Best way to improve fuel economy?

[Typrus]

Declaring me expert in all things automotive would be foolish. lol.

It just gets my hackles up when someone comes up and starts trying to call me foolish. Yes, sometimes I am.

Diatribe.. I'll have to look that one up!

But regardless....
Solenoid valves would be sweet... lol. Just have to wait for them to get better developed.

I tend to have huge posts. Not all of them, but quite a few. Doesn't make me smarter, I just talk a lot. Via keyboard and mouth lol.

My 40mpg+ trips were between here and Colorado Springs. Both ways and on every trip I made in that car, which was 4 or 5.

OOOHH.... 3800SC into a Fiero? That'll be sweet!! I'm going to have to look into that. I've seen Caddie engines and SBC's, but oddly never saw a 3800 let alone SC. Maybe I didn't look hard enough.

[keith]

3800 in a Fiero,um. I want to put one in my Nissan truck, I've heard they fit quite well. The only problem is that I have this thing about getting the very last drop of usefulness out of anything I buy and I can't get the damn thing to blow up so I can justify it. I even let my son drive it.

[Snax]

The current EPA mileage numbers for a Dodge Viper are 13 MPH City and 22 Highway. I have never seen a road test where anyone gets more than the EPA highway number.

Road tests however, like EPA mileage figures, are not the real world. I routinely exceed the EPA ratings on my Escort as well as with our Mazda5 and have gas and mileage logs to support that.

Here is a short quiz...

With regards to a modern car, will you save gasoline while coasting with the engine in gear or neutral? Hmmmm

Believe it or not the answer is "in gear." With modern computer controls, the car knows that you are coasting and fuel delivery to the injectors is completely cut off. If you put the transmission into neutral, the engine needs fuel to keep running.

It's really not that black and white. In gear, the engine must spin faster, creating higher internal parasitic drag - that may or may not be with reduced fuel delivery. The fact is, every fuel injected car I have ever driven loses speed faster if left in gear. The difference in injector duty cycle is so small as to not make up for the speed loss - and the advantage of injectors being shutoff usually goes away below a set rpm.

[Ron B.]

The current EPA mileage numbers for a Dodge Viper are 13 MPH City and 22 Highway. I have never seen a road test where anyone gets more than the EPA highway number.

Road tests however, like EPA mileage figures, are not the real world. I routinely exceed the EPA ratings on my Escort as well as with our Mazda5 and have gas and mileage logs to support that.

Here is a short quiz...

With regards to a modern car, will you save gasoline while coasting with the engine in gear or neutral? Hmmmm

Believe it or not the answer is "in gear." With modern computer controls, the car knows that you are coasting and fuel delivery to the injectors is completely cut off. If you put the transmission into neutral, the engine needs fuel to keep running.

It's really not that black and white. In gear, the engine must spin faster, creating higher internal parasitic drag - that may or may not be with reduced fuel delivery. The fact is, every fuel injected car I have ever driven loses speed faster if left in gear. The difference in injector duty cycle is so small as to not make up for the speed loss - and the advantage of injectors being shutoff usually goes away below a set rpm.

I stand by my statements. You may have logs to support your findings but they are not scientific. I believe the results of road tests and documented tests and statements from my aforementioned sources.

Cheers!

Ron B. in Lake George, NY

[Snax]

Miles traveled/gallons consumed = MPG. Over multiple fills (I have six for the last year with the Escort), the statistical margin for error is significantly reduced. I track my mileage at every fill. How much more scientific can you get than that? You are dreaming if you think the car magazines use as much data to come up with their figures. At best, they might fill a car 2 or 3 times - usually with some aggressive driving thrown into the mix.

YOU CAN exceed the EPA estimates. That's really all my point is. One just needs to try - and I do. People don't even really need to resort the more ridiculous stuff that I do like pusle and glide or engine off coasting to do it. It mostly just takes planning ahead and eliminating wasteful habits like idling in the drive through and racing between lights that are timed for slower speeds.

[Ron B.]

....You are dreaming if you think the car magazines use as much data to come up with their figures....

So, your anecdotal "evidence" is better than the laboratory equipment that is used by Consumers Union which tests their cars for many months and for many thousands of miles?????

I give up.

Ron B. in Lake George, NY

[Neu]

It's actually pretty well known that EPA estimates are just that, ESTIMATES. It's easy to get better mileage then those figures, drive very conservatively.

The EPA did just adjust their numbers a few years ago, that's pretty much admitting that their system sucked.

[Ron B.]

It's actually pretty well known that EPA estimates are just that, ESTIMATES. It's easy to get better mileage then those figures, drive very conservatively.

The EPA did just adjust their numbers a few years ago, that's pretty much admitting that their system sucked.

".... It's easy to get better mileage then those figures...." Really? How is it that Consumer's Union has been testing cars for years and can't exceed the EPA numbers?

Do you consider coasting with the engine turned off or the transmission in neutral "conservative" driving? I call that imprudent and dangerous driving. Are you going to inflate your tires to more than the recommended pressures? Sure that will give you slightly better mileage but at what possible cost?

The EPA numbers are determined in a lab on a dynamometer under conditions which simulate temperatures, humidity and other factors. In most cases those numbers are optimistic.

The EPA did NOT simply adjust their numbers! They changed the way they tested by adding new schedules (routines) to the City and Highway tests and the EPA numbers went down. They now test at High Speed, Cold Ambient Temperatures and with Air Conditioning turned on. From those five tests they make detailed comparisons and determine the numbers that you see on the sticker.

They don't check the mileage by filling up the car's tank and seeing how much it takes according to the pump in Wally's Garage. They use scientific measuring devices.

Of course, you can believe what you want to believe.

Cheers!

Ron B. in Lake George, NY

[Neu]

No what I'm saying is that there are millions of environmental and human variables. Maybe the gas the EPA used isn't the same gas that you're using, and your engine happens to drive a little better on it? I know chevron gas for me gets me about 25mpg, but shell nets me at least 28mpg. The air temperature where you live, along with humidity, barometric pressure, weather. It all matters.

I also get 2 to 3 mpg better in the winter then the summer, that's thank to slower driving along with the air temperature.

Going solely off the EPA estimates is just stupid. I haven't really researched their estimates and what they're testing is, but I'm sure it's an average for every different kind of environment. Certain parts of the world will get better mpg based on the environment.

All I'm saying is that going soley off the EPA estimates is just stupid. Your driving style, along with gas quality, and the environment can skew the EPA estimates so far off that you'll think they're doing something wrong. Or you can see the same results as the EPA.

[Ron B.]

This conversation is going nowhere, is pointless and is totally askew of the original intent. I give up.

Ron B. in Lake George, NY

[Neu]

You're giving up because your point is well..pointless. The EPA even says that you may exceed our estimates. Hence your entire argument is not valid.


Also http://www.fueleconomy.gov/feg/findacar.htm

It says anywhere from 22 to 29 mpg for our cars.

I'm pretty sure we have at least 5 members, including me, that beat that on almost every tank. And I'm missing 2 gears.

And even on fueleconomy.gov they let people list their own mpg, because they know people get different results based on so many factors.

[Snax]

This conversation is going nowhere, is pointless and is totally askew of the original intent. I give up.

Ron B. in Lake George, NY

Apparently you gave up well before reading this thread. If we can't beat EPA estimates, then why waste your time reading about trying here?

BTW, there's nothing anecdotal about my gas and mileage logs. It is measured fuel use compared to measured miles traveled. It is what it is.

I take your point and agree with it regarding coasting and turning the motor off etc., but I still consistently beat the EPA estimates without doing that stuff. It boils down to using one's head and anticipating traffic conditions. Driving our Mazda5 with a Scanguage and watching real time fuel consumption data demonstrates things like a 25% higher fuel consumption rate when cruising along at 40 mph in 3rd vs. 5th. Either gear works just fine, however 3rd clearly burns more fuel due to the higher rpms. Even following a semi at a 3 second gap is enough to boost highway economy by 10%, nevermind the act of actually driving slow enough to follow a semi - usually at the posted speed limit.

My point is that the EPA and Consumers Union both assume the idiot factor. In other words, while some people will be able to exceed the average, and most will come close to it, others will fall well under it. That's what an average is, and an average is what EPA and Consumers Union report with those considerations taken.

[Typrus]

Simple statements that apply most of the time with limited exceptions-
Drive hard- fuel economy goes down
Drive easy- Fuel economy goes up.

Now, I think it would be safe to assume that the EPA drives how they believe "everyman" drives. So an average. Not raping tires from stoplight to stoplight, but not taking 3 miles to get up to speed (which actually accelerating too slowly can have adverse effects also) So it would be safe to assume that if they estimate 12mpg for a car, the guy sitting there burning through tires on a weekly basis is going to get worse, and the guy sitting there watching revs and babying it into oblivion will get better.

EPA would logically not test in "absolute best" conditions because quite frankly, that would be unrealistic. Not many people see perfect conditions, let alone create them for themselves. HOWEVER, they likely woulsn't rate on the worst side either, because their rating system would be counted as "too harsh" or the likes. So they go middle ground. Meaning, its possible to both beat and be beaten by EPA.

Actually, if you watch the requested injector duty cycle window in an OBII or CAN interface program, you'll see that on deceleration, in gear (in manuals or upon downshift engine braking in automatics, and provided the revs are "X" above idle requested revolutions) the requested pulse width is 0.00. So nothing being injected. Until the temperature starts to drop off significantly, in which case a slight quantity is injected to keep from completely cooling off. And not all of them do that much.
So, the idea is, if going down a hill, or engine braking, all fuel is cut. Its like turning your engine off, only your alternator keeps charging, your power steering still works, and you are drawing a STRONG vacuum for your brakes. So, turning your engine off would be purely pointless.


Understand also, economy computers, both in cars from the factory, and plug-in types, use a calculation of fuel expected pressure, injector duty cycle, and distance traveled. Based off of the pressure of the fuel, it can be assumed a certain amount of fuel is being injected within "X" pulsewidth. Then it does the simple miles over gallons calculation. While relatively accurate, you will find if checking at the pump and odometer (or better yet, GPS) that it can be significantly off at times.


Understand this about tires-
The max recommended PSI is for a max rated weight. So, one can assume, that if you have 4200lb worth of tire capacity, and the car weighs 2400lbs, which seems relatively typical for us, that going 5PSI over is not going to kill you, unless you dwell near or over the max rated speed.

I have gone through, on our various vehicles, about 10 sets of tires, from the 81 Corolla-Tercels little donut 155/80R13's, to our big trucks 315/75R16's, also on our campers, flatbed trailer, old boat trailer, and new boat trailer (which has 45 profile tires lol) all running 5 PSI over max recommended. No blowouts yet. I have aired down our Truck and Excursion when loading down heavily. I air them down to exactly the max rating.

Our Passat is a good example also. 52PSI rated. I run ~57PSI. Never once have we had a blowout, not caused by 2x6's flying off the backs of trailers at 85MPH on I-25. lol. It handles like a monster, and gets about 52MPG with my folks driving. 44-46 with me driving. Which is an example in of itself of how driving styles affect economy.


I could easily get 100mpg in our Passat. Want to know how? Follow our Excursion about 20 feet back. LOL.

[terceldude]

Simple statements that apply most of the time with limited exceptions-
Drive hard- fuel economy goes down
Drive easy- Fuel economy goes up.

That's the very point I was trying to stress b4! If you drive slower, fuel economy goes up and faster, fuel economy goes down... Like with the Tercel, please don't go over 55mph as it clearly states that in the owner's manual and some people don't even READ the manual... That is sad!!

[tercel4wdrules]

Like with the Tercel, please don't go over 55mph as it clearly states that in the owner's manual and some people don't even READ the manual... That is sad!!

If you try to go 55 mph on a freeway where traffic is flowing at faster speeds, you'll get run over. There is a portion of freeways where the speed limit is 55 mph, everyone is going 60+mph at least. If you're going too slow and impeding the flow of traffic you could be cited. The manual states that 55 mph should be the target speed during the initial break-in period, which should have happened ages ago. Regularly, I try to stay at about 62 mph in the far right lane, and I'm still going "slow".