Originally Posted by 9000Andrew
Was this with just a k&N filter or with an open intake?
I'm not doubting what you're saying, but isn't 3hp too small to attribute to one thing? I would believe it if you did 20 runs, did an average, then replaced the air filter with the K&N, did another 20 runs, took a new average, and found the 3hp loss. To me though, something like 3hp is so small that it's probably not statistically significant at all. I also wonder if a car would need a certain amount of time to "adapt" to any changes the air filter might cause. Interesting...
We did three identical pulls with the K&N filter the three with a stock paper filter of the same size and it averaged out to 3hp differance. We found it hard to believe too. One thing we thought about was the fact of the oil in the K&N being freshlly redone and the paper filter was also new. Mabey after some laps as the get dirtier the K&N might be better. We also have found alot more dirt in our carb. after a race with the K&N. With the paper filter we have alot less dirt in the carb. We were always firm believers in K&N untill this.