K&N Airbox vs Smooth Tubes and Filters?

Kid97GTS

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The explanation I was given is that for about $400 more, the carbon fiber airbox will give you a little more power at high speed (i.e., when the effect of the forced air through the airbox is greatest). However, I was told by the dealer that the new airbox is not good with rain and water getting into the duct, unlike the stock airbox. I decided that for the amount of racing at high, sustained speeds versus the amount of street and possibly rainy driving I do, it wasn't worth it. But I would be interested to hear other experiences with the actual use of the airbox..........
 

GTS Dean

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I bought a Hennessey carbon fiber airbox last spring. I saw about 3-4 cars at TWS last weekend running the K&N setup. The K&N runs the cone filters which flow a little better, but the air then makes back-to-back 90 degree direction changes before the throttle plates. The HMS unit is extremely well crafted, whereas the K&N looks like it was hurried into production in about 1/2 a day.

As you can see in the accompanying photos, the HMS unit has a very gentle and well designed convergence area behind the panel filters - vastly superior to the stock setup. At TWS, I think the HMS box is worth 4-5 mph over the stock box with filters and hoses. (136 vs 140-141 mph)
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phoeve

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I, as several others before me, modified the K&N air box to flow better. I trashed the "S" curved tubes and replaced them with very large smooth tubes (truck radiator hose). I have never had any problems in the rain. I don't think the cones are positioned to allow much water to enter anyway.
 

Kurt 97 GTS

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I remember an older post (3-4 months) which covered this subject in detail. If I can recall correctly, I believe the K&N box did not have much, if any HP increase over the stock airbox with K&N's and smoothies. Check the archieves for more. Hope this helps
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