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Old 10-15-2019, 05:48 PM   #1 (permalink)
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Can't do pulse and glide at night?

Hello again all, thank you for your suggestions in the previous thread

I just tried pulse and gliding for the first time and it went pretty well. I'm still a bit wary of clutch wear as it seems changing to neutral and back to 5th every 15 seconds isn't the healthiest thing for the transmission, but I'm willing to give it a try for a tank to see if the difference is significant

I tried doing it tonight at night. My ignition has 3 positions and I ran into a problem.

1. When turning the key from "ON" (where the engine runs) to ACC, the headlights go off, only the sidelights stay on.
2. When putting the key back to "ON" to keep the lights on (necessary for safety), the engine starts up again as you'd expect, clutch depressed or engaged makes no difference.

Therefore I'm limited (without an engine kill switch) to just using neutral when on the "glide" part of the technique. I know neutral uses such a small amount of fuel by comparison to having your foot on the floor, but does this actually net a positive MPG result at the pump? In the day it would definitely be possible to kill the engine because well I don't need the lights and the steering isn't locked, just no power which is fine.

Also I'm just trying to work out my optimum speed. I get:
55mph@ 2600RPM
50mph @ 2400RPM
45mph @ 2200RPM

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Old 10-15-2019, 06:54 PM   #2 (permalink)
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Pulse & glide is not the same thing as EOC, Engine Off Coasting. Instead of just having your foot on the clutch, actually take it out of gear and see if that changes anything.

Neutral works fine- in warm weather at 60 mph, I get 300 mpg in neutral.
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Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 10-15-2019, 07:07 PM   #3 (permalink)
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Quote:
Originally Posted by Fat Charlie View Post
Pulse & glide is not the same thing as EOC, Engine Off Coasting. Instead of just having your foot on the clutch, actually take it out of gear and see if that changes anything.

Neutral works fine- in warm weather at 60 mph, I get 300 mpg in neutral.
I did try with the car in neutral and it just goes back to 1000rpm and sits there when I put the key back to "ON" to reactivate the headlights. I couldn't tell if the engine was actually on but tbh the wear on my battery probably isn't even worth the fuel saving. I'll keep experimenting but I'm still getting 45-47 on an NEDC tested car rated 45.4mpg so I'd say I'm doing very well. Gonna keep trying different speeds and just see what works, and do some pulse and glide with neutral and try to use neutral a bit more strategically as there's a significant difference vs keeping it in gear when it comes to speed reduction time.
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Old 10-15-2019, 07:29 PM   #4 (permalink)
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You have to turn the key to off for a couple seconds to kill the engine, which isn't safe because the steering lock can engage. Then you have to put the key back to run so that it's ready to start once you let out the clutch again.

My concern with wear would be syncros when constantly going from N and back into gear, although I'm not sure if syncros are involved in that or not. Either way, none of the hassle seems worth it to me unless it was a very long engine off coast; like a minute or more.

Cars like the Prius essentially capture most of the advantage of pulse and glide by keeping the engine at an optimal load, and killing it entirely when power requirements are low. After having the Prius, I've got almost no interest in EOC or P&G.
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Old 10-15-2019, 07:39 PM   #5 (permalink)
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Quote:
Originally Posted by redpoint5 View Post
You have to turn the key to off for a couple seconds to kill the engine, which isn't safe because the steering lock can engage. Then you have to put the key back to run so that it's ready to start once you let out the clutch again.

My concern with wear would be syncros when constantly going from N and back into gear, although I'm not sure if syncros are involved in that or not. Either way, none of the hassle seems worth it to me unless it was a very long engine off coast; like a minute or more.

Cars like the Prius essentially capture most of the advantage of pulse and glide by keeping the engine at an optimal load, and killing it entirely when power requirements are low. After having the Prius, I've got almost no interest in EOC or P&G.
Well it's literally impossible to be safe when turning the key to off at night because the lights turn off, and as much as I'm for hypermiling; freaking out other motorists isn't my goal at all. If the police passed me they'd be less than impressed.

I think I'm gonna try experimenting with neutral on longer hills though to be honest as the speed difference is massive with my car. If I stay in 5th on some hills because of my higher RPM's there's more friction I can stay the same speed but if I go into N I can be like 10mph faster than I would be if I was in gear. Surely idling uses such a small amount of fuel over that 20 seconds that it's in N but that extra 10mph gain would give me a significant saving by giving me an extra few hundred meters before having to reapply the throttle.

Guess it's just a matter of seeing what happens. Either way as long as I'm getting 45mpg I'm happy, and I got that having passengers in the car almost every day and they always had the windows down because I was too embarassed to ask them to put them up to save fuel Getting close to the NEDC rating is impossible for your average driver so I'm still feeling pretty good. Also shoutout to Redex as it increased my MPG by 25% on a 100k mile car so it's not just snake oil for everyone.
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Old 10-15-2019, 09:20 PM   #6 (permalink)
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Good move- you've got to be safe. No sense saving some gas if it kills you.

Every car and every road is different. Learn your car on your roads, and do your learning when it's safe. Night and the dead of winter aren't the best times for hypermiling.
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Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 10-15-2019, 09:33 PM   #7 (permalink)
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Quote:
Originally Posted by Fat Charlie View Post
Good move- you've got to be safe. No sense saving some gas if it kills you.

Every car and every road is different. Learn your car on your roads, and do your learning when it's safe. Night and the dead of winter aren't the best times for hypermiling.
Totally agree, it's literally pennies I'm talking at this point and I think the mental stress of being unsafe probably burns more calories, thus requiring more food for me and more spending if we're being really stupidly in detail about it

The only thing I do wonder is whether my car is more efficient at 50mph or 55mph. Being a petrol with optimum torque around 4700RPM thus I'd assume 55mph is better as the air resistance isn't much more but I tend to just sit at 52-53mph to get the best of both. With coasting efficiently though I reckon near 50mpg is in reach, although if not doesn't matter too much. My budget says my car does 40mpg, so every penny I save above that is just a bonus.

Note: The goal is to save on the overall running cost on my vehicle. If I save 50 in a year that's great but a new set of synchros is hundreds, and I've just robbed myself of money for no benefit.
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Old 10-17-2019, 03:56 PM   #8 (permalink)
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Quote:
Originally Posted by dude7691 View Post
Well it's literally impossible to be safe when turning the key to off at night because the lights turn off

So it's impossible to turn the headlights on without the keys in the car? I've never seen any car like that.

Is it possible there's some kind of "automatic" headlight setting? I've seen those before, and they might behave in the way you describe.

What kind of car? Make a garage entry so we have more context, please! Your Garage: [ Add new vehicle ]
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Old 10-18-2019, 05:16 AM   #9 (permalink)
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Steering lock does NOT engage unless key is REMOVED from switch.

Unless this car is some sort of freak or possessed by satin the engine shuts off when you key off. DON'T go back to ACC. It's between OFF, ON, and START, that's IT.
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Old 10-18-2019, 06:32 AM   #10 (permalink)
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The key pattern is OFF - ACC - ON - START on most cars?
AFAIK all cars I had lock the steering wheel in OFF (but not ACC) even with the key inside. My old '85 Civic would even hold on to the key if the steering lock catches a stop so you needed to wiggle the steering wheel to get it out or in.

I tried to EOC my wife's I10 last night, returning from a gas station (she never fills up).
While it does not kill the lights if you switch to ACC it will if you switch it OFF and also if you try to start it using the starter motor... Bump start is fine.
It does burn less bright (i.e. even dimmer) on ACC though, but the engine stalls in a second.
If the I10 was my DD I'd look into wiring an injector kill switch. The safe way to kill the engine.

Every car is different in some aspects of course. Always check before getting towed!

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Last edited by RedDevil; 10-18-2019 at 10:50 AM.. Reason: clarified engine stalling vs. killing lights
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