A Simple Intake Modification

[Rey]

The R-Spec air filter box is fairly restrictive, even with a K&N filter.

So far, no one has offered an aftermarket cone filter; and it seems unlikely that anyone will do so. The market is very small.

I adapted a K&N model RF1040 filter to my R-Spec. This is a large filter with a 4" (102mm) opening flange. I had previously had this same filter on my '05 Cadillac CTS-V, which is 5.6 liters. It was part of a Lingenfelter kit.

Filter size is everything. Do not buy one of those cute little cone filters offered at parts stores. Think big.

The install on a R-Spec is incredibly simple, and can be reversed to stock in a few minutes. The air box itself is held by three 10 mm bolts and is easily removed complete with an entry cone from the front of the radiator. You will first have to remove the decorative flange around the front of the hood. It is simple to do.

Just unbolt the exit flange from the air box. You will mount the filter on the interior side of this flange. It is just a bit loose, and you may want to try another K&N that has a 99 mm opening flange. Just choose one with the largest filter area.

The K&N filter can hang without support. You will want to remove the entry cone from the OEM air box. It has three clips - one of which is hidden. This cone fits loosely without connection to the air intake near the top of the radiator. It will not stay in place unsupported, so I suggest duct taping it to the air intake.

O.K. what is the result? There is a material power increase. By my measurements intake air temperature is reduced a couple of degrees. Pumping losses are reduced, and gas mileage is improved slightly on light throttle cruise. There is absolutely no noise increase under light acceleration or cruise. When you step on it you will hear a motor now.

Cost, about $50 plus shipping and an hour or so of your time. Have fun.

 

[wooshman]

Can you post a picture? What is the specific filter that you used? Appreciate the post. These are great cars and I have been a bit surprised that performance mods are rarely mentioned here.

 

[Rey]

No picture to date. The exact filter used is a K&N RF1040.

 

[newman]

The R-Spec air filter box is fairly restrictive, even with a K&N filter.

So far, no one has offered an aftermarket cone filter; and it seems unlikely that anyone will do so. The market is very small.

I adapted a K&N model RF1040 filter to my R-Spec. This is a large filter with a 4" (102mm) opening flange. I had previously had this same filter on my '05 Cadillac CTS-V, which is 5.6 liters. It was part of a Lingenfelter kit.

Filter size is everything. Do not buy one of those cute little cone filters offered at parts stores. Think big.

The install on a R-Spec is incredibly simple, and can be reversed to stock in a few minutes. The air box itself is held by three 10 mm bolts and is easily removed complete with an entry cone from the front of the radiator. You will first have to remove the decorative flange around the front of the hood. It is simple to do.

Just unbolt the exit flange from the air box. You will mount the filter on the interior side of this flange. It is just a bit loose, and you may want to try another K&N that has a 99 mm opening flange. Just choose one with the largest filter area.

The K&N filter can hang without support. You will want to remove the entry cone from the OEM air box. It has three clips - one of which is hidden. This cone fits loosely without connection to the air intake near the top of the radiator. It will not stay in place unsupported, so I suggest duct taping it to the air intake.

O.K. what is the result? There is a material power increase. By my measurements intake air temperature is reduced a couple of degrees. Pumping losses are reduced, and gas mileage is improved slightly on light throttle cruise. There is absolutely no noise increase under light acceleration or cruise. When you step on it you will hear a motor now.

Cost, about $50 plus shipping and an hour or so of your time. Have fun.

Hi Rey -

Thanks so much for sharing. I really appreciate all the knowledge that you are taking the time to share with us.

Of course, now that I read this post two days after installing a standard K&N air filter replacement I think that you just cost me $50

Question though - what do you think the difference is between this setup you describe and a CAI? How much performance jump do you think that there is between the standard air filter and the K&N versus the K&N and the setup you are describing?

Thanks,
Newman

 

[Rey]

There is definitely a performance jump from a K&N drop in filter to a stand-a-alone K&N cone filter. That was my experience.

 

[j-georges]

Seriously, we need pictures of this !

 

[wil_b]

Seriously, we need pictures of this !

+1 agreed!

 

[Rey]

Sorry about the photos. I am a beginner at digital photos, and it took some time to figure how to reduce pixels for this forum. Whatever, I think I have downloaded a couple of photos. If not, then someone email me at reykirkman@comcast.net; and I will email back photos for posting by someone who is more knowledgeable.

Let me point out a few things. One, I removed the "cover" over the radiator for this particular stage. The cover itself is restrictive and I wanted as much outside air as possible to the filter. In so doing I am preserving the ability to return to stock unmolested.

I had an extra airbox (long story) and am using the secondary airbox access, the one covered by the flap. This required butchering the old airbox, and I am not sure of any measurable benefit as this access point is not directly to outside air. You can see the top of the access port - it is bolted by two bolts in front of the K&N.

I also have an extra "cover" which I have modified, increasing the air flow opening and cutting off part which would partially cover the new cone filter. I have not photographed this final mod, as I wanted to show a mod that can be easily reversed to OEM.

I think it is vitally important to use the largest cone air filter you can find. There may be larger than the 1040 (sic) I am using, but I have not found any to date. Please let me know if you can find a larger filter.

I think if someone were to market this mod it should include a plastic/composition enclosure so as to block engine heat. This is the engineering which is unique, and allows a vendor to charge big bucks for a cold air intake. If you look closely, you can see a piece of brown sheet metal I have attached to the dipstick, which offers some heat shielding. Anything one can do to reduce intake air temperature is beneficial and "free horsepower" that not only increases power, but also efficiency (gas mileage).

Finally, after this mod, it would not hurt and probably be helpful to "reboot" your ECU. Merely disconnect the battery overnight is the easiest way to do this.

 

[bradyb]

doesn't the stock box have a cold air ram ( under the hood opening) and an additional cold air entry behind the right headlight (connected to the magnetized restriction flap) - btw i have the 4.6 so im not sure if the intake is the same setup...

 

[Rey]

BradyB,
The 4.6 air filter box is essentially the same in the R-Spec. The R-Spec does not have the secondary "filter". The R-Spec does not have a mass air flow meter, which the 4.6 does. I had a the same cone filter on my 4.6s, with a very important difference. I attached a 4" long aluminum tube between the air filter and the connection to the OEM air filter box. This is necessary to smooth air flow to the mass air flow sensor. I also removed the screen from the mass air flow sensor.
You can see that my mod retains the front over-the-radiator air intake and the secondary (flap protected) air intake in front of the right headlight.

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[newman]

Attempting a re-upload of Rey's modification pictures to see if we can get them a bit larger.

Cheers,
Newman

 

[rgarret2]

Sorry about the photos. I am a beginner at digital photos, and it took some time to figure how to reduce pixels for this forum. Whatever, I think I have downloaded a couple of photos. If not, then someone email me at reykirkman@comcast.net; and I will email back photos for posting by someone who is more knowledgeable.

Let me point out a few things. One, I removed the "cover" over the radiator for this particular stage. The cover itself is restrictive and I wanted as much outside air as possible to the filter. In so doing I am preserving the ability to return to stock unmolested.

I had an extra airbox (long story) and am using the secondary airbox access, the one covered by the flap. This required butchering the old airbox, and I am not sure of any measurable benefit as this access point is not directly to outside air. You can see the top of the access port - it is bolted by two bolts in front of the K&N.

I also have an extra "cover" which I have modified, increasing the air flow opening and cutting off part which would partially cover the new cone filter. I have not photographed this final mod, as I wanted to show a mod that can be easily reversed to OEM.

I think it is vitally important to use the largest cone air filter you can find. There may be larger than the 1040 (sic) I am using, but I have not found any to date. Please let me know if you can find a larger filter.

I think if someone were to market this mod it should include a plastic/composition enclosure so as to block engine heat. This is the engineering which is unique, and allows a vendor to charge big bucks for a cold air intake. If you look closely, you can see a piece of brown sheet metal I have attached to the dipstick, which offers some heat shielding. Anything one can do to reduce intake air temperature is beneficial and "free horsepower" that not only increases power, but also efficiency (gas mileage).

Finally, after this mod, it would not hurt and probably be helpful to "reboot" your ECU. Merely disconnect the battery overnight is the easiest way to do this.

Hi Rey, thanks for the post. Tried the mod on my 2012 Equus and it's just what the doctor ordered. Engine feels stronger throughout the rpm range, especially in the lower range, and you can hear a nice growl from mid to heavy acceleration.

I have a couple of suggestions for the install. Don't know if the filter element rubs against the high beam access cap on the Genny, but it does on the Equus. To reduce rubbing and/or have the filter steel top rest against the high beam cap and the wire directly below the filter, turn the filter at a 45 degree angle with the front pointed down and the rear pointed up. I also installed gorilla velcro (soft side) on the access cap and the wire to reduce wear and prevent filter element damage. With the engine heat, we'll see how long the tape lasts. My other concern is the reduced surface area that the filter neck is installing on, therefore, I'll be checking the filter for movement and clamp loosening due to vibration, etc.

I was able to save all of the decorative fascia, so the install looks about as OEM as it can be with the exception of the big a** K&N staring at you. The initial install took about an hour +, but with everything dialed in and practice, the conversion should take between 30-45 minutes.

I have not disconnected the battery to reboot the ECU yet since resetting equipment (i.e. sunroof, etc.) is required per the manual, but will be to see if additional gains can be had. BTW, I found the filter online through A****n.com for $42 and change with shipping included!!

For those wanting to convert their cars to an OEM box K&N panel filter, you may benefit from removing the magnetic flap by removing the screw securing the flap housing onto the intake box. After removing the screw, pull the flap housing away from you, if you're facing the rear of the vehicle, and pull up the flap housing to remove.

 

[forzza1]

What is the typical hp gain?

 

[Skywagon]

Folks,
I'm not looking for an argument. However, the only way one will ever know how much HP one gains from any modification is by doing dyno runs before and after the mod is completed and preferably on the same day when temperature, baromatric pressure and humidity are still the same. "Feeling" a difference is wishful thinking and I am guilty of it as much as anyone else.

 

[rgarret2]

I agree with Skywagon. The engine feels stronger but without an accurate dyno run in a controlled environment, it's anybody's guess.

Without a dyno, you can estimate HP gains by doing 0-60 runs with OEM box, then the conversion, as long as a controlled process (i.e. cool down period, outside temp, acceleration run direction, etc.) is followed.

I did not do the comparo and will not convert back to OEM anytime soon, otherwise, I'd gladly post times.

 

[Seanrspec]

Hey everyone I found a video on you tube I think will help.

 

[23Dawggg]

Attempting a re-upload of Rey's modification pictures to see if we can get them a bit larger.

Cheers,
Newman

What filter is this

 

[23Dawggg]

Sorry about the photos. I am a beginner at digital photos, and it took some time to figure how to reduce pixels for this forum. Whatever, I think I have downloaded a couple of photos. If not, then someone email me at reykirkman@comcast.net; and I will email back photos for posting by someone who is more knowledgeable.

Let me point out a few things. One, I removed the "cover" over the radiator for this particular stage. The cover itself is restrictive and I wanted as much outside air as possible to the filter. In so doing I am preserving the ability to return to stock unmolested.

I had an extra airbox (long story) and am using the secondary airbox access, the one covered by the flap. This required butchering the old airbox, and I am not sure of any measurable benefit as this access point is not directly to outside air. You can see the top of the access port - it is bolted by two bolts in front of the K&N.

I also have an extra "cover" which I have modified, increasing the air flow opening and cutting off part which would partially cover the new cone filter. I have not photographed this final mod, as I wanted to show a mod that can be easily reversed to OEM.

I think it is vitally important to use the largest cone air filter you can find. There may be larger than the 1040 (sic) I am using, but I have not found any to date. Please let me know if you can find a larger filter.

I think if someone were to market this mod it should include a plastic/composition enclosure so as to block engine heat. This is the engineering which is unique, and allows a vendor to charge big bucks for a cold air intake. If you look closely, you can see a piece of brown sheet metal I have attached to the dipstick, which offers some heat shielding. Anything one can do to reduce intake air temperature is beneficial and "free horsepower" that not only increases power, but also efficiency (gas mileage).

Finally, after this mod, it would not hurt and probably be helpful to "reboot" your ECU. Merely disconnect the battery overnight is the easiest way to do this.

Did you see improvement

Sorry about the photos. I am a beginner at digital photos, and it took some time to figure how to reduce pixels for this forum. Whatever, I think I have downloaded a couple of photos. If not, then someone email me at reykirkman@comcast.net; and I will email back photos for posting by someone who is more knowledgeable.

Let me point out a few things. One, I removed the "cover" over the radiator for this particular stage. The cover itself is restrictive and I wanted as much outside air as possible to the filter. In so doing I am preserving the ability to return to stock unmolested.

I had an extra airbox (long story) and am using the secondary airbox access, the one covered by the flap. This required butchering the old airbox, and I am not sure of any measurable benefit as this access point is not directly to outside air. You can see the top of the access port - it is bolted by two bolts in front of the K&N.

I also have an extra "cover" which I have modified, increasing the air flow opening and cutting off part which would partially cover the new cone filter. I have not photographed this final mod, as I wanted to show a mod that can be easily reversed to OEM.

I think it is vitally important to use the largest cone air filter you can find. There may be larger than the 1040 (sic) I am using, but I have not found any to date. Please let me know if you can find a larger filter.

I think if someone were to market this mod it should include a plastic/composition enclosure so as to block engine heat. This is the engineering which is unique, and allows a vendor to charge big bucks for a cold air intake. If you look closely, you can see a piece of brown sheet metal I have attached to the dipstick, which offers some heat shielding. Anything one can do to reduce intake air temperature is beneficial and "free horsepower" that not only increases power, but also efficiency (gas mileage).

Finally, after this mod, it would not hurt and probably be helpful to "reboot" your ECU. Merely disconnect the battery overnight is the easiest way to do this.

did you see improvement

 

[Karrit2049]

Hey Guys,

I liked this idea a lot but I didn't like not having a heat shield for the air filter. This might be a little overkill but it actually turned out pretty good.

I made a heat shield out of 1/8" plexiglass. I went ahead and also drew up the plans for it in case someone wants to make one, I'll do a write up on it if needed. The cost wasn't that bad either, I ordered the plexiglass off of Amazon and the weather stripping as well. Plexiglass was $45 and the weather stripping was $15. Add in about $20 for brackets, paint and primer. I used high temp. black paint and a self etching primer from Home Depot.

I have noticed a significant improvement in performance after the engines has warmed up, heat soak was pretty bad with just the filter.

 

[Karrit2049]

Hey Guys,

I liked this idea a lot but I didn't like not having a heat shield for the air filter. This might be a little overkill but it actually turned out pretty good.

I made a heat shield out of 1/8" plexiglass. I went ahead and also drew up the plans for it in case someone wants to make one, I'll do a write up on it if needed. The cost wasn't that bad either, I ordered the plexiglass off of Amazon and the weather stripping as well. Plexiglass was $45 and the weather stripping was $15. Add in about $20 for brackets, paint and primer. I used high temp. black paint and a self etching primer from Home Depot.

I have noticed a significant improvement in performance after the engines has warmed up, heat soak was pretty bad with just the filter.

I made an adjustment to the measurements on the second piece, thanks to NSXNEXT for catching the math error.