Choosing an air filter
#1
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Choosing an air filter
I'm tired of my current self-destructive pre-turbo intake setup. Yeah it doesn't like heat. Also I like to hear the turbo spooling. It gets nice cool air but I don't want to find out if a turbo likes deteriorating rubber. Please excuse the dirty engine bay.
DSC_0107.jpg
DSC_0108.jpg
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So I've been looking at the K&N filters, nice big selection, but amazingly I don't see a filter that has a 60mm flange that is angled. So that seems to leave me with 57mm and 62mm, specifically one of these...
http://www.knfilters.com/search/prod...x?Prod=RU-1720
http://www.knfilters.com/search/prod...x?Prod=RU-1770
Do I get the 57 or the 62?
Are these filters big enough to support 250ish HP?
I don't care about hot air from the radiator.
DSC_0107.jpg
DSC_0108.jpg
DSC_0109.jpg
DSC_0110.jpg
So I've been looking at the K&N filters, nice big selection, but amazingly I don't see a filter that has a 60mm flange that is angled. So that seems to leave me with 57mm and 62mm, specifically one of these...
http://www.knfilters.com/search/prod...x?Prod=RU-1720
http://www.knfilters.com/search/prod...x?Prod=RU-1770
Do I get the 57 or the 62?
Are these filters big enough to support 250ish HP?
I don't care about hot air from the radiator.
#2
I would say anything is better than the current setup. I take it you plan on going turbo-AFM-filter in a straight line? Depending on the size of the filter you might have clearance issues between the hood and near the radiator fan.
If you could, take the time to measure things and make a sweep back toward the firewall like alot of people do. But realistically, anything is better than what you have right now.
Vash-
If you could, take the time to measure things and make a sweep back toward the firewall like alot of people do. But realistically, anything is better than what you have right now.
Vash-
#6
Im sorry but I LOLd at the tin foil/kragen intake pipe set up. It may sound crazy but I personally see merit in a plastic intake tube(like the company that used to make iceman inkaes used) plus PVC type tubing isnt expensive and comes in a huge amount of sizes and shapes. Idk though, metal seems to be how most people do it
#7
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Im sorry but I LOLd at the tin foil/kragen intake pipe set up. It may sound crazy but I personally see merit in a plastic intake tube(like the company that used to make iceman inkaes used) plus PVC type tubing isnt expensive and comes in a huge amount of sizes and shapes. Idk though, metal seems to be how most people do it
PVC will get brittle with heat and I've never seen it in the right size. I can't say I haven't used it for a cold air intake on my old Eclipse gs though.
#9
A mom and pop exhaust shop will bend you some tubing for your intake if you want a single piece crazy intake setup like that. If you want to do a intake with a cold air box heatshield i suggest getting a pretty small filter like what you see on Saml01's car and the filter offered in the BEGI kits.
PVC is not a good option, it doesn't withstand that kind of heat very well and it emits some kind of vapor that is bad for O2 sensors I believe.
PVC is not a good option, it doesn't withstand that kind of heat very well and it emits some kind of vapor that is bad for O2 sensors I believe.
#14
The turbo intake is about 2.5" so a coupler and this should bring it over to the shock tower and than add filter.
http://store.summitracing.com/partde...5&autoview=sku
PS: nice intercooler.
http://store.summitracing.com/partde...5&autoview=sku
PS: nice intercooler.
#15
I used to have that same hose
DSC00487Medium.jpg
I currently use a K&N RU-5111 and route it to the wiper cowl via 2.5" tubing.
0e5bc851.jpg
DSC00487Medium.jpg
I currently use a K&N RU-5111 and route it to the wiper cowl via 2.5" tubing.
0e5bc851.jpg
#16
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https://www.miataturbo.net/forum/showthread.php?t=16531
My cowl CAI setup. Very similar to what SamS did above.
My cowl CAI setup. Very similar to what SamS did above.
#18
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I know he did, and there are two K&N filter part numbers listed in the link I posted, the one I used and the one Sam used. Here is the one I am using
http://www.knfilters.com/search/prod...x?Prod=RD-0720
According the the K&N sizing guide this is large enough for 250 HP.
If the filter is too small, there will be a higher pressure drop across the element that will effectively choke the turbo. It is not an all-or-nothing thing, but gradual. Go here for sizing formulas:
http://www.knfilters.com/filter_facts.htm#SELECT
The way I did it is I doubled the engine displacement to simulate doubling the volumetric efficiency under boost.
Short answer is, get the biggest one you can fit in the available space WITH room around the outside so the air can flow into the filter. See my CAI thread for an example of what NOT to do with allowing space around the filter.
http://www.knfilters.com/search/prod...x?Prod=RD-0720
According the the K&N sizing guide this is large enough for 250 HP.
If the filter is too small, there will be a higher pressure drop across the element that will effectively choke the turbo. It is not an all-or-nothing thing, but gradual. Go here for sizing formulas:
http://www.knfilters.com/filter_facts.htm#SELECT
The way I did it is I doubled the engine displacement to simulate doubling the volumetric efficiency under boost.
Short answer is, get the biggest one you can fit in the available space WITH room around the outside so the air can flow into the filter. See my CAI thread for an example of what NOT to do with allowing space around the filter.
Last edited by ZX-Tex; 06-02-2008 at 01:50 PM.
#20
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97.7 x 7000 / 20,839 = 32.8 sq in. required for minimum surface area.
RU-5111, 4.5" x 5.75", slight taper to 3.5" at tip.
4.5 x 3.14 x 5.75 = 81.24 -.75 = 80.49 sq in.
this is not factoring the small taper, but I doubt it will lower 48 sq in of area.
RU-5111, 4.5" x 5.75", slight taper to 3.5" at tip.
4.5 x 3.14 x 5.75 = 81.24 -.75 = 80.49 sq in.
this is not factoring the small taper, but I doubt it will lower 48 sq in of area.