Air Filter or Not???

NickTF

NickTF

Single turbo turd.
Joined
Jun 4, 2007
Messages
5,887
After running poorly yesterday I called AFE to get flow numbers for my filter. At 1.5" of water the filter only flows 527cfm (the 18" L version, mine is only 12" but I was told the inlet diameter is the biggest contributor to flow). Obviously that is a bit shy of what I estimate to be around 1500-1600cfm of compressor flow from my 11 blade s475. In any event I am curious as to how many of you are running with a filter and how many of you are taking it off completely???
 
hmmmm......... It certainly makes sense because at 1/3rd the flow rate of my turbo it should be costing me quite a bit of power! Ofcourse flow rate is probably at higher at the vacuum my turbo applies to it but still.......
 
The only thing i dont like about running no filter/intake setup is the fact it pulls soo much heat from the engine compartment into the turbo. Really thought about running the old Dmax headlight delete mod and running my intake piping there
 
In my case anything has to be better than running with roughly a third of the turbo's flow rate being supplied to it.......
 
I have ran my all kinds of different ways..filter on, no filter with boot and intake pipe still on, 5" pipe sticking out of my head light, and pipe sticking out the head light with a 10" funnel on it and it ran the same time every pass haha. Also I dynoed with all those different ways and it was like .xx difference in hp so not even one hp gain from it being removed. Hope this helps!
 
With a few mandrel bends you could make a pipe that runs from the turbo to behind the passenger headlight, dmax style
 
I went from 800's to 900's by taking mine off. It was apparently severely undersized.
 
r-rated diesel said:
I have ran my all kinds of different ways..filter on, no filter with boot and intake pipe still on, 5" pipe sticking out of my head light, and pipe sticking out the head light with a 10" funnel on it and it ran the same time every pass haha. Also I dynoed with all those different ways and it was like .xx difference in hp so not even one hp gain from it being removed. Hope this helps!
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What filter did you have on the truck?
 
like I said before, I went from 12.8 to 11.8 instantly on back to back runs at the track, and my filter is by no means undersized (recent cleaning it as well)

it was the difference of about 3 sec of spool up at the line.
 
ahale2772 said:
like I said before, I went from 12.8 to 11.8 instantly on back to back runs at the track, and my filter is by no means undersized (recent cleaning it as well)

it was the difference of about 3 sec of spool up at the line.
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WHAT! Alex, are you serious? My filter is a little on the small side. I might hit the track this weekend, just to see if it makes any difference at all.
 
So it looks like we have one guy who's had success with a filter on and all others indicating to drop there's off. Good thread, keep the input coming!
 
In my opinion, under hood air temp does not matter as the turbo compresses and heats the air anyway. I know I have heard of outlet temps on the compressor being over 500* and with a good CAC the IAT at the plenum being sub 200*. So the 200*(just pulling out of thin air) that is being pulled from the engine bay is irrelevant.
 
Mines the 12" long filter with the end of the filter sucking air as well. I got it from Johnny at Stainless diesel. Wish I could pick up those kinds of numbers by taking mine off..
 
You know, I had to put a smallish K&N on my truck after I trashed the previous filter playing. Now that I'm thinking about it...that's around the same time my truck started smoking a lot and getting worse mileage. I know how to oil a filter properly so I'm wondering if this pep boys special is choking my truck.
 
Mine didn't make any difference with or without. That's on a s&b big dry filter
 
My Junker Drag truck showed almost zero gain running back to back with and without the AFE (24-91026) 6" inlet, 9" base by 7" top by 9" long inverted cone filter. The gain was just under 1/2 mph, so little that I leave the filter in-place when I'm at a lazy track outing.

24-91026a_1600.jpg


I haven't tried back to back pulling the the filter on my 98' with the smaller HT60, I'll have to do that and report back.
 
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diesel_importer said:
WHAT! Alex, are you serious? My filter is a little on the small side. I might hit the track this weekend, just to see if it makes any difference at all.
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yes, that being said, it made a huge difference in spool up at the line, which helped launch the truck better, but even with my low traction I was at consistant 1.9ich 60's floating at about 12.2... then I pulled my filter 2 seconds before a run, and nailed my first 11.8, and ended up doing an 11.7 that night as well

not exactly a small filter either
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B1322961-B72D-4B11-BE8E-5324CE1FB0EA-277-0000001307A48D64_zps22de0131.jpg
 
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