Dr_Isotope

iTrader: (1)

I'll give that it exists-- but did you notice that according to the graph, DFCO only takes place in the narrow band between 2000rpm and idle? So the trick would be to coast downhill at about 40mph, which would put you in the middle of that band. Any higher, and the injectors will fire back up. I just honestly cannot see such a system having any substantial impact.

edit: but I'm still going to try it. And I have the ScanGauge to tell if it's having any effect at all.

hunterUnknown

iTrader: (1)

I'm not sure how everyone thinks that because the rpms are up, that gas is in use. it's just the ratio of the engine speed to the wheel speed based on which gear you're in. if the gear is engaged, you get an rpm. has nothing to do with gas usage unless you're ON THE GAS.

dont get me wrong, there is no reason you'd coast in gear unless you're good at controlling gas only when you need it, or when you are going down a hill, or guaranteed to come to a stop.

if your wheels are turning your engine because of clutch engagement, there is no necessity for fuel injection unless you need to accelerate. if fuel was entering the chambers and combusting, you need a spark from the computer-controlled ignition system, and thus, engine braking does not occur.

yet amazingly... when you let off the gas your car slows down because of engine resistance vs the momentum of the car while in gear, and thus engine braking. and my proof of turning the key to ACC while coasting works. it shows without throttle and pretty much all the important computer systems, the engine still spins.

but pretend i didnt say anything. i'm anxious to see the results of your testing, to put and end to this, whether i'm right or wrong. if im wrong id like to know the truth as well, but for now thats what ive come to believe from my own learning experiences.

Jayjr

the way i read that is the dfco starts at any rpm above 2k and then turns off at ~2k

the description sais high to moderate rpm's

flintgauge86

No way in hell the engine braking uses ZERO fuel. If that's the case then you could go to the top of a mountain in Colorado, and cruise all the way down in gear, never accelerating, and you would have used NO GAS, even while the tachometer says 2k or something like that. So if it takes no gas to do this, and it takes you an hour to get down the mountain, and since the engine isn't burning any gas, and it might be chilly up there, you'll have the heater on, so theoretically your engine should be cold by the time you get to the bottom of the mountain. Then , THEN go touch the manifold with your bare hands and leave it there for oh, say 30 seconds... and then call me and tell me how your hand feels and how you just got Infinite Miles per gallon cause you burned NO GAS! And , just think how happy this will make all the tree huggers. Zero Emissions.

You guys are full of crap! Quit posting BS that's misleading.

flintgauge86

Secondly, if the engine isn't firing, since you say it uses no gas, and is powered by the wheels, then how come the car won't roll away in gear with no e-brake( same situation, spinning wheels and NO GAS)... Because of the internal friction of the engine keeps the car there. Another thing, if you let the car engine brake all the way back down to idle with you foot off the gas and let if creep in idle is it still using NO GAS? F**K NO! YOU better believe you're burning gas! if you let the clutch out very slowly with no gas, and do it right, you will still be able to move forward, and even accelerate as the ECU tries to get the RPMS back up to idle. IF you let the car creep in gear and then turn the A/C on you'll accelerate too. Why? becuz the ECU wants to keep the Engine at a pre-set RPM. So when you're cruising as 50 and let off the gas, the reason you slow down is becuz the engine wants to go back to idle which it will do if you let (and have room to do so). And all the while, you are burning gas. OMG, that's right, a combustion engine burning gas! WHAT IS THE WORLD COMING TO?

flintgauge86

Shaolin

What the hell are you talking about

If you are engine braking, you are in gear, if you are in gear you will stall, if you are creeping in idle, you are not in gear, and yes you are burning gas.

I'm having trouble seeing your points here.

hunterUnknown

iTrader: (1)

uh no.

please go find a mountain and roll down it in gear and tell me how it goes. im not going to answer something i havent done. though i dont see whats hard to believe about no gas usage. you could very well roll down the mountain in neutral and use no gas witht he car powered off. but thats not too safe is it?

and by the way, if you "slowly let out the clutch while the car tries to idle" you're simply exploiting the idle process until the car gains enough momentum for you to engage the clutch completely.

the car doesnt roll away because yes, the engine resistance is too much. thanks genius. its called engine braking.

dont get cocky. until you've tried doing the things you're theorizing, dont talk.

1badTc2-0

i got 400 miles on my last fillup driving from SD to LA and then back to SD...going 75-80 the 90% whole time + 40 miles of street driving

flintgauge86

I'm saying that if you start out in first gear and let off the gas and let the car pull you around at idle speed(creeping), with your foot off the gas, of course the engine is still burning gas. It is absurbed to think that when you let off the throttle the engine isn't using gas.

flintgauge86

LoL... why would you stall? Maybe if your cars not burning any gas...
Which made me think of something. IF you're on the top of a big hill, and you're going 50, you start down the hill and then run out of gas. Following yalls logic, i should be able to keep on going, as long as I leave it in gear. Right? Is that what you guys are saying here?

hunterUnknown

iTrader: (1)

why not? is your car magically going to just stop dead in its tracks down a hill? go ahead, defy physics :]

id like to know more about this magic engine lock stop the car without brakes feature.

Shaolin

er that is exactly why you would stall... are you trying to tell me that if you are in gear and you let off the gas completely and are at idle speeds you will not stall?

If you are above 2000rpm, going down a hill, with no throttle, in gear, you are engine braking and the engine is turning over via the wheels. Have you even read this thread? o.O

hunterUnknown

iTrader: (1)

in case you forgot sir, a manual transmission car is very, very basic considering how far cars have come in general. its all still very mechanical and simplistic.

its a matter of which force is doing what. if the wheels are connected to the engine via the clutch, and the wheels are spinning faster, the engine will be forced to spin up higher. this causes engine braking.

if the engine is being given gas, it will spin faster, and thus spins the wheels faster. more force. this causes acceleration.

im not sure what you dont get about that. so what is so hard to believe about compression in the engine forcefully occuring? you all do it all the time when you engine brake. there is no other way you CAN engine brake. if fuel was being injected, it wouldnt be happening.

as long as the clutch is engaged, the wheels and engine will synchronize, somehow. period. there is no magical lock once fuel runs out. there is no defying the physical clamp that bonds the wheels and engine together.

as ive said way too many times, and dr isotope will be trying...
COAST IN A STRAIGHT LINE WITH NOBODY AROUND, JUST IN CASE, AND TURN YOUR KEY TO ACC.

flintgauge86

Of course I read this thread... I'm just asking the guys who made the original claim about using no gas when coasting in gear, to restate their claim after reading everything I've posted. IF you want me to turn the car to ACC in gear, why not just put it in nuetral and turn the car off. Cuz you're saying It's the same thing fuel consumption wise, and if you do it my way, it will keep miles off your car.

flintgauge86

And if it's burning no fuel, then you should be getting infinite/miles per gallon!!! And your engine should be cool, since the heat comes from BURNING GAS.

hunterUnknown

iTrader: (1)

grow up. dont act like everything you say put me in my place. you have yet to give any argument backed up with a fact.

there is a difference between shutting off your car and just letting off the throttle. the point of the experiment is to show they are the same thing in terms of fuel usage.

you cant have infinite mpg if your car is coming to a stop since its in gear after all. unless you're rolling down your coveted hill of 50 miles length.

and yes your engine will probably get colder. what a mythical event! temperature change...

io333

Um, you have no clue.

When I lived out near the Sierras, when I went downhill for LONG periods of time (sometimes near an hour), I'd have to take the car out of gear for a while to let the cylinders start firing again while idling, because the engine would start to get cold and my feet would begin to freeze. Of course this was a pain because then I'd be using only the brakes to keep from speeding up too much, and they'd start to get hot and fade. (driving in real mountains has it's trials, ask any trucker). The car was a Saab 900, with far more primitive tech that what the Scion has.

Also, I remember once I was curious as to whether the phenomenon was real, so I switched off the ignition a few times with the car at speed, and in gear. Result? zero difference, nada, zilch. In the old days, switching off the ignition at speed, and then switching it back on again would at the very least make the car buck, and at worst blow apart the exaust system with a gigantic backfire detonating all of the unburned gas in the outflow pipes.

io333

By the way kiddies, if you decide to switch off the ignition to try this out, remember that you'll lock the steering wheel, crash, and die. The Saab had the ignition key correctly placed down by the gearshift where it

1. didn't lock the steering, which is the stupidist thing on earth a car can ever do

2. didn't puncture your knee in a crash.

flintgauge86

The steering wheel won't lock in ACC... is locks in "LOCK"