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I'm guessing this thread wont get too far, but here we go:

Does anyone else hypermile their Elise? If so, when you turn off your engine for long descents:
1. do you put the key back forward one position so that you can see the trip and odometer working? If so, does that matter, will either the trip or odometer continue to advance even with the key in the 1st position (no #s displayed)?

2. At the bottom of the hill, do you push the start engine button or do you bump start it (put car in 6th gear and drop the clutch)?

I am not too interested in the "why would you hypermile an elise" questions. I'm not trying to save $ by daily driving an Elise, nor do I have even a small environmental/green bone in my body. Its easier to explain as a personality quirk.
 

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I don't do this with my Elise, but have been doing this with cars for almost 30 years. I can remember doing it with an MG Midget while on co-op from college (because I ran out of money to pay for college).

It depends. If I need to know how fast I'm going. Say it's a 30mph zone and I can roll down the hill at 50, I'd want to see the speedo and have my radar detector on (previous cars shut off the lighter/radar when the key went to off.

At the bottom of the hill, it depended on what was there. On my daily commute one hill ended at a train track, then a busy intersection. If there were a line of cars there, I'd stop with the car off and not start it until I ran out of hill and there was 20 feet empty in front of me. If I was simply continuing, I would clutch start it.
 

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I'm guessing this thread wont get too far, but here we go:

Does anyone else hypermile their Elise? If so, when you turn off your engine for long descents:
1. do you put the key back forward one position so that you can see the trip and odometer working? If so, does that matter, will either the trip or odometer continue to advance even with the key in the 1st position (no #s displayed)?

2. At the bottom of the hill, do you push the start engine button or do you bump start it (put car in 6th gear and drop the clutch)?

I am not too interested in the "why would you hypermile an elise" questions. I'm not trying to save $ by daily driving an Elise, nor do I have even a small environmental/green bone in my body. Its easier to explain as a personality quirk.
Don't drop the clutch bump-starting, it's too harsh, let it out normally.

Still, with modern cars, I think this is a very silly thing to do. If the RPM is high enough, and you are coasting downhill in gear, it'll actually stop injecting fuel above the minimum RPM, and only start doing it again once you get on the gas or the cat starts to get too cold. I'm not sure if the Elise does this, but most modern cars do. Might as well want to find out before going to excess :)
 

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no engine = no vacuum
no vacuum = no brakes
Elise does not have a vacuum reservoir, so if you use your brakes a few times on that hill, you will get to the bottom and realize that you have no brakes...

Not to mention that coasting down hills in neutral with the engine off is illegal...

As marcinr said the injectors shut off.
 

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it'll actually stop injecting fuel above the minimum RPM... I'm not sure if the Elise does this, but most modern cars do.
It does, my wideband O2 sensor confirms it. When coasting in gear the fuel injectors shut off until ~1500 rpms.
 

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Discussion Starter #6
Great input, thanks.

re: fuel injectors shutting off
- I didnt know that, very good to know. The speed on my daily commute long hill is 60mph and in 6th gear, I couldnt hold 60 if I coasted in gear. So I dont think that is an option for me.

re: brakes
- also interesting. I appreciate that I wont have power assisted brakes but I am not fully appreciating that I would have "no brakes". I recall running my motorhome (1975 GMC, the front wheel drive type) down the Mt.Whitney hill and without a baffled tank, ran out of gas. The brakes are marginal to begin with and it wouldnt stop once the engine cut out but the brakes still "worked", just with out power assist. I was more or less standing on the pedal for a good 5 or so miles coasting at speeds of 45mph for most and then 30mph for the last few minutes. The point is, I had brakes, they didnt drop to the floor, I just didnt have power assist brakes. On the Lotus, I feel no difference once at the bottom of the hill and I have to use the brakes to keep from speeding.

re: bump start
- Yes, I gradually let it out to start it but have since been pushing the button at the bottom of the hill.

If you read about a totaled lotus going down Valley Center grade in San Diego, then you can put it all together for folks.
 

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If you turn the key to 'off' position, won't you potentially activate the steering wheel locking mechanism, say for example, if you need to make a lane change maneuver?
This.

Seriously, this is stupid, I don't care about your damn personality quirk. Don't turn your car off while its traveling 60mph, making it a battering ram. Stupid, seriously. No brakes, potential steering lock and possible damage to engine on restart in gear.

If you want to play with gas mileage numbers, just coast down the hill. It takes more gas to start an engine than let one idle anyway.
 

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This.

Seriously, this is stupid, I don't care about your damn personality quirk. Don't turn your car off while its traveling 60mph, making it a battering ram. Stupid, seriously. No brakes, potential steering lock and possible damage to engine on restart in gear.

If you want to play with gas mileage numbers, just coast down the hill. It takes more gas to start an engine than let one idle anyway.
+1

Hypermiling is stupid. So unsafe! Go buy a bicycle if you're that concerned about saving money on fuel!
 

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It takes more gas to start an engine than let one idle anyway.
That was mainly back in the day with carbs and an accelerator pump guy...not FI...


No, the steering lock is only released once the key is pulled out of the ignition, you generally hear it as well. Try it in your car later, put the key in, turn the ignition and then turn it off but don’t remove the key, the steering lock will still be disengaged.

But the brakes is an important point to remember, if you have a small vacuum leak then you may get a big surprise. but as soon as you put it in gear and let the clutch out (even if it does not fire) and have the engine rotating then you will almost immediately get your brakes back.
You won’t have no brakes with no vacuum but you going to have to stand on that pedal as hard as you can in order to have some braking effort...(type of pad makes a big difference here)

And by the way, that factory down force (and associated drag) our cars come with really slows them down a lot when you freewheeling. On the same hill my lotus slows down to 95km/h where as my beetle slows down to 105km/h or less and the A4 I drive speeds up to 130km/h and my old Porsche 924 would get up to around 135km/h. The Elise sucks at hypermiling (I just take the car out of gear, I do not actually turn it off for any of those). I actually only do all these "tests" to see what the out come is. Also played a little with tyre pressures...
 

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This is a photo my girlfriend took at the end of a 35 mile drive, down hill, while I was driving our 2012 Honda Fit.

We filled up in town and cruised 35 miles after zeroing the computer.

Granted, it is not the same car you ask about; it has a 1.5 L motor, and is 2500lbs curb, ... but this was accomplished with the engine on and treating her as gently on the throttle as I possibly could.




Is it possible I could have had better mileage with engine off? Likely (although computer would be off) .... but I can live with this result!



.
 

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So dangerous. I would never do anything mentioned in this thread. It's not worth it.
 

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Would people stop posting "no brakes" please. People read these things and may actually believe you are correct. Stuff like this contributes to the idiots who make CNN drivng tens of miles with a stuck accelerator for fear (or lack of intelligence) of switching off the engine. With the engine off you loose the vacuum brake assist which does nothing to the mechanical connection between the brake pedal and the pads which touch the disks and make you stop. Christ, I had a 4000lb Dodge with drums all the way around and no power brakes. Push the pedal and it slows, want to slow faster? Push the pedal harder! But yes, switching off the engine seems quite pointless.
 

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:huh::huh: why....:confused:
 

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Would people stop posting "no brakes" please. People read these things and may actually believe you are correct. Stuff like this contributes to the idiots who make CNN drivng tens of miles with a stuck accelerator for fear (or lack of intelligence) of switching off the engine. With the engine off you loose the vacuum brake assist which does nothing to the mechanical connection between the brake pedal and the pads which touch the disks and make you stop. Christ, I had a 4000lb Dodge with drums all the way around and no power brakes. Push the pedal and it slows, want to slow faster? Push the pedal harder! But yes, switching off the engine seems quite pointless.
Obviously it's not "no brakes". I didn't mean to imply that the brakes fall out of the car....

Your example of a 4000 lb Dodge with non-boosted brakes isn't applicable either. A vehicle that was designed not to have boosted brakes will have much more mechanical advantage from a manual hydraulic master cylinder. A car like the Elise or my Esprit, which were designed to have vacuum boosted brakes, will take much much more pressure on the pedal to stop if the vacuum has been depleted. My Esprit is 2700lbs, and uses a mechanical vacuum pump since the turbo engine doesn't develop consistent vacuum. That vacuum pump died on me, while I was driving, and I could barely stop the car in time from 45mph!!! Almost went right through the red light.

I've had the same thing happen on an '83 Bronco with vacuum boosted brakes, the engine stalled while coming to an intersection. I had to stand on the brake pedal with both feet while almost ripping the steering wheel off... And that was from 30mph.
 

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Just as a clarifying point, you don't lose vacuum and power brakes immediately. Until you use up the stored vacuum, the power brakes work fine. But be aware that when the vacuum goes, it is very fast.
 

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Your example of a 4000 lb Dodge with non-boosted brakes isn't applicable either. A vehicle that was designed not to have boosted brakes will have much more mechanical advantage from a manual hydraulic master cylinder.
Negative. For my Dodge the only difference is one has the vacuum booster and the other does not. Significant amount of cars through into the 70s were this way. All parts the same and, including the cars you listed, all of them have the capactiy to lock the brakes or trigger the ABS unboosted. As you experienced, push harder same results. My point was by most of the replies it was not obvious you would not lose your brakes. Guaranteed a chunk of the few hundred people who have read this thread so far were left wondering if their car would lose braking if the engine died which it will not.
 

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As Jack FFR1846 clarified, you won't lose vacuum immediately. It will work for a few applications of the brake pedal. however on a long hill, such as the kind of hill that a "hypermiler" would turn the engine off for, it is conceivable that a person might actually have to apply the brakes several times down such a hill. The brakes might work fine a few times, and then they will suddenly get a lot firmer and take a lot more pressure to bring the car to a safe stop. Many people will not expect or be ready for this!

Now this is for holding a vehicle stationary, not slowing a car down, but tjis is a modern vacuum assisted car, and this shows how much more force is required without vacuum assist.
The amount of brake pedal force required to hold the test vehicles stationary with a wide open throttle ranged from 15.0 lbs. to 43.6 lbs with vacuum assist, well within the braking capabilities generated by the vast majority of, if not all, drivers. Without vacuum assist, the brake pedal force required to remain stationary increased substantially to a range from 86.7 lbs to 268.2 lbs.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&ved=0CGQQFjAI&url=http://www.nhtsa.gov/staticfiles/nvs/pdf/NHTSA-Toyota_vehicle_characterization.pdf&ei=adRtUN5JhL7JAbPggeAK&usg=AFQjCNFdRBLFdcjbBUOWDOoWu7roU6qzYw&sig2=zVQqDzHF70Zd7PMAOFjZ5A
 

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Negative. For my Dodge the only difference is one has the vacuum booster and the other does not. Significant amount of cars through into the 70s were this way. All parts the same and, including the cars you listed, all of them have the capactiy to lock the brakes or trigger the ABS unboosted. As you experienced, push harder same results. My point was by most of the replies it was not obvious you would not lose your brakes. Guaranteed a chunk of the few hundred people who have read this thread so far were left wondering if their car would lose braking if the engine died which it will not.
I think the point that Vulcan Grey was making is that vehicles designed without servo-assisted brakes have a greater mechanical advantage than those with.
I remember well when servos were an extra, they reduced braking effort and were very popular with women, I recall. But that was before assisited braking became the norm.
 

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And he is correct about an increased effort which may be a dangerous surprise to the OP. I just wanted to be sure someone experiencing 2ZZ stalling issues or the like was not freaked by this:

no engine = no vacuum
no vacuum = no brakes
 
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