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Consumer Reports tested a '73 Dodge Dart 318 V8 and a Dodge Coronet 318 V8. The Dart weighed 3340, the Coronet weighed 3780. Both cars got the same fuel economy, 10-20 mpg in normal driving and 15 mpg on a 300 mile trip
Why didn't the lighter smaller(440 lbs difference) Dart get better mileage than the Coronet?
The Dart, already pretty big and heavy for it's size, actually rode more comfortably and quietly than the bigger Coronet in it's tests. For several years, the Dart has excelled in ride comfort, actually surpassing larger cars like the '68 Cadillac (in '68 a fully loaded Dart actually rode better than a '68 DeVille in CR's tests)
Does this kind of point the way to the idea that the Dart may have been the better value(since it's price would be lower) than the Coronet?
also, would you think that 10-20 mpg and 15 mpg for a V8 compact car would be respectable in '73?
I have never driven a stock dart or coronet but I have driven modified versions for both. The dart I drove was actually a bit stiff. It kind of surprised me. The Coronet was your normal late 60's, early 70's float boat.
I personally think 20 mpg in either car is wishful thinking even with the small 318cid. Back then those cars got about the same mileage on the street and highway because of gearing. You didn't mention rear axle ratios for either car but I'm willing to bet the reason the Dart got the same miles as the Coronet was because it had lower gearing causing the motor to spin faster and using more gas.
I've owned and driven dozens of older muscle cars and I cant say I ever remember getting an honest 15 mpg from any of them. My current 72 Monte is about the best I've seen at 14 mpg but that is mostly due to a perfect tuneup (tuned with a wideband 02 sensor) and killer (modern) ignition system.
tests of the '73 350 V8 Monte was 8-17 normal driving, 15 mpg on a 300 mile trip (which they considered respectable for that car)
here's the odd thing. the '73 Grand Prix with the 454 V8 got 8-19 normal driving and 16 mpg on a 300 mile trip, making it the car with the highest mpg for a V8 that year
Consumer Reports tested a '73 Dodge Dart 318 V8 and a Dodge Coronet 318 V8. The Dart weighed 3340, the Coronet weighed 3780. Both cars got the same fuel economy, 10-20 mpg in normal driving and 15 mpg on a 300 mile trip
Why didn't the lighter smaller(440 lbs difference) Dart get better mileage than the Coronet?
The Dart, already pretty big and heavy for it's size, actually rode more comfortably and quietly than the bigger Coronet in it's tests. For several years, the Dart has excelled in ride comfort, actually surpassing larger cars like the '68 Cadillac (in '68 a fully loaded Dart actually rode better than a '68 DeVille in CR's tests)
Does this kind of point the way to the idea that the Dart may have been the better value(since it's price would be lower) than the Coronet?
also, would you think that 10-20 mpg and 15 mpg for a V8 compact car would be respectable in '73?
well that is pretty much what my 91 lifted F250 4x4 gets with the 5.0EFI/ ZF-5 speed manual tranny combo and 4.11 gearing and it is my daily driver/work truck to boot... so no that is not too bad fuel economy IMO
I had a 73 dart with a slant 6 and it got great mileage. It had lots of guts too. I had a 75 plymouth fury 3 police special ordered car. It had a high output 440 and a special suspension. I just loved that car. It didn't get the best of mileage but it's my favorite car I ever had. The only car I had that was even close to it was a 95 BMW 535II. It was good but not as good as the plymouth.
tests of the '73 350 V8 Monte was 8-17 normal driving, 15 mpg on a 300 mile trip (which they considered respectable for that car)
here's the odd thing. the '73 Grand Prix with the 454 V8 got 8-19 normal driving and 16 mpg on a 300 mile trip, making it the car with the highest mpg for a V8 that year
odd hah?
Having owned several big block cars i'll tell you first hand that nothing with a 454 and a carburetor has ever or will ever get 16 mpg on a road trip. 73 was the start of the emission controls and the first whispers of fuel economy and it sounds to me like motor trend was doing their part to help sell some cars by exaggerating on a few details.
My 72 Monte is a basically stock 402 BBC with a good ignition system and a very good tune and it recently got 14 mpg on a 550 mile road trip. The car has a stock TH400 trans and 3.23 rear gears and we made the whole trip at 60/65 mph stopping only for gas. The motor was spinning under 2K the entire trip.
The difference in weights of the first 2 cars mentioned isn't enough to make a lot of difference for the engine to move. To around 50 mph there isn't much difference in terms of fuel used from base idle. The main difference there is the added air.
Idle mix is overly rich to enable the stationary object to become a moving object. Once the object is moving under not a real heave load (cruise) it doesn't take a whole lot more fuel to keep it moving, untill you pass the point of resistance, (traction and air resistance)
You could almost mount the engine/tranny to a go cart, and not really improve MPG's. Back then there was wasted fuel always, since a carb worked by engine vacuum and the venturii effect of air dragging over the venturii to draw fuel by another form of vacuum the air flow in the carb created.
By improving the engine air flow, (swapping to a better carb, say from a 2 barrel to a 4 barrel) people found they got more power, and could get better MPG's.
In general carbs didn't 'Atomize' fuel as well as injection does. The carbs used moving air thry the carb and around it;'s devices mainly the venturii, a constricted air space, the throttle plate and the vacuum the pistons created timed with the valves, and last back pressure to break up fuel particals.
A rough example of that is to toss a lit ciggy butt or a match even into a full bucket of gasoline.
Either one will just go out.
However if one kicks that bucket and tosses either one over the spill, there is likey to be a real big flash fire instantly, becayse the fuel has far more surface area.
Injected cars use a series of sencors to tell the ecu what needs must be met upon demand, and fuel pressure at the injector nozzels mists a circular fan spray of far smaller particals of fuel than a carb can make. So less fuel does more work.
Still there is a minimum demand of how much fuel is required to just run the engine, more to make it move, and so there still is a law of physics as to how much fuel an engine must have. But don't tell the EPA I said that. They believe you can run engines on practically no fuel at all.
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Consumer Reports
