Quote:
Originally Posted by harp00n
any thoughts about the AFE drop-ins? are they good at filtering? 
p.s. I also thought about heat shielding stock airboxes, so it would be nice to know if it makes sense  |
Personally, I'm a fan of oiled cotton media, but a lot of new synthetics have spec sheets that suggest they flow about as well.
Interestingly enough, AEM used to post evidence that their media outperformed paper and oiled cotton medias when literally caked with dirt. However, they also showed that it was inferior in flow to oiled media that was clean (go figure, they pulled the chart off their site -- I posted it here somewhere; probably in my gallery).
Anyway, on a N/A motor the difference will be pretty negligible in terms of power (maybe a bit more of a difference on a boosted engine), but I find the oiled media tends to do a better job of rejecting moisture in the air, and it seems to flow better when clean, so that's what I go with.
Additional heat shielding may or may not be worth it. It's pretty much unknown, but if metered air temps are close to ambient already when moving, then no.
It might reject some radiant heat sitting at idle, especially on an already blazing hot day, but I doubt the difference would be more than 1-2 whp because the air itself is still going to be heated up above ambient as it's drawn inside the bumper.
Won't hurt to experiment for sh!ts and grins, but really all this extra shielding is overkill for a DD -- The OEM airboxes proably work very well as they are and any further imporvements will yeild diminsihing returns.
This might be something to think about for drag racing, but if so, while your at it, why not mist the IM down to control even more heat?
Again, unless you can log what the ECU is seeing (or get a very good estimate with sets of thermistors) it's really hard to determine what effect if any extra shielding would have anyway.