coasting

[MetroMPG]

<b>the results:</b>

- <b>60.3 mpg</b> (US) - lap 1 "engine OFF while coasting"

- <b>53.4 mpg</b> (US) - lap 2 "engine idling while coasting"

[rh77]

As always, compliments on the experimentation. I've been using the idle at long-stops technique lately. I'd like to use an engine-off kill switch but with the automatic, I'd have to use the starter to get it going again...unless...

I haven't tried it, and I'm sure it would be murder for the transmission, but I wonder if it's possible move the transmission from N to possibly 2 or 1 -- would the momentum turn the engine to fire it back up, or would the TC be entirely disconnected and not translate the rotational energy back to the crankshaft? Just frustrated as usual with the automatic.

By the way, is it that windy all the time? I thought Kansas was windy...

RH77

[philmcneal]

welcome to my world, except you have a scangauge ;(!!!! Although that kill switch sounds nice but I wouldn't know where to start wiring :S

But my speedo comes right back on when I key on so I'm hoping my upcoming scangauge would too...

[JanGeo]

In the "old days" autotranny's could be bump started at about 25mph but I don't recommend it now - the hydralic pressure comes from the engine side of the torque converter so with the engine stopped no oil flow in the tranny. Seals cook pretty fast too.

[JanGeo]

Nice results! I took the long gentle down hill home last night in the fog, way weird coasting at 35-25mph using pulse and glid in the heavy fog but trip mpg rose for a 20 mile trip from 43mpg to 46.5mpg by doing P+G for a few miles. Was really weird when it hit the steeper down hill just before it levels out and starts up the steep hill at the end - no street lights but great to have the gps to "see" where I was. One thing I noticed is if you have to coast with the engine on the faster you are going the better the mpg - you are still burning gas at a constant rate at idle so going faster yields more mpg. Wish my idle would drop lower - think the torco may be changing the cleanness of the exhost forcing 800+ rpm idle?? Seen it as low as 650rpm when stopped. Seems mpg is a few less at night than day time too.

[MetroMPG]

I've been using the idle at long-stops technique lately.

no engine-off stops at all? i don't mind using the starter once in a while, even in the manual shift car. 13 times in 9.7 km would be excessive, but i don't think 3 is. (it would have been 2 key starts, but i botched one of the clutch starts when i used my kill switch improperly.)

By the way, is it that windy all the time? I thought Kansas was windy...

um, there's almost always some wind, yes. but that day was windier than normal. i remember that last fall was particularly windy.

[MetroMPG]

that kill switch sounds nice but I wouldn't know where to start wiring

my switch is wired into the positive wire to my distributor's pickup coil. (helps if you have a shop manual.) and your engine may use a different ignition approach, so i can't say for sure if it's applicable to your situation.

But my speedo comes right back on when I key on so I'm hoping my upcoming scangauge would too...

that would be nice! but it seems to depend on what OBD protocol your car uses. if it's ISO, then interrupting the power to the scangauge will force it to wait while things re-initialize, and your data will be skewed by the delay.

another possibility that i didn't look at: krousdb suggested powering the scangauge independently of the OBD port.

as always: caveat experimentor! we modify our vehicles at our peril.

[MetroMPG]

since running this test, of course i've been shutting off the engine more for coasting than i used to.

my segment mileage, according to the scangauge, has shot way up. example:

68.1 mpg (US) over 30.5 km of sub/exurban driving (23 mph avg speed / 42 mph max; rain, wet roads; 6 C / 46 F ambient; 1.25 hrs EBH.)

this trip was actually above the 70 MPG level on the way back to the house, and then i got hit by 3 red lights in a row and a train crossing at the bottom of my best hill, and these things dragged it down to 68.1

i suspect that through using engine-off coasting more i'm going to see the "hybrid FE flip flop": where my non-highway driving FE is going to exceed my highway-only numbers.

[JanGeo]

That local driving better than highway is to be expected as air drag is a big factor of fuel use and low power engine use is the other big factor of fuel use. You usually get one or the other but not both at the same time - that is the reason I always got good mileage in my Geo no matter how fast I drive. SO by shutting down your engine at low speed you reduce the low power losses and get great results. The xB is a little different because of the additives helping the low power operation as well as the Variable Valve Timing at low speeds but air drag is the major factor over 40mph no matter what I do. That's why I think that a small electric motor power assist at low speed level operation would be the perfect solution - a small battery pack for less weight and small light efficient electric motor would propel the car at 20-30 mph without the ice running and could regen down hills and while stopping to recoup the energy losses. Just need to workout the connection to the wheel thing. Would love to tap into the input shaft of the tranny and on the Geo that could be done on the left side out the end of the case instead of the engine side.

[krousdb]

that kill switch sounds nice but I wouldn't know where to start wiring

my switch is wired into the positive wire to my distributor's pickup coil. (helps if you have a shop manual.) and your engine may use a different ignition approach, so i can't say for sure if it's applicable to your situation.


Remebber that I removed my kill switch because my Honda will shut off the fuel pump if it senses that the engine has stopped. The only way to restart is to turn the key off then back on again, which defeats the purpose of the kill switch. I don't know if it is any different in a 2005 honda, but my guess would be that you will have the same issue.

If I were you Phil, I would consider going through a tank with your normal off while coasting technigue, and then calibrating the ScanGuage. As long as your off times and frequencies don't vary wildly from tank to tank, I would expect that you will get good results.

[krousdb]

since running this test, of course i've been shutting off the engine more for coasting than i used to.

my segment mileage, according to the scangauge, has shot way up. example:

68.1 mpg (US) over 30.5 km of sub/exurban driving (23 mph avg speed / 42 mph max; rain, wet roads; 6 C / 46 F ambient; 1.25 hrs EBH.)

this trip was actually above the 70 MPG level on the way back to the house, and then i got hit by 3 red lights in a row and a train crossing at the bottom of my best hill, and these things dragged it down to 68.1

i suspect that through using engine-off coasting more i'm going to see the "hybrid FE flip flop": where my non-highway driving FE is going to exceed my highway-only numbers.

Looks like you will back on top of the gassavers gaslog standings in no time.:) I will have to work hard just to get past basjoos. And then you will be leapfrogging both of us.

I am going out today to get a new hacksaw blade. Which cylinder should I cut out, 2 or 3? Hmm. I will need a welder also I guess.

[MetroMPG]

Looks like you will back on top of the gassavers gaslog standings in no time.:) I will have to work hard just to get past basjoos. And then you will be leapfrogging both of us.

we'll see. my driving habits are about 70/30 highway/non-hwy, so won't get to use this technique as much.

i've still got to figure out ways to improve my highway (50 mph+) mpg.

btw: i would go for #2 and #4.

[JanGeo]

Actually take the one on the end and then you have to twist the crank for the 120 degree offset per rod journal. Funny was in a junk yard last year looking down the headless block of a Geo and saw just how short the bore really was and small . . . it's TINY!!

[MetroMPG]

Just need to workout the connection to the wheel thing.

what about an electric drive wheel that engages against one of your rear tires for low speed driving? you've got room in the back to make mechanism that would raise or lower the wheel a few inches. of course, you'd have to cut an access hole through the wheel arch...

[JanGeo]

Was actually thinking of using a 5th wheel that could be raised and lowered that would simplify the gearing. Problem with rubbing against the car tire is tread wear and contact patch plus the travel on a bumpy road is brutal. The Fifth wheel could be suspended properly and could be lifted over bumps and have limited down travel to prevent pot hole damage. Plus it would not interfere with normal vehicle operation and safety issues. Going to take a lever with a throttle grip to operate the 5th wheel . . . hummmm . . . separate digital speedo to record usage and to allow sycronization of ground and wheel speed . . . hummm . . . gear up . . . gear down . . . hummm.

[MetroMPG]

why not just a pusher trailer?

[JanGeo]

No hitch for trailing and safety issue when backing up as well as bridge tolls increase for another axle. Not to mention lack of control wires in the same vehicle and registration extra . . . need I say more? Guys do that on a bicycle to get around the powered vehicle laws.

All I need to make it work is a motor on a mount with a swing arm to the wheel and a belt drive and a lever to lower and raise the wheel. All wiring is on the chassis without anything moving other than the swingarm on cable or spring tension to the ground. Actually the drive angle can provide down force for traction and make it slip if braking action gets to great.

[rh77]

No engine-off stops at all? i don't mind using the starter once in a while, even in the manual shift car. 13 times in 9.7 km would be excessive, but i don't think 3 is. (it would have been 2 key starts, but i botched one of the clutch starts when i used my kill switch improperly.)

If I go to the ATM, then I shut down and coast to the machine, and when I go to the local coffee shop, I park instead of using the drive-thru. Subtle changes. But at lights, (city driving) which is 20% of my driving, the shut-down/re-start raises the RPM to a higher level of approx. 1500 RPMs intitially. If I shift immediately, the excessive revs create a hard engagement. If I wait the second to get the engine back to around 800-1000 RPM, then I get honked at. The neutral shift is faster and is easier on the aging tranny.

What I really need to do to get my mileage up is to improve the Cd. Nearly 80-90% of my driving is around 55-60 MPH. The techniques mentioned earlier are nearly to identical to those of a hybrid, which I've calculated to not be a benefit to my driving (other than the tax credit). Since joining gassavers.org, I've reduced my speed on the highway from 75-80 mph down to 57 mph. My gaslog shows a steady, but slight increase in my average FE. I continue to use the HAI, because the fuel trim is consistently lower, and more throttle is required to perform the same tasks (which has been proven to up the FE because of the increase in air pumped with no increase in RPM).

I don't know what to do next. If I invest in a ScanGuage, I can see in real-time what seems to be working. Maybe aero changes or lowering could help. I'd hate to have hit the proverbial "wall" with this car, as I've resolved to drive it until it becomes more costly to maintain than drive, then maybe it'll re-incarnate into a Rally car (don't tell my fam ;-) ). I feel as if I've summed up my entire feelings about my situation in one post, but progress has been minimal over the last few months since I've joined this site. I refuse to give up just because I have a short-geared final drive automatic connected to a moderately-high horsepower "LS" engine. Maybe when the automatics forum opens, some more brainstorming can occur, but probably 90% or more of members here have manuals, so how much input can we generate? I'm just frustrated -- I came back from the Auto Show this weekend just sickened of the average fuel economy of the vehicles out on the floor. Of course, I could get a different car but that isn't an option right now. The challenge lies in bettering what I have. OK, I'm done now. Thanks, sorry, good night and good luck.

RH77

[JanGeo]

the bigger the engine the better the improvement - try some friction reducing oil additives - believe me they WORK!

[MetroMPG]

did a little errand run today and man, the engine-off coasting continues to be awesome:

57.4 mpg (US) on a 15 km round-trip, from a cold start (5 C ambient), in city driving, where literally 9 out of the 10 traffic lights on my route was red.

i'm probably overdoing the engine-off business at this point, and still botching the occasional clutch start, mainly from waiting too long - e.g. road speed too slow to start in 5th. i need to figure out the range of speeds at which 5th, 4th or 3rd would be most appropriate for a clutch start.

[diamondlarry]

i'm probably overdoing the engine-off business at this point, and still botching the occasional clutch start, mainly from waiting too long - e.g. road speed too slow to start in 5th. i need to figure out the range of speeds at which 5th, 4th or 3rd would be most appropriate for a clutch start.

I'm not sure how your car is geared, but in my Saturn, I can start the engine in 4th as slow as 20 mph; sometimes 15 if the engine is good and warm. If I get to 15 and below I usually use 3rd. I usually use 5th down to around 30-35mph.

[JanGeo]

I would think that the gear you select should have at least 500-1000 rpm at the motor and if your engine starts as well as my Geo it should start if you get one compression cycle on any of the three cylinders. You should just pop the clutch and push it back in really quick and the engine should start. Leaving it out too long at too low an rpm will kick the clutch springs back and forth and probably stall the engine before it gets up to minimum running speed.

[MetroMPG]

thanks for the advice guys.

i think my problem (in addition to mistakenly using 5th when i'm going too slow for it) is i'm trying too hard to be smooth: sometimes i'm not releasing the clutch far enough, or for long enough. and if i'm down below 10 mph when i make one of these false attempts, it just slows me down that much more. at which point i'm toast and forced to use the key.

it doesn't happen *too* often. i botched it once today. it'll come with practice. i'm still getting used to the car, too...

[MetroMPG]

well, 136 miles so far on this tank of gas and the scangauge says 59.2 mpg (US) - mainly sub/ex/urban driving with a little highway thrown in.

engine-off while coasting is the key - though temps are also rising as well. my previous best tank in the blackfly is 53.1

and this tank isn't exclusively engine-off technique; i filled up on march 2 and did the experiment on march 10. so there's some old-skool driving in the mix as well.

the only "downside": at this rate it's going to take me a couple of months to use a full tank of gas. i'm eager to compare the scangauge's readings against a fill-up. my fuel needle is still on "F" for this tank...

i'm getting smoother at the clutch re-starts also. no botched attempts today. i'm getting a better feel for whether to use 3, 4 or 5 for the re-start depending on road speed.

[krousdb]

Metro,
Do you work at home or are you independantly wealthy? Some people use more gas in thier daily commute than you do in a whole month. You are the best candidate for an EV of anyone that i know. Hmmm. Maybe you should build your own! I have an idea. First, scan the all of the forklift enthusiast mags for used forklift ads in your area, then .................... :)

[MetroMPG]

yup, work at home.

independent, yes - wealthy, no. i'm on one of those "get rich slow" plans. (probably because i spend too much time taking apart forklifts instead of really working.)

you know... half the people in this town are ideal candidates for EVs. anyone with more than one car, anyway.

[krousdb]

well, 136 miles so far on this tank of gas and the scangauge says 59.2 mpg (US) - mainly sub/ex/urban driving with a little highway thrown in.

Congrats on 59.2 so far. I am at 160 miles 57.2 MPG. Can't wait for higher temps. I will send you whatever I don't use. :)

What tires are you running again? I am too lazy to check your garage.

[MetroMPG]

you know, i'm not even sure what brand they are - i'm too lazy to check my own sidewall!

whatever they are, they're 155/80/13 original rubber. tigerpaws? i'll have a looksee tomorrow and get back to you.

pressure's more like 51 now that ambient has gone up. it's soooo harsh, i'll be letting a little of that out, i'll tell you.

we'll just see if that 59 holds - i've got a couple of highway trips coming up in the next 2 or 3 weeks.

[MetroMPG]

What tires are you running again? I am too lazy to check your garage.

original 8 year old goodyear invicta GL

treadwear 260, traction A, temperature B, sex appeal 0, traction in snow F

[krousdb]

What tires are you running again? I am too lazy to check your garage.

original 8 year old goodyear invicta GL

treadwear 260, traction A, temperature B, sex appeal 0, traction in snow F

I would give them an "A" for hypermiling.

[MetroMPG]

i have read (can't remember where) that OEM tires (like i have) are different than aftermarket replacement tires of the exact same brand & model. the original tires are supposedly more lightly built and may return better fuel economy.

anyone else heard this?

[rh77]

the original tires are supposedly more lightly built and may return better fuel economy.

anyone else heard this?

I know lots of people that buy OEM tires for vehicles 5+ years old. The problem is that today, on the average of every 2 years, breakthroughs in tire technology yield lower rolling resistance, better traction, handling, etc. I'm sure that the OEM tires will become less expensive until they become rare, then an alternative will be the only option. As far as weight, that may be a misnomer.

For me, my personal research has shown that simply for improved safety (wet and snow) in addition to better economy and handling, I'll find the newer design that fits and put OEM behind me. I've never used OEM as a replacement tire on 8 vehicles over the years.

RH77

[Ryland]

I've noticed that alot of new cars come with tires that have a low wear life, and that they are normaly a cheap tire, why? because very few people are going to complane about having to replace their tires after a few years, it's one of those normal things you do with a car, so very few people notice cheaper tires, of course some of them are also chosen because they boost the MPG by just enough to get that EPA rating knocked up a notch, either by useing a harder rubber, or making them out of less rubber and steel belting, but I've noticed a number of OEM tires that have a wear life in the area of 180-240 and look at what else is avlible in that size and they are in the 380-440 wear life...

[philmcneal]

damn its funny scangauge has the same distance in the trip view when comparing to my car's tripA(reset when filling) odometer. So I'm pretty sure my car's odometer is still regestering after keying off but I'm having the delay that metrompg used to have before although not as long (5 seconds). But still that's enough to mess up data if you do it enough. What I also noticed when I switch data from km to miles and litres to gallons, the conversions work out all right except for gallons which still show an awfuly big number since it wasn't touched at all.

Setting the hybrid mode on the scangauge at least it won't turn off, but data still freezes... distance is still recorded but fuel economy trip resumes after 5 seconds later skewing the data. Hopefully recalcuating by hand will save the day. Bleh how hard can a kill switch be? am I going to be running into any problems if I have an engine immobilizer?

[tomauto]

How do you go about "clutch starting" exactly? This sounds interesting.

[krousdb]

How do you go about "clutch starting" exactly? This sounds interesting.

While moving, choose the appropriate gear for your speed and let out the clutch. Usually the highest gear will provide the least amount of commotion.

[JanGeo]

actually you should pop the clutch quickly then push it back in to just give the engine a spin to start in a high gear then shift to a lower gear to match the rpm to speed. Just letting it out can be hard on the gears if the engine rpm is too low to run smoothly.

[tomauto]

So you dont have to turn the key? The car just springs to life?

[krousdb]

Yes, as long as the ignition is on. I kill the ignition to coast and then switch back on immediatly (as soon as the engine dies) so the odo/speedo will record distance. You can clutch start any time after turning the ignition back on.

[tomauto]

How long have you been doing clutch starting?

[krousdb]

Clutch starting this car since I got it in January. Any car that I owned over the past 20 years that had a manual transmission I also clutch started. Mainly the 85 HF and the 90 teg.

[tomauto]

Nothing abnormal then, I can't wait to try this.

[philmcneal]

yup i saw my mechanical teacher today. Boy he still looks the same and still loving to teach even after 20 years later. I told him about bump starting and he said, "nope can't harm the car." I even asked about dumping raw fuel into the catatlic converter and he said, "Nah don't worry about it. What you doing will not kill the car."

COAST OFF ~~~~~~~~~~~ art of bump starting. (http://www.gassavers.org/wiki/view/14)

[MetroMPG]

What tires are you running again? I am too lazy to check your garage.

original 8 year old goodyear invicta GL

hmm! i just discovered that my tires were/are actually classified as LRR after doing a quick web search.

i've seen them on a number of EV conversions. that's what prompted me to do the search.

that would explain their high sidewall max pressure and their general lack of traction (i've understeered them in the wet in a moderately quick turn, and they're absolutely utterly useless in snow).

[philmcneal]

What tires are you running again? I am too lazy to check your garage.

original 8 year old goodyear invicta GL

hmm! i just discovered that my tires were/are actually classified as LRR after doing a quick web search.

i've seen them on a number of EV conversions. that's what prompted me to do the search.

that would explain their high sidewall max pressure and their general lack of traction (i've understeered them in the wet in a moderately quick turn, and they're absolutely utterly useless in snow).

mine pumps up to 51 psi, and its been rumored that my tires were LRR, but finding out the potenzas SP20 were not after all. If they were I'd be pretty dissapointed! As for snow its all right, but not the greatest I guess, I go much slower anyway when its snowing.

[Ryland]

Low traction in snow is why I have a full set of snow tires, I know they are going to use more gas, but the fuel savings in needing the driveway plowed less, and the energy saved in not crashing the car in to something on a slipery road, and the time saved not getting stuck, I think it's worth it.

[MetroMPG]

i agree about the snows. i have a full set also, but i didn't install them this winter because i did so little driving. i think i drove twice in the snow. verrrrryyyyy slooooowwwlllyyyy.