I don't know if this has ever been done (probably has) or what the increase in HP would be. But here goes:

I was thinking of taking an intercooler and attaching a conical style filter and duct to the inlet side. On the outlet side run duct (or pipe) to an airbox mounted directly on the carburator. I would think this would result in a much cooler, denser airflow.

And if you really wanted to throw some $$$ at it, you could plumb the intercooler with R134A and use a A/C setup to recirculate it, thusly lowering the air temperature even more.


You think this would be a good set up for a real world 10%-15% increase in power?

Of course this would probably present itself if one had already done other modifications to the intake,exhaust,heads, and raised the compression of their engine.

Well, what do think? Sure it would cost money, what doesn't? Flame away

 

General law of thermodynamics PV=nRT where P is absolute pressure, V is volume, n is number of gas molecules, R is a thermodynamic constant for the temps and pressures you are working with, and T is absolute temperature. I would suggest (because I dont have the time to do it now) that you see what percentage the n increases for your actual application. Assuming that ambient air behaves near ideally (which it should for these temp/pressure ranges) you are only going to see about a 1% increase in air molecule count in the cylinders for a 20 degree F drop in temperature. If you used liquid nitrogen to cool the air or something extreme (about 200F drop) youd probably see much more of an increase, but you would cause all kinds of other problems in your engine.

My opinion - its not worth it.

 

I was under the impression that for 10*F the inlet air is dropped, you gain about 1% in power. I dunno.

 

Shades of perpetual motion machines here... No AC or refrigeration won't work. You have to pay for the refrigeration with energy somehow.

Pulling ambient air thru an intercooler cooled with ambient air will do not anything more than restrict the inlet of the motor making it work harder.

Most vehicles are fitted with a cold air intake already that draws air from the front of the vehicle. Unfortunately many people remove them and draw in hot underhood air instead.

 

Yeah, I started thinking about that as I was posting the original post. The refrigerent idea was more of a "pipe" (no pun) dream.

Oh well................

 

I was thinking more along the lines of ice or something for short runs. Also, I always wondered aobut how people always put those air intakes under their hood. All that hot air cant help

 

You're right, it doesn't. That's what Torque1st was stating. I was thinking of improving cold air induction over the factory CAI.

The last thing you want is an open element air cleaner.

 

Using an intercooler alone will slow down the intake charge of air. An intercooler works with forced induction (turbo/supercharger), because the air coming in is being forced through the intertcooler. It isn't being sucked in by vacuum, like with regular EFI or carb. The intercooler would just act like a restriction under vacuum. Even under boost, factory intercoolers act like a restriction. Go buy a good aftermarket, larger intercooler, and your boost numbers will actually go down a little from stock. The larger and more free flowing intercooler is less of a restriction under boost. Even with cooler air being pushed or sucked into an engine, the gain isn't hardly measurable. Other things would have to be changed too. More fuel pressure/flow, advanced timing, etc. would have to be entered into the equation to make more power.

 

Oh my...........with all the dyno & track studies that have been done, there is almost negligible difference between under hood and exterior air intake temps while the vehicle is in motion. With regards to the intercooler concept, while it is true that if you place the air exchanger directly in front of the intake it will cause air obstruction, check out how the F150 lightning does that applies that exact concept....and gains IIRR, 50+ hp?

 

I get closer to 4-5% using the ideal gas law (PV=nRT) for each 20degF change - not insignificant imho. But as other posters pointed out, there are more problems than that with a refrigerated air intake.

'seems I vaguely recall a late70's aftermarket doodad one filled with a bag of ice, intake air was drawn through the matrix of cubes. 'claimed to be good for significantly reducing intakes temps for up to ... 1/4 mile at WOT!

 

how come we dont see any big power increase when its -20 below zero ?

dont think there is any merit to this line of thinking

 

Not so, my own readings showed a wide difference in air temperature at the carb in a moving vehicle.

 

I would be really interested in seeing those readings, if you have them compiled. I think you are right. That is why I have not bought a FIPK K&N for the Expie yet. I can't imagine sucking in underhood air would be better than the factory cold-air setup

 

Sorry, I took them a number of years ago and I have slept too many times since then.

 

Subaru Sti's come with a water spray on the intercooler, with the idea that the water will evaporate and take heat with it. There is definetly some merit to the idea that cooler air is better, but you have to be careful about home you obtain it.

As others have mentioned, the idea of using AC for cooling intakes is a non starter because you'll use more energy to run the AC then you will gain from the cooler air.
It would be interesting to get some temperature probes and find out what the real difference between underhood temps and ambient is at different speeds. I'll bet it's very little. Has anyone done this?

Also, it's not just the temperature of the air, it's how much you can draw in. that's why some people build those warm air intakes. They are trading temperature for flow. Depending on the stock setup, it could be worthwhile.