Interesting Carb Arcitcle

[A20A1]

http://www.aircarecolorado.com/repair/honda.htm

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[2ndGenGuy]

That is interesting. Now, are all cars marked high-altitude and low-altitude? Or are only the high-alitude cars marked that way? Also, how high do they consider high-altitude?

I was under the impression that the majority of cars out there are low-alititude cars, with a small percentage being high-altitude, and the other small percentage being California emissions cars.

I thought it was interesting how Honda said that the modifications to the carb systems weren't the right way to do it. And how to get any of their test cars to pass emissions, just required repairs... I wonder how many people wound up getting screwed over because their carbs were modified, and then couldn't run properly when back at the appropriate altitude for the car. And fixing the problem the right way, by finding the actual problem would have solved the issue.

Also interesting is how Honda said that it would be running lean after the modifications, and bringing it back down to low altitude. I didn't think that there was THAT much difference in the air density.

I wonder how my static-tuned carb will run when I take it up into the mountains, considering I've got it tuned at just about sea level...

[shepherd79]

very interesting.

i like them to do the same for carbed 3G.

PS. if you take low altitude carb up to a mountains you will experience what is called Running RICH.
not enough O2 and too much fuel.

[A20A1]

The technicians were not trained to fix honda carb systems.

It's all keihins fault for not making the carbs come with replaceable jets. :) or hondas fault for not specifying that when they ordered carbs from Keihin.



Also interesting is how Honda said that it would be running lean after the modifications, and bringing it back down to low altitude. I didn't think that there was THAT much difference in the air density.


Altitude(feet) Pressure(in. Hg) Temp.(F°) Density(%)
00,000 29.92 59.0 100
02,000 27.82 51.9 94.3
04,000 25.84 44.7 88.8
06,000 23.98 37.6 83.6
08,000 22.22 30.5 78.6
10,000 20.57 23.3 73.8
12,000 19.02 16.2 69.3
14,000 17.57 09.1 65.0
16,000 16.21 01.9 60.9

[lostforawhile]

it's hondas fault for making such a nightmare of a carb control system. it's japanese technology run amuck:gun:

[Boltgunner]

If I heard it right, the CVCC motor is supposed to run rich, and all of the various tubes, valves, solenoids, the black box on the firewall, the sensors, the oh two sensor and its brain work in concert to lean the motor into minimum emissions numbers.

All I know is, after my last dyno emissions test, the Weber comes to stay a while (gonna mod the air cleaner so it fits) and cosmetically she will be a boring bland little 47 shades of black engine bay.

[2ndGenGuy]

Well, the CVCC motor sorta runs rich, but runs lean at the same time.

There is a chamber in the head, where there is a really rich mixture, then in the main combustion chamber, the mixture is lean. When the spark plug fires, it ignites the rich mixture, then the ignition of that lights the lean mixture in the chamber. I think it all balances out, and causes a more complete burn.

[lostforawhile]

right,the cvcc has an extremly lean mixture in the main chamber,and an extremly rich mixture in the precombustion chamber,the plug in the precombustion chamber lights the extremly rich,but small volume mixture, the flame front propagates out of the holes in the prechamber,and lights the mixture in the main chamber,which is too lean to light with a standard spark plug by itself. the end result is an extremely lean mixture that burns at a high temp and helps eliminate a lot of pollutants before they even leave the engine. for years when american cars needed converters to meet emission standards, a lot of hondas didn't have them and still met the standards,the design was so efficient. a lot of the 81 to 83 civics would pass emissions without a converter,but had one because it became mandated. didn't make much sense,if the car met the standards without it,why force it on the car? but thats our goverment for you. the carb on these cars is the worst thing ever made,it's two carbs in one, a main two barrel carb of standard design, with a small single barrel carb attached to the side of it. the single carb actually had it's own fuel supply, it's own float chamber, and it's own passages into the head,as well as it's own lobes on the cam,and it's own valves, it was just cast into the side of the other carb like an evil siamese twin.

[79cord]

& don't forget most car companies were deliberately making it harder for owners to adjust their cars carburettor settings & thus possibly deviating from 'low-emission' settings!