I now live in very hilly area: narrow roads, very curvy, hairpins, steep gradients, speeds rarely above 35mph.
Wear & tear is high: you spend a lot of time on the brakes as you slow on a downhill, or for a curve, or for a stop sign at the bottom of a hill. And of course the transmission never gets a chance to stay long in any ratio; it's all upshifting & downshifting.
So things are very different from the flat suburban environment I was in before, & I've noticed my fuel consumption has increased.
Would a hybrid make sense? I know the stereotypical use case for them is that, to maximize their advantages, their best application is for heavy stop-start urban traffic. But I'm thinking one would also work here: torquey electric motor for low speeds & all that regenerative braking.
Thoughts?
Quote from: Morris Minor on December 14, 2017, 06:13:04 AM
I now live in very hilly area: narrow roads, very curvy, hairpins, steep gradients, speeds rarely above 35mph.
Wear & tear is high: you spend a lot of time on the brakes as you slow on a downhill, or for a curve, or for a stop sign at the bottom of a hill. And of course the transmission never gets a chance to stay long in any ratio; it's all upshifting & downshifting.
So things are very different from the flat suburban environment I was in before, & I've noticed my fuel consumption has increased.
Would a hybrid make sense? I know the stereotypical use case for them is that, to maximize their advantages, their best application is for heavy stop-start urban traffic. But I'm thinking one would also work here: torquey electric motor for low speeds & all that regenerative braking.
Thoughts?
Weren't you driving a Prius?
Quote from: Rockraven on December 14, 2017, 06:57:16 AM
Weren't you driving a Prius?
I was until about two years ago - it's now owned by my daughter out in Texas.
Quote from: Morris Minor on December 14, 2017, 07:53:56 AM
I was until about two years ago - it's now owned by my daughter out in Texas.
Well, being one of the few here with real world hybrid experience, you're probably the best qualified to answer your own question.
A forum discussion that may be informative...http://gm-volt.com/forum/archive/index.php/t-6989.html (http://gm-volt.com/forum/archive/index.php/t-6989.html)
Hybrid would certainly save on brake pad wear. That said, while you will be reclaiming energy going down the hills, you'll be consuming it again when you inevitably go back up them on your return trip. And your consumption should exceed your regeneration.
Most any modern, fuel injected engine I'm familiar with will basically shut the fuel injectors off under engine braking. You should be getting pretty good mileage going down those hills unless your gearbox is holding a high gear or decoupling the torque converter and idling. Manually selecting a lower gear, or just holding gear, should help fuel economy in that case.
I'm intervening far more with the gear shifting that I did. The G37's transmission is not terrific at the best of times and it gets completely discombobulated in the terrain here. So I shift it in to "S" mode and hold gears on the downslopes to get engine braking. Nevertheless the brakes are taking a beating like they never had when I was in the suburbs.
So I was thinking the downhill regen would be a plus. However a hybrid's ICE still has to lug the motors & battery pack on the uphills.
Brakes are designed to bring a vehicle from 100mph to zero multiple times a day for over 50,000 miles. The hills'o'Georgia shouldn't be having any noticeable impact on wear.
One common mistake people make while braking is to be too easy with them, causing them to both stay on brake for longer than necessary and give their strongest pulse at the end of the maneuver. What you want to be is firm, brief, and "lifting off" as opposed to "digging in."
Get a manual and don't worry about the brakes. :thumbsup:
My brother drove his Prius all around central WA, which is extremely hilly, and got great fuel economy. :huh:
I always get fantastic fuel economy when I drive through the Rockies.
Interesting question. Interesting results.
Quote from: Tave on December 14, 2017, 10:14:56 AM
Brakes are designed to bring a vehicle from 100mph to zero multiple times a day for over 50,000 miles.
Not on a street car. I don't do that and my front rotors are toast after about 20% of that mileage.
I think this application would be perfect for a hybrid. There is a ~4 mile loop around my subdivision with no stop signs or lights, but a shit load of hills. I've got as much as ~50MPG in the G on that loop on fresh MPG reads. With what he will capture from regen he should be able to sip fuel and save his brakes. I think the hybrid move is the right one.
Quote from: 12,000 RPM on December 14, 2017, 12:30:48 PM
Not on a street car. I don't do that and my front rotors are toast after about 20% of that mileage.
Rotors every 10k? You really do drive like an asshat, don't you. :nutty: :lol:
Dragging brakes to maintain speed down a hill is one of the most surefire ways of burning them out quickly. Hell, it's one of the best ways to experience sudden brake failure.
There's a huge difference in the heat/cool cycle between a sudden stop from any speed and a slow grind down a hill.
Quote from: giant_mtb on December 14, 2017, 12:43:56 PM
Rotors every 10k? You really do drive like an asshat, don't you. :nutty: :lol:
Either he's really exaggerating, or you're 100% correct.
A hybrid would work nicely. Plus, you could feel completely superior to those Neanderthals that drive lifted 4x4 diesel trucks. :lol:
Quote from: shp4man on December 14, 2017, 01:21:16 PM
A hybrid would work nicely. Plus, you could feel completely superior to those Neanderthals that drive lifted 4x4 diesel trucks. :lol:
Lots of trucks around here. I'd have to put an NRA sticker on the back of my hybrid to ward off harassment from the wispy-beard-&-meth-mouth crowd.
Quote from: Soup DeVille on December 14, 2017, 01:09:24 PM
Either he's really exaggerating, or you're 100% correct.
Probably both.
Quote from: Soup DeVille on December 14, 2017, 01:07:38 PM
Dragging brakes to maintain speed down a hill is one of the most surefire ways of burning them out quickly. Hell, it's one of the best ways to experience sudden brake failure.
There's a huge difference in the heat/cool cycle between a sudden stop from any speed and a slow grind down a hill.
Reminds me of a vacation I took in Gatlinburg a couple of summers ago. We were staying at a place right on the edge of town, right at the entrance to the Smoky Mountain Park. All those lush pines, but all you could smell was burning brake pads from people riding their brakes down the long decent from the mountains into town.
Quote from: MX793 on December 14, 2017, 06:40:12 PM
Reminds me of a vacation I took in Gatlinburg a couple of summers ago. We were staying at a place right on the edge of town, right at the entrance to the Smoky Mountain Park. All those lush pines, but all you could smell was burning brake pads from people riding their brakes down the long decent from the mountains into town.
:lol:
I've driven there and it's 5x worse between Park City and SLC, Utah. Sometimes you get inexperienced semi drivers that smoke up the entire canyon.
Just get a manual and engine that shit down.
Quote from: Xer0 on December 14, 2017, 07:19:04 PM
Just get a manual and engine that shit down.
Don't need a manual for engine braking, why do people keep repeating this?
Quote from: Soup DeVille on December 15, 2017, 04:18:02 AM
Don't need a manual for engine braking, why do people keep repeating this?
Engine braking in most autos I've driven is far reduced compared to any MT car I've own. If I let off the gas in my Jetta to try to engine brake, it will either upshift or outright decouple the torque converter so the only "braking" I get is from the rolling resistance of the wheels. Even if I put it in Tiptronic and force it into a lower gear, the amount of braking is far less than I'd get out of any MT car I've ever driven. I have to shift down into 2nd at 40 mph to get the same kind of engine braking that I'd have gotten in 3rd or even 4th in MT cars I've owned.
Bolt and the new Leaf regen makes brake wear a non issue.
Quote from: Soup DeVille on December 15, 2017, 04:18:02 AM
Don't need a manual for engine braking, why do people keep repeating this?
Quote from: MX793 on December 15, 2017, 05:45:44 AM
Engine braking in most autos I've driven is far reduced compared to any MT car I've own. If I let off the gas in my Jetta to try to engine brake, it will either upshift or outright decouple the torque converter so the only "braking" I get is from the rolling resistance of the wheels. Even if I put it in Tiptronic and force it into a lower gear, the amount of braking is far less than I'd get out of any MT car I've ever driven. I have to shift down into 2nd at 40 mph to get the same kind of engine braking that I'd have gotten in 3rd or even 4th in MT cars I've owned.
Somewhere I've read few times that it's better to wear out your brakes faster than it is to put stress on your transmission from engine braking. Is this not true?
Quote from: veeman on December 15, 2017, 08:03:44 AM
Somewhere I’ve read few times that it’s better to wear out your brakes faster than it is to put stress on your transmission from engine braking. Is this not true?
Hard shifts would be bad, it is indeed easier to change brakes than transmissions.
But if you shift properly (not slamming gears or massive downshifts at high RPMs) transmission should be fine. With bicycles and cars- always downshift before you need to.
Quote from: MX793 on December 15, 2017, 05:45:44 AM
Engine braking in most autos I've driven is far reduced compared to any MT car I've own. If I let off the gas in my Jetta to try to engine brake, it will either upshift or outright decouple the torque converter so the only "braking" I get is from the rolling resistance of the wheels. Even if I put it in Tiptronic and force it into a lower gear, the amount of braking is far less than I'd get out of any MT car I've ever driven. I have to shift down into 2nd at 40 mph to get the same kind of engine braking that I'd have gotten in 3rd or even 4th in MT cars I've owned.
Yes, absolutely you need to shift down manually, be it tiptronic (useless in all forms), or regular AT.
Is it less? sometimes. Do you sometimes need to hit the real brakes to downshift, then let it ride? Yes; this is basic stuff though.
Who cares what gear you need to put it in? Unless you're going under about 10 MPH, there will be a gear that will hold you at a safe speed
Quote from: veeman on December 15, 2017, 08:03:44 AM
Somewhere I've read few times that it's better to wear out your brakes faster than it is to put stress on your transmission from engine braking. Is this not true?
It's absolute balderdash.
Dangerous and irresponsible shite.
Quote from: mzziaz on December 15, 2017, 06:55:26 AM
Bolt and the new Leaf regen makes brake wear a non issue.
It's definitely an issue here: I know my brake rotors are starting to warp.
Quote from: Soup DeVille on December 15, 2017, 09:11:25 AM
Yes, absolutely you need to shift down manually, be it tiptronic (useless in all forms), or regular AT.
Is it less? sometimes. Do you sometimes need to hit the real brakes to downshift, then let it ride? Yes; this is basic stuff though.
Who cares what gear you need to put it in? Unless you're going under about 10 MPH, there will be a gear that will hold you at a safe speed
People tend to look at you funny when your car is winding out at 5K+ RPM as you coast to a stop? There are a number of hills around here where I can downshift from 6th to 5th or 4th in my Mustang and hold speed down the entire hill without touching the brakes. My VW won't, even when manually shifted into the lowest gear possible for the speed I'm traveling.
You don't engine brake to a stop; it doesn't work that way.
Why do i get the feeling you're missing something totally here?
Quote from: Soup DeVille on December 15, 2017, 09:52:33 AM
You don't engine brake to a stop; it doesn't work that way.
Why do i get the feeling you're missing something totally here?
I obviously use the brakes at some point if I'm stopping. I engine brake as much as possible. If I see a traffic light turn yellow ahead and I know I'm going to hit it while it's still red, I let off the gas and start engine braking. I only touch the brake pedal once speeds are low enough that engine braking isn't doing anything for me, or if there's another car ahead slowing more than I am and I can't get enough engine braking to avoid a collision. I don't get the decel out of the VW than I do/did in any of my MT vehicles even when manually shifting the auto. Same can be said of any auto I've driven.
It's easier and cheaper just to use the brakes. Long downhills are good for O/D off or lower gears, though.
The Subaru's CVT is worthless for engine braking. It makes a lot of ugly boxer noise, but doesn't slow down the car much at all.
A carb'd manual trans car can basically come to a complete stop without touching the brakes
Quote from: MX793 on December 15, 2017, 10:05:27 AM
I obviously use the brakes at some point if I'm stopping. I engine brake as much as possible. If I see a traffic light turn yellow ahead and I know I'm going to hit it while it's still red, I let off the gas and start engine braking. I only touch the brake pedal once speeds are low enough that engine braking isn't doing anything for me, or if there's another car ahead slowing more than I am and I can't get enough engine braking to avoid a collision. I don't get the decel out of the VW than I do/did in any of my MT vehicles even when manually shifting the auto. Same can be said of any auto I've driven.
See, there it is.
I'm not talking about using engine braking to slow or stop the car, but to maintain speed on a downhill slope; since the question in the thread was about hills, I'd have thought that obvious.
I don't know why one would do as you're describing, or what the advantage is.
Quote from: Soup DeVille on December 15, 2017, 10:45:42 AM
See, there it is.
I'm not talking about using engine braking to slow or stop the car, but to maintain speed on a downhill slope; since the question in the thread was about hills, I'd have thought that obvious.
I don't know why one would do as you're describing, or what the advantage is.
Do you not downshift when coming to a stop even on level terrain?
Quote from: Soup DeVille on December 15, 2017, 10:45:42 AM
See, there it is.
I'm not talking about using engine braking to slow or stop the car, but to maintain speed on a downhill slope; since the question in the thread was about hills, I'd have thought that obvious.
I don't know why one would do as you're describing, or what the advantage is.
Saves on brakes and fuel?
Clearly, if the car doesn't offer much engine braking on flat ground, it's not doing much to hold speed on downhills either. There's a fairly large hill not far from here that, at its steepest, is roughly 10% over just shy of a mile. Speed limit is 55. On my MT cars, I could downshift one gear at the top of the hill, traveling 55 mph, and I might have to just touch the brakes near the bottom to keep from going over 70. Even downshifting 3 gears at the top of the hill, I have to apply a fair bit of brake on the VW to keep it under 70 starting before I've even made it halfway down the hill.
Quote from: FoMoJo on December 15, 2017, 10:51:23 AM
Do you not downshift when coming to a stop even on level terrain?
To stay in the proper gear, not to slow the car.
And of course in an automatic, no, no I don't. And neither does anybody else.
Quote from: MX793 on December 15, 2017, 10:55:45 AM
Saves on brakes and fuel?
Clearly, if the car doesn't offer much engine braking on flat ground, it's not doing much to hold speed on downhills either. There's a fairly large hill not far from here that, at its steepest, is roughly 10% over just shy of a mile. Speed limit is 55. On my MT cars, I could downshift one gear at the top of the hill, traveling 55 mph, and I might have to just touch the brakes near the bottom to keep from going over 70. Even downshifting 3 gears at the top of the hill, I have to apply a fair bit of brake on the VW to keep it under 70 starting before I've even made it halfway down the hill.
Does it work at all?
Your VW would be an exception, not a rule then, and may have more to do with the engine than the transmission. As I've studiously avoided modern VWs for a few years now, so I'll have to trust you there. I've gone down the Pikes Peak road in a number of different cars, most of them automatic, and have very rarely had to use the brakes to do anything other than stop.
There's certainly some engine braking. Following other people in autos that don't downshift for hills, I'm probably on the brakes less.
Like I said, I'll have to take your word for it.
But I've never driven a car, automatic or manual, that could not maintain any reasonable speed (over about 15 MPH) on any slope (that would be considered an actual road) under engine braking alone, and I would consider any car that couldn't to be dangerous.
Quote from: Morris Minor on December 15, 2017, 09:16:38 AM
It's definitely an issue here: I know my brake rotors are starting to warp.
What I mean is that on those cars you can use the excess energy from going downhill to charge the battery instead of putting wear on the brakes.
http://www.youtube.com/watch?v=XjmeaufF6ZM
This is all very interesting to me. Having driven an MT Beetle for 3 years and putting 75,000 miles on it and currently an MT Crosstrek and putting 25,000 miles on it I rarely straight downshift from a higher gear to maintain speed or slow down when going downhill. If I'm at 80 mph on the highway and the road dips down and I want to maintain speed or slow down, I'll tap the brakes with or without the clutch until I'm at the speed I want to be. In the Beetle if I was still above 50 mph, I'd keep it in the same 6th gear. In the Crosstrek if I'm above 40 mph, I'd keep it in the same 5th gear (it's a 5 speed). If it's a long and steep hill, which I rarely drive on in my commute, I'll hit the brakes and clutch until I get to the speed I want to be, and then downshift. I found that if I downshifted straight without tapping the brakes and I'm already going 65-80mph, the tach would jump to 4 or 5 thousand RPM and the engine would make a racket.
Course I don't regularly drive very steep hills typically.
Yes, of course one has to blip the throttle when downshifting.
One should NEVER ride the brakes to maintain speed down a hill for any amount of time.
Engine braking is friend off road.
And on motorcycle. High compression + next to no mass = only use brakes to stop
Brake to slow down, downshift to prevent speeding back up.
Quote from: AutobahnSHO on December 17, 2017, 10:15:40 AM
Brake to slow down, downshift to prevent speeding back up.
Poke the brake, declutch, blip the throttle, shift down, engage. Should be as automatic as scratching our nose.
Quote from: FoMoJo on December 17, 2017, 03:16:47 PM
Poke the brake, declutch, blip the throttle, shift down, engage. Should be as automatic as scratching our nose.
Yup.
Quote from: FoMoJo on December 17, 2017, 03:16:47 PM
Poke the brake, declutch, blip the throttle, shift down, engage. Should be as automatic as scratching our nose.
I would think so.
Yet, one guy claims you can do 100 MPH panic stops several times a day, and your brakes will last 50,000 miles. The next replaces the rotors every 10,000 and drives normally. Then the next guy says engine braking is a gas saving technique, and several say it can't be done on an automatic.
Who knows what the next crazy thing to be said will be?
LOL the road in front of my house goes from the base-standard 35mph to 25mph because of some soccer fields. And it's downhill, with wide wide shoulders. It's really too low a limit so people zip up and down it at 35-40mph all day long. So the MPs like to camp at the top of the hill.
Odyssey has 3spd Auto plus Overdrive. Putting it into regular "D" doesn't slow it at all, often when I come home I shift down to "2" and it slows and maintains 26mph until the hill flattens out. No brake lights for cops. Autos do indeed engine brake if you downshift, but most people are freaked out by it because they never rev their car very high so the sudden downshift to high RPMs "isn't normal".
Quote from: mzziaz on December 16, 2017, 03:48:59 AM
What I mean is that on those cars you can use the excess energy from going downhill to charge the battery instead of putting wear on the brakes.
I enjoyed this review of the Nissan Leaf 2.0. The guy had a hard time adjusting to its one-pedal regen braking.
https://youtu.be/xOJyiKy0MOQ (https://youtu.be/xOJyiKy0MOQ)
The Outback cruise control is great. The CVT gives it a lot of flexibility to engine brake, and then it'll actually hit the brakes if the EB isn't doing the job, which happens surprisingly seldomly.
My A4 used to hit the brakes while using CC if necessary. Wasn't programmed very well, though. If the brakes came on, it was a jolt and not a gentle application as you'd do yourself.
Quote from: Soup DeVille on December 18, 2017, 07:10:21 AM
I would think so.
Yet, one guy claims you can do 100 MPH panic stops several times a day, and your brakes will last 50,000 miles. The next replaces the rotors every 10,000 and drives normally. Then the next guy says engine braking is a gas saving technique, and several say it can't be done on an automatic.
Who knows what the next crazy thing to be said will be?
I didn't say panic stops, I said 100mph (very slight hyperbole) to zero, which is exactly what happens in and around a lot of large cities during popular commuting times.
I agree that a lot of people fry their brakes on sustained, steep descents (like Pike's Peak you mentioned earlier). Descent control is a very good skill to practice for the health of your vehicle. I'm just saying—if the brakes can handle a 1/4-mile long 80-0 stop on the I-XX every morning; a steep residential neighborhood shouldn't have more than a minimal impact on the lifespan of the part.
I'm not aware of any cars other than hypercars which recommend 10K brake replacements.
Quote from: Soup DeVille on December 15, 2017, 09:11:25 AM
Yes, absolutely you need to shift down manually, be it tiptronic (useless in all forms), or regular AT.
Is it less? sometimes. Do you sometimes need to hit the real brakes to downshift, then let it ride? Yes; this is basic stuff though.
Who cares what gear you need to put it in? Unless you're going under about 10 MPH, there will be a gear that will hold you at a safe speed
I have noticed that generally auto trucks and SUVs are better at engine braking than cars are, so there's that.
Quote from: CaminoRacer on December 15, 2017, 10:41:42 AM
A carb'd manual trans car can basically come to a complete stop without touching the brakes
I had a couple of shitty carbed manual cars with such terrible compression that they wouldn't even stay stopped on more than a few percent grade without brakes. :lol:
Broken parking brakes, too...
Quote from: Rupert on December 21, 2017, 06:44:44 PM
I have noticed that generally auto trucks and SUVs are better at engine braking than cars are, so there's that.
It generally tracks with displacement. I mean, lots of other factors are there too, but a bigger engine means more engine braking.
Quote from: Rupert on December 21, 2017, 06:44:44 PM
I have noticed that generally auto trucks and SUVs are better at engine braking than cars are, so there's that.
I've noticed this as well. I imagine it's programming for towing/load purposes or just the nature of larger engines.
Quote from: giant_mtb on December 21, 2017, 11:07:26 PM
I've noticed this as well. I imagine it's programming for towing/load purposes or just the nature of larger engines.
Big pistons + more pistons = more vacuum when you shut the throttle. And more surface area along the cylinder walls to create friction.
Edit: although I'm not positive that larger pistons = more braking force if the compression ratio is the same as a smaller displacement engine.
Slow down? Hit the Jake!
Quote from: Soup DeVille on December 21, 2017, 07:05:14 PM
It generally tracks with displacement. I mean, lots of other factors are there too, but a bigger engine means more engine braking.
Yes. Weight, displacement and compression ratio. My Sunbeam Tiger would skid the rear wheels if I tried to gear down into second without proper coordination of engine revs and speed. Don't think I tried it too often. Even third was a bit dicey if I was going a bit fast.
Quote from: FoMoJo on December 22, 2017, 03:03:34 PM
Yes. Weight, displacement and compression ratio. My Sunbeam Tiger would skid the rear wheels if I tried to gear down into second without proper coordination of engine revs and speed. Don't think I tried it too often. Even third was a bit dicey if I was going a bit fast.
Sunbeam Tiger, eh? I applaud your exquisite taste. :golfclap: .
At Brit car shows people ignore the hordes of lowly MGBs & gather round the Alpines & Tigers.
Quote from: FoMoJo on December 22, 2017, 03:03:34 PM
Yes. Weight, displacement and compression ratio. My Sunbeam Tiger would skid the rear wheels if I tried to gear down into second without proper coordination of engine revs and speed. Don't think I tried it too often. Even third was a bit dicey if I was going a bit fast.
I chewed the hell out of my motorcycles back tire on my last track day. Only 649cc but I think it has 11:1 compression and only weighs 700lb with me on it. They make clutches that slip on back torque for motorcycles
Quote from: 12,000 RPM on December 27, 2017, 10:34:19 PM
I chewed the hell out of my motorcycles back tire on my last track day. Only 649cc but I think it has 11:1 compression and only weighs 700lb with me on it. They make clutches that slip on back torque for motorcycles
Factory tire size on a Tiger was only 155 wide. I think they had an open diff, too. Throw in the crappy, low-grip bias plies of the era, and it wouldn't be hard to get it to slip a tire either on acceleration or under engine braking.