Part # for K&N 'Shorty' 4 inch air filter
I use a 6 inch to 4 inch velocity stack with a Stainless Mesh filter with a 6 inch opening which connects to the velocity stack.
A 45 degree steel reinforced 4 inch silicon hose that is slightly angled upward sit the filter perfectly for my set up. Gets a little bit of cold air in that location as well.
Definitely did not hinder power on the dyno.
A 45 degree steel reinforced 4 inch silicon hose that is slightly angled upward sit the filter perfectly for my set up. Gets a little bit of cold air in that location as well.
Definitely did not hinder power on the dyno.
Instead of using a short filter, I modified the top of my Koyo rad.
Cut off the 45 degree downward bend of the top pipe.
Buy a metal hose from my http://www.coolflex.com/cfm/welcome.cfm.
Bend to fit and cut an appropriate length.
You will need two silicone adapters as the rad and hose are different diameters.
Cut off the 45 degree downward bend of the top pipe.
Buy a metal hose from my http://www.coolflex.com/cfm/welcome.cfm.
Bend to fit and cut an appropriate length.
You will need two silicone adapters as the rad and hose are different diameters.
Someone shared his concern over my type of setup failing on some cars.
The problem is with the hose adapter that they supply, two pieces glued together, and of not best quality.
The "Hose Techniques" adapters are way supperior. At the beginning I even used two clamps per end but found it was not necessary.
The problem is with the hose adapter that they supply, two pieces glued together, and of not best quality.
The "Hose Techniques" adapters are way supperior. At the beginning I even used two clamps per end but found it was not necessary.
Thread Starter
Joined: Mar 2001
Posts: 30,807
Likes: 648
From: FL-->NJ/NYC again!
Juuuuust bought another RU-2510 for the CYM i recently picked up, which has similarly restrictive area for the filter for the GT35R.
Would you believe the filter I removed came from my old VR R1, back when IRP built the CYM it fit on perfectly and the customer was happy to have a free 'OG' filter..... made 400 rwhp all these years with no problems
Would you believe the filter I removed came from my old VR R1, back when IRP built the CYM it fit on perfectly and the customer was happy to have a free 'OG' filter..... made 400 rwhp all these years with no problems
I just melted my K&N RC-8180 as it attached to the turbo housing on my S366.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.
I killed a 4” ID K&N filter in exactly the same way. It was installed on a Holset HE351 VGT. Very small VGT A/R with rotary EGTs ended up melting the rubber boot on the filter! The filter is now a cup holder on my desk and K&N replaced it no questions asked.
Last edited by Shainiac; Nov 18, 2015 at 03:45 PM.
I just melted my K&N RC-8180 as it attached to the turbo housing on my S366.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.
Thread Starter
Joined: Mar 2001
Posts: 30,807
Likes: 648
From: FL-->NJ/NYC again!
I just melted my K&N RC-8180 as it attached to the turbo housing on my S366.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.
a quick google search resulted with this:
BMS Silicon Single Turbo Filter 4.5" 3.75"- BurgerTuning.com
Its a BMW thing, but it might work.
i was also thinking that maybe i can slip a short coupler over the turbo and mount a larger diameter filter with a larger flange over the top of a silicone couple to better insulate.... but I am still looking around.

I measured and only the smallest of filters may fit. I ordered the K&N RX-4130-1 Universal X-Stream Clamp-On, Universal Air Filters
If it seems to be a problem I will have an offset aluminum pipe made and put on a full size filter. Right now I need a quick fix so I don't continue to destroy the compressor wheel and enjoy what's left of the driving season.
If it seems to be a problem I will have an offset aluminum pipe made and put on a full size filter. Right now I need a quick fix so I don't continue to destroy the compressor wheel and enjoy what's left of the driving season.
Joined: Oct 2001
Posts: 6,279
Likes: 728
From: Florence, Alabama


manifold design is lots more than where does the turbo fit easiest in the engine compartment and the airfilter is one of the considerations.
it is all about maximizing oxygen molecules into the engine...
a couple of A list items in that process:
1. minimize flow restriction
filters are an important item here and as someone earlier said.... bigger is better.
restriction measured at 1.5 inches of water by K&N indicates short filters only flow 350 CFM while large filters flow over 1100.
my filter flows 1187 CFM at 1.5 water.
500 rotary rwhp takes 960.
2. minimize heat. cooler air contains MORE oxygen. more oxygen means more power. the last thing you want is to have your filter directly in front of a heat exchanger


Howard
Lol, thanks Howard. I actually didn't build this setup. I'm just looking to make it work for now. Before the final tune I may get the coupler so I can run the filter down the side of the intercooler.
might try scooting the intercooler over an inch if possible, in order to get a 45* coupler in there.
ran into a similar issue with my new electric fan, but still had wayyyy more room than that.. lol
sadly turbos really don't like to draw air from a tube, even one with a slight radius, but sometimes you gotta do what you gotta do to not suck on dirt.
ran into a similar issue with my new electric fan, but still had wayyyy more room than that.. lol
sadly turbos really don't like to draw air from a tube, even one with a slight radius, but sometimes you gotta do what you gotta do to not suck on dirt.
Last edited by RotaryEvolution; Nov 19, 2015 at 05:03 PM.
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