Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 06-11-2019, 10:39 AM   #1 (permalink)
Master EcoModder
 
Join Date: Oct 2011
Location: ellington, ct
Posts: 829
Thanks: 44
Thanked 104 Times in 80 Posts
Question about braking for turns while hypermiling.

Most every day on my way home, I have a fairly steep down hill S turn followed by a nearly 90 degree right turn up hill.

Hypermiling 101 says stay off the brakes. Brakes eat precious momentum which would largely carry you up that hill.

The problem with this is that following this practice means my tires are howling around that right hand turn. I typically do the downhill in 4th gear in DCO. This provides enough braking that I can negotiate the turn, at the expense of some tire wear. Also, if there is a car sitting at that intersection, the driver may get a bit wide-eyed as some idiot comes barreling straight at him at speed in his Sportwagen.

So the question is do I consume tire or brake pads/diesel? I suspect it probably makes sense to lean towards braking, especially since I have a very efficient engine that absolutely loves to pull hills anyway.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 06-11-2019, 11:31 AM   #2 (permalink)
Redneck Ecomodder
 
Join Date: Feb 2019
Location: North Dakota
Posts: 437
Thanks: 11
Thanked 91 Times in 71 Posts
Quote:
Originally Posted by pete c View Post
Most every day on my way home, I have a fairly steep down hill S turn followed by a nearly 90 degree right turn up hill.

Hypermiling 101 says stay off the brakes. Brakes eat precious momentum which would largely carry you up that hill.

The problem with this is that following this practice means my tires are howling around that right hand turn. I typically do the downhill in 4th gear in DCO. This provides enough braking that I can negotiate the turn, at the expense of some tire wear. Also, if there is a car sitting at that intersection, the driver may get a bit wide-eyed as some idiot comes barreling straight at him at speed in his Sportwagen.

So the question is do I consume tire or brake pads/diesel? I suspect it probably makes sense to lean towards braking, especially since I have a very efficient engine that absolutely loves to pull hills anyway.
Keep in mind that hypermiling always comes secondary to safety. You may be able to pull that corner at speed when it's sunny, 75, with no wind. But what happens if it rained while you were at work and you don't realize that bit of ground is still wet. Or what if someone drove over that piece of ground and their car leaked some oil there? What if there's a little bit of sand/gravel on that stretch?

I would use the transmission to slow down as much as you can (if you have a manual), but definitely don't take corners at top speed, the little bit of fuel you save doing that won't nearly cover the cost if you wipe out just one time.
__________________
  Reply With Quote
Old 06-11-2019, 11:32 AM   #3 (permalink)
EcoModding Apprentice
 
Join Date: Mar 2019
Location: Russellville, KY
Posts: 120

Little Blue Fuel Sipper - '16 Nissan Versa SV Sedan
Team Nissan
90 day: 45.75 mpg (US)
Thanks: 5
Thanked 36 Times in 27 Posts
I hate to use my brakes but sometimes you just have to use them. The road that turns onto the to road I live on if coming from one direction has a hill with a stop sign at the bottom at the intersection going to my house so if I'm coming from that direction I have no choice but to brake and lose the momentum from the hill I just came down. In your case I say brake enough to be safe and save as much momentum as possible.
  Reply With Quote
Old 06-11-2019, 12:20 PM   #4 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

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: 2,373
Thanked 2,172 Times in 1,469 Posts
You might be able to start your downhill at a slower initial speed and so therefore save a little fuel on your last pulse before this combination of curves and a turn on a downhill comes. In other words, recontextualize the combination to include adjustments that will save more fuel before and after it. Definitely do not make a practice of screeching through a hairpin turn. You might also, on the downhill, choose a lower gear to spin the engine faster and therefore the alternator for more DFCO ("free") power generation.
__________________
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 06-11-2019, 02:14 PM   #5 (permalink)
Master EcoModder
 
mpg_numbers_guy's Avatar
 
Join Date: Feb 2018
Location: VA
Posts: 1,363

Toby - '13 Toyota Prius C
90 day: 64.01 mpg (US)

Daz - '15 Mazda 3 iTouring w/ Tech Package
90 day: 38.2 mpg (US)
Thanks: 321
Thanked 480 Times in 365 Posts
Safety first, always!

Try starting your descent at a lower speed. On my drive home, I have a steeper hill, then a steep downhill, then a right turn with a slight uphill about 100 or 200 feet right after the bottom of the steeper hill (2 way stop, I don't have to).

I generally downshift from 5th to third, keep engine load at best BSFC (70%-80% load) and allow my speed to bleed off from 35 mph down to 20-25 mph, then just before the crest of the hill I kill my engine, and am down to 15 mph by the top of the hill, then I roll down the hill and by the time I'm at the bottom (there's a small flat after the hill before the turn) I'm usually at around 20 mph by the time I make the turn. I typically am able to make the turn without using brakes (and then it's 2nd gear half throttle to 30 up the hill, then EOC the next half mile into my driveway).

The key is to be at the slowest possible speed at the crest of the hill. The lower the amount of fuel you use to climb the hill, the less kinetic energy you will have at the bottom that must be wasted either in brake heat or tire wear.

Also keep in mind traffic behind you. My drive home is typically past 10 PM at night when there is pretty much no traffic. Going that slow on the other side of a hill is not safe in heavily trafficked areas.
__________________
2013 Toyota Prius C 2 (my car)


2015 Mazda 3 iTouring Hatchback w/ Tech Package (wife's car)
  Reply With Quote
Old 06-11-2019, 05:50 PM   #6 (permalink)
Moderator
 
Vman455's Avatar
 
Join Date: Feb 2012
Location: Urbana, IL
Posts: 1,935

Pope Pious the Prius - '13 Toyota Prius Two
Team Toyota
SUV
90 day: 51.62 mpg (US)

Tycho the Truck - '91 Toyota Pickup DLX 4WD
90 day: 22.22 mpg (US)
Thanks: 198
Thanked 1,797 Times in 937 Posts
Move to Illinois. We don't have hills. Or curves. Problem solved!
__________________
UIUC Aerospace Engineering
www.amateuraerodynamics.com
  Reply With Quote
The Following 2 Users Say Thank You to Vman455 For This Useful Post:
deluxx (06-11-2019), Fat Charlie (06-15-2019)
Old 06-11-2019, 09:04 PM   #7 (permalink)
Master EcoModder
 
mpg_numbers_guy's Avatar
 
Join Date: Feb 2018
Location: VA
Posts: 1,363

Toby - '13 Toyota Prius C
90 day: 64.01 mpg (US)

Daz - '15 Mazda 3 iTouring w/ Tech Package
90 day: 38.2 mpg (US)
Thanks: 321
Thanked 480 Times in 365 Posts
Quote:
Originally Posted by Vman455 View Post
Move to Illinois. We don't have hills. Or curves. Problem solved!
But then you have the risk of falling asleep on the road from the boring drive! Lol. I-57 going all the way down through Illinois is by far the most boring and sleep-inducing road I've been on. But it is true that there isn't really any downshifting for hills necessary though.
__________________
2013 Toyota Prius C 2 (my car)


2015 Mazda 3 iTouring Hatchback w/ Tech Package (wife's car)
  Reply With Quote
The Following 2 Users Say Thank You to mpg_numbers_guy For This Useful Post:
deluxx (06-11-2019), Fat Charlie (06-15-2019)
Old 06-12-2019, 09:46 AM   #8 (permalink)
Redneck Ecomodder
 
Join Date: Feb 2019
Location: North Dakota
Posts: 437
Thanks: 11
Thanked 91 Times in 71 Posts
Quote:
Originally Posted by mpg_numbers_guy View Post
But then you have the risk of falling asleep on the road from the boring drive! Lol. I-57 going all the way down through Illinois is by far the most boring and sleep-inducing road I've been on. But it is true that there isn't really any downshifting for hills necessary though.
Illinois isn't nearly as boring as driving I29 through North Dakota. Other than where it goes over one railroad, and one spot it goes over the other highway instead of having a normal overpass, and a couple road crossings in Fargo there is literally not a single hill to be seen for the entire length of the state on that road. The Agassiz basin is FLAT
__________________
  Reply With Quote
Old 06-12-2019, 12:11 PM   #9 (permalink)
Master EcoModder
 
Join Date: May 2019
Location: California
Posts: 512

2020 - '08 Chevy Tahoe H
Last 3: 18.4 mpg (US)

2021 - '08 Chevy Tahoe H
90 day: 17.08 mpg (US)

2022 - '08 chevy Tahoe LT
Last 3: 14.38 mpg (US)

2023 - '08 Chevy Tahoe
90 day: 25.57 mpg (US)
Thanks: 2
Thanked 105 Times in 96 Posts
Quote:
Originally Posted by pete c View Post
Most every day on my way home, I have a fairly steep down hill S turn followed by a nearly 90 degree right turn up hill.

Hypermiling 101 says stay off the brakes. Brakes eat precious momentum which would largely carry you up that hill.

The problem with this is that following this practice means my tires are howling around that right hand turn. I typically do the downhill in 4th gear in DCO. This provides enough braking that I can negotiate the turn, at the expense of some tire wear. Also, if there is a car sitting at that intersection, the driver may get a bit wide-eyed as some idiot comes barreling straight at him at speed in his Sportwagen.

So the question is do I consume tire or brake pads/diesel? I suspect it probably makes sense to lean towards braking, especially since I have a very efficient engine that absolutely loves to pull hills anyway.
just fall back to EV mode
  Reply With Quote
Old 06-12-2019, 02:31 PM   #10 (permalink)
Moderator
 
Vman455's Avatar
 
Join Date: Feb 2012
Location: Urbana, IL
Posts: 1,935

Pope Pious the Prius - '13 Toyota Prius Two
Team Toyota
SUV
90 day: 51.62 mpg (US)

Tycho the Truck - '91 Toyota Pickup DLX 4WD
90 day: 22.22 mpg (US)
Thanks: 198
Thanked 1,797 Times in 937 Posts
Quote:
Originally Posted by Shaneajanderson View Post
Illinois isn't nearly as boring as driving I29 through North Dakota. Other than where it goes over one railroad, and one spot it goes over the other highway instead of having a normal overpass, and a couple road crossings in Fargo there is literally not a single hill to be seen for the entire length of the state on that road. The Agassiz basin is FLAT
I drive 57 all the time, and I've driven 29 through ND. I've driven across most of the country, and IMO the most boring stretch of interstate is I-90 across southern Minnesota, hands down.

__________________
UIUC Aerospace Engineering
www.amateuraerodynamics.com
  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