Re: Air filters on race cars??
[Re: Thumperdart]
#1715107
12/25/14 07:04 PM
12/25/14 07:04 PM
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Joined: Jan 2003
Posts: 4,329 Morrow, OH
markz528
master
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master
Joined: Jan 2003
Posts: 4,329
Morrow, OH
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I use the K&N filter that mounts inside the harwood hood scoop. I really like it.
67 Coronet 500 9.610 @ 139.20 mph 67 Coronet 500 (street car) 14.82 @ 94 mph 69 GTX (clone) - build in progress......
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Re: Air filters on race cars??
[Re: DemonDust]
#1715108
12/25/14 10:10 PM
12/25/14 10:10 PM
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Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
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New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
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Quote:
What are you guys using for air filters? I notice if I take mine off I can Rev above 9200 rpms. Is there a air cleaner that can handle high rpms and cfm?
Or do you just run without them?
For a long time I used a K&N flat panel filter that fit inside my Harwood Mini-Aero scoop. I had to build the framework to mount it inside the scoop but it worked out well. The AFR tended to richen up gradually above 6500rpm but not enough to worry about. I think the Fram equivalent I used for a while actually flowed better. I never oiled the K&N element. The most recent engine is a 500ci B with Indy intake and 1150 Holley.
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Re: Air filters on race cars??
[Re: @#$%&*!]
#1715109
12/25/14 10:22 PM
12/25/14 10:22 PM
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Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
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New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
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Now I use a Wix Racing 16"x3.5" filter in a homemade box, taking air from the grill area (no more hood scoop for me). AFR no longer richens up at the top end of the 1/4 mile, no speed or ET lost (ran 132.5mph at the recent bracket finals at woodburn.) It's a little different Carburetor is IN the airbox, bottom of the box is sandwiched between the carb and intake. Underside of the hood IS the top of the air cleaner (about 2-1/2" clearance for carb top). This way the filter element is as high as possible. Airbox just lifts off once the hoses are disconnected. One nice thing about running an air cleaner is that it shows you the items that WOULD have gone through the engine, all trapped outside the filter. To generate some pressure I fabbed two panels that closed off the areas above and below the grill, making it a closed space. Air coming into the grill has to go through the air cleaner or radiator.
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Re: Air filters on race cars??
[Re: DemonDust]
#1715112
12/26/14 11:13 AM
12/26/14 11:13 AM
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Joined: Aug 2003
Posts: 1,314 Charlotte, NC
LSP
pro stock
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pro stock
Joined: Aug 2003
Posts: 1,314
Charlotte, NC
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Quote:
What are you guys using for air filters? I notice if I take mine off I can Rev above 9200 rpms. Is there a air cleaner that can handle high rpms and cfm?
Or do you just run without them?
The Wix Racing filter is what was used on your motor in NASCAR, no hp loss in the airbox, get the tallest one you can fit.
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Re: Air filters on race cars??
[Re: DemonDust]
#1715114
12/26/14 03:00 PM
12/26/14 03:00 PM
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Joined: Aug 2003
Posts: 1,314 Charlotte, NC
LSP
pro stock
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pro stock
Joined: Aug 2003
Posts: 1,314
Charlotte, NC
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Quote:
Doesn't the NASCAR air pan require duct work as well to make it efficient? The wix filters are fairly cheap if I remember correctly.
Yes, the air pan goes to a duct in the cowl, I was just talking about using the Wix Racing element.
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Re: Air filters on race cars??
[Re: MR_P_BODY]
#1715115
12/26/14 03:52 PM
12/26/14 03:52 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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our track unfortunately has some stones lifting off the seal on the return road & after seeing 1 racer get a stone flick up from their front wheel & lodge itself into carbs butterflies, i would never ever run without some kind of filtration on my carb. the car with the stone in the butterflies took off with front brakes locked on & plowed into another racecar before the owner could shut it off. not a happy day for 2 racers that day. i'm using Frams Airhogg air cleaner. it's pretty good, virtualy no difference with it on or off, but i now leave it on.
and if you are going to use a "conventional" round style air filter, get one with a breathable top. Just that much more area that is seldom used.
I found the top lid causes issues on flow... you get 2 different air paths that crash into each other and in the end you get less into the carb... I also see that its worse if you have a drop base because the air is going up first then has to turn down to get into the carb.. but the side air is plowing into the lid air ... on the track I dont run a air cleaner
All I can add to this discussion is from my own on-track testing some years ago. I was using a 14" Moroso drop-base housing w/ a K&N 14" x 3" filter and the carb was dialed in for best MPH under the conditions. I swapped to a K&N X-Stream lid and back-to-back testing the car picked up .4-.5 MPH over the standard Moroso lid.
I have limited hood clearance and this was the only way to add filter area I could work out at the time. Although I've heard more than one person p!ss on the X-Stream lid, on my car it helped.
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Re: Air filters on race cars??
[Re: mshred]
#1715117
12/26/14 05:38 PM
12/26/14 05:38 PM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
top fuel
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top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
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The trick seems to be to run enough filter surface area not to measurably restrict. For example, Holley ran a test in 1971 of air flow through a carb. No air cleaner 713 cfm Chevy hi-perf open element cleaner 675 cfm Same as above but with two filter elements stacked 713 cfm. They didn't publish the hights, but the point is once they had enough area, the restriction was the carb. (Mike Urich and Bill Fisher Holley Carburetors & Manifolds 1987 edition page 71) Another thing to consider along the line of what Mr P was describing is the impact on the bowl vents. With Holley type carbs the vent could be placed into a pressure stream, or in a weird turbulent area and that can mess up the fuel curve. A ton of ideas on modifying Bowl Vents shared at Racing Fuel Systems.
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Re: Air filters on race cars??
[Re: Mattax]
#1715119
12/26/14 05:51 PM
12/26/14 05:51 PM
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Joined: Jun 2006
Posts: 5,173 CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,173
CT
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How about running a bigger filter with a drop base? Is that really helping or is the drop base causing other issues worse than a smaller filter?
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
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Re: Air filters on race cars??
[Re: GTX MATT]
#1715120
12/26/14 06:01 PM
12/26/14 06:01 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
How about running a bigger filter with a drop base? Is that really helping or is the drop base causing other issues worse than a smaller filter?
From the testing I did the drop base causes the air to go up then turn down into the carb... it can cause disturbance with the direction changes.. but is it greater or lesser than the small height air cleaner.. I'm sure that at some point its a wash.. but if you can go to a larger diameter that should help so the air has a longer area to make the turn
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Re: Air filters on race cars??
[Re: BradH]
#1715121
12/26/14 06:03 PM
12/26/14 06:03 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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our track unfortunately has some stones lifting off the seal on the return road & after seeing 1 racer get a stone flick up from their front wheel & lodge itself into carbs butterflies, i would never ever run without some kind of filtration on my carb. the car with the stone in the butterflies took off with front brakes locked on & plowed into another racecar before the owner could shut it off. not a happy day for 2 racers that day. i'm using Frams Airhogg air cleaner. it's pretty good, virtualy no difference with it on or off, but i now leave it on.
and if you are going to use a "conventional" round style air filter, get one with a breathable top. Just that much more area that is seldom used.
I found the top lid causes issues on flow... you get 2 different air paths that crash into each other and in the end you get less into the carb... I also see that its worse if you have a drop base because the air is going up first then has to turn down to get into the carb.. but the side air is plowing into the lid air ... on the track I dont run a air cleaner
All I can add to this discussion is from my own on-track testing some years ago. I was using a 14" Moroso drop-base housing w/ a K&N 14" x 3" filter and the carb was dialed in for best MPH under the conditions. I swapped to a K&N X-Stream lid and back-to-back testing the car picked up .4-.5 MPH over the standard Moroso lid.
I have limited hood clearance and this was the only way to add filter area I could work out at the time. Although I've heard more than one person p!ss on the X-Stream lid, on my car it helped.
Helped on mine also. I have some issues with it disrupting air flow in to the carb, especially since it covers a lot more area than the inlet area of the carb it is sitting on. If there is an air flow disruption, I would think a lot depends on the distance of the top to the carb inlet. I still think the more filter area you have, the better.
Fastest 300
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Re: Air filters on race cars??
[Re: mshred]
#1715122
12/26/14 06:07 PM
12/26/14 06:07 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I run a 14x5" tall K&N reusable filter...My buddy harassed me to make a pass with it off because the car would pick up.
I removed it and lost a tenth...He couldn't believe it! LOL...FWIW I would rather run it and know that my engine is getting the cleanest air possible instead of take the chance of feeding it dust and other debris that could possibly damage or wear it out quicker. I have seen people do tests where they lost no power with the filter, so hopefully mine is the same way
Did you jet up or down after taking the air cleaner off... without finding the A/F point that your engine likes for max power you didnt do anything but change the A/F ratio.. nothing is ever as easy as.. just do this or that and this occurs
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Re: Air filters on race cars??
[Re: Crizila]
#1715124
12/26/14 06:17 PM
12/26/14 06:17 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
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our track unfortunately has some stones lifting off the seal on the return road & after seeing 1 racer get a stone flick up from their front wheel & lodge itself into carbs butterflies, i would never ever run without some kind of filtration on my carb. the car with the stone in the butterflies took off with front brakes locked on & plowed into another racecar before the owner could shut it off. not a happy day for 2 racers that day. i'm using Frams Airhogg air cleaner. it's pretty good, virtualy no difference with it on or off, but i now leave it on.
and if you are going to use a "conventional" round style air filter, get one with a breathable top. Just that much more area that is seldom used.
I found the top lid causes issues on flow... you get 2 different air paths that crash into each other and in the end you get less into the carb... I also see that its worse if you have a drop base because the air is going up first then has to turn down to get into the carb.. but the side air is plowing into the lid air ... on the track I dont run a air cleaner
All I can add to this discussion is from my own on-track testing some years ago. I was using a 14" Moroso drop-base housing w/ a K&N 14" x 3" filter and the carb was dialed in for best MPH under the conditions. I swapped to a K&N X-Stream lid and back-to-back testing the car picked up .4-.5 MPH over the standard Moroso lid.
I have limited hood clearance and this was the only way to add filter area I could work out at the time. Although I've heard more than one person p!ss on the X-Stream lid, on my car it helped.
Helped on mine also. I have some issues with it disrupting air flow in to the carb, especially since it covers a lot more area than the inlet area of the carb it is sitting on. If there is an air flow disruption, I would think a lot depends on the distance of the top to the carb inlet. I still think the more filter area you have, the better.
More air is better... I'm sure that if you run a taller filter the lid has less effect on it than a shorter filter.. but air coming in from 2 different directions and 90* from another does have effect... and the closer they are the worse things get
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