If anything, his gas mileage is nothing to brag about.
I knew a guy whose brother-in-law had a neighbor, who had a friend, who had a cousin, who knew someone who regularly got 123 mpg from a CRX.
Doesn’t that sound like a very reliable source?
3 Likes
It would be if he would have a friend of a friend in there some where. 
And always remember, “The enemy of my enemy is my friend”.
1 Like
That car didn’t have a 6th gear
3 Likes
According to this site the 1986 CRX HF turned 1846 rpm at 60 mph in 5th gear.
1 Like
No way!!! Only on a long downhill when coasting.
One of our secretaries bought one and was very pleased with the mileage, but it was not anywhere near that number.
I do not believe any car ever achieved 70 mpg, and certainly not in mixed city and highway driving. Even the 3-cylinder 5-speed Geo Metro, which was legendary for its efficiency did not come close to this.
The first car I ever owned was a 1988 Toyota Corolla, with the carbureted engine and 3-speed automatic. With careful driving, it could achieve about 40 mpg, which I thought was very efficient. I have owned several vehicles since then, and none have crested the 30 mpg mark, and I try to drive as efficiently as possible.
I think it would be possible with current technology to build a lightweight (by today’s standards) car with a 100 to 120 hp 4-cylinder engine and 4-speed automatic transmission, which could achieve 40-50 mpg in mixed city and highway driving. Of course, there would be very little market for such a car in the U.S. however in other markets, people would want such a vehicle.
Back in the day, when I had 3 CRX’s and was active in the scene, the HF guys were regularly getting in the mid 40’s to mid-50’s. A couple did report 70mpg on the highway, but they were also dopes who tailgated semis and did other “hypermiling” shenanigans like coasting down hills, slowing down to dangerous speeds up hills, and generally being a pain in the neck for other drivers.
I usually got high 30’s and sometimes broke into the 40’s in my DX, and in the Si I’d get mid to high 30’s when I wasn’t hooning it.
Other way 'round.
Nope. Cooler air is denser. This is why normally aspirated engines lose power and efficiency as altitude increases. The sweet spot is in the upper 50s/lower 60s degrees Fahrenheit.
The main reason you might see a drop in fuel efficiency is if you run the air conditioner. But then modern cars run the air conditioner in the winter too, to help the defrost, so you probably won’t see much of a drop there either, anymore.
BTW on the mountain driving thing, you lose power because there’s less air. But when there’s less air, the computer reduces the fuel it injects. The reason your efficiency drops in the mountains is not because of how high you are, but because you’re going up hill a lot.
If you drive around a high elevation city that doesn’t have a lot of elevation changes, your car will be less powerful than the guy at sea level, but also use less gas.
Winter temperatures induce there own set of fuel-robbing areas. That’s why the optimum temperature is well above freezing. This doesn’t include frequent short trips when a lot of the energy in the gas is wasted bringing the engine up to operating temperature. Remember, these replies are to someone with a rather primitive car operating on an extended trip.
To put another way, all else being equal and the car at operating temperature, maximum efficiency occurs at moderate temps.
It has been done with 63 hp Kei cars in Japan for decades.
The best non-hybrid MPG rating sold in the US right now is the Mitsubishi Mirage with its 78 hp 1.2 liter 4 popper rated at 39 combined MPG. And very few are sold.
A decent sized Hyundai, the Elantra, sports a 147 hp - 4 getting 37 mpg with a CVT.
It occurs at higher temps for the reasons the government listed. Additionally, as you said, higher temps involve lower air density, which means less air is being drawn into the cylinders and as a result, less fuel is being sprayed into them.
In the old days you might have been right, as if your manually-adjusted fuel trim were set for denser air then you’d be dumping the same amount of fuel even though there was less oxygen with which to burn it, and so you’d waste fuel running rich. I remember dad having to make that choice because we lived on top of a mountain, but he worked in the city which was about 4,000 feet below us. He had to either set up his car to run well at high altitude, or the lower city altitude. He picked the city because most of his commute was at the lower elevations. But that meant the car ran rich once he climbed into the mountains, which lowered his fuel efficiency because of all the unburned fuel he was dumping out the exhaust pipe.
It could be done here too, even with bigger cars. But as engine efficiency has increased, we have reacted not by enjoying the better mileage we could get, but by increasing the engine’s power as well. This has resulted in cars that are, by older standards, insanely powerful but with little to no fuel economy improvements. If we went back to the days when a 150 hp engine was considered powerful, but applied modern design to it, we’d easily have cars that got 40+mpg all day long. In fact, we do - my wife’s Veloster does that. Yeah, it can’t keep up with many of the other cars on the road off the line but - and I say this as a car guy - if we want to stave off the worst of the impending climate disaster that we’re already experiencing, we’ve really got to get over the mentality that every car should be a race car.
BTW, anyone happen to know why the ‘84 CRXs were recalled?
What change to the vehicle was made?
The only recall I could find was for the hood latch.
In 1988 there was a recall for after market fuel pumps.
I believe that it was a conspiracy between Honda and the major oil companies, to alter the car so that it would get worse gas mileage.
2 Likes
Yep, just like the oil companies buying the patents of the carburetors that provided 110MPG in the early 60s.
Another urban myth.
1 Like
Yup! A good example would be the fable that began this thread more than a decade ago:
His theory was that, by decreasing gas mileage on that particular Honda model, people would drive less, and that this would help to improve air quality. Ummm… yeah… sure…
1 Like
Based on how you describe it, your method for measuring and calculating your fuel economy was less than precise.
Perhaps your fuel tank was bigger than you thought, and had more fuel in it than you thought.
If you’d told me you’d measured fuel use and mileage as precisely as possible each time you put fuel in your vehicle, I’d believe you.
Telling me you made it a certain distance on a single tank of fuel tells me next to nothing.
1 Like