My theory on fuel mileage...........

[MountaineerGreen]

I am by no means old by most anyones standard, though I have owned several vehicles for a person my age, and driven virtually every kind of vehicle from vintage to the newest, most modern vehicles.

In the years past, fuel mileage wasn't a concern for me, I don't believe I ever checked my mileage on my first truck, a 1990 Ford Ranger. It didn't matter, I needed gas, I got gas. It was barely over $1 a gallon, $20 would fill it up.

My second car I checked mileage occasionally, but only for an indicator of how the engine was running. Now, I check my mileage at every tank.

Anyway, back to my theory, spurred on my Geralds post in Al's HHO thread. He said something about his old Honda cars getting 40+ mpg all the time. How can this be?? :scratch:

Let's go back a bit to the 60's, when the muscle car era came about. Big carburetor fed V8 engines, 3 speed transmissions, never overdrive. Even those cars with the exception of the big blocks got decent mileage given the cars size and weight. AKA mid teens. Trim those big heavy bodies and install a smaller carb, better mileage.

The 70's brought the fuel crunch, and the smaller cars, the initial response was smaller bodies and smaller motors- aka early Honda's, Datsun pickups, etc. Still "crude" fuel delivery and ignition systems, but ever increasing mileage.

The 80's- ugh- junk, ugly cars for the most part until the late 80's when fuel injection technology began to bloom (corvette withheld as FI began for those in the 60's) The early years of FI were throttle body, coupled with electronic ignition systems, reliability got better with new developments and advancing technology.

The early nineties were the best years for vehicles, IMO which brings me to my point. My 1993 Ranger is a multiport fuel injection system, electronic ignition, push rod V6 engine, it coupled with a 5 speed manual transmission deliveres 25 miles a gallon in nearly stock form. I have heard stories of an early to mid nineties model Crown Victoria with a 5.0 v8 and an automatic overdrive transmission getting 25-26 MPG on the highway. How is that possible when newer, more sophisticated vehicles are getting worse mileage?

It's very simple- our government agency, the EPA keeps making stricter and stricter regulations on vehicles emissions. Certain gases are allowed, others are prohibited. Some of those gases are indeed true pollutants, others are banned based on theories, some of which have been proven not to be harmful to our atmosphere.

What does this mean?

In order to control emissions, catalytic converters are used. They heat up burning "excess" gases as the exit from the engine. This secondary combustion burns the excess. As emissions regulations get stricter and stricter, the secondary burn has to be hotter and hotter to consume those gases. The only way to heat the converters is more fuel which means less miles per gallon in the end. My proof for that? The early 6.0 Powerstroke diesels were emissions controlled and had a catalytic converter. Ford engineers programmed the PCM to occasionally push some extra fuel into the converter to keep it cleaned out and warm enough to work effectively. That's when the infamous burning taipipes started happening, and a PCM reflash came out shortly after that to correct the problem.

The proof? As unscientific as it sounds, compare the mileage figures for early nineties cars vs. today's models. You'll find that most cars get the same or worse mileage as they did 15 years ago. In Gerald's case, it takes a hybrid to get the same mileage as he did 20 years ago.

Owners of newer rangers with the same engine and transmission combination can't achieve the mileage I can with my 93 model truck. The frame, beds and cabs have changed little in the life of the truck, yet mileage has gotten worse??

I saw a bit on Horsepower TV with Vic Edelbrock driving a car with a big block, fuel injected V8. He has developed a fuel injection system for classic cars and his testing showed the big block 502 cubic inch engine in his car could get 25 MPG and make 500 HP. How is that so?? The car is emissions exempt.

I am not saying we need to do away with emissions regulations or systems, rather the automakers need to start all over in their engineering. Disregard the emissions requirements, tune a modern overhead cam, variable valve timing, electronic fuel and spark engine to run at it's peak. Then and only then figure out how to make the emissions legal without altering the engine. Maybe go back and re-evaluate the gases banned for their effects to make sure they are indeed harmful.

Me, I am temped to find a 302, build it with the most advanced components available, skip the OBDII route, use a standalone fuel injection with an electronic ignition system and see what kind of mileage and power it can make.

This is all my theory, based on little to no research other than my observations and TV watching and does not represent the opinions of ExplorerForum.com, it's owner, or any of it's affiliated sites.

I'd still bet a dozen doughnuts that an engine like I described in the paragraph above would outperform my Mounty's engine any day.


If you don't agree, that's fine, it's just a theory. :

 

[igiveup]

Hello

I know with my 86 t-bird with the 93 mustang computer with no emissions so ever I can get 34 mpg imperial/hwy. Most of my buddies say bull **** but I have owned my car for 12 years and used to record the millage all the time. Now that it has the SD computer back in I get 29 mpg imperial/hwy. Now I have the 93 computer in my stang with all emissions the best I can get is 30 mpg imperial/hwy. Next summer I will be getting rid of the emissions and see what it will do.

Just my .02cents

igiveup

 

[MountaineerGreen]

nobody else - I expected some discussion

 

[Maniak]

Just some added info for thought..

I now have a 2000 Honda Civic HX which has a 1.6L vtec-e and I'm averaging 40-45mpg. From my readings on the Honda sites, the newer models (2001+) with vtec-e and manual trans (same as mine) are averaging high 30's to low 40's. The consensus is that the newer cars are heavier. They have more air bags, abs and other things to make them heavier... My honda with a full tank of gas and me in it is < 3000 lbs.

The mid 90's Honda vx got even better mileage (closer to 50).. They had small engines (less hp) and were even lighter.

I agree that the mid to early cheaper slower ligher cars got decent mileage but as they added safety equipment (weight) and added hp (thats what people want.. more HP. .muhaha) along with more emisions they had to fight to keep the same mileage.

 

[Gator Jeff]

The proof? As unscientific as it sounds, compare the mileage figures for early nineties cars vs. today's models. You'll find that most cars get the same or worse mileage as they did 15 years ago. In Gerald's case, it takes a hybrid to get the same mileage as he did 20 years ago.

Not sure if you're using all real-world mpg figures or published, but have you taken into account that the EPA totally changed how they figure fuel economy to a much more realistic method. So a car that was advertised to get 45 MPG, 2 years ago, would now only be rated in the mid to high 30's.

I agree that the mid to early cheaper slower ligher cars got decent mileage but as they added safety equipment (weight) and added hp (thats what people want.. more HP. .muhaha) along with more emisions they had to fight to keep the same mileage.

What's weird is that people are rushing out to buy $15,000 golf carts, that weigh 1600lbs with 3 cyl.,1 liter/70 HP engines, AKA SmartFor2(Who?). Here's the kick in the groin... it only gets 33 City and 40 Hwy.

So good yes, but not great. Especially considering the weight. I have to wonder if a slightly larger 4 cyl would actually get better fuel economy as it wouldn't have to work as hard.

My theory is that in addition to Mountineer's and Maniak's theories is that cars are being built for absolute idiots as someone so aptly mentioned in Al's HHO thread. I mean Volvo actually considered building a car (geared for women, they claimed) that had no real hood or easy way to get to the engine. All it had was two caps on the exterior, one for gas and the other for washer fluid. Point being, when you build such high tolerances for stupidity, the efficiency goes WAY down.

Fortunately, we have people like Al, and others that can reflash the computers and install devices that while leaving little room for error, are also much more efficient.

 

[E.B. Cornburner]

You hit it spot on. The emissions regulations are what's killing the mileage. Every few years, the EPA mandates stricter emissions regulations, and the technology in the vehicles has to struggle to keep up. The latest one that I'm familiar with happened in the 2004 model year, when NOx emissions had to be drastically reduced. Since the technology in catalytic convertors has all but hit a brick wall, the only way to reduce the NOx was to reduce the combustion temperatures, and the easiest way to do that is to run the engines richer with less spark advance. Since the start of the emissions era, we've been burning more fuel to make less pollution. Seems counter-productive, doesn't it? A 1989 Geo Metro would flunk every current emission standard out there today, even though it hardly used any fuel to go down the highway, but a guzzler like the Hummer H2 passes with flying colors.

It won't be until technology catches up with current and future emissions standards that you'll start to see MPG start climbing back up where it once was. Gasoline direct injection is one possible answer. Mitsubishi has some very interesting technology in ultra-lean burn combustion, having idling and part-throttle A/F ratios as lean as 65:1 (!) and still are able to meet or exceed all emissions regulations.

That's what's killing the diesels too...It's not just the particulates, but the NOx from compressing the air to searing hot temperatures and thereby creating chemical reactions before any fuel is even injected into the cylinders. You could turn a diesel engine over on its starter and see emissions coming out the tailpipe on a 4-gas analyzer. That's just chemistry, and the overall design is to blame. Modern diesels don't have nearly the high compression ratios as the early ones, but they're using massive amounts of turbo boost to make up for the power loss.
The one diesel that really makes me kind of chuckle is the Mercedes BlueTEC. It claims to be the cleanest diesel ever produced. The funny part is how they got it there. They inject a fluid known to the layperson as "AdBlue Fluid" into the catalytic convertor/soot trap, which creates another chemical reaction and reduces NOx emissions greatly. The fluid...Urea! More specifically, chicken urine!
I wonder who thought of that...I would have loved to be at that engineer's conference. They were probably banging their heads on the table trying to brainstorm a new way to get the emissions levels down, and someone sarcastically said, "Hey, why don't we shoot chicken pee into the catalytic convertor?"
http://www.autoblog.com/2008/03/13/mercedes-benz-launching-urea-injected-diesel-suvs-this-fall/

 

[Lanky]

fuel mileage

I work in the construction equipment rental company. We had a salesman visit one day from canada. He said that his vehicle could get 40 mpg in Canada but only mid 20's mpg in the U.S. That tells me that it might have something to do with our fuel mixture regulations.
As far as hybrids go, I have wondered what size gas or diesel motor and generator you could use to power up an electric drive motor. You would still have your gas engine for a.c. and power steering but go to electric drive. No battery pack needed. I know that doesn't get away from oil, but a smaller engine to push a vehicle with an electric drivetrain would ease fuel consumption. Just my thought! Kinda like a locomotive only downsized.

 

[dogfriend]

I wish that I had seen this thread earlier.

Re: How come it takes a hybrid to get similar mileage to a early 90's Honda? It is a combination of all the factors listed above:

The Honda was much lighter - Gerald says his CRX weighed less than 2,000 pounds - my Prius weighs almost 3,000 lbs.

Emission regulations have caused a drop in mileage, particularly the reduction of NOx. Honda used to use "lean burn" technology to get very good FE. The Honda Insight also used lean burn but was discontinued a couple of years ago, apparently because of the NOx standards. But, NOx is one of the worst emission w/r/t forming brown smog, so IMO it is a good thing to regulate.

And the EPA estimates were recently revised to be more realistic. I think the new estimates are more realistic, but I have found that I am closer to the old highway EPA figure (51 mpg) than I am to the new highway figure (45). In all around driving, I'm averaging between 48 -50 mpg vs. the new EPA combined 46 mpg.

 

[1996xlt]

Sometimes it doesn't take all the latest and greatest technology to get good mileage: case and point, in 1964 Ford had a small campaign for the Falcon after it set a new record of 25 MPG and included a keychain with the new cars to calculate your mileage.

Back to the original point, after a discussion with a friend of mine (and a project I did recently for school) I realized that the technology available to automakers now is by leaps and bounds better than what was available 20 years ago. Yet with a far simpler amount of technology they were able to get engines more efficient and stretch each gallon. I understand that a lot of it has to do with weight (airbags, etc.) but why aren't more bare bones optioned vehicles available other than those sold to government agencies and rental companies?

My main point is there is no excuse for cars these days to get less than 25 MPG, the technology is there for them to do 40+.

 

[jah81592]

One thing to note is that smaller engines are producing more power now. For a small engine to produce the same power as a larger engine the fuel requirements will be greater. A perfect example is the Vette. 500 hp and 27mpg. Light,aerodynamic and oh yeah gets better economy than most small "economy" cars. And it has a v-8!-j