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http://www.slate.com/id/2192187/

Good article on idling times and considerations as well as vehicle warm-up.

Good find! Thank you.

Im really curious what all you Scanguage owners see for gph during idle. This article claims 0.156gph, but references another that claims several times that. I have a 2.2L 4cyl.. anyone care to post their engine size, cylinders, approximate idle speed and gph?

My 1996 civic (1.6L 4-cyl) reads .3 gph, and my 2004 Odyssey (3.5 V6) reads .4-.5 or .6 with AC.

Chevy Tracker 2.0L (@60F ambient):

Initial fuel surge at startup: .93gph decreasing instantly to ~.68gph

~.01gph/sec decrease until, Idle: .24gph

add ~.3 for AC

Chevy Prizm 1.8L .3 GPH at idle.

If I am coasting in neutral so that the engine is just idling, it is around .13 GPH.

2001 Prizm-1.8 lt- .2gph AC on in park.
2003 Pilot 3.5 V-6 .4-.5 GPH AC on in park
2004 Titan 5.6 V-8 .6GPH AC on in park
1998 Suburban 5.7 V-8 .67 GPH AC on in park.

We take long trips in the summer,and frequently sleep in the vehicle with AC on,so the gph used were a big concern. 6 hours sleeping in the Suburban could cost >$15.I'm hunting for another way(tried a crude fan blowing in ice chest-didn't work). Evaporative coolers won't work in higher humidity areas-TX.I'm considering some sort of ice and water cooled mat and blanket with cheapo 12v fan.I'm not wild about a 250 hp AC.

Charlie

Elantra 2.0lt -- 0.34gph at idle around 700RPM.

Don't know about the Insight because I've not used a SG in it -- the lean burn throws off mileage calculations.

Thanks folks. Interesting how much variation there is between engines of similar displacement. On the low end we have a 0.13gph for a 1.8L, but then a 1.6L civic that burns .3gph, more than twice what the larger engine burns.

@PaleMelenesian and/or RightLaneCruiser: did you two get these numbers with a warm engine, no load (such as a/c, headlights, fans, transmission in drive-maybe even park? I dunno) I guess another relevant fact would be ambient temperature when you took these measurments. If it is cold outside the engine is probably adding more gas. The reason I ask you two is because your numbers seem significantly higher than other people with similar engines. I am especially surprised at the civic...

I have the older Scangauge that only reads one digit.

In the summer, fully warmed up, it sometimes drops to 0.2 and then back to 0.3 and back and forth. So let's say .25.

Little/no load. Warmed up, idling at a stop, the manual trans in neutral, no fan/ac/headlights. Add some/all of those and it can go up to 0.4.

The .156 gph is certainly not correct for the majority of USA vehicles.My lowest was .2 gph with the Prizm and it didn't change-resolution not fine enough on gallons-with the AC.

I have an excellent idea how much they actually use with the AC on because I've run 3 of them for 6 hours at a time-stopped in P- with the AC on. I knew how much extra I used because I knew almost exactly what I was using on that leg.

Our Pilot was probably an AVERAGE USA vehicle if my eyeball estimate of our current road mix is about right.It used .4gph no AC and slipped between .4 and .5 gph with the AC on. Probably 25% of the vehicles on the road are V-8s-they will be .6gph-maybe 55% are V6-.4 and the 4 cyl are maybe 20% and rising.

.156 gph is bs for the USA- .3-.4 gph is about right.We use more AC than the Canadians also.The Suburban seems to use about .2 liters per hour more(.06gph) with the AC, but it has a huge interior vol.

Charlie
Charlie

Jaral, that is idling with a warm engine, no accessories on, in neutral. I've never seen it drop below 0.32 or so. That's part of the reason I never broke past mid 30's before using more advanced hypermiling techniques -- as soon as I started throwing some of those in I broke through 40mpg and kept going up.

The car coasts like a dream but the engine just isn't very efficient at all. :p

1996 Honda Accord 2.2L reads .34 or so if idling in D (drive) and if I toss it into neutral it falls down to .28-.29.

Aha! Thanks, BlueGenie, Im pretty sure the 1996 engine is 98% identical to the 1990 one I have. It is still pretty interesting how much idle fuel consumption varies between vehicles.

TorqueNada pulls between .22 and .29 at idle, depending on its mood it would seem, most often I see .24-.26

2002 Hyundai Accent 1.6L.

.25 in neutral no AC, .37 with AC.

.33 in drive no AC, .45 with AC.

Also at speeds of 40-60 MPH turning on the AC adds about .3 GPH. A huge difference.

V6 auto avenger 2.5L .39-.45gph

Dang, you guys are seeing .3 in 2L engines. I'm kinda scared about my Wrangler's 4.0L engine!

This might be closer to your style:
my 2004 Odyssey (3.5 V6) reads .4-.5, or .6 with AC.

Man this thread makes me want to buy a SGii. Unfortuanately I can't afford one. Maybe I should start a thread where people donate money to me to buy one.

Good article. I am new to this and have had no trouble cutting out my morning idle to "warm up" my engine. But this is summer time. I worry about what I will do during the winter when the temps drop. I dont know if I have a comfort level of just taking off with a cold engine. Unfortunatley my car stays outside so whatever the temps are, the engine block will be as well. My initial winter plan is to idle my engine the same each day, thinking 30 seconds. Any thoughts?

30 seconds shouldnt be too bad for a warm up, most modern cars are warm by then. Last winter I had a towel and glove that were kept quite warm. I'd throw the towel over the seat and dwg (drive w/ glove) by the time that wears off, the car is already warm enough ;)

30 seconds shouldnt be too bad for a warm up, most modern cars are warm by then. Last winter I had a towel and glove that were kept quite warm. I'd throw the towel over the seat and dwg (drive w/ glove) by the time that wears off, the car is already warm enough ;)

LOL...I am not worried about ME. I am more worried about cold oil and engine internals. Besides, we are not talking extreme cold temps for my region. Average low in the winter might stay around 30-35 degrees with maybe 7-10 nights in the low to mid 20s.

Should cars be idled immediately after starting up in, say, 70° temperatures? And by "idled" i mean for ~2 seconds, as opposed to throwing the car in gear as soon as you release the key.

Also, when restarting a warm engine after a traffic light or something, how long should the engine run before i pull the shifter back into D?

I always throw my car into gear as soon as it is started. Of course, I idle out of my driveway in reverse, and that takes about 10seconds.

Scion xA 1.5L automatic

0.14-0.16 = neutral idle no A/C
0.20 = drive idle no A/C

Wow. That's great.

Maybe it's because of my small engine? I was rather surprised when it dropped to 0.14 but there it was.

My 2008 Fit reads 0.24gph when warmed up.

One of the 1st items of interest for me was this when I started my SG happy trails. Noticed how sensitive that could see the HVAC fan or parking light wow.

Then I did a little math that made me say wait a sec,

11gal tank .24gph
So if I parked it with eng at idle and full tank it would run for 46 hrs or about 2 days.
Nawww ain't buying that.

I don't have a scangauge or supermid, but I use a duty cycle meter on my injectors, and at about 600rpm my VX shows a duty cycle of 0.9%, which translates to 0.108gph. (190cc/min injectors). I would be curious what a supermid shows on someone else's VX at that idle speed.