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

View Poll Results: Which vehicle would you rather have?
Vehicle A: 10.0 lower Cd than Vehicle B 4 44.44%
Vehicle B: 1000 lbs lighter than Vehicle A 5 55.56%
Voters: 9. You may not vote on this poll

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-29-2020, 09:05 PM   #21 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
When I throw my car in 5th or 6th and idle along at 20mph, I get around 65-70mpg with my 2.4L engine.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-29-2020, 11:14 PM   #22 (permalink)
EcoModding Pro
 
Join Date: Oct 2020
Location: Abilene, Texas
Posts: 74
Thanks: 9
Thanked 41 Times in 27 Posts
weight vs drag

I guess I misunderstood your post. Looking at a very small engine pulling a heavy vehicle, it looks as if gearing is a major factor, coupled with the number of gears in the tranny, plus the height of the driving tires. Like I said, you must have an almost perfect combination. Overcoming weight is the single biggest factor in stop-and-go city driving as it relates to economy. My work is in building a vehicle for ALL TYPES of driving under normal conditions. If one simply adapts driving habits MPG can be improved, but the vehicle must be built for the task it is assigned. I am an old car builder who puts the overall LOOK of the vehicle near the top of my objectives, with efficiency at the very top, which causes compromises in all areas. A butt-ugly car that gets great MPG probably won't sell, and one that is what we call a Trailer-Queen Show Car, that gets very poor MPG, probably won't sell either. I think my reading of your post was me not understanding your parameters...MY BAD.
  Reply With Quote
Old 10-29-2020, 11:43 PM   #23 (permalink)
Master EcoModder
 
oldtamiyaphile's Avatar
 
Join Date: May 2009
Location: Australia
Posts: 1,510

UFI - '12 Fiat 500 Twinair
Team Turbocharged!
90 day: 40.3 mpg (US)

Jeep - '05 Jeep Wrangler Renegade
90 day: 18.09 mpg (US)

R32 - '89 Nissan Skyline

STiG - '16 Renault Trafic 140dCi Energy
90 day: 30.12 mpg (US)

Prius - '05 Toyota Prius
Team Toyota
90 day: 50.25 mpg (US)

Premodded - '49 Ford Freighter
90 day: 13.48 mpg (US)

F-117 - '10 Proton Arena GLSi
Pickups
Mitsubishi
90 day: 37.82 mpg (US)

Ralica - '85 Toyota Celica ST
90 day: 25.23 mpg (US)

Sx4 - '07 Suzuki Sx4
90 day: 32.21 mpg (US)

F-117 (2) - '03 Citroen Xsara VTS
90 day: 30.06 mpg (US)
Thanks: 325
Thanked 452 Times in 319 Posts
Quote:
When I throw my car in 5th or 6th and idle along at 20mph, I get around 65-70mpg with my 2.4L engine.
Racecar gearing is not a brag on this forum though

Your engine capacity to weight ratio is about the same as my Jeep (4.0), but even that can't pull 6th until ~40mph.
__________________






  Reply With Quote
The Following User Says Thank You to oldtamiyaphile For This Useful Post:
aerohead (10-30-2020)
Old 10-30-2020, 10:53 AM   #24 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
50% CITY / 50% HWY

The premise of the thread contains 50% Hwy driving, which for example, in Texas, today, would include up to 85-mph, legally, between Austin and San Antonio.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
Old 10-30-2020, 11:55 AM   #25 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: New Zealand
Posts: 5,005

ND Miata - '15 Mazda MX-5 Special Package
90 day: 42.54 mpg (US)
Thanks: 2,866
Thanked 2,501 Times in 1,547 Posts
Quote:
Originally Posted by oldtamiyaphile View Post
Racecar gearing is not a brag on this forum though

Your engine capacity to weight ratio is about the same as my Jeep (4.0), but even that can't pull 6th until ~40mph.
I'm getting off into the woods a bit here, but I had, at considerable expense, a custom final drive cut a full 40% taller than what came in the transmission, and installed a 6th gear a further 14% taller, then upsized my tires a bit. I'm turning 650rpm @ 20mph, and 2100 @ 65mph, in a high revving engine (revs out to near 8000).

My fuel economy vs speed curve is approximately:




The displacement to weight may be similar to your Jeep's, but the power to weight is closer to that of a base C7 Corvette. It's less efficient than it was with the stock 1L engine, but I'd hardly call it "racecar" gearing.
  Reply With Quote
The Following User Says Thank You to Ecky For This Useful Post:
aerohead (10-30-2020)
Old 11-02-2020, 07:02 AM   #26 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
Quote:
Originally Posted by aerohead View Post
......average mpg upwards in spite of the inertial penalty. So I voted for aero........
Interesting list of experience, but all from a single person, a person that is interested in getting maximum fuel mileage.

This means that you probably accelerate with purposeful intent of higher mpg (slow and steady retiree on a Sunday) verses a more typical American that is trying to get there yesterday and their hair is on fire.

Meaning weight penalties for quick acceleration will be far more costly based on driving style.
__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
  Reply With Quote
Old 11-02-2020, 10:40 AM   #27 (permalink)
Master EcoModder
 
aardvarcus's Avatar
 
Join Date: Apr 2012
Location: Evensville, TN
Posts: 676

Deep Blue - '94 GMC Suburban K2500 SLE
90 day: 23.75 mpg (US)

Griffin (T4R) - '99 Toyota 4Runner SR5
90 day: 25.43 mpg (US)
Thanks: 237
Thanked 580 Times in 322 Posts
Acceleration is an investment in kinetic energy, one that would be best made based on results from an engine specific bsfc map. For my engines, those bsfc minima useful for charging my "inertia battery" are at moderate to high load. That coupled with my manual transmission means I have a bit of "jackrabbit starts" which is counterintuitive but works better for me. Others may have vastly different bsfc maps requiring different techniques.

The difference i have found lies in drawing down my "inertia battery" as much as possible via coasting to minimize the conversion of its energy to heat via the brakes. Thus I roll out of the throttle much sooner than most when approaching a stop. I leave additional following distance to have reaction time. Time the redlights. Know the speed you can comfortably take a turn, and the landmark that defines canceling the cruise on approach to that turn. Adjust behaviors based on weather or significant (2000lb+) loads being carried.

Yes there are times you have to slam on the brakes. Deer, other drivers, debris, etcetera. But under normal situations brake use is the enemy of fuel economy in a heavy vehicle.
  Reply With Quote
Old 11-02-2020, 12:01 PM   #28 (permalink)
Master EcoModder
 
kach22i's Avatar
 
Join Date: Jul 2011
Location: Ann Arbor, Michigan
Posts: 4,158
Thanks: 120
Thanked 2,790 Times in 1,959 Posts
What amazes me is what I call "straight line" drivers.

Might be the software doing the actual throttle in todays cars, but I notice an acceleration slower than what I do, but where I ease off to do the speed limit they quickly catch up and pass me like I'm standing still. They have to be doing 10-15 over the speed limit.

And an irony, they come to almost a complete stop to turn, like a G-force allergy.

I mean seeing a $75,000 BMW turn at the same speed as a 1970's pickup truck overloaded with scrap metal is mind shattering.

Compared to myself people fly up on stops and brake at last second. No patience for coasting I guess.

Driving style is part of the math here, no doubt.
__________________
George
Architect, Artist and Designer of Objects

1977 Porsche 911s Targa
1998 Chevy S-10 Pick-Up truck
1989 Scat II HP Hovercraft

Chin Spoiler:
http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
  Reply With Quote
The Following 2 Users Say Thank You to kach22i For This Useful Post:
aardvarcus (11-02-2020), Ecky (11-02-2020)
Old 11-02-2020, 01:43 PM   #29 (permalink)
Master EcoModder
 
aardvarcus's Avatar
 
Join Date: Apr 2012
Location: Evensville, TN
Posts: 676

Deep Blue - '94 GMC Suburban K2500 SLE
90 day: 23.75 mpg (US)

Griffin (T4R) - '99 Toyota 4Runner SR5
90 day: 25.43 mpg (US)
Thanks: 237
Thanked 580 Times in 322 Posts
Also "interesting" is when the straight line drivers tailgate me into a curve, my junk makes the turn no problem while they last second stomp the brakes in their luxury cars ending up out of control and in other lanes... they don't seem to tailgate me after that...

Unless someone is coming the other way and I slow way down for turns so the streight line tailgater doesn't kill them...
  Reply With Quote
Old 11-02-2020, 03:51 PM   #30 (permalink)
Master EcoModder
 
freebeard's Avatar
 
Join Date: Aug 2012
Location: northwest of normal
Posts: 27,562
Thanks: 7,738
Thanked 8,554 Times in 7,041 Posts
I lured a 4WD pickup into a corner once with my Notchback. It went up on three wheels.

OTOH, a red Audi lured me onto a freeway onramp that had a solid sheet of ice one December night. I had to fight to keep the title clear on that one.

__________________
.
.
Without freedom of speech we wouldn't know who all the idiots are. -- anonymous poster

____________________
  Reply With Quote
The Following User Says Thank You to freebeard For This Useful Post:
Ecky (11-02-2020)
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