In Reply to: i see... posted by pikachu! on October 03, 2000 at 18:12:43:
You're so sneaky....
Of course the stock airbox will be cooler. It's plastic, fairly insulated and helps to isolate incoming air from the engine.
But it's flow rate tends to be less than optimal.
So here's the trade-off....
Yes, the intake temps will still be high in some cases (at least with the VW dub here), but the power gains by going to a more efficient filter has to outweigh the temp/power loss.
The intake charge issue is better illustrated or even more relevant on SC or Turbo cars. Pressurized air already is hot. A warm day is even more deathly to a force fed car. Thus, an efficient intercooler is needed to cool the intake charge down.
If intake charge wasm't an issue, then why are the drag cars running intercoolers? Or why do the GT/race cars run the filter (shielded or far way from a hot spot) in the direct path of cool fresh air?
Well anyway, in our friends case...no the car probabluy won't blow up without the heat shield...but on a warm day...the motor won't appreciate it.
Feel free to disagree, but I'm willing to bet you will find more info saying keep the filter nice and cool versus exposing it to heat sources.
Just a design guy who built 4 GReddy/Spearco turbo systems and 3 supercharged systems in the Japanese world.