More than likely they are getting about 50-55mpg at that speed . . . is there a minimum speed limit in that lane - take his plate and call it in on a cell phone and for god's sake don't tailgate the jerk or they may slow down even more!!

 

SO were are all those people who claimed that the engine used no gas when engine braking and lambasted me for saying coasting in neutral was better(as far as MPG was concerned)???

 

Bump! For answer to my question?

 

You didn't ask a question. U just made a statement and put a ??? on the end

But as far as which is better, it seems that with actual experience, not just someone that thinks they know everything, neutral shows better mpg than engine braking...
Including me

 

+1, I have no tolerance for rude behavior on the road and will sometimes (unwisely, I know) actually encourage road rage by doing things like boxing in tailgaters instead of going out of MY way to make an open passing space for them.

 

I stumbled across this thread while looking for info about the tC, which I'm thinking about purchasing.

I'm really surprised that most of you don't seem to get this concept. Overrun fuel cutoff has been implemented in fuel injected automobiles for at least 30 years. "Overrun" means the engine is being driven by the wheels. That's what happens when you're coasting in gear, using engine braking. Here's how overrun fuel cutoff works:

Assuming an engine that is warmed up into the normal range of operating temperature, if the throttle is in the idle position, and the engine speed is above about 1400 rpm, the injector duty cycle is zero. There is no fuel flow through the injectors. This is done both to save fuel and to reduce exhaust emissions.

How do I know this? Here's one source, an excerpt from a Bosch Technical Manual entitled Emission Control.

Also, I own a 2003 Audi A4, and a software package for my Palm that enables me to see engine control parameters such as throttle position, fuel flow, mass air flow, etc. Whenever I am coasting in gear with the throttle at idle, there is NO FUEL FLOW until the engine speed falls below 1400 rpm (1200 rpm if the A/C is off).

Actually, in every fuel injected car I've driven since my '86 Prelude Si, I've noticed the effect of the engine turning back on below a certain rpm when coasting down. You can gain a fair amount of fuel mileage around town if you maximize the length of time the engine is in overrun.

Believe me or not, I don't care. I just thought I would try to explain.

 

^^^Thats a great story and all, and it even seems plausible, but not one person has said that they experimented and that they get better gas mileage by riding out the gears. But everyone that has experimented with the neutral coast, swears that they get better gas mileage.
Those that say riding the engine is better only have ideas to back up their opinions
Those that say neutral is better have actually tried it.

And as for the software package you have, lots of us have software and hardware too, that states that we are using less gas and getting better MPGs in neutral.

So who is right??? Maybe its different in different cars? But in my experience, a couple times i did this test where i coasted around in neutral whenever and wherever possible and got 39 mpg, and with engine breaking over the same exact roads (To work and back, and thats it, no joy riding) i only got 32 mpg.

You can show me all the documentation in the world that tells me one thing, but if i go out and try it myself, and i dont see the same results. That documentation means absolutely nothing I trust my experience and not words in a book

 

well, considering ive gotten anywhere from 27-29mpg with 70% city driving lately, i'd say there is a point. nobody wants to go out of their way to try something new most of the time.

driving in gear is something that requires some driving talent. most people can't drive, so results aren't typical. it requires self control, and speed awareness. also gotta know when to use it.

i have great results from it and im very pleased.

 

The ScanGuage I and II that I have says that it is still injecting fuel when I engine brake although I have heard that it does this in error . . . maybe the injectors are firing and the fuel is shut off - I don't know. But I do know that when I want to coast and NOT slow down then I pop it in neutral. I need to use my brakes more anyway because on my last car the rotors actually got thicker with rust from lack of use. Now if I find that on my next tank of gas I use engine braking and get a fuel usage error on the ScanGauge that it indicates I used a lot more gas than the pump says when I fill it then maybe the thing is measuring gas being used when it really isn't during engine braking. The only other way I can tell is maybe some header temperature monitoring or some other type of direct fuel flow monitoring?

 

I think some of you guys also need to consider lurking variables. How do you all normally brake? There's a difference between

1) Always coasting x number of feet, then braking for the last x feet
2) On the throttle for x number of feet, then braking for the last x feet

Possibly what some people here could be doing is instead of doing their normal procedure of being on the gas, then braking when they need to slow down (throwing it in neutral, I assume), to test their neutral theories, they throw it in neutral for the x number of feet they are normally on the throttle.

So what happens? The car is in idle position instead of throttle open position. So naturally, in that case, yes, you would get increased mileage - but that proves nothing.

The only way to see this effect in action is if you ALWAYS coast the same number of feet before begining wheel braking. Then you should see the difference between coasting in neutral vs. coasting in gear.

I'm sorry I wasn't able to explain that clearly (if someone else understood my post, please feel free to clarify), but basically I think I can summarize it like this:

Those who see fuel savings in neutral probably only started coasting in neutral, instead of coasting in gear (before they would only stay on throttle).

Please note this is only a theory, not some attack on everyone.

 

I rarely tail gait people but heck, if you box me in, you are in for some @$$ kicking.And if you think you're just gonna not go home and drive around, I will follow you around till you run out of gas, and then kick your @$$. And if you think you're gonna out run me, wrong again. Go look at my profile. Back to Fuel Milage now.
I know Dr Isotope is a well repescted guy on SL, yet all the "noob experts" berated him with such lame unbased idiotic facts that he left the thread, and hasn't posted in here in weeks. I guess he got tired of trying to tell the blind people there's a hole in front of them. You guys that think engine braking uses no fuel, Do it as much as you can, that way, you can get infinite MPG, so you won't have to fill up again, as long as you're going downhill or stopping. Plus less gas burned means lower demand, and lower prices! Just think, if everyone engine braked, we would save so much gas, we could stop relying on foreign oil!

 

Yeah you are probably right and guys I know with Hondas tell me their injectors shut off on decelleration just like you say but I am not seeing that on my xB AND I would really like too especially when going down hill with the A/C cranked on high but dang if it doesn't add more gas with the A/C on when I want to slow down and I even feel the car decellerate less and go from .2gph to .3gph with my foot off the gas.

 

i think i get what you're saying, and if i do, then i agree totally. the idea is you can coast in neutral much further than you can if you're in gear. so you're starting your coast, IN GEAR, later, meaning your fuel cut off is later, meaning you're on the gas longer.

 

yes you need to know when to neutral it and when to stay in gear. part of knowing how to drive. point is, you can save gas by taking advantage of the fact that no fuel is required at some times. fuel injection is not necessary to generate power. the engine just needs to be spinning up.

 

ironic you're talking about speaking idiotically. dont throw out random sentences you threw together while high in an attempt to sound like you have a point. yes im sure if earth was infinitely downhill, we'd never even need engines. so please, stop posting useless demeaning comments.

 

Whatever fool! You're saying I was high while posting??? You couldn't be more wrong! And the earth is round , so technically it's all downhill. But then, you misunderstood what I wrote, because I said you'd be getting infinite MPG "as long as you were going down hill, or stopping" So don't go off the deep end and put words in my mouth! I never said anything about not needing engines! Don't act like you just shut me up and had a good comeback! You just made up a bunch of random s**t that had little to do with what I said. And I was just saying that if engine braking saves so much gas, and we could convince everyone to do it, it would lower the demand for fuel! You have even admitted yourself that you have no clue about either side and what is right and wrong. Quit straddling the fence and crushing your nuts. Then this thread won't seem so painfull for you! Get off my back!

 

I usually get about 19-20 mpg...

 

49.7mpg driving 88 miles yesterday in my xB - last tank 441 miles 9.745 gallons 45.25mpg average mostly city/country with some highway . . . coast more . . . brake less!

 

Very nice!

 

I really don't care how much mpg they're getting by holding back the rest of traffic. It's funny that very few of these people slow down even more when I tailgate them.

It was great because this weekend I visited my bro and we took his Tundra V8 double cab and I was driving it. Spotted a Prius doing 60mph in the car pool lane and tail gated that piece of crap. Believe me, he moved out of the way. When you have about 8,000lbs with over 300hp (his truck is fixed up) running inches behind you, knowing he'll rip thru you like hot knife thru butter in a collision... they'll move out of the way.