What's the most efficient speed?

tomvcarter · 10-16-2010, 05:53 PM

Hi, has anyone worked out what the most fuel efficient speed to be in Cruise control is? When I'm in the car with the family I try to at least try to be green...

Radiation Joe · 10-16-2010, 06:23 PM

About 50 mph in top gear. The slower you go, the more efficient the car is. I can't do that.

bobbyd1961 · 10-16-2010, 08:13 PM

Quote:

Originally Posted by tomvcarter

Hi, has anyone worked out what the most fuel efficient speed to be in Cruise control is? When I'm in the car with the family I try to at least try to be green...

90

Krozi · 10-16-2010, 08:39 PM

1st gear constantly bouncing up and down on the fuel cut-off.

SPQR M3 · 10-16-2010, 11:32 PM

Standing still with the engine turned off. Best way to be green.

pmeloche · 10-17-2010, 12:19 AM

0 is the most fuel-efficient speed since no gas is burned.

Krozi · 10-17-2010, 12:47 AM

Quote:

Originally Posted by pmeloche

0 is the most fuel-efficient speed since no gas is burned.

Actually 0mph is the most fuel-inefficient speed because the engine could be on but your not making any progress.

richardbb85 · 10-17-2010, 01:29 AM

i never cruise in the M

tomvcarter · 10-17-2010, 04:31 AM

Still no clue...

elmariachi · 10-17-2010, 05:03 AM

Quote:

Originally Posted by Radiation Joe

About 50 mph in top gear. The slower you go, the more efficient the car is. I can't do that.

Best Answer in this thread!
Hahahahha...Same here mate!

joseph328 · 10-17-2010, 06:17 AM

Prius.

xxxryno · 10-17-2010, 06:27 AM

55; the study was done decades ago which is why most states have a 55 speed limit.

M3PGH · 10-17-2010, 06:50 AM

I beleive in the M it is 70. There was a thread about it a long time ago

aka_phox · 10-17-2010, 10:07 AM

between 75 and 90 for me.

///V\3Dude · 10-17-2010, 10:12 AM

WOT to 55 then cruise

cawest19 · 10-17-2010, 10:31 AM

Actually, it's 76.2361932 mph. I did the math... I would show you the calculations but you would

and explode

Dntlvet · 10-17-2010, 10:47 AM

Actually ~76 is my experience.
Pretty consistent 22.4 mpg.

mdosu · 10-17-2010, 11:26 AM

Quote:

Originally Posted by Radiation Joe

About 50 mph in top gear. The slower you go, the more efficient the car is. I can't do that.

+1 in this situation on flat ground you'll get about 30 mpg! But your engine speed in a 6MT will be 1500 rpms, so you might be lugging the engine.
http://www.m3post.com/forums/showpos...9&postcount=16

Remember to turn off cruise control when you go up or down a hill and turn off the power button.

When going down the hill, the car actively uses the brakes to adjust the speed, when going up, it may not be the most efficient way of accelerating up to speed.

mdosu · 10-17-2010, 11:26 AM

Quote:

Originally Posted by cawest19

Actually, it's 76.2361932 mph. I did the math... I would show you the calculations but you would

and explode

I'd like to see this, what would be the mpg for a 6mt?

mocsman · 10-17-2010, 12:22 PM

Quote:

Originally Posted by xxxryno

55; the study was done decades ago which is why most states have a 55 speed limit.

not applicable to today's engines anymore. i believe that it's up to 75 now, might be +5-10 mph on our cars. so those who are the most gas mileage conscious m3 owners are the ones getting the tickets

Dengel · 10-17-2010, 12:41 PM

Quote:

Originally Posted by Dntlvet

Actually ~76 is my experience.
Pretty consistent 22.4 mpg.

+1 this is your answer right here.

bruce.augenstein@comcast. · 10-17-2010, 01:49 PM

Quote:

Originally Posted by tomvcarter

Hi, has anyone worked out what the most fuel efficient speed to be in Cruise control is? When I'm in the car with the family I try to at least try to be green...

The straight answer is to go as slowly as top gear will permit while the engine is still cruising smoothly.

More speed brings more air and rolling resistance, not to mention that more speed takes more power even without that. More power being used means more fuel is used. Always.

As it's certainly not practical to cruise at, say, 40 mph in top gear out on the highway, just remember that more speed takes more power, and more power takes more fuel.

55 will return better mpg than 70, 100% of the time.

Even 55 is dangerous, though. If you drive down in the 5th percentile, you're just as dangerous as if you were cruising at the 95th percentile, accident-wise. Speed doesn't kill, but speed differential certainly does - meaning the old guy trundling down the road at ten under the limit is just as dangerous as the punk at 25 over.

10-16-2010, 05:53 PM	#1
tomvcarter First Lieutenant 31 Rep 344 Posts Drives: bmw E92 M3 Join Date: Jan 2009 Location: LONDON, UK iTrader: (0)	What's the most efficient speed? Hi, has anyone worked out what the most fuel efficient speed to be in Cruise control is? When I'm in the car with the family I try to at least try to be green... __________________ HRE P40 Wheels (20" Charcoal), BMW Performance ZCP Spoiler & Splitters, Eisenmann Race, BMW Performance Steering Wheel, Carbon Fibre Exterior Trim (Front & Side Grills), Eibach Pro Springs (Not yet fitted).
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10-16-2010, 06:23 PM	#2
Radiation Joe Veni Vidi Vici 49 Rep 2,750 Posts Drives: '11 JB/BBe-6sp-e90 Join Date: Jul 2008 Location: Macungie PA iTrader: (0) Garage List 2011 e90 M3-Sold [4.25] 2003 RS6 - Sold [0.00] 2009 e90 M3 - Gone [0.00] 2003 M3 SOLD [0.00] old 2002 [5.00]	About 50 mph in top gear. The slower you go, the more efficient the car is. I can't do that. __________________ Dinan compliment of stuff plus PF rotors and RG63s. Enough for now. Why, yes. I am an abrasive bastard.
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10-16-2010, 08:39 PM	#4
Krozi Colonel 80 Rep 2,730 Posts Drives: 2008 E92 ///M3 Alpine White Join Date: Oct 2009 Location: SoFla - Bonita Springs iTrader: (24)	1st gear constantly bouncing up and down on the fuel cut-off. __________________ 2008 E92 ///M3 Alpine White//Fox Red//6MT// Florida Bimmer - Join us on FaceBook!
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10-16-2010, 11:32 PM	#5
SPQR M3 First Lieutenant 17 Rep 330 Posts Drives: 2009 E92 325i Join Date: Jan 2009 Location: Australia iTrader: (0)	Standing still with the engine turned off. Best way to be green.
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10-17-2010, 12:19 AM	#6
pmeloche Lieutenant Colonel 17 Rep 1,611 Posts Drives: 2013 F25 X3 xDrive35i Join Date: Feb 2008 Location: Montréal, Canada iTrader: (0)	0 is the most fuel-efficient speed since no gas is burned. __________________ Patrice 2013 F25 X3 xDrive35i Vermillion Red
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10-17-2010, 01:29 AM	#8
richardbb85 Lieutenant Colonel 61 Rep 1,656 Posts Drives: e92 m3 Join Date: Apr 2010 Location: annandale, va iTrader: (0)	i never cruise in the M __________________ 2011 E92 Space Grey/black + Tech + Premi + Heated Seats
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10-17-2010, 04:31 AM	#9
tomvcarter First Lieutenant 31 Rep 344 Posts Drives: bmw E92 M3 Join Date: Jan 2009 Location: LONDON, UK iTrader: (0)	Still no clue... __________________ HRE P40 Wheels (20" Charcoal), BMW Performance ZCP Spoiler & Splitters, Eisenmann Race, BMW Performance Steering Wheel, Carbon Fibre Exterior Trim (Front & Side Grills), Eibach Pro Springs (Not yet fitted).
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10-17-2010, 06:17 AM	#11
joseph328 Private First Class 5 Rep 155 Posts Drives: 94' E36 M3 Coupe Join Date: Jul 2009 Location: Slovak Republic iTrader: (0)	Prius. __________________ 94' E36 M3 Coupe Daytona Violet
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10-17-2010, 06:27 AM	#12
xxxryno New Member 1 Rep 26 Posts Drives: E92 M3 Join Date: Aug 2010 Location: Chicago, IL iTrader: (0)	55; the study was done decades ago which is why most states have a 55 speed limit.
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10-17-2010, 06:50 AM	#13
M3PGH Captain 28 Rep 635 Posts Drives: Too Many Join Date: Mar 2009 Location: Pittsburgh,PA iTrader: (0)	I beleive in the M it is 70. There was a thread about it a long time ago
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10-17-2010, 10:07 AM	#14
aka_phox Captain 44 Rep 641 Posts Drives: 2011 M3 Convertilble Join Date: Jun 2010 Location: AZ iTrader: (0)	between 75 and 90 for me.
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10-17-2010, 10:12 AM	#15
///V\3Dude I Drive Slow To Save Gas :D $///V\3Dude's Avatar$ 18 Rep 464 Posts Drives: 08 M3, MY11 STi Join Date: Jul 2009 Location: I <3 NY iTrader: (2)	WOT to 55 then cruise __________________
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10-17-2010, 10:31 AM	#16
cawest19 Livin' the M life 7 Rep 151 Posts Drives: 2008 E90 M3 Join Date: Mar 2010 Location: Princeton, NJ iTrader: (0)	Actually, it's 76.2361932 mph. I did the math... I would show you the calculations but you would and explode
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10-17-2010, 10:47 AM	#17
Dntlvet Dntlvet 8 Rep 448 Posts Drives: 10 M3 Sedan,13 GT-R BE,13 Pors Join Date: Jul 2009 Location: Wisconsin iTrader: (0)	Actually ~76 is my experience. Pretty consistent 22.4 mpg.
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