800 cc Honda Accord CVCC (disabled 2 cylinders of 1600cc engine) - Fuel Economy, Hypermiling, EcoModding News and Forum

arcosine · 01-30-2011, 05:28 PM

I had a 1600 cc CVCC 1977 Honda Accord in 1986 and I disabled 2 cylinders so it was 800cc. The gas mileage increased from 40 to 48 mpg, but it only had half the power (30 hp). It idled at twice the speed and I had to rev it much higher.

The Honda CVCC engines had a single overhead camshaft with rocker arms. I simply turned the rockers upside down on cylinders 1 and 4, and they acted as air springs. I drove it this way for about 200 miles, 150 highway. The car could not get out of it's own way, It was a struggle to get up to 55 mph. Semi trucks could out accelerate it.

I loved this car, it was great, but rusted out. Later I bought another and put in a 1355 CC engine with 10:1 compression ratio and it was 50 lbs lighter. I changed the 5th gear from a 75 civic and put on 185/80R15 tires. I got 50 MPG most of the time. It had a 13.5 gallon tank so it got 650 miles between fill ups.

HowStuffWorks "1977, 1978, 1979, 1980, 1981 Honda Accord"

Ninjapizzadude206 · 01-31-2011, 05:27 AM

Not sure what you mean by air springs, but I wonder how much faster it would have been if you found a way to prop open the valves for those cylinders 24/7, so you're not losing power to all those unused compression strokes. I'd say shim them open, but then they might hit the pistons, depends on the motor.

arcosine · 01-31-2011, 08:57 AM

Cant do that, think about it the piston would hit the valves and then it would be 24/365. It would be sucking in mixture or exhaust. Also think about reversibility, after the compression stroke there is an equal expansion stroke, thats an airspring. If I wanted faster, I would have used all four cylinders, which I did. Cadillac's 8-6-4 engine turned off cylinders in the same fashion.

arcosine · 01-31-2011, 09:01 AM

I also had a 1984 Accord that had 2 intake valves (beside the auxiliary valve) and one exhaust. In 1992 made this operate with only one intake valve opening and the other staying closed the result were:

Much smother idle
Significantly more heat and faster warm ups (due to increased turbulence and swirl)
increased fuel mileage, about 2 mpg.
Loss of power.

I drove it this way for several months.

MetroMPG · 01-31-2011, 09:55 AM

Interesting experiments. It's one of those subjects that people talk about all the time, but few have attempted. Thanks for posting the details.

EdKiefer · 01-31-2011, 10:32 AM

Quote:

Originally Posted by arcosine

I also had a 1984 Accord that had 2 intake valves (beside the auxiliary valve) and one exhaust. In 1992 made this operate with only one intake valve opening and the other staying closed the result were:

Much smother idle
Significantly more heat and faster warm ups (due to increased turbulence and swirl)
increased fuel mileage, about 2 mpg.
Loss of power.

I drove it this way for several months.

The gen7 Accord (2002-2007) K24 do that stock (the 2 intake valves only work from 2500 rpm up, at low speed only one really opens fully giving it turbulence an swirl conditions .

Frank Lee · 01-31-2011, 11:24 AM

I'm amazed it started! Mine wouldn't on two.

Jim-Bob · 01-31-2011, 08:39 PM

The Honda CVCC was what is known as a stratified charge engine. It basically had 2 intake tracts: a lean one and a rich one. The rich one fed a pre-chamber which started combustion in the larger chamber that ran a lean mixture. You probably cut off the pre-chamber valve which is why it ran a little better on gas.

arcosine · 02-01-2011, 01:13 PM

Jim- Bob you have book smarts, but you are wrong. It will not run that way.

It had the 12 valve engine non-CVCC, but carbureted.

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