carbed car .. think a warm air intake will help?

[ebacherville]

MY crx is carbed, any one know how warm air intakes effect carbed cars? Seems carbs are kind of "dumb" they see x mass of air and in go so much fuel.. unlike a injected car that strictly monitors everything the car does..

However i suspect my CRX has some logic in its carb.. cant see how they can get 55 mpg on a straight up card standard.. there are tons of vacuum controls on this thing.. any way your thoughts on warm air on a carbed car.. since its carbed i cant get any really instant feedback.. so anything I do i got to wait a few tanks to see if it made any noticeable improvements..

[Duffman]

I am not familiar with Honda's but 99% of domestics built during the 70s and 80s were WAI. They had a heat riser from the exhaust manifold to the air cleaner's snorkle.

Go for it!

[Ryland]

Your CRX already has a warm air intake that keeps the air going in to the carb at 100-110 degrees, if your warm air intake is missing or not working then it most likely will show this by running really poorly when it's 60F or less out side, you will also risk over heating your engine if you run it like this but it is a popular part to remove by teenagers.
For your warm air intake to work properly you need to make sure that the flexible ductwork going from the exhaust heat shield to the under side of the air intake is intact, if it is missing then the flexible duct designed for under dash heat vents often works very well and is available at auto part stores, next is the vacuum diaphragm that opens the flap, this should hold vacuum that is applied to it, simply sucking on the hose that goes to it should make it pull in/up, if it doesn't do this, or it pushes back out/down then it might have a hole in it and must be replaced, Majestic Honda is the cheapest to get it from, also if you have a vacuum leak in some of the hoses that go to your carburetter then the warm air intake might stop working as well, or the fuel cut off that happens when engine braking might not work, or any number of things that help your engine safe gas, last longer and run better.

[ebacherville]

yeah i have the WAI on my car.. was just wondering if warmer would be beneficial but i assume from what your saying it would not be.

My idea was to pipe the WAI hose that runs to the exhaust manifold directly to the main air intake and seal off the vacuum operated valve.

[adam728]

With a carb you risk vapor lock if you get things too warm. Running off only the heated air on a hot day could lead to troubles, but there's really no way to know without testing it.

[ebacherville]

Ill wait a bit and get some good baseline FE numbers before I start modding the engine

[ttoyoda]

Vapor lock: I suspect (but don't know) this car has a return fuel line back to the gas tank, so cool gas is moving all the time by the T to the carb.
WAI: The car will run rich, unless the carb can reduce the F/A ratio enough to compensate. The economy might still be better. Look at the color of your spark plugs to figure out how well it is doing.
look at normal, overheated, and carbon fouled in these pics
http://www.verrill.com/moto/sellingg...colorchart.htm

[ebacherville]

yeah i changed plugs and the plugs looked pretty good.. no signs of major problems.. I guess i'm just tinkering at this point..lol

[adam728]

Even if it has a return fuel system you can still get things too hot and boil the gas in the bowl or other passages/pockets in the carb body.

[justpassntime]

You don't want warm air always being sucked into the carb, it lowers the horsepower. Watch some drag racing, these guys love cold days because the air is more dense and improves fuel burn. The warm air intake is only for cold days to keep the carb from icing and to help the engine until it reaches operating temp on cold days. A cold air intake and a thermostatically controlled warm air intake is the way to go. Yeah those under the hood air intakes look cool but they don't help mpgs.