Engine technology and MPG

[patssle]

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?

[peppy]

The beretta gets 27mpg

Fuel Economy of the 1996 Chevrolet Beretta

[peppy]

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.

[patssle]

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)

[peppy]

Compare Old and New MPG Estimates

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

[patssle]

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.

[jluetjen]

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.

[peppy]

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

[lendaddy]

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

[jyl]

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.

[kaisen]

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

[patssle]

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.

[kach22i]

55 mph verses 75 mph speed limit.

[kaisen]

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

[patssle]

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

[red-beard]

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.

[porsche4life]

Diesel... We need diesels....

[kaisen]

Originally Posted by porsche4life

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.

[porsche4life]

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

[kaisen]

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.