Engine technology and MPG
 

One thing that has always bugged me is how my college car, a 1996 Chevy Beretta, got great gas milage (37 mpg highway), yet it wasn't an undersized piece of crap - it was a regular car. Whereas today, still most small cars average in the mid to higher 30s for highway MPG. You often hear the argument that engine technology has increased, but MPG has not skyrocketed because of safety equipment adding weight to cars.

Fact or myth?

1996 Chevy Beretta: 120 hp, 2700 lbs, 33 mpg (37 according to old EPA estimates)
2011 Chevy Aveo: 108 hp, 2500 lbs, 35 mpg
2011 Ford Fiesta: 120 hp, 2400 lbs, 37 mpg

How can 15 years later, the numbers be all the same? Is there an explanation?

The beretta gets 27mpg

Fuel Economy of the 1996 Chevrolet Beretta

I think it has to do with the gearing in the transmissions. Some of the new cars I have been in are at 3K rpms doing 65 mph. If we lost a bit of acceleration with taller gears we could see some larger mpg improvements.

That's the 6 cyl version. The 4 got 37 mpg on the highway. (though that website says 33, but that's not what the sticker said and other websites say)

Compare Old and New MPG Estimates

Here is the 37 mpg. It says they figure mpg different now.

Ok, that explains it a little. But still...15 years and 2-4 MPG increase in engine technology despite lighter cars (and even less horsepower in the Aveo)?

And we did obtain 37/38 mpg in the Beretta with my dad driving to Chicago.

Features. Today's cars have a lot more features, which equal weight, which drags down the mileage (and performance). When I was in college Honda came out with the CRX-HF(?) with a 1.3 liter engine, 2 seats and not much else -- and it would go for well over 40 mpg. Today's cars though have satnav, electric everything, ABS, Cruise-control, traction control, and twice the horse-power. The result -- the mileage isn't even as good as the 1976 Fiesta I drove soon after college.

I would bet the #1 reason that we don't have cars with better mpg is people won't buy them.

Well my '89 Honda CRX HF got nearly 50MPG and weighed ~2200lbs I think. Great...no, fantastic little car.

Sure, but how many of you chose cars as small and as spartan as the CRX when you bought your most recent car? Be honest. I don't think a lot of you have Yaris'es sitting in your driveway.

Cars from 1990 wouldn't even come remotely close to meeting the safety standards for 2012. Not even close.

A new 2011 Hyundai Elantra will get an honest 40mpg with either the 6spd manual or 6spd auto, has a 1.8L N/A making 148hp, and weighs 2700-2900lbs. Six airbags, ABS, stability control, and more room inside than a 1990 Toyota Camry, Nissan Maxima, or Honda Accord.

It's changing, slowly

Features and weight are a valid reason. But my examples show the Beretta weighing 200-300 lbs more. 200 lbs more than the Aveo, more horsepower, and just 2 mpg less.

55 mph verses 75 mph speed limit.

The speed limits were 65 in 1996, and 75 some places

Peppy mentioned that, that's why it's rated 33 mpg. In 1996 it was 37 mpg.

My 1978 Datsun B210 would get 39 mpg on the highway. It weighed less than 2000 lbs and the engine was a 60 hp 1.6 l. I will add, I do not remember if the mileage was 39 mpg with the A/C turned on...

It was zero to 60 in a couple of days and if you tried to get to 80 mph, the wheels seemed like they were going to come off.

Diesel... We need diesels....

My mom's 1984 Olds 88 Custom Cruiser Wagon (8 passenger) with the 5.7L Diesel and TH200R4 overdrive auto got 33-36mpg at 62mph. And thing was neither small, nor light. My mom used to tow her all-aluminum horse trailer with two thoroughbreds with that thing.

I've seen 50mpg in a TDi bug....

Last year about this time I had a 2002 Jetta TDI 5 spd that had grendaded its engine. With rebuilt engine, new turbo, and new injection pump/injectors, etc it got 50 mpg if you kept it under 65mph, then lost about 1mpg per mph from there up.

My '92 Audi 100 used to routinely get 30-32 mpg cruising at ~65mph on the highway - until E10 came to play. Now I'm lucky to get 25-27mpg.

I like how Toyota is advertising a Prius getting 45mpg. It makes me laugh, I don't think either one of the two in the fleet get 45, I know the 07 I drive gets around 37 on good day, on the highway, driving down wind. However it has 150K and a clogged cat, at least that's the code it throws.

I'm not impressed.

I think they get higher mpg around town, when the battery and electric motor are in effect. They aren't really hybrids on the highway.

I am a firm believer that E10 is really E10/W10/G80. The only way that mileage should drop off is if there is water there.

25, 30, 45 mpg?......bah, whatever.
The only "true" hybrid daily driver on the market today is the Honda Insight: 70+mpg when driven considerately. That is more than double the milage of a 2011 Subaru, the same rating as 15 years ago.

The Insight chassis and interior is based somewhat identically on the Toyota Prius, but the powerplant is considerably superior.




All of this "recent debate" pales in comparison with the world cars designed decades ago.

When you learn more about the history, the more it all seems comical.

Can ethanol and water co-exist in the same liquid?

WTF do you smoke?

The ethanol is what allows the water to be added and still be burned. The H2O and EToH bond. The water is burned off with the etoh and goes unnoticed...

To answer the previous question, when it came time to buy a "new" car, what did I end up with? An unmolested 91 CRX Si. An honest 40MPG(@65-70MPH) and fun as heck to drive. The only issue is, it's a tin can, the only safety features are seat belts, acres of glass, and an active mind behind the wheel. There's no way in hell it would pass any federal standards 20 years later.

I try not to intake unknown and unwanted substances. Period.
But if I was to willingly inhale a known substance into my lungs, it would be within the framework of the constitutional fathers or common sense.


The CAFE standards the OP mentioned, and of which I spoke of before,..ummm...speaks for themselves.

25mpg.
Same as the Model T.

So without the, ahem, enhancement of such substances....

Please enlighten us and elaborate on how a 2011 Honda Insight is 'considerably superior' to a 2011 Toyota Prius

I had a new Opel GT in '73, I think. Seems like it got up in the over 30 mpg range.

The federal standards which require airbags and abs and traction-control directly contribute to the weight and milage of new vehichles.

This is all in relation to corporate insurance statistics in relation to the 7,500lbs vehicles, currently registered as "cars", which are now on the road.

I've been thinking about this......

get an old beetle (pre all this overweight safety shat) take the body off, turn it into a small ultralight dune buggy thing styled like an Ariel Atom, and put in a small diesel engine.

Summer use only high mpg DD. Unfortunately, I don't think Canada will see summer again, it's still snowing.

Run it off vegetable oil from Costco when diesel goes above $1.40cdn :) (I checked yesterday)

The laws for modified cars in Canada are so ridiculous, you need to start with something pre safety/mileage/emissions.

Yes, Kaisen.
Now that I've officially declared myself decades free off marijuanna, aka the demon drug, we can now begin to discuss the federal CAFE standards of millions of American vehicles on the road daily.

A more important and relavent comparison is the CAFE milage standards to those 20 years ago....
I beleive that was the intent of the original post.

The federal requirements are biased towards larger, faster, more expensive vehicles.

Everyone else pays more, in one form or another.

Federal subsidy.(sp)

I'm much more interested to how an Insight is superior to a Prius, given that it runs counter to just about everyone else's opinion.

That's why they're called 'threads'

Kaisen, you want to know why CAFE standards haven't improved in 100 years?

I'm sorry.
I can't be of help there.

However, let's also discuss CAFE and what it stands for: Corporate Average Fuel Economy

Anything under 8,600 pounds gross vehicle weight falls under the average.
Ten years ago, twenty years ago, there weren't as many 'large' vehicles sold. Yet manufacturers STILL found ways to meet the CAFE standards.
So even a 1/2 ton pickup that will be used to tow and haul is calculated in the average. They get considerably better fuel economy today than they did ten or twenty years ago. And since more of them are sold than hyper-mile economy cars, MORE fuel is saved in the SUV/CUV/Truck segments than will ever be saved by an Insight or Prius or Jetta TDI

gasoline to mechanical energy = 30% efficiency (someone will probably correct me), in an internal combustion engine. this isn't going to change. the rest is lost as heat, hence the relatively large radiator and coolant reservoir.

bmw was (is?) trying to do something with this heat by using it to create HP via steam. it looked VERY complicated to me.

edit: i was optimistic, it seems: 15%

http://www.fueleconomy.gov/feg/atv.shtml