# Hypermiling **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** transmissions, accord, honda\ **Created:** [July 15, 2008, 11:03pm UTC](https://community.cartalk.com/t/hypermiling/16769 "2008-07-15T23:03:37Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![HybridFan](https://avatars.discourse-cdn.com/v4/letter/h/958977/32.png) [@HybridFan](https://community.cartalk.com/u/HybridFan)\ **Post date:** [July 19, 2008, 12:58am UTC](https://community.cartalk.com/t/hypermiling/16769/21 "2008-07-19T00:58:21Z")
Hypermiling is taught for free at [www.cleanmpg.com](http://www.cleanmpg.com) If you don’t want to do it, or believe that it won’t help you, OK fine. If you wish to impugn the dignity honesty etc. of those who do hypermile, that would be a bit insulting. For operating info on the 96 Accord AT, I would go straight to a mechanic who knows them well. DAS ---
**Author:** ![NYBo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nybo/32/17281_2.png) [@NYBo](https://community.cartalk.com/u/NYBo)\ **Post date:** [July 19, 2008, 1:05am UTC](https://community.cartalk.com/t/hypermiling/16769/22 "2008-07-19T01:05:14Z")
It’s not a matter of impugning anyone’s honesty or dignity. A disclaimer right on the [www.cleanmpg.com](http://www.cleanmpg.com) site: Some posts may describe situations which may in some cases be unsafe or illegal in some jurisdictions. Please use common sense and consult your local laws to make sure you do not hurt yourself or others or break any laws. ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 19, 2008, 3:08am UTC](https://community.cartalk.com/t/hypermiling/16769/23 "2008-07-19T03:08:56Z")
Notice the phrase “please use common sense” in their legal disclaimer. If you see signs like this: [http://www.digitalstudio7.com/graphics/product/Steep%20Grade.jpg](http://www.digitalstudio7.com/graphics/product/Steep%20Grade.jpg) Please do not coast in neutral. However, most of us live in the places like the Texas Hill Country, not in the mountains and there are many situations where coasting is quite safe. Your common sense will tell you if it is. If you are common sense challenged, then I can only advise never to coast in neutral. ---
**Author:** ![ken\_green](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/ken_green/32/816_2.png) [@ken\_green](https://community.cartalk.com/u/ken_green)\ **Post date:** [July 19, 2008, 4:16pm UTC](https://community.cartalk.com/t/hypermiling/16769/24 "2008-07-19T16:16:42Z")
miniscule. How many decimal points would you like to save ? ---
**Author:** ![newpony](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@newpony](https://community.cartalk.com/u/newpony)\ **Post date:** [July 20, 2008, 4:25am UTC](https://community.cartalk.com/t/hypermiling/16769/25 "2008-07-20T04:25:40Z")
Please just consider driving sensibly, keeping your tires properly inflated and keeping your car in tune. If you want to blow a few hundred on a “Mileage Minder” (or whatever), think of this; while you’re obsessing over what mileage you’re getting at any given nanosecond, you’re not keeping your mind on the job at hand. Which is DRIVING YOUR CAR!!! I get 23 mpg. from my 2001 Jeep Cherokee Sport 4X4 with an inline six, and I don’t bother with half of the crap the “Hypermilers” do. Just a thought. ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 20, 2008, 2:31pm UTC](https://community.cartalk.com/t/hypermiling/16769/26 "2008-07-20T14:31:01Z")
The first rule of hypermiling is complete situational awareness. Hypermilers are always looking way ahead to see if there are red lights or traffic bottlenecks up ahead so that they will not waste any fuel accelerating to a speed that only makes them use their brakes and wait at a red light. Also, if they see brake lights turning on way up ahead, they instinctively let up on the gas because those drivers ahead see something that has not come into the hypermiler’s view yet. Most hypermilers don’t draft either, instead allow a more than normal cushion to open up in front of them so that they don’t have to make a surprise stop just because the car ahead suddenly decided to pull into a driveway or have to ride their brakes down a small downgrade just because the car ahead of them is doing so. Rather than being crazy, irresponsible, and dangerous, they are probably some of the safest drivers on the road. The irresponsible crazy hypermiler image is mostly a straw man that the detractors conjured up to attack in the media. Most hypermilers don’t use a Scanguage II to constantly look at their instantaneous gas mileage, they use it to compare different driving strategies to see what gives the best results without having to wait to use a full tank of gas to see if it works or not. Some of the best strategies actually give really bad instantaneous mpg readings for short distances. Just like paying off your credit card debt in full rather than making the minimum payment is the best long term financial strategy. ---
**Author:** ![Manolito](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/manolito/32/3070_2.png) [@Manolito](https://community.cartalk.com/u/Manolito)\ **Post date:** [July 20, 2008, 3:39pm UTC](https://community.cartalk.com/t/hypermiling/16769/27 "2008-07-20T15:39:43Z")
In response to some of the earlier posts, an automatic does not really freewheel when coasting in gear. That is why your RPM stays up and you can limit your speed on downhill grades by selecting a lower gear. A fuel system that shuts off the fuel completely (not triggering injectors at all) on deceleration would have no adverse effects on brakes, antilock brakes, power steering, or anything else, but I don’t think a '96 Honda does that. That would require logic in the system that would monitor RPM and throttle position and know to ignore the oxygen sensor on deceleration. Not a technically difficult design, but I don’t think it was used in '96. In your specific case, and assuming that we are correct that it does not cut off fuel, you do burn about three times as much fuel in gear at 1800 rpm as idling at 600 rpm. But either way, the amount is negligible and you will not likely ever notice the difference. Weigh this against the fact that it is illegal to coast in neutral in most (if not all) states. If you want more mileage and you have done all the basic maintenance stuff: in town, reduce weight; on the highway, reduce wind resistance. Experiment with different air dams on the front of the car and with shields that smooth the bottom of the car, particularly just in front of the rear bumper. As noted in other posts, the aerodynamics, gearing, and engine design of different cars will result in different optimal highway speeds. Taking a car that was geared and optimized for 70 mph and driving it 45-50 may not give the mileage benefit that the “average vehicle” math would predict. I say this because improving the aerodynamics of the underside of your car may move the ‘sweet spot’ of optimum mileage up a few mph. Only way to tell is to experiment. Let us know what works! ---
**Author:** ![MrPhil](https://avatars.discourse-cdn.com/v4/letter/m/ecccb3/32.png) [@MrPhil](https://community.cartalk.com/u/MrPhil)\ **Post date:** [July 20, 2008, 3:41pm UTC](https://community.cartalk.com/t/hypermiling/16769/28 "2008-07-20T15:41:18Z")
I saw a feature on hypermiling on CNN’s website, and I had to cringe at some of the stupid things they were doing. Push starting and jumping in the car? Refusing to use the brakes coming off a highway and going around a curve with tires squealing? Shutting off the engine and coasting? Driving much slower than the other traffic, and giving the finger to anyone trying to get by them? Overinflating tires (beyond the sidewall limit)? These guys are nuts! ---
**Author:** ![Manolito](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/manolito/32/3070_2.png) [@Manolito](https://community.cartalk.com/u/Manolito)\ **Post date:** [July 20, 2008, 3:43pm UTC](https://community.cartalk.com/t/hypermiling/16769/29 "2008-07-20T15:43:40Z")
Thinking about this a bit more, deceleration or ‘coasting in gear’ total fuel delivery will not be three times idle fuel delivery. It will be more than idle fuel delivery, but not in linear proportion to RPM. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 20, 2008, 3:50pm UTC](https://community.cartalk.com/t/hypermiling/16769/30 "2008-07-20T15:50:53Z")
Why should it be any more fuel use than idle, if not less? The movement of the car is keeping the engine turning over, no need for additional fuel. That’s why I would expect no benefit from coasting in neutral. Also, the engine vacuum is much higher when coasting down a hill in gear that at idle in neutral, so much less air/revolution is being used. ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 20, 2008, 4:34pm UTC](https://community.cartalk.com/t/hypermiling/16769/31 "2008-07-20T16:34:15Z")
The air per revolution is lower but the total cubic feet per minute going past the throttle is higher. In order to not go so lean that the engine misfires, more fuel has to be sprayed into the intake air. On my ZRX1200 motorcycle, I have been able to up my gas milage from mid 44-48 to nearly 50 mpg just by making it a habit to hold in the clutch when decelerating. I have since been able to up that mpg to nearly 55 mpg by hitting the kill button during deceleration and leaving the engine off until the light turns green. ---
**Author:** ![grampy](https://avatars.discourse-cdn.com/v4/letter/g/a9adbd/32.png) [@grampy](https://community.cartalk.com/u/grampy)\ **Post date:** [July 20, 2008, 4:40pm UTC](https://community.cartalk.com/t/hypermiling/16769/32 "2008-07-20T16:40:19Z")
Its not worth the effort. Your shifting pattern puts undue wear on the mechanical parts of the tranny. Drive it like you have been. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [July 20, 2008, 4:45pm UTC](https://community.cartalk.com/t/hypermiling/16769/33 "2008-07-20T16:45:11Z")
Is that fuel injected? Regardless, I have trouble extentending results from high performance motorcycles to cars. ---
**Author:** ![newpony](https://avatars.discourse-cdn.com/v4/letter/n/41988e/32.png) [@newpony](https://community.cartalk.com/u/newpony)\ **Post date:** [July 20, 2008, 9:23pm UTC](https://community.cartalk.com/t/hypermiling/16769/34 "2008-07-20T21:23:30Z")
Reread both my post and yours. Do you realize that you use a lot of “absolutes”? IE. “ALWAYS” “SAFEST” etc. The shrinkologists say that’s a sure sign of delusion. Hypermiling is a fool’s paradigm. Drive sensibly. Oh yeah, and while you’re watching out for bottlenecks ahead, you’re not noticing that 18 wheeler rushing up behind you with lights flashing because he can’t stop his rig fast enough because you’re not doing the speed limit and he is/was until he encountered YOU. ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 21, 2008, 2:32am UTC](https://community.cartalk.com/t/hypermiling/16769/35 "2008-07-21T02:32:04Z")
What part of “complete situational awareness” don’t you get? If you don’t check your rear, you are not in a state of complete situational awareness, and if that speeding 18 wheeler can’t slow down for me, how on earth is he going to stop at that red light that’s only 1/8 mile farther down the road? Since when is hypermiling and sensible driving mutually exclusive? Sucessful hypermiling takes a focus that rivals road racing. This alone makes them some of the safer drivers on the road. Isn’t “sure sign” an absolulte? How about “every nanosecond” an absolute combined with hyperbole. What do shrinks say about that? A nanosecond is the time needed to travel 30 centimeters at the speed of light. ---
**Author:** ![scepticus](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/scepticus/32/782_2.png) [@scepticus](https://community.cartalk.com/u/scepticus)\ **Post date:** [July 21, 2008, 7:49am UTC](https://community.cartalk.com/t/hypermiling/16769/36 "2008-07-21T07:49:04Z")
The key point to understand is some engine management computers employ Deceleration Fuel Cut Off (DFCO) and some don’t. For some reason, some posters deny the existence of DFCO as if it were the Flying Spaghetti Monster. I don’t know how DFCO works with automatic transmissions, but two recent discussions addressed this in the context of manual transmission: [http://community.cartalk.com/posts/list/1242810.page](http://community.cartalk.com/posts/list/1242810.page) [http://community.cartalk.com/posts/list/1252812.page](http://community.cartalk.com/posts/list/1252812.page) ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 21, 2008, 11:04am UTC](https://community.cartalk.com/t/hypermiling/16769/37 "2008-07-21T11:04:06Z")
No, Kawasaki ZRX 1200 motorcycles use carbs. Most EFI motorcycles don’t use DFCO. The early FI BMW K models used DFCO but too many riders complained about the slight hitch in the power deliver as they opened the throttle in the middle of a turn when the engine went from DFCO to normal. Maybe the few bikes that “throttle by wire” are using the feature. A servo can close the throttle completely during DFCO shutting off all the airflow along with the fuel and that most probably helps make the transition seamless. Shutting off all airflow along with fuel flow also helps keep the catalytic converter lit during deceleration. ---
**Author:** ![B.L.E](https://avatars.discourse-cdn.com/v4/letter/b/848f3c/32.png) [@B.L.E](https://community.cartalk.com/u/B.L.E)\ **Post date:** [July 21, 2008, 11:19am UTC](https://community.cartalk.com/t/hypermiling/16769/38 "2008-07-21T11:19:15Z")
Don’t believe everything that CNN tells you. Most of them don’t “refuse to use their brakes”, they plan their stops so they don’t have to. For the most part, they drive just as fast as everyone else, they just spend less time standing still behind red lights. There’s a big difference between going 70 mph and actually being 70 miles away from here one hour from now. ---
**Author:** ![Whitey](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/whitey/32/24680_2.png) [@Whitey](https://community.cartalk.com/u/Whitey)\ **Post date:** [July 21, 2008, 1:51pm UTC](https://community.cartalk.com/t/hypermiling/16769/39 "2008-07-21T13:51:16Z")
In my experience, “complete situational awareness” is an unattainable goal. I believe there are degrees to which one is aware of his environment, but no human is completely free of distractions. Our minds are just not that quiet unless we are meditating. The average driver has too many internal and external distractions to be completely aware, even a hypermiler. It is a good goal for which you can strive, but don’t expect to ever get there. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [July 21, 2008, 7:23pm UTC](https://community.cartalk.com/t/hypermiling/16769/40 "2008-07-21T19:23:26Z")
“A fuel system that shuts off the fuel completely…but I don’t think a '96 Honda does that” My '85 Accord SEi (the first fuel injected Accord) with an automatic did it. Way back when I confirmed it by putting it in low and coasting down from ~10MPH. When the fuel kicked in the RPM would bump up a little, at ~1200RPM if I remember right. It was described in the service manual. [Previous page](https://community.cartalk.com/t/hypermiling/16769.md?page=1) [Next page](https://community.cartalk.com/t/hypermiling/16769.md?page=3)