Just a little idea i've had for Increasing HP on a budget. it's designed for an A-series engine. If your handy with a welder, you could do it all yourself.

I like the thinking here, but I believe that the air filter element will flow a lot more air than the stock carb can pass at full throttle, so the velocity of air in the air filter housing [teapot?] would be fairly low.
Additionally, I suspect that the wave shape of the air filter element would disturb the circular motion of the air around the outside enough to ensure that the vortex swirl did not cary through to the inside of the element, but hey, a few simple experiments with some short strands of wool taped inside could confirm or refute my assumptions.
Have a go with a test or two & see if it works & good luck to you.

some datsuns, like my 81 sunny had factory cold air intakes that went from a hole to the side of the radiator and hooked on to the teapot thing like you describe.

so apparently the factory though this was a bit of a good idea.

Quote:
Cold air intake? Are you able to post a pic as I would like to have a look at that.

Generally speaking, our little Datsuns were sold as economy cars, & one method of making the most of every drop of fuel was to supply HOT air from the exhaust manifold area, via a flexible hose, in an attempt to vaporise every droplet of fuel. This allowed leaner mixtures which kept both the thrifty motorist & the EPA happy.
The warm air was drawn to a fitting on the underside of the intake pipe on the air cleaner with a vacuum operated flapper valve above it.
At full throttle, vacuum was about nill & the flapper closed off the hot air, to admit cold air only. It also went to the cold air position when the temperature inside the air filter housing rose above a certain point [like on hot days]This 'cold air' was drawn from the underhood area, so if the metal pipe on the aircleaner was extended to a place beside the radiator with another flex hose, then it would get colder air.

Dedicated cold air intakes were normally linked to the persuit of POWER at full throttle, which was not a small Datsuns main selling point. Full time cold air would also defeat the other two points that I mentioned earlier, so a pic would be really appreciated.

Dodgeman, you have a point, now that you have mentioned it, the filter will disrupt the air flow but i will still test the theory when i get round to making it.

it still had the warm air system, but that was only for start up, I'll have to look and see if i can find the pics of when i got the car and it still had the OE carb.

i use the hole that the pipe went through now for my oil cooler lines.

look here... bone stock.

Yes, that was for emissions control. Sometimes it got too hot under the hood (in the engine compartment). So they brought cooler air in from outside. It still kept the air at a constant temp as the heated air intake functioned at the same time. The idea was to keep the air temp constant via a balance of warm and cold air rather than to get the coldest possible air. That's what the big diaphragm on the intake snorkel is for, it controls the flap that regulates the hot and cold sides.

B210sleeper, thanks for the picture.
It's as I thought. I think that you will find that the warm air thing is for more than just startup & is in operation most of the time. The cold air ducting from the front is an improvement from the earlier system when it drew so called cold air, from under the bonnet.

Many carmakers were drawing cold air from outside the engine bay by the time the 80's rolled around, but like I said earlier, I think you will find that the warm air is operational all the time untill a certain temperature is reached inside the air cleaner housing when the cold air is admited instead, although I think the thermostat control was able to control a mixture of hot & cold air to stabilise the temperature of the air passing into the carb

notice there's no pipe on the heater and you can probably see it's got the vacuum motor disconnected. I live where it's warm enough to get away with that most of the year.

so if you do that, then it's a cold air intake. but normally not so much so.

Yes, that is correct. Just disconnect the vacuum and it's a real "cold air intake".

Here it is from the 1980 service manual: It is called A.T.C. (Automatic Temperature Control) and is a mix of hot/cold until the temperature sensor (inside the air cleaner housing) reaches 127F (53 celsius), at which time it is "cold" air only (127 degrees cold ...).