up when the range hits 60-80 miles.

 

[Danoff]

I've gone down pretty low accidentally before, but try not to most of the time. I'll usually let it dip below 1/4 of a tank though, unless I'm on a longer trip and can't guarantee a fuel station will appear in a short enough distance.

I usually try to fill up when the range hits 60-80 miles.

I suppose one of you guys knows what the gas mileage improvement is for the reduced weight of fuel. It occurs to me that hypermilers could end up with setups that look like race cars. AC? That has to go. Not gonna use it anyway due to increased fuel consumption, might as well not tote the weight. Power seats? replace with lightweight manual seats. Radio? remove. Back seat? remove. spare tire? remove. Fuel? just enough to get me there. Sound deadening? remove. Sunroof? I'll take the hardtop. Hood latch? pins'll do. Open stay pistons? Nope. Power steering? I'll take manual. Special tires? check. Lightweight rims? Check.

Have any of you really tried to optimize your fuel economy by heavily modding the car?

 

[CodeRedR51]

Have any of you really tried to optimize your fuel economy by heavily modding the car?

I was going to with my Kia since it was an auto, but only to the extent of tires with less rolling resistance and a better flowing air filter. With the Hyundai, it's already exceeding the EPA numbers by quite a bit so I have no complaints.

 

[mustafur]

You would have to be a speical kind of person to heavily modify your car for economy tbh, outside of having minimal items in your car and some fuel saving tyres that would probably be the furthest i would go, but I don't drive that much anymore so I don't really care about economy much at this point,ill do it if i feel like it but it's not going to save me more then a few dollars a month.

My car barely costs me anything as it is, and if i do try to save fuel it's more to know what the potential is rather then a full on hobby or what not.

 

[20832]

I suppose one of you guys knows what the gas mileage improvement is for the reduced weight of fuel. It occurs to me that hypermilers could end up with setups that look like race cars. AC? That has to go. Not gonna use it anyway due to increased fuel consumption, might as well not tote the weight. Power seats? replace with lightweight manual seats. Radio? remove. Back seat? remove. spare tire? remove. Fuel? just enough to get me there. Sound deadening? remove. Sunroof? I'll take the hardtop. Hood latch? pins'll do. Open stay pistons? Nope. Power steering? I'll take manual. Special tires? check. Lightweight rims? Check.

Have any of you really tried to optimize your fuel economy by heavily modding the car?

No, and I don't think anybody (here, at least) would go as far as doing that.

Some of the things, I look out for:

- Keeping my tyre pressure at 2.8bar (40.6psi) as that is the recommended "ECO" pressure from Suzuki
- Keeping as much weight as possible out of the car (My car doesn't even have a spare tyre, only a compressor and sealant.)
- Keeping my A/C off as much as possible. If I need it, I switch it onto the lowest and coolest setting.
- Until 70KpH I opt to open a window instead of using my A/C (The additional drag until that speed hasn't as big of an impact than the A/C, after that the A/C will be more efficient)

 

[homeforsummer]

I suppose one of you guys knows what the gas mileage improvement is for the reduced weight of fuel. It occurs to me that hypermilers could end up with setups that look like race cars. AC? That has to go. Not gonna use it anyway due to increased fuel consumption, might as well not tote the weight. Power seats? replace with lightweight manual seats. Radio? remove. Back seat? remove. spare tire? remove. Fuel? just enough to get me there. Sound deadening? remove. Sunroof? I'll take the hardtop. Hood latch? pins'll do. Open stay pistons? Nope. Power steering? I'll take manual. Special tires? check. Lightweight rims? Check.

Have any of you really tried to optimize your fuel economy by heavily modding the car?

Never really been interested in doing so, nor had either the right car for it (hot hatches, MX-5s) or a car that wasn't already optimised (Honda Insight). Until you start going crazy with modifications there are much greater gains to be had by just changing the driving style, or buying the right car in the first place.

I mean... there's no spare tyre, only one seat, and no radio in my MX-5, but that's more through either laziness or tiny performance gains than fuel saving. And the Peugeot I've just bought has no power anything, not much sound deadening, 889kg with a full tank when I put it on our scales (1960 lbs, or a fair bit lighter than the 959kg/2114 lbs I measured the MX-5 at), but that's also for performance/fun.

In contrast, the Insight was "modded" from the factory. That was 835kg (1840 lbs) when we put it on the scales a while back, and checks most of the boxes you listed already, plus a few of its own tricks (lean burn, hybrid, aero mods), so without doing things that would make it look ridiculous (more so, some might say) or drive terribly (ditto) I doubt there'd be much wiggle room for improvement. I was averaging 75mpg (62mpg, 3.8L/100km) in what I'd consider fairly normal driving (going as quickly or quicker than the flow of traffic, minimising braking, reading traffic ahead) while my colleague I sold the car to a couple of years ago has done over 100mpg (83mpg, 2.8L/100km) on his trafficked freeway commute before.

As far as the weight of fuel goes, I'd rather have the convenience of not having to stop more frequently to top up. I enjoy driving economically when the car is suited to it, but I also enjoy making progress, and having to constantly top up is a pain in the ass.

Of course, there are whole forums dedicated to people modifying vehicles exclusively for economy. I'd say about 50% of the stuff I see on them is quite neat (like a Prius transplanted into a 40s Chevy pickup), and the other 50% I wouldn't be seen dead in.

 

[niky]

I suppose one of you guys knows what the gas mileage improvement is for the reduced weight of fuel. It occurs to me that hypermilers could end up with setups that look like race cars. AC? That has to go. Not gonna use it anyway due to increased fuel consumption, might as well not tote the weight. Power seats? replace with lightweight manual seats. Radio? remove. Back seat? remove. spare tire? remove. Fuel? just enough to get me there. Sound deadening? remove. Sunroof? I'll take the hardtop. Hood latch? pins'll do. Open stay pistons? Nope. Power steering? I'll take manual. Special tires? check. Lightweight rims? Check.

Have any of you really tried to optimize your fuel economy by heavily modding the car?

You should read ecomodder.com. @homeforsummer and I both troll the forums there.

There are guys who do go that far, and then some. Some guys do an alternator delete and charge the battery overnight. No AC, no PS, no alternator, engine kill switch (for engine off coasting)... you can go pretty darn far on one tank of gas that way.

 

[W3H5]

Wake up call for hypermiling.

It’s been some years and I’ve been hypermiling the whole time. 50mp(US)g/ 21.8km/l (my best so far).

About a year ago I stopped measuring tank to tank and took my results from each 1000 miles driven. I find the outcome to be more accurate over the longer stint.

I recently took the rear seats out of my Honda hatch and I’m up to over 22km/l. They were rather heavy.

I wonder if anyone out there has formulated a league for hypermiling.