Cold air

[Brightonuk]

Not really a Caterham question but I can someone educate me on the following question?

 

I get that cold air holds more oxygen molecules which in turn = more horsepower which is why those aftermarket relocation filter don't work (if pulling air from the engine bay)

Is there a point of diminishing returns when it come to air temp vs the amount of oxygen molecules in a given volume of air?

[fastg]

Play with this Dyno correction factor calculator and you can see, it's not as much as you think. Some say 1% hp per 10 degrees.

 

https://wahiduddin.net/calc/calc_cf.htm

 

Graham

[Brightonuk]

KK just a silly thought came to mind..... that is if cold air = horsepower then why not plum a cars AC into the intake still drawing air from the outside but mixed with the cold AC would that not make for denser air (more Oxygen?)

[panamericano]

KK just a silly thought came to mind..... that is if cold air = horsepower then why not plum a cars AC into the intake still drawing air from the outside but mixed with the cold AC would that not make for denser air (more Oxygen?)

 

Not to get carried away, but cold fuel is great too. I used to have trouble with vapor lock in rallies at high altitude in central Mexico. Got fed up and put a drag race (Summit) cool can in the fuel line, in the engine compartment. Add ice, or even pop cycles if all available, and the engine roared off the line. Really like a different motor.

[lucky dawg]

"In order to make sure the Demon's intake receives air cool enough to make 840 supercharged horsepower, Dodge used the car's air-conditioning system to chill intake temps. How do they do it? It actually pretty simple."

 

http://www.hemmings.com/stories/2020/12/07/ready-to-race-1957-lotus-7-should-take-podiums-not-pedestals?refer=news&utm_source=edaily&utm_medium=email&utm_campaign=2020-12-07

[coffee break]

But how much HP gets consumed to AC cool the air?

[fastg]

The AC does sap power but not as much as you would think probably 10-15hp. But the AC does not know how powerful the engine is, so it would drain the same amount of power on a Honda Civic as a Dodge Redeye. But it would pay huge dividends when you already have 700bhp. I don't think you can use the setup on a race/trackday car, the system would just heat soak quickly, but on a daily driver it would be prefect.

 

Graham

Edited January 28, 2021 by fastg
spelling auto correct

[panamericano]

Anyway, when you're ready to blast off the line, switch off the compressor. Everything should cold for some seconds...

[CarlB]

I worked for a industrial engine manufacturer. One of our distributors built a compressor package that needed a little more power. He installed a refrigeration circuit on it where the evaporator was used like a intercooler. Like the Dodge there was a net power gain at the flywheel. The refrigeration circuit needs to be designed to the engine air flow. You are moving BTUs of heat and more power requires more hot air to cool. This was a natural gas engine driving a compressor that pumped natural gas from the wells through a collection system.