Go Back   EcoModder Forum > EcoModding > The Unicorn Corral
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 07-10-2016, 11:11 AM   #1 (permalink)
EcoModding Lurker
 
Join Date: Jun 2015
Location: Finland
Posts: 63
Thanks: 1
Thanked 18 Times in 13 Posts
Speed limiter helps fuel economy?

I have had a couple of Mercedes where the cruise control can be used as a speed limiter, so that you drive normally, controlling speed as you require, but the car will not exceed whatever speed you have pre-set. I rarely used that feature but just recently I started using it consistently and was surprised to find that it seemed to help with fuel economy. Possibly without it I inadvertently exceed the maximum speed at which I wish to travel, but I wouldn't have thought I do that often. The only other explanation I can think of is that driving a little faster down hills, which I often do, actually uses more fuel rather than (as I would expect) saving fuel by using gravity to my advantage. I would find that surprising if it were true, partly because of the logic and partly because I don't encounter large hills in my area.

I should perhaps point out that this was in a car with an automatic transmission in which I was not happy using EOC so my technique was more DWL rather than P&G.

Has anyone else noticed this? Or indeed tried a speed limiter without seeing this effect?

Unfortunately I have just changed cars and the replacement does not have a speed limiter so I am unable to perform tests to verify/quantify the effect.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 07-10-2016, 02:31 PM   #2 (permalink)
Master EcoModder
 
JRMichler's Avatar
 
Join Date: Feb 2011
Location: Phillips, WI
Posts: 1,013

Nameless - '06 GMC Canyon
90 day: 37.45 mpg (US)

22 Maverick - '22 Ford Maverick XL
90 day: 41.9 mpg (US)
Thanks: 188
Thanked 466 Times in 287 Posts
It's helping you to drive more smoothly, which helps mileage. We call this DWL. When I got good at DWL, not only did I get better mileage, but I regularly put my passengers to sleep.

True story: My very first car, a well used 1961 Rambler American with the flathead six cylinder engine, came with a speed limiter. The gas pedal flat on the floor would only open the carburetor throttle valve a little over halfway. That was good for 60 MPH on a level road. I got 30 MPG.

Then I fixed the linkage, used the extra power, and got 24 MPG from then on. Brake lining wear increased also.
__________________
06 Canyon: The vacuum gauge plus wheel covers helped increase summer 2015 mileage to 38.5 MPG, while summer 2016 mileage was 38.6 MPG without the wheel covers. Drove 33,021 miles 2016-2018 at 35.00 MPG.

22 Maverick: Summer 2022 burned 62.74 gallons in 3145.1 miles for 50.1 MPG. Winter 2023-2024 - 2416.7 miles, 58.66 gallons for 41 MPG.
  Reply With Quote
Old 07-11-2016, 08:36 AM   #3 (permalink)
Master Novice
 
elhigh's Avatar
 
Join Date: Jan 2008
Location: SE USA - East Tennessee
Posts: 2,314

Josie - '87 Toyota Pickup
90 day: 40.02 mpg (US)

Felicia - '09 Toyota Prius Base
90 day: 49.01 mpg (US)
Thanks: 427
Thanked 616 Times in 450 Posts
Well, it strongly suggests that without the limiter, you would generally drive faster. Speed kills economy.
__________________




Lead or follow. Either is fine.
  Reply With Quote
Old 07-11-2016, 04:12 PM   #4 (permalink)
EcoModding Apprentice
 
KrautBurner's Avatar
 
Join Date: Mar 2014
Location: SUNNY Sequim, Wa
Posts: 239

Cavalier of D00M - '05 Pontiac GTO LS2 T56
90 day: 23.2 mpg (US)

The New One - '10 Toyota Prius II
90 day: 51.55 mpg (US)

Chick Magnet - '91 Geo Metro 3cyl/5sp
90 day: 48.07 mpg (US)
Thanks: 79
Thanked 40 Times in 34 Posts
not always the case

my GTO gets solidly better fuel economy @70-75mph than at 60
as did my Camaro

but both cars were torque monster V8's with Double OverDrive 6 speeds and tall final gear ratios


when my GTO was stock
I routinely got 31-32mpg (with an avg speed of 70mph over a 400 mile drive)
but in order to get that, I had to keep the speed up the whole drive (coming down to 55 and back up, or taking exits, and getting back up to highway speed brought it down quick)

__________________
2005 GTO 6.0 V8 (600hp)

1991 Geo Metro 1.0 3/5 base

2010 Prius II (replaced 2001 Tahoe 5.3 V8 April 2014)

1994 F-350 7.3 TurboDiesel (Rollin' Coal)
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com