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[Pete02LSE]

The other day, I was under our LSE changing the oil and I noticed where the stock air box draws it's air. Behind the headlight, there is a hole (maybe 3" in diameter) in the inner fender that has a duct for the air box pointing toward it. This got me to thinking...what if...

What if you cut the bottom of air box out to open it up and install a K&N panel filter? Why would this not flow as well as a K&N cone on the end of the MAF? Seems like the surface area of the panel filter would be close to the same as that of the cone. A side benefit is a built-in heat shield. The bottom half of the box could serve as a heat shield to protect the air tract from engine heat.

I have done this on two previous cars (a 99 Grand Prix GT and a 96 Sonoma). Both seemed to perform better all around...particularly at speed. There was some what of an increase in noise (the infamous bog) but nothing like a cone filter would add.

Anyone ever tried this with an LS? Or...can someone disprove why it wouldn't work as well as a cone filter?

TIA,
-Pete
02 LSE

 

[Quik LS]

The other day, I was under our LSE changing the oil and I noticed where the stock air box draws it's air. Behind the headlight, there is a hole (maybe 3" in diameter) in the inner fender that has a duct for the air box pointing toward it. This got me to thinking...what if...

What if you cut the bottom of air box out to open it up and install a K&N panel filter? Why would this not flow as well as a K&N cone on the end of the MAF? Seems like the surface area of the panel filter would be close to the same as that of the cone. A side benefit is a built-in heat shield. The bottom half of the box could serve as a heat shield to protect the air tract from engine heat.

I have done this on two previous cars (a 99 Grand Prix GT and a 96 Sonoma). Both seemed to perform better all around...particularly at speed. There was some what of an increase in noise (the infamous bog) but nothing like a cone filter would add.

Anyone ever tried this with an LS? Or...can someone disprove why it wouldn't work as well as a cone filter?

TIA,
-Pete
02 LSE

yep - lots of folks have chopped the air box and installed a K&N filter - not as much gain as a full new intake - but you'll notice the difference.

 

[Katshot]

The K&N panel filter, while being less restrictive than the OEM replacement filter, is still MORE restrictive than a K&N cone filter. What I've seen many people do is run a new inlet pipe down into that same area and install a cone filter on the end. That way you have the best of both worlds. The inlet air is cool, and is taken from a relatively high-pressure area, AND the cone filter and new inlet piping is less restrictive due to the design of the pipe and the freer-breathing filter media.

 

[GrayGhost1]

Pete,

Lou and Kevin are right about forcing air into the filter area. What I did was I bought some 3" air hose and routed it from that hole you talk about and brought it down next to the fog light. This forces much cooler air into the intake area. I've had this setup now on my car for about 3 weeks and I can tell a big difference in mid to high range acceleration. Also, here in Knoxville, TN we've had nothing but rain for the past week and I have not experience any water ingesting into the air hose. Also, I've driven on the highway at speeds above 70 MPH and have not seen any water in the engine compartment or on the filter. I was concerned about this thinking I may get the filter wet, ingest water and hydrolock the engine but all seems to be well. Your mileage may vary with this setup since you have the LSE which is what I have. Here are a couple of pictures showing a similar setup that I have now:

 

[Pete02LSE]

Just out of curiosity...how much better flowing is a cone vs. a panel? Does anyone have a CFM comparison? Plus, on a stock headed/intake engine would there be any difference in HP gain from a cut airbox v. a cone?

 

[mikepietras04]

Pete,

Lou and Kevin are right about forcing air into the filter area. What I did was I bought some 3" air hose and routed it from that hole you talk about and brought it down next to the fog light. This forces much cooler air into the intake area. I've had this setup now on my car for about 3 weeks and I can tell a big difference in mid to high range acceleration. Also, here in Knoxville, TN we've had nothing but rain for the past week and I have not experience any water ingesting into the air hose. Also, I've driven on the highway at speeds above 70 MPH and have not seen any water in the engine compartment or on the filter. I was concerned about this thinking I may get the filter wet, ingest water and hydrolock the engine but all seems to be well. Your mileage may vary with this setup since you have the LSE which is what I have. Here are a couple of pictures showing a similar setup that I have now:

With that set up, you will NEVER hydrolock your engine. Even if you were up to your bumper in water. The tube doesnt make a direct connection to your intake pipe (if you had that flex tube FILLED with water, the cars intake would just suck air from under the hood). You need to actually fill a cylinder up with water to hydro lock it, meaning more water displacement than cylinder displacement after compression... reason: water doesnt compress. And as for the filter getting wet, cotton mesh filters dont mind the occasional drenching in water... after all, that IS how you clean them, just make sure it is always properly oiled.

 

[GrayGhost1]

With that set up, you will NEVER hydrolock your engine. Even if you were up to your bumper in water. The tube doesnt make a direct connection to your intake pipe (if you had that flex tube FILLED with water, the cars intake would just suck air from under the hood). You need to actually fill a cylinder up with water to hydro lock it, meaning more water displacement than cylinder displacement after compression... reason: water doesnt compress. And as for the filter getting wet, cotton mesh filters dont mind the occasional drenching in water... after all, that IS how you clean them, just make sure it is always properly oiled.

Thanks for the heads up!

 

[craigh]

I cut a large hole in the bottom of the airbox. It about the size of my hand and can't be seen when the hood is opened. I also removed the snorkel tube that goes from the airbox to the fender area. I'm running a stock filter.

I do notice a slight difference in the HP, but the real benefit was the sound from the intake! Makes it sound mean.

 

[Pete02LSE]

Just out of curiosity...how much better flowing is a cone vs. a panel? Does anyone have a CFM comparison? Plus, on a stock headed/intake engine would there be any difference in HP gain from a cut airbox v. a cone?

I just realized that no one has shown a CFM comparison chart of a panel vs. a cone.

Anyone...anyone...Bueller.

 

[MAT88GT]

doesn't matter on shape, its all in terms of filter area. more area, more flow

Pleated K&N filter material will flow 6.03 cfm of air per square inch.

but! you only need so much area for a given engine size and operating rpm...adding more filter area/flow potential isn't going to make a difference. There's actually an equasion for this...

effective (measured) filter area = cu. in x rpm at max power / 20,839

 

[Pete02LSE]

doesn't matter on shape, its all in terms of filter area. more area, more flow




but! you only need so much area for a given engine size and operating rpm...adding more filter area/flow potential isn't going to make a difference. There's actually an equasion for this...

effective (measured) filter area = cu. in x rpm at max power / 20,839

Right...which is why I said this in my original post:

Seems like the surface area of the panel filter would be close to the same as that of the cone.

I suppose it would have been better for me to ask...what's the surface area difference b/t the cone and the panel.

Not to step on anyones toes but...I just think that an intake tract other than a stock gutted box is a waste on a stock headed/intake/cam'd engine. I really wish I could have dyno'd the car before and after...but...I was too impatient and wanted to go ahead and gut the box.

So...I gutted mine yesterday and snapped some decent photos of the process. So far, I am pleased with the results. It's definitely got more SOTP feel than it had with the stock box. And as posted above, there is an increase in noise. Nothing like the noise out of my Silverado with the lid flipped over but...a decent sound.

I'm hoping to have the pics resized today and be ready to post up a how to in the LS section.

 

[Pete02LSE]

Right...which is why I said this in my original post:



I suppose it would have been better for me to ask...what's the surface area difference b/t the cone and the panel.

Not to step on anyones toes but...I just think that an intake tract other than a stock gutted box is a waste on a stock headed/intake/cam'd engine. I really wish I could have dyno'd the car before and after...but...I was too impatient and wanted to go ahead and gut the box.

So...I gutted mine yesterday and snapped some decent photos of the process. So far, I am pleased with the results. It's definitely got more SOTP feel than it had with the stock box. And as posted above, there is an increase in noise. Nothing like the noise out of my Silverado with the lid flipped over but...a decent sound.

I'm hoping to have the pics resized today and be ready to post up a how to in the LS section.

I finished the write up and sent it to Joey for review and to be submitted into the LS technical section. However, if you want a preview (before any edits) here you go:

http://webpages.charter.net/zerohz/cars/Modded_LS_AirBox.htm

If you have anything that you think should change, please let me know.

Thanks,
-Pete
02 LSE

 

[GoldCoastLs]

similar to grayghost

my setup is similar to grayghosts, but i put a large square funnel on the end by the fog light. Sorry no pics, can't get my computer to upload to lvc today.
Also i didn't cut a hole in the air box, i just sawed the factory pipe in half and fastened my flexhose on the end of it. Should i wrap my MAF to Intake hose with heat tape..... proly would keep the cold air.......cold

 

[Quik LS]

before the hood scoop I ran this:

 

[Pete02LSE]

my setup is similar to grayghosts, but i put a large square funnel on the end by the fog light. Sorry no pics, can't get my computer to upload to lvc today.
Also i didn't cut a hole in the air box, i just sawed the factory pipe in half and fastened my flexhose on the end of it. Should i wrap my MAF to Intake hose with heat tape..... proly would keep the cold air.......cold

I wouldn't bother wrapping the intake tube. The only time the intake charge will be impacted by underhood heat will be at idle or low speeds. At any other time, the speed at which the air is travelling will overcome any of the heat on the outside of the tube. The biggest concern would be the temperature of the air that is at the inlet of the air tube.

One other thing to consider. An air source mounted too low will inhale higher temps than one at behind the headlight. Why? Because the closer to the asphalt you get...the higher the temps. That's why you never saw factory cold air systems pick up air from below the front bumper. The only one that I can recall is the 66-67 Olds 442. From then on, it was either from the top of the hood (front and lower pressure) or from the rear (cowl induction and higher pressure) where the air was cooler. All of this will hold true...even at speed.

 

[SurfjaxLS]

Are all you guys running the kkm intake, or have any tried to fab up an adapter for the cone. I have a cone sitting in my room taking up space, but haven't ordered any type of adapter to fit it. I've made one out of an abs sheet and 3 pvc tube solvent welded together, but not sure if it would work. Anybody know if it will. I know it doesn't have a velocity stack like the kkm intake, but how will that affect performance?