Cold air intakes tend to cost much more than a simple warm air intake. The justification being that cold air equals more power and who doesnt want more power?
Banks Power say this “The general rule of thumb is that for every 10º (5.5 Celcius) of temperature drop, the density (and oxygen content) increases 1 percent. It’s actually more like 1.8 percent.”
To put it another way, lower intake temps by 10 Celcius gives (using 1.8%) a 3.2% increase in power
10/5.5*1.8 = 3.2%.
On a 400bhp engine that means +12bhp
We have done a test where we compared an open cone filter in the engine bay without heat shields to a cone filter using heat shields to isolate it from engine heat.
We saw a 12 Celcius drop using heat shields versus the standard air box
And a 4 Celcius increase in intake temps with an open filter versus the standard air box
Total difference between an open filter and a shielded filter was 16 Celcius
16 / 5.5 * 1.8 = 5.2%
On a 150 hp engine the difference between a cold air intake and an open filter would be 7.8bhp or 5.2% increase.
This is one example on one car, other cars will have different results but it should give an idea of what is possible when you use a cold air intake over an open cone filter.
Is a cold air intake worth the cost? Depends on your car and the intake system and the cost of the intake system
It is also worth bearing in mind that some cold air intake might even increase intake temps over the standard air box……..
In our testing the routing of the cold air intake could have the opposite of the intended effect if the hose/piping is routed badly.
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