Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-21-2014, 01:20 PM   #1 (permalink)
Master EcoModder
 
jedi_sol's Avatar
 
Join Date: Mar 2009
Location: Tustin, CA
Posts: 929

2013 STi *SOLD* - '13 Subaru Impreza WRX STi
Subaru
Sports Cars
Team Turbocharged!
90 day: 26.59 mpg (US)

1996 Geo Metro *RETIRED from Ecomodding* - '96 Geo Metro Base
90 day: 58.68 mpg (US)
Thanks: 368
Thanked 378 Times in 236 Posts
Squeezing extra MPG out of P&G (EOC WHILE KEEPING THE CAR ON??)

Ever since I took my car into the dealership to service, I disconnected my kill switch, so I have just been doing regular ENGINE ON P&G this whole week. I noticed something interesting.

This might not apply to all cars, but on my 2013 Subaru WRX Sti, I notice then when I shift to neutral to ENGINE ON coasting, my ScangaugeII indicates 9999mpg for a half second when rpms reach approx. 900rpm.
Does this mean my injectors are actually turning off for that half second around 900rpm? I busted out my Torque App and drove to my regular “testing grounds” to verify.

Testing grounds – 1 mile stretch of road with a slight incline, late at night, in a business park so no traffic to disturb

I setup the Torque App to read FUEL USAGE to the 1000th decimal point, because I know fuel usage for 1 mile neutral coast would be minimal, but this is simply for testing purposes.

I drove up to 40mph, shifted to neutral to initiate coasting , set the app to start reading fuel usage until a pre designated ending point. I did bi directional runs

Straight engine on coasting
.018
.015
.016
.015
AVERAGE - .016 fuel used

Engine on coasting, blipping the throttle to allow rpms to sweep 1000rpms down to 900rpms
.014
.014
.014
.014
AVERAGE - .014 fuel used

Straight engine on coasting
.015
.015
AVERAGE - .015 fuel used

Total fuel used with STRAIGHT ENGINE ON COASTING IN NEUTRAL - .0156
Total fuel used with ENGINE ONE COASTING IN NEUTRAL WHILE BLIPPING THE THROTTLE – .014

That’s a potential extra 10.26% savings in fuel WHILE USING A FUEL SAVING TECHNIQUE!

I’m thinking of the potential benefits for ecomodders
1) Achieve “simulated” EOC while keeping the engine on means you keep power steering on, you keep full braking power, you keep your ac running.
2) Less wear on clutch on transmission if you no longer need to bump start

On this morning’s commute to work, there is a long downhill I normally coast in neutral, typically scangauge II reads 150-200mpg during the whole coast down, I blipped the throttle more rapidly to stay in the 900rpm sweet spot and my scangauge II indicated 9999mpg on the whole way down.

I’ll do more testing and post up my Torque App readings later!

__________________







See the rest of the Sti project log:
http://ecomodder.com/forum/showthrea...log-26612.html
  Reply With Quote
The Following 5 Users Say Thank You to jedi_sol For This Useful Post:
California98Civic (03-22-2014), Joggernot (03-22-2014), mikeyjd (03-21-2014), sarguy01 (03-25-2014), WilliamYH09 (03-25-2014)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-22-2014, 03:28 PM   #2 (permalink)
EcoModding Lurker
 
Join Date: Nov 2013
Location: lakewood, co, usa
Posts: 53

subey - '99 Subaru Impreza Outback Sport

rav4 - '07 Toyota Rav4
Thanks: 3
Thanked 1 Time in 1 Post
It could be. But keep in mind that scangage & torque don't actually measure fuel consumption, they estimate it. They probably use mass air flow & O2 sensor.
  Reply With Quote
Old 03-22-2014, 04:25 PM   #3 (permalink)
Master Novice
 
elhigh's Avatar
 
Join Date: Jan 2008
Location: SE USA - East Tennessee
Posts: 2,309

Josie - '87 Toyota Pickup
90 day: 27.96 mpg (US)

Felicia - '09 Toyota Prius Base
90 day: 53.29 mpg (US)
Thanks: 422
Thanked 608 Times in 446 Posts
That doesn't make sense. I think you've found one of the many places where the real world and the technological world aren't quite in the same plane. I suspect - and I'm going to subscribe to this thread because I really want to know more - that when you fill up it will turn out you've actually used more fuel.

If you haven't, well, I got nothin'. That would be me with a big heapin helpin of egg on my face.
__________________




Lead or follow. Either is fine.
  Reply With Quote
Old 03-22-2014, 05:44 PM   #4 (permalink)
Master EcoModder
 
vskid3's Avatar
 
Join Date: Jun 2008
Location: Utah
Posts: 975

Civic DX (sold) - '97 Honda Civic DX
90 day: 34.15 mpg (US)

GTO (sold) - '04 Pontiac GTO
90 day: 22.62 mpg (US)

Green Brick (sold) - '06 Ford Escape Hybrid
90 day: 31.93 mpg (US)
Thanks: 193
Thanked 312 Times in 221 Posts
Quote:
Originally Posted by bikenfool View Post
It could be. But keep in mind that scangage & torque don't actually measure fuel consumption, they estimate it. They probably use mass air flow & O2 sensor.
I suspect it has something to do with the refresh rate and how the fuel usage is calculated by the scanners. I don't think I would trust anything other than an MPGuino in this testing scenario.

Was the car fully warmed up for the first A sets? I would suggest doing another B set after the second A to try to rule that out (so ABAB). Your sets are all extremely close, with your second A being right in the middle of the first A and your B. Looks too close to call it, in my mind, especially without being sure the instrumentation is inaccurate in this situation.
__________________


Camry Thread
E-Bike Thread
  Reply With Quote
Old 03-22-2014, 08:03 PM   #5 (permalink)
Master EcoModder
 
jedi_sol's Avatar
 
Join Date: Mar 2009
Location: Tustin, CA
Posts: 929

2013 STi *SOLD* - '13 Subaru Impreza WRX STi
Subaru
Sports Cars
Team Turbocharged!
90 day: 26.59 mpg (US)

1996 Geo Metro *RETIRED from Ecomodding* - '96 Geo Metro Base
90 day: 58.68 mpg (US)
Thanks: 368
Thanked 378 Times in 236 Posts
I've still got my old mpguino , I'll hook it up and see.

I'll post my findings soon!
__________________







See the rest of the Sti project log:
http://ecomodder.com/forum/showthrea...log-26612.html
  Reply With Quote
Old 03-24-2014, 11:30 AM   #6 (permalink)
Smeghead
 
Join Date: Oct 2009
Location: South Central AK
Posts: 933

escort - '99 ford escort sport
90 day: 42.38 mpg (US)

scoobaru - '02 Subaru Forester s
90 day: 28.65 mpg (US)
Thanks: 32
Thanked 146 Times in 97 Posts
my subaru does the same thing. I think it is actually using zero fuel for an instant as your foot comes off the gas it goes into open loop. which means it is disregarding the O2 sensor and fueling according to the fuel maps. at some rpm >~1000 and off the throttle it goes into DFCO.

am looking forward to confirmation or correction on this.
__________________

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

One mile of road will take you one mile, one mile of runway can take you around the world.
  Reply With Quote
Old 03-24-2014, 12:50 PM   #7 (permalink)
Master EcoModder
 
jedi_sol's Avatar
 
Join Date: Mar 2009
Location: Tustin, CA
Posts: 929

2013 STi *SOLD* - '13 Subaru Impreza WRX STi
Subaru
Sports Cars
Team Turbocharged!
90 day: 26.59 mpg (US)

1996 Geo Metro *RETIRED from Ecomodding* - '96 Geo Metro Base
90 day: 58.68 mpg (US)
Thanks: 368
Thanked 378 Times in 236 Posts
Quote:
Originally Posted by bestclimb View Post
my subaru does the same thing. I think it is actually using zero fuel for an instant as your foot comes off the gas it goes into open loop. which means it is disregarding the O2 sensor and fueling according to the fuel maps. at some rpm >~1000 and off the throttle it goes into DFCO.

am looking forward to confirmation or correction on this.
good, so im not crazy then!

I'm trying to find the floppy disk drive cable that came with my old mpguino, then i'll hook it up this week.

I'll also grab my volt meter and hook it up to the injectors as well to see if the signal goes to 0 during that ~1000rpm range.
__________________







See the rest of the Sti project log:
http://ecomodder.com/forum/showthrea...log-26612.html
  Reply With Quote
Old 03-24-2014, 03:46 PM   #8 (permalink)
EcoModding Lurker
 
Join Date: Nov 2013
Location: lakewood, co, usa
Posts: 53

subey - '99 Subaru Impreza Outback Sport

rav4 - '07 Toyota Rav4
Thanks: 3
Thanked 1 Time in 1 Post
Actually this might make a lot of sense. Perhaps its going into DFC for a bit. It could be more efficient to pulse the engine, blips, instead of just idling.
  Reply With Quote
Old 03-24-2014, 04:11 PM   #9 (permalink)
Master EcoModder
 
jedi_sol's Avatar
 
Join Date: Mar 2009
Location: Tustin, CA
Posts: 929

2013 STi *SOLD* - '13 Subaru Impreza WRX STi
Subaru
Sports Cars
Team Turbocharged!
90 day: 26.59 mpg (US)

1996 Geo Metro *RETIRED from Ecomodding* - '96 Geo Metro Base
90 day: 58.68 mpg (US)
Thanks: 368
Thanked 378 Times in 236 Posts
Quote:
Originally Posted by bikenfool View Post
Actually this might make a lot of sense. Perhaps its going into DFC for a bit. It could be more efficient to pulse the engine, blips, instead of just idling.
EXACTLY ...this is what I am experimenting!

The potential is that i can get the same effect as EOC while keeping the engine on...thus less wear on clutch due to no more need to bump starting, you get to keep power steering on, you get to keep full braking power on, you get to keep air conditioning on, no need to hack wires to install a kill switch.

My girlfriend approves this technique, she says
"as long as you dont have to kill switch the car, its ok with me..."
__________________







See the rest of the Sti project log:
http://ecomodder.com/forum/showthrea...log-26612.html
  Reply With Quote
Old 03-24-2014, 05:28 PM   #10 (permalink)
Smeghead
 
Join Date: Oct 2009
Location: South Central AK
Posts: 933

escort - '99 ford escort sport
90 day: 42.38 mpg (US)

scoobaru - '02 Subaru Forester s
90 day: 28.65 mpg (US)
Thanks: 32
Thanked 146 Times in 97 Posts
Quote:
Originally Posted by bikenfool View Post
Actually this might make a lot of sense. Perhaps its going into DFC for a bit. It could be more efficient to pulse the engine, blips, instead of just idling.
I think this has been tested (though not necessarily for a subaru with it's added AWD drag), leaving it in gear pulsing then coasting down in gear with dfco. from what I remember the coast downs were short enough that coasting in neutral with the engine idling was more efficient.

The wear from a bump start is pretty negligible given the forces involved. With a bump start you are getting the weight and drag of the moving parts of the engine going. Compared to just getting the car moving you are getting the whole mass of the vehicle moving.

__________________

Learn from the mistakes of others, that way when you mess up you can do so in new and interesting ways.

One mile of road will take you one mile, one mile of runway can take you around the world.
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com