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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-14-2009, 07:31 PM   #1 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
Test: comparing Blackfly vs. ForkenSwift rolling resistance (Goodyear Invicta GL)

For quite a while I've had the suspicion that the dinosaur burning Blackfly (Pontiac Firefly) is a better roller/coaster than the wind & hydro powered ForkenSwift (electric Geo Metro).

But! I don't put much faith in Butt-o-Meter readings in general, even my own.

So today I ran a simple, controlled-as-possible comparison to gauge the cars' relative rolling performance to see if one was really better than the other.

The winner? In a way, both cars are winners! But in another a more accurate way, the Blackfly was the winner.

And in an even more accurate way, the Blackfly's tires were the winners.

Preparation:
  • I made sure both cars had the same tire pressure.
  • I equalized the weight between the two cars, which meant adding 240lbs to the Firefly (~1830 lbs stock) to equal the heavier electric Metro (~2070 lbs post-conversion). (I actually ended up adding 260 lbs, since at 65 lbs each, 4 flooded golf cart batteries were a quick way to do it.)
  • I washed, waxed and Armor Alled each car (OK, no.)

Methodology:


The distance of the "course" between the ForkenSwift (blue) at the start, and Blackfly (black) where it rolled to a stop.
  • I drove each car the same distance (from a cold soak start - overnight) to a quiet dead end road with a small downhill followed by an almost level "run-out" (very slightly uphill).
  • Start: at a marked position on the hill, engine/motor was shut off, transmission placed in neutral and the brakes were released (from a stop).
  • Finish: after rolling down the hill (maxing out at approximately 21-22 km/h) and coasting to a stop, the "end" position was marked on the road with chalk for each run.
  • 3 runs were done for each car
  • Then the wheels/tires were swapped between the two cars
  • 3 more runs for each car were measured
  • There was also waving at and/or talking to several neighbours who were either curious about or suspicious of the repeated slow driving up and down the hill on their quiet street.

Conditions:
24 C / 75 F - clear & dry
wind west 6 km/h (~4 mph)
humidity 34%
pressure 101.4 kpa / ? in. hg

Results:
First set of runs (tires in their "proper" places)

219.9 m / 721.5 ft - Average Blackfly distance

201.6 m / 661.4 ft - Average ForkenSwift distance

18.3 m / 60.1 ft - difference in coasting distance

Second set of runs (wheels/tires swapped between cars)

205.3 m / 673.4 ft - Average Blackfly distance

221.1 m / 725.5 ft - Average ForkenSwift distance

15.9 m / 52.1 ft - difference in coasting distance
That's not insignificant.





The tires:
Firefly:
Goodyear Invicta GL M+S (79S)
155/80/13
Max Load 436 kg / 969 lbs @ 44 PSI
Treadwear 260
Traction A
Temperature B
Tread: 3 plies (1 polyester cord + 2 steel cord)
Sidewall: 1 ply polyester cord
Made in Canada

ForkenSwift:
Magna Grip Radial HT M+S (82S) (Walmart winter tires)
175/70/13
Max Load 470 kg / 1036 lbs @ 240 kpa / 35 PSI
Tread: 3 plies (1 polyester cord + 2 steel cord)
Sidewall: 1 ply polyester cord
Made in Canada
Experiment, part two!

The next part isn't at all scientific, but after doing the controlled comparison, I took the ForkenSwift for a drive - still wearing the Blackfly's Goodyear Invictas (and borrowing its smooth wheel covers) - to see if there was a measurable difference in energy consumption compared to recent driving.



I won't argue that this is in any way a valid comparison. All I can say is I tried to do similar driving to previous cycles - ie. all sub/urban use, in light traffic, while trying to maximize efficiency.

The car is on the charger now - should be done in about an hour. So while waiting for the numbers, here are some (subjective) differences I noticed:
1) the Goodyear tires seemed quieter (makes sense when you look at the blocky tread pattern of the snow tires)

2) even at the same inflation pressure, they seemed to absorb bumps better (which makes sense, since the narrower tires should deform more on impacts)

3) not surprisingly, I found myself coming in "hot" when coasting up to several familiar stops & turns. I had to adjust my driving as the "test" went on.
Power consumption results to come!

Attached Thumbnails
Click image for larger version

Name:	fs-flea-start.jpg
Views:	298
Size:	35.7 KB
ID:	3699   Click image for larger version

Name:	fs-flea-end.jpg
Views:	326
Size:	43.3 KB
ID:	3700   Click image for larger version

Name:	flea-fs-end.jpg
Views:	386
Size:	27.6 KB
ID:	3701   Click image for larger version

Name:	fs-flea-wheels.jpg
Views:	272
Size:	29.2 KB
ID:	3702  
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
The Following 2 Users Say Thank You to MetroMPG For This Useful Post:
Intrigued (08-22-2009), raquatrac (08-18-2009)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-14-2009, 10:47 PM   #2 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
WOW.

OK, I know it's still not at all scientific, but today's ForkenSwift test drive with the Invictas on it was an all time record and beat my recent similar driving by a big margin:

27.6 km / 17.2 miles @ 3.43 kWh

199.7 Watt hours per mile / 124.1 Watt hours per km or 168 mpge (US)

My two best recent results are 224 and 228 Wh/mile. My previous all time best was 207 Wh/mile.

Maybe I should be putting together a pit crew to swap the tires back and forth between the two cars for me.
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-14-2009, 11:05 PM   #3 (permalink)
Left Lane Ecodriver
 
RobertSmalls's Avatar
 
Join Date: Aug 2008
Location: Buffalo, NY, USA
Posts: 2,257

Prius C - '12 Toyota Prius C
Thanks: 79
Thanked 284 Times in 197 Posts
So the Forkenswift outrolls the Blackfly by 1.3m on Invictas, but the Blackfly beats the Forkenswift by 3.7m on WalMart snow tires. Is this a statistically significant difference? If not, then both cars are, near as we can tell, equally good rollers, with unequal tires.
  Reply With Quote
Old 06-14-2009, 11:21 PM   #4 (permalink)
Master EcoModder
 
NeilBlanchard's Avatar
 
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,891

Mica Blue - '05 Scion xA RS 2.0
Team Toyota
90 day: 42.48 mpg (US)

Forest - '15 Nissan Leaf S
Team Nissan
90 day: 156.46 mpg (US)

Number 7 - '15 VW e-Golf SEL
TEAM VW AUDI Group
90 day: 155.81 mpg (US)
Thanks: 3,426
Thanked 2,914 Times in 1,827 Posts
Hi Darin,

That's a lot of (good) work there! I was surprised to figure out how important tire pressure is (duh!) on my wife's xD. And yes, part of the gains to be had from better rolling can only happen after you (re)adjust your driving habits. After installing my video mirrors, it has taken me a few weeks to begin to realize the improvement. You keep getting surprised at how fast you come up to a stop, and so after you start to adjust, then you get the higher FE...

It's nice to confirm that your Butt-O-Meter wasn't lying!
__________________
Sincerely, Neil

http://neilblanchard.blogspot.com/
  Reply With Quote
Old 06-14-2009, 11:22 PM   #5 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
If all else were equal except the tires, the distance between them would have stayed the same after swapping the wheels/tires.

But the gap between the cars shrunk slightly. When the ForkenSwift was wearing the snow tires, it came in 18.3 m / 60.1 ft behind the Blackfly. The Blackfly, wearing the snow tires, rolled to a stop 15.9 m / 52.1 ft behind the ForkenSwift.

I wasn't surprised to see both cars roll further in the second set of runs. Likely because the tires were warming up throughout the testing. (In almost all cases, each successive run was a little bit longer than the previous one by a couple of feet. I took an average for each set.)

Overall the tests took nearly 4 km of driving (both cars going exactly the same total distance).
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-14-2009, 11:25 PM   #6 (permalink)
Master EcoModder
 
NeilBlanchard's Avatar
 
Join Date: May 2008
Location: Maynard, MA Eaarth
Posts: 7,891

Mica Blue - '05 Scion xA RS 2.0
Team Toyota
90 day: 42.48 mpg (US)

Forest - '15 Nissan Leaf S
Team Nissan
90 day: 156.46 mpg (US)

Number 7 - '15 VW e-Golf SEL
TEAM VW AUDI Group
90 day: 155.81 mpg (US)
Thanks: 3,426
Thanked 2,914 Times in 1,827 Posts
Hi,

Did the air temperature change? If it got warmer, then the aero advantage of the Blackfly would have been reduced...
__________________
Sincerely, Neil

http://neilblanchard.blogspot.com/
  Reply With Quote
Old 06-14-2009, 11:25 PM   #7 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
Neil - definitely. And that additional coasting distance can have a seriously big impact on your numbers if the engine is off for those extra car lengths. The power of infinity on your fuel economy.

That's why I suspect the EV did so much better even with a modest increase in rolling ability - of course the car stops using energy every time the accelerator is released.
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-14-2009, 11:29 PM   #8 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
Aero would have been a small factor: peak speed in the coastdown testing was 22 km/h (13.7 mph).

The average speed would have been significantly less (but I didn't measure that).

EDIT: and yes, the ambient temp was probably also going up during the testing. Looks like 1 degree C change, or from 73.4 to 75 F. Though the temp of the asphalt was probably going up faster than the air temp.
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-14-2009, 11:33 PM   #9 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
Quote:
Originally Posted by NeilBlanchard View Post
It's nice to confirm that your Butt-O-Meter wasn't lying!
Yeah, but I still won't trust it!
__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Old 06-14-2009, 11:42 PM   #10 (permalink)
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,272

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.07 mpg (US)

Winter beater Metro - '00 Chevrolet Metro
90 day: 61.98 mpg (US)

Fancy Metro - '14 Mitsubishi Mirage top spec
90 day: 58.72 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)
Thanks: 3,808
Thanked 6,687 Times in 3,466 Posts
Also: I would have done a steady speed MPG comparison between the two sets of tires on the Flea, but I still don't have a functioning cruise control. I need to replace it (again).

__________________
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: Oops, I did it again! Bought another cheap, 3-cylinder Mirage. Mods in progress...
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Top 5 most fuel efficient tires (Lowest Rolling resistance: LRR) blackjackel General Efficiency Discussion 144 01-26-2016 12:39 AM
Discussion on tire efficiency Ernie Rogers General Efficiency Discussion 69 12-27-2014 02:17 PM
Electric car conversion: Project ForkenSwift MetroMPG Fossil Fuel Free 1041 07-28-2014 10:19 AM
Calculating Rolling Resistance SVOboy EcoModding Central 2 02-15-2012 09:43 PM
Bounce Test for Rolling Resistance? Ernie Rogers General Efficiency Discussion 14 05-25-2009 07:38 PM



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