I removed my air cleaner at the track last year because the Jegs 14x4 filter I bought ( that was adverised to have air flow that was similar to the same size K&N filter ) cause my car to run about a half second slower than when I ran it without a filter. I didn't like running the car without a filter so this year I decided to bite the bullet and pay the extra money for the K&N filter, 14x4 race filter ( #E-3730R ), XSTREAM filter lid, and their STUB STACK. What worked I was going to keep and what didn't I was going to send back. I know their are a lot of variables, so the results that I got won't necessarily be the same as someone with a different set up. I have a 55 Chevy, 3700 lbs., 350/350hp sb, turbo 350 trans., 2800 stall, 3.90 rear, 275/60/15 tires. I thought that anyone with a similar set up to mine may be interested in the 1/4 mile ET results of my test last week at our local tracks opening test and tune weekend. Below are the results. 1st run - no filter - 13.79 2nd run - with filter - 13.80 3rd run - with filter & Stub Stack - 13.81 4th run - with filter, Stub Stack, & XSTREAM filter lid - 13.85 I repeated the same four runs with a 20 min. cool down period between each run and had similar results. The air temp. stayed within a few degrees all day and I ran in the same lane every time, also, my car is a little more consistent if I let it shift itself so that's what I did. As you can see, the K&N filter did perform better than the Jegs so this year I can run with a filter and not loss any performance, but the EXTREAM filter lid and the Stub Stack didn't improve my cars performance at all. K&N's race filter is advertise to flow 200 cfm more than their Universal filter of the same size ( 1200 cfm to 1000 cfm for a 14x4 ) but it doesn't filter quite as well, so I plan to us the race filter at the track and keep the Jegs filter for street use.
If I was running for best time on a track. I would not use any filter but only a panty hose material and change it every time I run it. That'll give you all the air your engine wants. I'll be interested to hear the responses I get from those running the tracks.
I did a test like that on my car at the time,and it went better with the air cleaner on (k&n with XSTREAM filter lid) than without an air filter. so no more dirty carburetors for me.
One of the rags did a dyno filter test with the K N extreme and it produced a couple more hp. I know some of you guys will hate this but I just bought a used one time K N 14 X 3 with extreme lid for 40 bucks off craigs list. The guy had it on a flat bottom boat with an open engine, it rained the afternoon he put it on and didn't realize the extreme top would let water through. I already had a 14 X 4 element on my 41 so I added the extreme lid to that.
Don't know about the run, but since the K&N flows more air, it'll flow more dirt too. Had an experienced engine builder tell me this a long time ago - saw an article on it about two years ago too. Great for track, not sure I'd run 'em on a daily if I was in a truly dusty dirty environment...normal around town? Probably.
we ran them in our offroad rigs,,mainly cause you could wash them out ..didnt use the lids though....
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