Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-01-2008, 09:58 PM   #1 (permalink)
EcoModding Lurker
 
zx3zetec's Avatar
 
Join Date: Aug 2008
Location: Minnesota
Posts: 11

ZX3 Focus - '01 Ford Focus ZX3
90 day: 31.47 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
In neutral, no rpm drop?

I was driving my wife's new 2008 Ford Focus today.
It is an automatic transmission.
Anyway, I thought I'd try popping it in neutral while coasting down a hill to do a little "hypermiling". To my surprise, the RPMs stayed right where they were! (1500 rmp) I tried this a couple more times during my drive and experienced the same result. The RPMs stayed the same as just taking my foot off the gas and coasting in drive.
Idle in park is 900ish RPM, so I was quite surprised...

Anyone know what's going on???
By the way, the 2008 Focus is really really nice. We got 42 mpg on a trip last week by driving 60mph with the AC running.

__________________
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-06-2008, 01:06 PM   #2 (permalink)
EcoModding Lurker
 
fanamingo's Avatar
 
Join Date: Jan 2008
Location: Virginia
Posts: 46
Thanks: 0
Thanked 0 Times in 0 Posts
It's not just your car. My '99 Mercury Sable (Ford Taurus) with automatic transmission does the same thing. Even worse, when shifting from overdrive to neutral the rpms increase to what they would be if I were just in drive! I haven't hooked my ScanGauge up to see the actual effects on fuel consumption. I think it's just a characteristic of the transmission, but I don't know why it's built that way.
__________________
  Reply With Quote
Old 09-06-2008, 03:49 PM   #3 (permalink)
EcoModding Lurker
 
Join Date: Aug 2008
Location: Maryland
Posts: 92

Taurus - '99 Ford Taurus SE
90 day: 17.89 mpg (US)

Windstar1 - '97 Ford Windstar Cargo
90 day: 16.99 mpg (US)

Vulcan - '97 Kawasaki Vulcan 750
90 day: 45.96 mpg (US)

Suzuki - '09 Suzuki SX4 Technology AWD
90 day: 24.62 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
i know from the Taurus it also if you're doing a neutral coast at high speeds like 45 or higher, the RPMs will actually go up quite a bit. I believe its to have the transmission spin at the same speed the engine is so it wont destroy the transmission when you reengage Drive.
  Reply With Quote
Old 09-06-2008, 04:26 PM   #4 (permalink)
CAUTION: May Stink!!!
 
BlackDeuceCoupe's Avatar
 
Join Date: Jul 2008
Location: Central Arizona (USA) Missing Posts: 225
Posts: 210

BDC's Honda CiViC HX/Si - '98 Honda CiViC HX/Si (HX Shell/Si Swap)
90 day: 40.56 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via ICQ to BlackDeuceCoupe Send a message via AIM to BlackDeuceCoupe Send a message via MSN to BlackDeuceCoupe Send a message via Yahoo to BlackDeuceCoupe
Quote:
Originally Posted by zx3zetec View Post
RPMs stayed right where they were! (1500 rmp)...

Idle in park is 900ish RPM, so I was quite surprised...

Anyone know what's going on???
Interesting!

My ride has a close-ratio, 5-speed tranny (S4C) with 4.4:1 final gearing.

I typically cruise @ 3000-4500 RPM (55-75 MPH).

Engine-on-coasting is 1100ish RPM, regardless of speed, 1-150 MPH...

As soon as the speedo hits '0' MPH, the idle falls to 900ish RPM too. Weird!

I *assume* this is due to some vagary in the ECU programming...

The ECU ultimately controls the idle speed in my car... probably yours too!
__________________
.:: B16A2 HX/Si Coupe | '98 HX shell with full '99 CiViC Si swap | 40+ MPG
Listen to the people who fail. They know what they're talking about!
  Reply With Quote
Old 09-08-2008, 01:53 PM   #5 (permalink)
EcoModding Lurker
 
zx3zetec's Avatar
 
Join Date: Aug 2008
Location: Minnesota
Posts: 11

ZX3 Focus - '01 Ford Focus ZX3
90 day: 31.47 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
Thank you all for your input!
I suppose it can all be attributed to all this drive-by-wire computer controlled stuff...
I guess it's a good thing, because once I missed neutral and threw it in reverse while going 50mph, and nothing happened :-)
__________________
  Reply With Quote
Old 09-08-2008, 03:59 PM   #6 (permalink)
Pokémoderator
 
cfg83's Avatar
 
Join Date: Dec 2007
Location: Southern California
Posts: 5,864

1999 Saturn SW2 - '99 Saturn SW2 Wagon
Team Saturn
90 day: 40.49 mpg (US)
Thanks: 439
Thanked 528 Times in 355 Posts
zx3zetec -

In my Saturn, at highway speeds, the "neutral idle" RPM is higher then my normal idle. My normal idle is between 800 and 900 RPMs. At highway speeds, the idle is usually between 1000 and 1200 RPMs. We have deduced that the ECU/PCM is changing the setting of my Idle Air Control valve because it is seeing higher MPH.

As long as your coasting-in-neutral RPM is lower than your coasting-in-gear RPM, then it's a win. But, not as good as it could be, .

CarloSW2
__________________

What's your EPA MPG? Go Here and find out!
American Solar Energy Society
  Reply With Quote
Old 09-08-2008, 05:46 PM   #7 (permalink)
EcoModding Apprentice
 
ptsmith24's Avatar
 
Join Date: Aug 2008
Location: Statesboro, GA
Posts: 177

El Camrino - '90 Toyota Camry LE
90 day: 32.47 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
The RPMs while coasting in neutral and while sitting still in neutral are basically equal. I've only tried at speeds of ~50 MPH and lower, though. I try not to re-engage Drive before completely stopping though. I do that because I am unsure of the consequences. Interesting side note: The instant MPG on the MPGuino (still calibrating, but seems pretty accurate) is about the same whether I'm coasting in D or in N (different RPMs). Fuel cut-off, maybe? I'm still not sure how cut-off works, though.
__________________
"It is foolish and wrong to mourn the men who died. Rather we should thank God that such men lived."
- General George S. Patton, Jr

  Reply With Quote
Old 09-09-2008, 06:33 AM   #8 (permalink)
Eco Noob
 
Doofus McFancypants's Avatar
 
Join Date: Jan 2008
Location: Tosev 3 - Atlanta GA
Posts: 293

Red Rover - '01 Nissan Altima GXE
90 day: 30.07 mpg (US)
Thanks: 5
Thanked 7 Times in 5 Posts
In my wife's PT Cruiser - the RPM drop VERY VERY slowly.
like over a 3 minute period they drop.
I was trying to gather data on coasting in gear compared to coasting in N and i noted the RPM did not drop.
Since i have the SG hooked up, i could see the MPG increase in both cases.

After playing with it some more - I have chalked it up to ECU Programming to try to decrease delta in engine RPM and transmission RPM.
__________________
Steve - AKA Doofus McFancypants
------------------------------
"If there's a new way, I'll be the first in line - But it better work this time"

First Milestone passed - 30 MPG (city) 5/15/08
Best City Tank - 8/31/09- 34.3 MPG (EPA= 20)
Best Highway Tank - 5/20/09 - 36.5 MPG (EPA= 28)
------
In effort to drive less:
Miles NOT driven in 2009 = 648 (Work from home and Alt Transporatation)
  Reply With Quote
Old 09-09-2008, 12:05 PM   #9 (permalink)
EcoModding Lurker
 
Join Date: Mar 2008
Location: Speedway, Indiana USA
Posts: 56
Thanks: 0
Thanked 0 Times in 0 Posts
I'm not knowledgeable about all makes, but some of this is intended to reduce the load on internal transmission parts when you go from neutral back to drive (if your vehicle speed is well above zero).

Also more engine speed to the converter means more trans pump speed means more lube flow - in some cases important to lubing various parts internal to the auto trans.

This is all made possible by the full authority powertrain electronic controls.
  Reply With Quote
Old 09-09-2008, 07:25 PM   #10 (permalink)
EcoMod Wannabe
 
Sean T.'s Avatar
 
Join Date: Apr 2008
Location: Lake Orion, MI
Posts: 448

Taurusaurus Rex - '97 Ford Taurus GL (Sedan)
90 day: 19.39 mpg (US)

Blue Wagon - '00 Ford Taurus Wagon SE Comfort
90 day: 19.61 mpg (US)
Thanks: 6
Thanked 16 Times in 9 Posts
you guys beat me to it. I was gonna say, in my taurus, sometimes it goes up when I shift into neutral.

__________________
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Can low rpm damage the engine? KiaRio2004 Hypermiling / EcoDriver's Ed 24 10-03-2017 03:16 PM
Honda IACV explained TomO Off-Topic Tech 16 12-21-2015 01:49 AM
Coasting in Neutral Vs. Coasting in Drive observation fonque Hypermiling / EcoDriver's Ed 21 07-17-2008 03:49 PM
Car Won't Start While Moving in Neutral Any Ideas? Axaday EcoModding Central 3 06-29-2008 11:26 PM
Experiment: EV coastdown in gear vs. neutral (in the ForkenSwift) MetroMPG Fossil Fuel Free 6 03-17-2008 10:12 AM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com