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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-03-2020, 05:19 PM   #1 (permalink)
Master EcoModder
 
Join Date: May 2010
Location: Illinois
Posts: 431

Oh Deer - '03 Ford Ranger XL
90 day: 33.16 mpg (US)
Thanks: 54
Thanked 71 Times in 55 Posts
What RPM range do YOU get the best mileage at?

Is there a general rule of thumb for better/best FE in certain RPM range?

For my Ranger it's around 2k rpm. That's 55 mph in 5th gear. At 1900 rpm the engine really gets smooth but I can't drive that slow on the highway without causing other drivers to have some "road rage".

I know there are a lot of factors that go into FE. Things like speed, gearing, tire size, etc. And that all vehicles are different. Things like weight, aero, drive train (FWD/RWD/AWD), etc. And where we drive them most often, either in town or on the highway.

So where do YOU get YOUR best mileage?

__________________



  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-03-2020, 11:48 PM   #2 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,732

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,571
Thanked 3,507 Times in 2,194 Posts
I use 1000-1200 ft/mn piston speed as optimal efficiency zone. I have not personally tested it but several sources that seem legit to me point in that direction.
__________________


  Reply With Quote
Old 04-04-2020, 11:34 AM   #3 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 3,950

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 25.19 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 44.74 mpg (US)
Thanks: 1,706
Thanked 1,670 Times in 1,065 Posts
As slow as possible. With both my current 2.4L engine and the previous 1.0L engine, it would peak around 30mph and remain nearly constant until ~50mph, where it would begin to drop pretty rapidly.

1.0L engine: 1075rpm - 1720rpm
2.4L engine: 975rpm - 1560rpm

Last edited by Ecky; 04-04-2020 at 04:06 PM..
  Reply With Quote
Old 04-04-2020, 11:45 AM   #4 (permalink)
Master EcoModder
 
Join Date: Feb 2014
Location: Missoula, MT
Posts: 2,087

Dark Egg - '12 VW Touareg TDI Sport AWD
90 day: 25.81 mpg (US)
Thanks: 176
Thanked 874 Times in 597 Posts
You ask a question, then give your answer that doesn't fit the question. You are adding speed into the equation when you are looking for peak miles per gallon or liters per 100 km or however you measure fuel economy. If it happens at 35 mph, then it happens at 35 mph. If 35 mph isn't allowed on say an interstate, that doesn't mean that your peak efficiency now happens at 55 mph.

To answer the question for my TDI touareg I'd say right about 38 mph in 7th gear which puts me at about 1300 rpm and it goes over 40 mpg on a steady level road, and that's with winter fuel. The problem is, I can't force the shift to 7th gear until I'm goin over 40 mph so I have to get it up to 41, shift to 7th, and then let it drop back down to 38. If I go as low as 35 mph it will probably shift back into 6th with any addition of throttle. It still gets pretty good economy at 55 mph and will run in 8th gear there but it's more like high high 30's mpg vs into the 40's. At 65 it's dropped into low 30's
__________________

  Reply With Quote
Old 04-04-2020, 12:36 PM   #5 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 3,950

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 25.19 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 44.74 mpg (US)
Thanks: 1,706
Thanked 1,670 Times in 1,065 Posts
Unfortunately most vehicles can't divorce RPM from speed, and it seems to me a rare case where going faster in top gear actually improves economy.
  Reply With Quote
Old 04-04-2020, 01:30 PM   #6 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 5,782

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,153
Thanked 1,857 Times in 1,266 Posts
Quote:
Originally Posted by Frank Lee View Post
I use 1000-1200 ft/mn piston speed as optimal efficiency zone. I have not personally tested it but several sources that seem legit to me point in that direction.
How do you calculate/track that while driving? Is there a formula? Seems like you'd need a variety of piston and stroke data as well as RPM.

To the OP: my preferred shift ranges are 1500-2000 rpm or 1700-2200 rpm, and I kinda use the latter more often. My fav cruise option on the freeway is 60 MPH @ about 1900 rpm. At that speed I can get high 60s mpg on average. But I often do pulse and glide on the freeway, using 55-65 mph, 55-70 mph, or 60-70 mph speed ranges.
__________________


See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

  Reply With Quote
Old 04-04-2020, 03:20 PM   #7 (permalink)
Master EcoModder
 
Join Date: May 2019
Location: California
Posts: 352

Tahoe 2020 - '08 Chevy Tahoe H
90 day: 20.75 mpg (US)
Thanks: 0
Thanked 76 Times in 70 Posts
Quote:
Originally Posted by hat_man View Post
Is there a general rule of thumb for better/best FE in certain RPM range?

For my Ranger it's around 2k rpm. That's 55 mph in 5th gear. At 1900 rpm the engine really gets smooth but I can't drive that slow on the highway without causing other drivers to have some "road rage".

I know there are a lot of factors that go into FE. Things like speed, gearing, tire size, etc. And that all vehicles are different. Things like weight, aero, drive train (FWD/RWD/AWD), etc. And where we drive them most often, either in town or on the highway.

So where do YOU get YOUR best mileage?
at 45MPH = 40-45mpg reading on the instant gauge @1,080rpm
3.0L/6.0L V8 engine btw.. once it flips to v8 mode it drops to 25-29mpg but soon will shift back to v4 mode and 40-45mpg..

the best ever was 31.5mpg


I just reset my MPG average it's at 30MPG avg in 4 miles of travel..


the reason for resetting it as my suv have some issues with a dirty power cable causing issues with the engine. =poor mpg my fill up was only 18.9 but i did idle and short trips = lost mpg it probably would have been in the 22-25 mpg range otherwise

Last edited by Tahoe_Hybrid; 04-04-2020 at 03:28 PM..
  Reply With Quote
The Following User Says Thank You to Tahoe_Hybrid For This Useful Post:
Ecky (04-04-2020)
Old 04-04-2020, 06:38 PM   #8 (permalink)
Master EcoModder
 
Join Date: Dec 2010
Location: arkansas
Posts: 656

"Proper Shitbox" (SOLD) - '96 Honda Civic LX fully optioned no weight reduction
90 day: 41.9 mpg (US)

Plue Brius - '10 Toyota Prius II
90 day: 57.73 mpg (US)

The Smoke Bomb - '96 Ford Ranger
Thanks: 189
Thanked 119 Times in 95 Posts
I have found that for large v6 engines of the american style. (3.0-4.X L) anywhere from 1200-2700 RPM are within a couple % of peak BSFC.
I really tested this out on the Ranger when I only had 1,2, and 5th. I would drive anywhere from 1st to 2700 RPM at 90% load, 2nd to 3000 RPM at 90% load, then shift to 5th and hit about 1075 RPM at 30 mph and continue increasing speed at 90% load to 45 mph. (28" tire and 3.73s) Then I would just stay in 5th and cruise around at 45 mph since that is the speed limit here. A little pulse and glide with EOC and what not, DWB up to stop signs. I did note that you get charging issues doing that and wouldn't dare use the starter. I actually had a tank of cruising around town at 25 mpg for about 100 miles on a stock 1996 Ford Ranger 3.0 5 speed with EGR issues, vaccum leaks, and more sensor issues. Been working on getting the transmission back in it now that Quarantine has hit and I have more free time. It has been one hell of a pain in the ass!

*I think skip shift is the way to go on these bigger non 4 cylinder engines. Going gear to gear at 90% load on the bigger stuff is a little too brisk for me versus how slow the old 96 civic was at doing it.
__________________
"I feel like the bad decisions come into play when you trade too much of your time for money paying for things you can't really afford."

2010 Prius
1996 Ranger
1987 Bass Tracker 70hp Yamaha
1970s 15' Water Rover 30hp Yamaha
2009 Suzuki GS500F
  Reply With Quote
Old 04-05-2020, 01:11 AM   #9 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 12,732

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,571
Thanked 3,507 Times in 2,194 Posts
Quote:
Originally Posted by California98Civic View Post
How do you calculate/track that while driving? Is there a formula? Seems like you'd need a variety of piston and stroke data as well as RPM.
Get the stroke then online calculators can tell you the rpm range that 1000-1200 ft/mn piston speed is. If your car has a tach you are now golden. If not then you need gear ratios and tire size and another online calculator to spit out the ideal speed range in top gear. Incidentally most of my cars don't have tachs so that is how I did it, and they usually calc out to be in the 45 to 50 mph area.

Stroke differences are how a large engine can be putting along and a tiny engine can be screaming and they will both be at the same piston speed and optimal efficiency range.
__________________


  Reply With Quote
The Following User Says Thank You to Frank Lee For This Useful Post:
California98Civic (04-05-2020)
Old 04-05-2020, 02:05 AM   #10 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,437

spyder2 - '00 Toyota MR2 Spyder
Thanks: 89
Thanked 267 Times in 204 Posts
Quote:
Originally Posted by Frank Lee View Post
Stroke differences are how a large engine can be putting along and a tiny engine can be screaming and they will both be at the same piston speed and optimal efficiency range.
This is a very good approximation at high load, but cars that are geared way too short or have really overpowered engines do better if you run them on the slower side.

  Reply With Quote
Reply  Post New Thread


Thread Tools




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