Downforce i take vs cold air intake

[dmscrx]

One thing I know from my motorcycle days is that Honda spent lots of time tuning the air intakes of their motors to optimize the charge using the sound waves of the intake.
I would think that Honda decided for the NSX engine, that they would build a tuned intake system as well, so would guess there was research done on the design of the NSX intake.

Here in BC we get a lot of rain so the large Downforce type air scoops don't work well in the wet.
An air filter placed directly behind the side air intake as mentioned by dmscrx would get soaked and plugged with road dirt almost immediately.
The oem intake works well in all climate conditions but perhaps is a compromise and in sunny dry desert climes improvements can be made

Unless you are driving through the mod bogs of a tractor pull, the filters do not get clogged. The foam filters I use and the K&N filters I use are designed and oiled to prevent this very thing from happening. They even work on freaking dirt bikes in the messiest of races that have (big surprise) water. I would like to meet the NSX owner who drives in those conditions so I can skake his hand. NSXs and all other vehicles here in my area and even 1200 miles away will see suspended dirt particles in the intake charge and the occasional water droplets just like the factory airbox. A little more here and there is only going to warrant a sooner than later cleaning and oiling of the filter element. The customers do not care if they have to clean the filter every few years for some extra power..just like everyone else with a CAI that places the air filter closer to these dirty conditions.

Oems have been using resonant frequencies to tune intakes for a long time not just for power but for adding a good sound while eliminating the bad ones. Honda did not pull out all of the stops for the NSX intake box. The tech they have in F1 shows us of what they are capable. People are reading waay too much into this.

 

[greenberet]

Maybe the Honda Formula 1 engineers who designed the NSX's airbox did tune its resonant frequency to where they wanted. I'm sure it would have been really easy for them to do so. It's also possible that they had to keep the air filter reasonably accessible for servicing reasons so they had to keep it in the engine compartment and in the engine compartment, the amount of space they had was limited so maybe they couldn’t make its volume as large and therefore its resonant frequency as low as they wanted. I don't know what resonant frequency would be good to maximize an NSX's power output or what the resonant frequency of the OEM airbox is so that issue is hard to judge.

It's a lot easier to judge the restriction the intake is likely to cause. Whatever kind of filter you use (K&N, foam, paper, etc.), the smaller it is, the more restrictive it will be. If my measurements are correct, the plate filter in an NSX's airbox has an area of 496.9 cm2, not counting the pleats. So if you use a different filter, it would be good to use one that is larger than that to make sure you are not choking the engine. How easily the air can flow to and from the entire surface of the filter is important as well but that's going to be as difficult to judge as the resonant frequency. Practically, you can make sure you don't use a filter that's smaller than stock.

You can also take a stab at judging the restriction the piping is likely to cause. Ideally, I believe the engine can breathe easiest if the intake tract is kind of funnel shaped with its cross section slowly getting larger the further you get away from the intake ports. Where there are steps, there should be bellmouths to keep the air flowing smoothly. An NSX's intake tract fits the bill except that the main intake opening of the intake snorkel closes down a bit again. It has a bellmouth on it, but its cross section is only 50.6 cm2, which is equivalent to a 3.2” diameter. The airbox itself has a smallest diameter of 3.4". If you modify the OEM intake snorkel or replace it with something else, 3.4" will be the smallest diameter in your intake upstream of the throttle body. If you replace the intake, you can try to make sure the diameter of whatever you put on is not smaller than 3.4".

And of course, if the goal is a horsepower gain, the intake should breathe cool air from outside the engine compartment.

So if you want a performance gain, it seems that an intake system with a diameter larger than 3.4", a filter area larger than 496.9 cm2, that breathes cool air from outside the engine compartment, and has bellmouths at any steps should have a shot at outperforming the stock setup.

The best way to check whether it actually does would be a before/after dyno test. Same car, same dyno, same day with the rpm measured from the tachometer pickup loop in the engine compartment and with nothing changed except the intake. While those tests are being carried out, it would be cheap and easy to also measure the pressure drop caused by the stock and aftermarket intake systems. A $30 Dwyer Magnehelic differential pressure gauge could measure the air pressure at the intake opening in the fender and the pressure just in front of the throttle body. It will display the difference between the air pressures and the intake with the lower pressure drop should be the one that makes more horsepower. Unless the intake with a higher restriction produces more horsepower due to resonance effects.

 

[dmscrx]

Maybe the Honda Formula 1 engineers who designed the NSX's airbox did tune its resonant frequency to where they wanted. I'm sure it would have been really easy for them to do so. It's also possible that they had to keep the air filter reasonably accessible for servicing reasons so they had to keep it in the engine compartment and in the engine compartment, the amount of space they had was limited so maybe they couldn’t make its volume as large and therefore its resonant frequency as low as they wanted. I don't know what resonant frequency would be good to maximize an NSX's power output or what the resonant frequency of the OEM airbox is so that issue is hard to judge.

It's a lot easier to judge the restriction the intake is likely to cause. Whatever kind of filter you use (K&N, foam, paper, etc.), the smaller it is, the more restrictive it will be. If my measurements are correct, the plate filter in an NSX's airbox has an area of 496.9 cm2, not counting the pleats. So if you use a different filter, it would be good to use one that is larger than that to make sure you are not choking the engine. How easily the air can flow to and from the entire surface of the filter is important as well but that's going to be as difficult to judge as the resonant frequency. Practically, you can make sure you don't use a filter that's smaller than stock.

You can also take a stab at judging the restriction the piping is likely to cause. Ideally, I believe the engine can breathe easiest if the intake tract is kind of funnel shaped with its cross section slowly getting larger the further you get away from the intake ports. Where there are steps, there should be bellmouths to keep the air flowing smoothly. An NSX's intake tract fits the bill except that the main intake opening of the intake snorkel closes down a bit again. It has a bellmouth on it, but its cross section is only 50.6 cm2, which is equivalent to a 3.2” diameter. The airbox itself has a smallest diameter of 3.4". If you modify the OEM intake snorkel or replace it with something else, 3.4" will be the smallest diameter in your intake upstream of the throttle body. If you replace the intake, you can try to make sure the diameter of whatever you put on is not smaller than 3.4".

And of course, if the goal is a horsepower gain, the intake should breathe cool air from outside the engine compartment.

So if you want a performance gain, it seems that an intake system with a diameter larger than 3.4", a filter area larger than 496.9 cm2, that breathes cool air from outside the engine compartment, and has bellmouths at any steps should have a shot at outperforming the stock setup.

The best way to check whether it actually does would be a before/after dyno test. Same car, same dyno, same day with the rpm measured from the tachometer pickup loop in the engine compartment and with nothing changed except the intake. While those tests are being carried out, it would be cheap and easy to also measure the pressure drop caused by the stock and aftermarket intake systems. A $30 Dwyer Magnehelic differential pressure gauge could measure the air pressure at the intake opening in the fender and the pressure just in front of the throttle body. It will display the difference between the air pressures and the intake with the lower pressure drop should be the one that makes more horsepower. Unless the intake with a higher restriction produces more horsepower due to resonance effects.

That is what most fabricators/manufacturers think of and take into consideration when designing an intake and also posting power gain/loss results. K&N has had a calculator on its website for a loooong time to determine surface area/flow of a type of a filter. Then you can pick which one flows the best for your setup. Old news. The quickest/easiest way to determine airflow differences in the setup is a wideband and a dyno. Seeing the A/F mixture go lean after bolt-ons has always put a smile on my face. It has always correlated to power gains on top of it. It means the VE of the engine has changed and it is moving more air. Engines are air pumps. Afterwards, fatten the mixture back to like for like before said mod then you can compare your results.

You say a minimum of 3.4 inch for a gain? I didn't have to go that big for decent gains throughout the whole powerband. You can calculate things to death but it gets half of nothing accomplished until you do the damn thing, build it, and post real world results. There is nothing wrong with experimentation and I wish more people would try new things!

 

[greenberet]

I also think it's great when people try new things and when vendors develop new or improved parts. Technology advances over time, cost pressures ease, and improvements can be applied to our cars. When parts are sold that are supposed to being performance gains, it's nice to see a sound explanation of how the gains were achieved and reliable measurements to document them.

Regarding the intake, I said 3.4" because that's the smallest diameter of the stock airbox. If you want to reduce the restriction, go bigger than stock, right?

 

[dmscrx]

I also think it's great when people try new things and when vendors develop new or improved parts. Technology advances over time, cost pressures ease, and improvements can be applied to our cars. When parts are sold that are supposed to being performance gains, it's nice to see a sound explanation of how the gains were achieved and reliable measurements to document them.

Regarding the intake, I said 3.4" because that's the smallest diameter of the stock airbox. If you want to reduce the restriction, go bigger than stock, right?

Not necessarily. The problem with most airbox designs is that is squeezes air through the inlet (speeds it up) to the box where the air stalls in a much larger chamber (the box itself) and it's slowed down even further (stock filter). The reason the velocity stack was added (NSX)was to speed the air back up before it got back to the throttle body. Air box designs also usually have a maze of turns the air has to travel through which also slows air down. The goal is to maintain velocity with volume at every rpm, not one or the other. Going to a giant pipe isn't always the best because it reduces velocity. The other end of the spectrum is increased velocity with a smaller pipe, but is can lack the volume engines need if they are to breather better at higher rpms. Resonant frequency sometimes gives a little extra but it can take a lot of time/money to tune the Helm resonators and sometimes it just isn't worth the extra 1 HP. The AEM V2 is a good example of this where as on one vehicle it made a sh*t ton more than a cold air and others it didn't make much of a difference.

 

[JD Cross]

Honda did not pull out all of the stops for the NSX intake box. The tech they have in F1 shows us of what they are capable. People are reading waay too much into this.

I'd like to learn more about this.
Why do you conclude Honda didn't pull out the stops for the NSX intake?
Is it in the design or materials?
What do you mean by "people are reading waay too.........."

 

[greenberet]

In an intake runner, I fully agree that you want to maintain the highest velocity you can without restricting the volume. A high velocity in the intake runner will sling air and fuel molecules past the intake valves even when the pressure in the combustion chamber is increasing because the piston has started its upward stroke. However, the situation is different in an airbox that never faces an adverse pressure gradient. There, you don't need the individual molecules to have high kinetic energy, you just want the overall momentum of the air column to be maintained.

If air flows fast in a tube leading into an enclosure, slows down in the enclosure, and then speeds up again in the tube leading out of the enclosure, at some points you will have a small amount of air flowing fast and at others a large amount of air flowing slow. However, the air will apply the same overall force regardless at which cross section you measure it. As long as you have smooth transitions and bellmouths to minimize turbulence, the air should maintain its overall momentum.

Air filters have a larger cross section than the rest of the intake tract so the airflow will be slower there than at other points. But I don't think the restriction of an intake system will be impacted very much by where along its length the air is slower – where you place the filter.

If you want to minimize restriction, it seems to me that you shouldn't use a smaller filter or smaller diameter piping than Honda did. However, at the end of the day only a dyno test can say whether a newly-developed intake system brings gains or not.

 

[dmscrx]

In an intake runner, I fully agree that you want to maintain the highest velocity you can without restricting the volume. A high velocity in the intake runner will sling air and fuel molecules past the intake valves even when the pressure in the combustion chamber is increasing because the piston has started its upward stroke. However, the situation is different in an airbox that never faces an adverse pressure gradient. There, you don't need the individual molecules to have high kinetic energy, you just want the overall momentum of the air column to be maintained.

If air flows fast in a tube leading into an enclosure, slows down in the enclosure, and then speeds up again in the tube leading out of the enclosure, at some points you will have a small amount of air flowing fast and at others a large amount of air flowing slow. However, the air will apply the same overall force regardless at which cross section you measure it. As long as you have smooth transitions and bellmouths to minimize turbulence, the air should maintain its overall momentum.

Air filters have a larger cross section than the rest of the intake tract so the airflow will be slower there than at other points. But I don't think the restriction of an intake system will be impacted very much by where along its length the air is slower – where you place the filter.

If you want to minimize restriction, it seems to me that you shouldn't use a smaller filter or smaller diameter piping than Honda did. However, at the end of the day only a dyno test can say whether a newly-developed intake system brings gains or not.

It seems we are almost on the same page except for the decision of intake tubing size for the intake and the fact that a lot of filters create turbulence of aiflow which disturbs its trajectory. A good air filter being used in an intake system is pretty standard, but substandard air filters(most oem) can be a burden on the induction system. The facts I/we have described has been discussed and proven elsewhere, along with the dyno results I posted in this very thread that show there is an obvious restriction in the stock airbox as well as the carbon airbox...even with a decent panel type filter. I use 3 inch piping in all of the intake systems I make for the NSX. They have all made more power. To go bigger with the pipe (3.5 inch) would be significantly bigger than the throttle body. There is only so much airflow the stock throttle body can draw into the manifold. a bigger intake pipe isn't going to make the throttle body flow any more. I don't think it would make much of a difference if any but there is only one way to find out. Someone needs to build one and test it

 

[phryxis]

Maybe the Honda Formula 1 engineers who designed the NSX's airbox did tune its resonant frequency to where they wanted.

This now makes me curious about the Downforce intake since it is a replica of a Mugen, who did supply some F1 engines in their history. I've always found Mugen parts to be well engineered and their performance line has always provided more performance but with OEM-like quality.

 

[greenberet]

Looking a bit at what's used in other cars, according to a recent article by Renault (who produce Red Bull's engines), the air intake opening in a modern Formula 1 car is made as large as can be without disturbing the aerodynamics at the rear of the car too much. The opening is really big:

From the intake opening, the air flows down "a hollow tube that opens out to a horn shape at its base, where the air filter is situated", as Renault put it. You can see that pretty well in this picture:

A modern Formula 1 air filter is flat, mounted just above of the throttle bodies, and is big. You can see it in this picture:

So a modern Formula 1 engine inhales cold air from outside the engine compartment, which is first piped into an airbox. The airbox is large so the air slows down as it enters and then it passes through as large of a flat filter as the engineers could fit in there. Past the filter, the air speeds up again as it enters the throttle bodies, which have bellmouths at their entrances. If that's what engineers have designed for modern Formula 1 cars, the basic principle can't be that bad. And it's the same basic design used in an NSX's intake system.

One difference is that the air filter is placed at an angle to the throttle body in an NSX's airbox. I don’t know how much of an impact that makes. However, looking at other street cars, a Ferrari 458 has an arrangement like that as well. Here's a picture from the Ferrari parts catalog:

Ferrari puts a flat, pleated paper air filter (that looks a lot larger than the one in an NSX) into the 458's airbox and mounts it at an angle to the throttle bodies. You can see the angle better in this picture, showing an aftermarket filter in a stock Ferrari 458 airbox:

I’m sure an NSX's airbox and filter can be improved upon. But the basic layout of the stock system can't be fatally flawed if it's still used modern Formula 1 cars and the Ferrari 458.

 

[JD Cross]

greenberet and dmscrx
Thank you for these posts.
This is a most informative thread!

 

[NSX1145]

The downside to the factory air box in my opinion is not the filter itself quite so much, it's more the problem with the bellowed intake tube. The bellowed section creates turbulence inside as the air flows through it. Any decent intake designer would point that out as the foremost flaw of the OEM design. By simply switching out that tube for one with a completely smooth transition (from air box to throttle body) should provide an increase in the amount of air flow capable, while maintaining a high velocity.

 

[dmscrx]

The downside to the factory air box in my opinion is not the filter itself quite so much, it's more the problem with the bellowed intake tube. The bellowed section creates turbulence inside as the air flows through it. Any decent intake designer would point that out as the foremost flaw of the OEM design. By simply switching out that tube for one with a completely smooth transition (from air box to throttle body) should provide an increase in the amount of air flow capable, while maintaining a high velocity.

You're right about that design element of the box. I also think the density of the stock filter is a little too restrictive and small in surface area. Even the higher flowing panel filters for that box are better flowing but still, I think there could be a little more surface area along with a smoother flowing design. I have been studying F1 intake boxes for sometime so I'm glad there are people looking at these facts and pictures. In the Ferrari road cars and the F1 cars you will notice the surface area of those filters are huge. But another important aspect everyone should see is that both of these types of setups rely hugely on the ram air effect. They put all of the aero into the package to make the intake flow better. I wish I had my FEA pictures of the F1 airbox system to post right now. I will post them when I have time. It clearly shows huge velocities entering into the airbox. No problem getting through the filter there and any stalling (if any) of the air charge will be sped up by the V stacks on the ITBs. The downforce scoop will help achieve that effect, but the NSX side vent isn't technically a ram air design. Airflow can only be nudged into that side vent. One would be better off placing the intake opening into areas of the car with the greatest amount of air volume. Ferrari does this in the rear side pods on the 360 and in front of the rear wing on the 458 which sees a ton more airflow than the side vents of the NSX. The fact that the intakes I have made make more power is clearly obvious there is a restriction in the airbox design. There are even aftermarket airboxes for the Ferraris that are carbon and bigger volume which is a sign that even with those vehicles there can be room for improvement.

 

[Caustic]

This now makes me curious about the Downforce intake since it is a replica of a Mugen, who did supply some F1 engines in their history. I've always found Mugen parts to be well engineered and their performance line has always provided more performance but with OEM-like quality.

I had the DF Intake stack (without fender scoop) installed on my mostly stock '02 NSX. All I had was a Tubi exhaust. I had three dyno runs done before and after the intake install that same day. All I saw was a 1 hp increase, and of course that could just be variance. If there is an SC installed, I can understand how gains may be seen. But from everything that I have read and viewed on Prime on this subject, the stock airbox seems to be very well optimized for a stock NSX.

 

[greenberet]

Regarding the bellows, here's what the air coming out of the airbox flows through:

With the throttle body attached:

Looking back at the bellows through a bored-out throttle body:

I have a Science of Speed bored-out throttle body and they also bore out the entrance. You can see how the bellmouth of the stock bellows is no longer port matched to the thinner side wall of the modified throttle body. If you just clamp a tube around the entrance of a stock throttle body, the sharp edge of its side wall will jut into the airflow. You can see the thickness of the side wall in this picture by NSX Prime member MvM with an SoS bored out throttle body on the left and a stock throttle body on the right.

You can get a feeling for how the OEM bellows is port matched to the throttle body and its stock side wall thickness by looking at its exit end in the picture below:

Since the air intake is attached to the chassis on one end and a rocking engine on the other, I guess you have to have something that allows for relative movement without breaking or ripping over time. If you look at the picture of the 458 above, Ferrari use bellows for that purpose. The B-Line intake seems to use a kink in the silicone coupling to do that and I don’t know whether that is really better for the airflow or, for that matter, for longevity. Looking at the inside of the stock bellows, I was surprised at how much thought seems to have gone into it.

 

[JD Cross]

The downside to the factory air box in my opinion is not the filter itself quite so much, it's more the problem with the bellowed intake tube. The bellowed section creates turbulence inside as the air flows through it. Any decent intake designer would point that out as the foremost flaw of the OEM design. By simply switching out that tube for one with a completely smooth transition (from air box to throttle body) should provide an increase in the amount of air flow capable, while maintaining a high velocity.

It doesn't seem to make sense for Honda to have developed the C30 for the then new NSX then decide to put a poorly designed cheesy intake system on it.
They could have put in a smooth flexible joining tube instead of a corrugated one and as Ferrari also uses corrugated tubes there might be more to it.
Could you elaborate why the corrugated joint would flow less than a smooth one?

 

[Honcho]

I had the DF Intake stack (without fender scoop) installed on my mostly stock '02 NSX. All I had was a Tubi exhaust. I had three dyno runs done before and after the intake install that same day. All I saw was a 1 hp increase, and of course that could just be variance. If there is an SC installed, I can understand how gains may be seen. But from everything that I have read and viewed on Prime on this subject, the stock airbox seems to be very well optimized for a stock NSX.

The conversation should end here lol. Actual dyno, stock NSX.... 1 hp. And, it was on a 3.2 where there actually is supposed to be a slight restriction in the intake tract.

It doesn't seem to make sense for Honda to have developed the C30 for the then new NSX then decide to put a poorly designed cheesy intake system on it.
They could have put in a smooth flexible joining tube instead of a corrugated one and as Ferrari also uses corrugated tubes there might be more to it.
Could you elaborate why the corrugated joint would flow less than a smooth one?

+1 Agree.

Almost all OEM's use these tubes because the engine rocks and they don't want customers complaining about cracked tubes, intakes, etc. I doubt there is much turbulence there, as I recall Adnan at AS Motorsport had flow charts for the stock intake tract and the airflow was smooth through the bellows. If OEM's like Ferrari and Lambo (really VW) are using these in hypercars where they search for every last horsepower, then I doubt it is a problem.

Also, remember Honda's F1 engineers were designing the intake system to a specific standard: 280 ps, which was the gentleman's agreement stated max power level for Japanese cars. They also were designing it to standards of reliability, driveability, ease of maintenance and suitable sound levels for every day driving. Under these conditions, the stock system is ideal. It should be obvious, then, that if you slap a supercharger on the car or convert it to a race engine, you are altering the standard and thus a different intake system may be a better solution (Honda's own ARTA team went to a hatch scoop and ITB). However, Caustic's dyno shows the stock system is nearly ideal for a base-level NSX and is very well designed.

This thread is a great discussion on intake design, however.

 

[L_RAO]

dmscrx's results with his intake on an SC'd NSX are similar with what LMR got with the B-Line intake on his SC'd application.

I doubt that an aftermarket intake is worth a statistically significant power gain on an N/A car, except for maybe the Prospeed intake, but there needs to be a much larger sample size, as well as independent results.

That being said, I think there is a lot of power potential on both a larger throttle body as well as a larger inlet/snout on the Autorotor/Lysholm type superchargers. Those things just suck in massive amounts of air, and there never seems to be a "big enough" design.

 

[Hapa88]

So what is everyone's opinion of just removing the snorkel on the stock airbox system? Seems like the easiest & cheapest mod, while still maintaining the cold air from the fender.
I have the DF intake scoop and while it adds a cool noise, it also makes my filter dirtier quicker. Was thinking of just removing it all together and not putting the stock snorkel back in.. Thoughts?

 

[JD Cross]

So what is everyone's opinion of just removing the snorkel on the stock airbox system? Seems like the easiest & cheapest mod, while still maintaining the cold air from the fender.
I have the DF intake scoop and while it adds a cool noise, it also makes my filter dirtier quicker. Was thinking of just removing it all together and not putting the stock snorkel back in.. Thoughts?

Why do you think removing the snorkel will improve anything?

 

[Honcho]

So what is everyone's opinion of just removing the snorkel on the stock airbox system? Seems like the easiest & cheapest mod, while still maintaining the cold air from the fender.
I have the DF intake scoop and while it adds a cool noise, it also makes my filter dirtier quicker. Was thinking of just removing it all together and not putting the stock snorkel back in.. Thoughts?

Well for starters you would lose any resonance tuning, though it is only worth 1 or 2 hp in the best case. It would sound more badass though.

 

[greenberet]

So what is everyone's opinion of just removing the snorkel on the stock airbox system? .. Thoughts?

I think it's a good idea in principle.

In other cars, manufacturers refer to the intake snorkel leading into the airbox as the "intake silencer". I believe the Helmholz resonator in the NSX's intake snorkel was designed specifically for that purpose as well. Not to resonate at a frequency that boosts power but to resonate at a frequency that dampens the intake noise.

Just getting rid of the whole OEM intake snorkel will get rid of the slight constriction at its intake opening (I don't want to call it a bottleneck because in stock cars, it doesn't seem to be). Then, the airbox will breathe through a 3.6" opening. However, according to an article titled "Design of an intake bellmouth" in the September 2006 issue of Racecar Engine Technology, a pipe with a bellmouth at the end inhales about 16% more air than a plain pipe without a bellmouth at the end. So without a bellmouth over the end, the 3.6" intake opening should flow about as well as a 3.3" opening with a bellmouth would.

3.3" is still a bit larger than the 3.2" of the stock, bellmouthed intake snorkel opening so that should be a slight improvement and without the snorkel, the air will be able to follow a straighter path. Doing away with the resonator will let you hear the induction sound better, too.

But to maximize the breathing ability of the 3.6" opening so that it's comparable to what you have with the Downforce scoop now, you'd need a bellmouth. Given the oval shape of the opening, the bellmouth would need to be formed somehow. If the OEM intake snorkel gets soft when it's hot, maybe that could be appropriately modified.

 

[Hapa88]

I think it's a good idea in principle.

However, according to an article titled "Design of an intake bellmouth" in the September 2006 issue of Racecar Engine Technology, a pipe with a bellmouth at the end inhales about 16% more air than a plain pipe without a bellmouth at the end. So without a bellmouth over the end, the 3.6" intake opening should flow about as well as a 3.3" opening with a bellmouth would.

So it sounds like the best option would be to find someone to make a bellmouth that'll connect to the factory OEM airbox (replacing the OEM snorkel).
That piece would maximize airflow through the 3.6" opening, maximize intake sound output (by removing the snorkel) and minimize additional debris into the OEM airfilter (by elminating the direct ram air effect which does minimal performance gains anyway).
Sounds like a Win, Win, Win combination to me! Someone build it!


- - - Updated - - -

Why do you think removing the snorkel will improve anything?

It'll improve the intake sound, and remove the "slight" restriction of the smaller diameter piping.

 

[Honcho]

So it sounds like the best option would be to find someone to make a bellmouth that'll connect to the factory OEM airbox (replacing the OEM snorkel).
That piece would maximize airflow through the 3.6" opening, maximize intake sound output (by removing the snorkel) and minimize additional debris into the OEM airfilter (by elminating the direct ram air effect which does minimal performance gains anyway).
Sounds like a Win, Win, Win combination to me! Someone build it!


- - - Updated - - -

It'll improve the intake sound, and remove the "slight" restriction of the smaller diameter piping.

I was having the same thought this morning on the way into work. Injection molded plastic (just like the OEM snorkel) would be cheap and effective. SOS are you listening? lol

 

[L_RAO]

What is this "snorkel"?

I have a BPi velocity stack that I can try to retrofit onto the assembly...