Neutral at stop lights, save gas?? - Fuelly Forums

Android Users - Coming Soon! - Migrating from aCar 4.8 to 5.0

Reply
 
Thread Tools Display Modes
 
Old 01-11-2007, 04:05 PM   #1
ELF
Registered Member
 
ELF's Avatar
 
Join Date: Jan 2007
Posts: 245
Country: United States
Neutral at stop lights, save gas??

I don't know if this has been discussed before but, I learned something today.
Until recently I never paid much attention to my GPH on the scan gauge.
So today I had it on and while at a stop light I checked to see how much fuel I was using, 0.3 GPH in gear. I put the tranny in N and the GPH changed to 0.2

So at least in my car I can save some gas by using neutral at stop lights. Don't think I'll be saving a lot but every little bit helps.
__________________

__________________
ELF is offline   Reply With Quote
Old 01-11-2007, 04:16 PM   #2
Registered Member
 
omgwtfbyobbq's Avatar
 
Join Date: Jul 2006
Posts: 1,516
Country: United States
Awesome info, I've been meaning to ask about this. Imo it means that no matter what, coasting in N should result in better mileage. I think. If you have the time, could you check the fuel flow when coasting in N compared to decelerating in gear at a kinda slow speed, like ~40mph? If the idle consumption when decelerating is greater than coasting in N, then coasting must be a win win no matter what.
__________________

__________________
Quote:
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
omgwtfbyobbq is offline   Reply With Quote
Old 01-11-2007, 04:46 PM   #3
Registered Member
 
Join Date: Oct 2006
Posts: 245
Country: United States
i have found with my car that in gear coastng shows higher milage reading on my scanguage than neutral coasting.
__________________
"Sylvie" 2000 Honda Insight 5 Speed


LxMike is offline   Reply With Quote
Old 01-11-2007, 05:16 PM   #4
Registered Member
 
omgwtfbyobbq's Avatar
 
Join Date: Jul 2006
Posts: 1,516
Country: United States
Really? That's very interesting. Do you know if fuel is being injected or not? For example, on the Camry, depending on coolant temps, when I coast (in gear) and drop below ~1200-1500rpm fuel starts being injected, and it pretty much idles down the road in gear. But if I'm coasting (in gear) above those rpm in top gear (greater than 50mph), no fuel will be injected. I'm wondering if the fuel flow for in gear idling is the same as N idling...
__________________
Quote:
Originally Posted by FormulaTwo
I think if i could get that type of FE i would have no problem driving a dildo shaped car.
omgwtfbyobbq is offline   Reply With Quote
Old 01-11-2007, 05:43 PM   #5
Registered Member
 
Join Date: Oct 2006
Posts: 245
Country: United States
I'll have to check gph readings and see.
__________________
"Sylvie" 2000 Honda Insight 5 Speed


LxMike is offline   Reply With Quote
Old 01-11-2007, 05:51 PM   #6
Registered Member
 
Join Date: Oct 2005
Posts: 1,978
Country: United States
ScanGuage Glitch

Quote:
Originally Posted by LxMike
i have found with my car that in gear coastng shows higher milage reading on my scanguage than neutral coasting.
My SG does the same thing, but what it doesn't know is that the injectors actually cut fuel while coasting in D (so it should read 9999).

Several vehicles benefit from Neutral idling -- the GPH arguement is quite valid. For maximum efficiency, long idling situations should be in engine-off mode (like at traditionally long lights, etc).

BUT...

The TSX, for example, has variable cam timing (i-VTEC) that cuts the cam timing dramatically at idle and uses very little fuel. It actually uses more fuel to shut-down and re-start if you're not sitting for at least 2-minutes (according to the on-board FE recorder). I don't use neutral idle anymore in the 'Teg either, as I'm worried about the longivity of the transmission going from N to D at a stop (a bit of a hard engagement). Coasting in engine-off N, starting up, and back to D with a rev-match seems to work well, tho...

RH77
__________________
rh77 is offline   Reply With Quote
Old 01-11-2007, 05:51 PM   #7
Registered Member
 
Peakster's Avatar
 
Join Date: Sep 2006
Posts: 467
Country: United States
Quote:
Originally Posted by LxMike
i have found with my car that in gear coastng shows higher milage reading on my scanguage than neutral coasting.
Same with my dad's Chrysler. It depends on the car whether its sensitive to being in gear or not.
Peakster is offline   Reply With Quote
Old 01-11-2007, 11:00 PM   #8
Supporting Member
 
Join Date: Apr 2006
Posts: 318
Country: United States
According to Ben (SVOboy) the fuel injectors on hondas turn off while coasting in gear, so the same goes for us.
budomove is offline   Reply With Quote
Old 01-11-2007, 11:15 PM   #9
Registered Member
 
Join Date: Nov 2006
Posts: 358
Country: United States
Do you know if this applies to all Hondas? I generally drop into neutral for short coasts and turn the engine off for longer coasts because when I eave it in gear it slows down considerably faster and I know that when I'm stopped that going into N will save gas. I would just experiment, but I don't drive very often except when I'm on a job, so for me to go from tank to tank would be difficult, and I don't have a SuperMID.
repete86 is offline   Reply With Quote
Old 01-12-2007, 06:57 AM   #10
Registered Member
 
Join Date: Dec 2006
Posts: 113
Country: United States
Using liters instead of gallons on the SGII will give better resolution of the idle fuel consumption. I found that my idle fuel consumption at a stop went down about .1l/h in neutral. One gallon = 3.785l. Watch for any transitional changes that may eat up any gains over a short time out of gear.

If you do a lot of ICE-off coasting, changing the SGII engine type to "hybrid" and keeping the key in the "run" position as much as possible should give the trip mileage better accuracy.

GPH Fuel consumption in my car is about the same coasting in neutral or drive, but above 30 MPH it slows down faster in drive because of engine braking. MPH/GPH = MPG, so the faster you're going during ICE-on coasting, the better the gas mileage. ICE-on coastdowns in neutral at high speeds will give better gas mileage in my car because it remains at high speed longer.
__________________

__________________
GasSavers_Bruce is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Country/Currency Preference pb Fuelly Web Support and Community News 1 10-29-2008 07:27 AM
Hydrogen or H2O Systems 1Jal1 General Fuel Topics 4 10-11-2008 02:20 AM
An American Perspective on Driving in Canada rh77 General Discussion (Off-Topic) 28 03-24-2006 10:42 PM
Experimenting with a new route to work krousdb General Fuel Topics 5 03-18-2006 09:58 AM
"active" aero grille slats on 06 civic concept MetroMPG General Fuel Topics 21 01-03-2006 01:02 PM

Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 10:20 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.