str8ridin

Summer time is rolling around and I am feeling the effects of the hot weather on my car’s performance. So I perused quite a few SAE articles regarding intake temperatures and their effect on different engine applications and found an interesting standard: By using the SAE correction factor "B" for temperature's effect on horsepower, we see that the correction factor for temperature is approximately 1% per ten degrees. That is, you get a 1% increase in horsepower for each 10 degrees you lower the temperature of the incoming air into your filter.

I am certain that many of you have personally felt the difference, on a cool, perhaps damp
(there is another correction for that) morning, when your car seemed to have more power than usual, and that those of you who have been lucky to participate in track days have posted lap times in the cool of the morning you could not equal on the warmer afternoon sessions.

So, when comparing the extremes of winter and summer weather, say 10F vs. 90F and using the 10degree/1% power gain correction factor equation, in the CLK 430’s case:
90-10 = 80 * .10 = 8% power increase for a 275hp car which is somewhere around a 22hp difference between the extreme summer and extreme winter case, then I guess cold air should be taken seriously.

Interestingly enough, our cars have their air intake on top of the engine, thus heating our intake housing and filters up significantly. Bad design? Necessity for packaging? I don’t know. But the idea of heat blocking shields that sit between the intake and the engine has been tossed around. Even if it’s good for reducing intake temperatures by 20 degrees, that’s about 6HP. People pay a lot for 6HP, when a simple piece of insulation can get that for you.

If you have any ideas on how to lower the intake temperature or induce it differently in our cars, please feel free to comment.

RX_Renesis

maybe taking the insulation off under the hood would keep the engine compartment a little cooler? they're design to keep heat in during winter days... so y not take them off in summer days?

E55AMG99

There are a lot of guys running around with their intake box insulated. Search the E55 forum for more details.

Josh K

Actually, I believe the insulation is there for noise reduction purposes.

str8ridin

That's a good idea, but wouldn't it also compromise the paint on the hood? For example heat the hood too much? I'm not sure.

str8ridin

Cool. But has any one done a intake temperature test on the difference it makes? Or even dynoed different results?

Ghostrider

Hey str8ridin where did you get your CLK 55 airbox?

str8ridin

Some guy off benzworld.com who supercharged his CLK55.

Ghostrider

Hey thanks, I've been having a hard time finding one. But then again I've only been looking for a week.

E55AMG99

I don't remember but I think some of them track tested before ad after. Take a look at the posts for more info.