Different cold air thinking -

[computiNATEor]

MA sounds like a real jewel

[fullthrottle540]

Couldn't smog today because I forgot I had secondary air pump unplugged. Gotta clear OBD2 and drive a bit to OK the monitors

[ss2115]

For anyone who wants to follow the true and original intention of this thread -
Had another job to do on the engine (dipstick modification) which involved me taking out the air box. Noticed it has a trumpet insert which could be removed. The trumpet narrowed the intake from 93mm diameter to 50mm diameter but also extended back to quite close to the air filter so that the entire surface of the air filter was hardly being used.
I well know the performance trumpets can provide, but at the same time this was quite a big reduction in area of the intake snout.
I removed it and reinstalled the airbox.

Our Australian summer is creeping in. When I first started this thread a few weeks ago the average day ambient was around 18 - 20 or so and I was seeing intake temps around 60 - 70 degrees C.
The last few days the ambient has been averaging 26 degrees, yet I am only seeing intake temps of 32 - 43 degrees - quite a difference from opening out the intake snout.
I'm not noticing any driving feel differences. No different intake noise. I don't know about fuel consumption as yet because the 85litre tank lasts me quite a while and I have only seen a real time average drop by 0.1 litre/100klms which isn't over enough time to include it as a result or just different driving conditions.

[douglawrence42]

That is a substantial difference. No other measurable effects though? Thanks for bringing it back on topic


Sent from my iPhone using Tapatalk

[4dri4n]

I come from the e34 subforum. Well, I usually keep myself in a spanish forum but sometimes I come around to see whats going on here and there.
The problem itself is not that the air gets warmer and then the dme leans the mixture. It has to do with detonation. Detonation is more prone to happen when the aire is hotter, at low rpms with large throttle openings. I think every single BMW suffers from that heat soak and high IAT readings. I read like 70 degrees when outside we were like 10 degrees or so. It is OBD1 of course.
I dont know you but I can really feel that the car performs better when cold. When I start the engine and keep it runing through some roads and so it seems like it pulls ok until I stop and do some city driving and so. Then the sensor heats up and I can clearly notice it loses some bit of grunt. Forgot to mention that I placed the IAT sensor at the begining of the air duct, just before the aire filter... inside the filter airbox. And it recieves directly the air stream coming from the outside, inside the engine... So it should read the temperature as it is... the fact is that it recieves radiation from the radiator (what would a radiator do... it radiates heat as a motherfucker) and from the steering pump oil reservoir shich is next to the airbox. That is why it gets heat soked aswell even it is far from the engine... although it takes a little bit longer...

Interrstingly, I was going to swap a resistor in place of the IAT tomorrow, and see what happens. Some of you may argue it is dangerous for the engine and so but I dont really think so... a resistor so it always reads like 15C, I thi k it will be safe.... as long as I do not floor it at 1000 rpms in 4th gear during a traffic jam in summer, I think nothing will happen... and if it does, well, thats why the knock sensor is there for...

[JaxPlanet]

ss2115 > The horn (a.k.a. trumpet/funnel/doohickey) compresses the air entering the air box, which increases its velocity, so air flows faster than it would through a larger opening so there is no decrease in volume. The added velocity and horn-shaped exit force and distribute air across the filter for even filtering. IMHO: You will lose more than you will gain without it. Put it back.

[geargrinder]

ss2115 > The horn (a.k.a. trumpet/funnel/doohickey) compresses the air entering the air box, which increases its velocity, so air flows faster than it would through a larger opening so there is no decrease in volume. The added velocity and horn-shaped exit force and distribute air across the filter for even filtering. IMHO: You will lose more than you will gain without it. Put it back.

this times a billionty.

Sadly most shade tree boys are fundamentally incapable of understanding velocity and mass as dual factors in aspiration. Hence we are destined to have this pointless debate a 1000 times over with the phrase “obviously less restrictive!” Being used ad infinitum.

[ss2115]

Rather than launching into my automotive qualifications and experience of 52 years and turning this into a who's got the biggest d..k, I'll simply say that I am fully aware of the purpose and advantages of a trumpet and have utilised them in various ways over my 50+ years of automotive shop and race building. And stated as such earlier. (so I quite took offense at the shade boys comment!).

The evidence at the moment is quite a large intake temperature drop in removing the trumpet insert.
I have been observing this as being consistent over the last weeks worth of driving. For the first time in quite a few weeks we had another cool day with showers and the ambient temp dropped back to around 19 - 20 degrees. The intake temperature wandered between 29 - 37 degrees during my normal city and short freeway driving. Its a massive decrease over the higher intake temps I had been experiencing prior to the trumpets removal.

I cannot feel any appreciable difference in engine power or behavior. There is no difference in engine/intake noise. My fuel consumption is maintaining a 0.1 litre/100klm improvement - no big deal but never the less an observable improvement now that I've had a longer driving period.
I wont deny or argue that if I had access to a dyno and all things being equal I might observe a fraction of a horsepower decrease with the removal of the trumpet, but then my feeling is I'd be back up same or perhaps a tiny bit better with the significantly lowered intake air temperatures.

However, I do still maintain that the extension intake being placed low and near the radiators hot tank is affecting the air temp and I qualify this by being stuck in a line of traffic at traffic lights that took about three light changes before i eventually got through. Under these circumstances the cooling temp rose and sat at 97degrees and the intake air temp slowly rose to 63 - similar territory to prior of removing the trumpet. What was amazing to see was once through the lights and moving at only 5 - 10 klms per hour the intake temp plummeted to 49 degrees while the coolant dropped back to about 93 and then slowly settled back on 95 as I came back up to normal driving speeds and the intake temp continued to drop quickly to 37 and then much slower came down to 33.
ie: I still think the vicinity to the radiator and roadway is affecting the intake temp as shown by still air temp at the traffic lights and how quickly it dropped when moving again.

While originally I was thinking of some heat shielding, I'm now thinking relocating the intake much higher in the front of the car would be more beneficial. Trouble with the E39 is there isn't much space large enough above the front bumper bar. Cannot even pull air from behind the headlights due to the complete enclosed headlight design.
I'm pretty happy with the present improvements though and inner city freeway driving with an air intake temp only 10 - 15 degrees over ambient is very satisfying. Can't wait for the next country drive to see if it gets even closer to a 1:1 with ambient.

[Uturn540]

The primary reason for the trumpet in the 540i airbox is that the MAF connects directly to the airbox. Without the trumpet the air tumbles over the lower edge of the MAF intake and creates turbulence through the MAF. It can create some stumbling at idle and possibly some minor surging at speed. One method is to remove the tube from below the airbox to the radiator pulling the intake air from behind the foglight. I know it has been done but do not recall anyone actually reporting the results.

[ss2115]

The primary reason for the trumpet in the 540i airbox is that the MAF connects directly to the airbox. Without the trumpet the air tumbles over the lower edge of the MAF intake and creates turbulence through the MAF. It can create some stumbling at idle and possibly some minor surging at speed. One method is to remove the tube from below the airbox to the radiator pulling the intake air from behind the foglight. I know it has been done but do not recall anyone actually reporting the results.

Thank you for a useful informative reply. I could understand this 540i situation certainly.
Its the reason for putting trumpets immediately on carby inlets, throttle body inlets and in certain other applications, so in the confines of a 540i engine bay, I can understand its employment and as you state - evidence supports its use in that removing it cause stumbling and surging.

My engine is the M54 straight six 3 litre. The trumpets end finishes only some 40mm away from the air filter thus concentrating the 'increased/smoother' air flow velocity to a small section of the air filter, after which the airbox turns the air flow not quite 90 degrees and heads it through the MAF and short curved large diameter flex rubber connections to the throttle body.
While I understand the use of a trumpet, it doesn't seem to be of much use in this situation and the evidence supports removing it for lower intake temps and a minuscule fuel consumption improvement.

The bolt-on cold air intake brigade never worried about a trumpet and the sellers of such gear advertise the virtues of replacing the air box with a cone filter in its place, walled off in an attempt to avoid engine heat. What a farce. Where's their retention of the trumpet Mr Geargrinder?

Anyway, getting back to subject: I'm just reporting my findings and experiences. I could never see the sense of the cone filters walled off under the bonnet anyway, trumpet or no trumpet (I didn't even know it was there). I started the thread originally so as not to reinvent the wheel if someone had already methodically explored the high intake temps.

At the moment, removing the trumpet has opened up the full volume of air into the filter box, and is now utilising the full surface of the air filter, and there is a big cavity behind the air filter before the air is turned and headed through the MAF. Measured evidence shows a significant decrease in intake air temps will no ill effects regards engine idle or behaviour.
It might be that in a hotter climate or perhaps a much colder climate removing the trumpet may cause some stumbling. Perhaps in cold climate some ice forming inside the airbox due to the slower moving air - I don't know. I'm just presenting the evidence in front of me living and driving in Sydney Australia.
By the way, our BMWs are all sold as hot climate cars with the bigger radiators, electronic thermostats and the stupid diptick tube with walled drain for the PVC (CCV) system which I have now also dealt with. The trumpet is an insert and not integral with the airbox. It may be its left out in some countries, or it may be there are a range of different inserts perhaps. I don't know - havn't explored it. For me removal and opening up the entire diameter of the inlet quite a distance in front of the air filter is showing benefits.

[computiNATEor]

What is the hot-climate radiator? I don't recall reading about that before.

All M54 E39s have electronic thermostats, as far as I know.

[geargrinder]

The bolt-on cold air intake brigade never worried about a trumpet and the sellers of such gear advertise the virtues of replacing the air box with a cone filter in its place, walled off in an attempt to avoid engine heat. What a farce. Where's their retention of the trumpet Mr Geargrinder?

WTF d-bag kind of nonsensical dig is that? I'm the first person to take a crap on a crappy pointless non-power-producing in-engine-bay "CAI". Those things are even more stupid than your imaginary fictional power / efficiency gains from removing the trumpet in your stock box. You're arguing the wrong end of the stick with me there pal.

As for the in-fender long-run CAI's that are made from the 540's...well I don't believe they really do much of anything either, but if you want to force me to argue with you, those probably flow OK due purely to the long length and straightened bends of the design, vs. the tight square corners and bends of the OEM box. Regardless, OEM boxes flow fairly excellently as has been proven time and again by objective testing, but shade-tree'ers won't ever be convinced otherwise. Weee it makes more noise so I am sure it is +7.93 hp on the butt dyno!

And with that, a hearty #unsub to you my friend.

[computiNATEor]

The bolt-on cold air intake brigade never worried about a trumpet and the sellers of such gear advertise the virtues of replacing the air box with a cone filter in its place, walled off in an attempt to avoid engine heat. What a farce. Where's their retention of the trumpet Mr Geargrinder?

Right here:

Screen Shot 2017-10-22 at 10.15.05 AM.jpg

From their website:
Billet 3-Angle Adaptor: A billet 3-angle adaptor is used to speed up the air flow for improved performance and throttle response.

Now whether or not that works, I don't know. At least they tried.

https://afepower.com/afe-power-51-10...-intake-system

[ss2115]

What is the hot-climate radiator? I don't recall reading about that before.

All M54 E39s have electronic thermostats, as far as I know.

I have the build sheet of my car when it was originally ordered by the previous owner and it shows the Hot climate Pack. Quite some time ago I had the top hose plastic connector split (seems a common problem) and had to replace the radiator. I purchase many of my parts from California being cheaper than domestic prices even with freight added. They have my VIN# so when I inquired about price they explained there were several thickness cores available and my hot climate pack was the second thickest after a V8 radiator. It was quite some time ago so I cannot remember the various measurements, but the hot climate pack was thicker core than standard. In the end I actually purchased and installed a V8 radiator from a domestic supplier as it was only a little bit more expensive and immediately available.

In regards the electric thermostat I may well be incorrect. I made an assumption based on my reading up of it and finding that there was a standard mechanical thermostat available as well. The electric thermostat doesn't actually control the temp electronically but instead is an electro-mechanical device that the ECU can shove the valve open in anticipation of a load event as it monitors throttle position, probably MAF and other sensors and then its allowed to go back to its normal thermo-mechanical action. As I could not see any way this was an optional order on the engine I have made the assumption it is part of the Hot Climate Pack - aplogise if this is incorrect. Its not important to this thread anyway other than I wondered and suggested if the trumpet being a removable insert was also perhaps climate dictated.

those probably flow OK due purely to the long length and straightened bends of the design, vs. the tight square corners and bends of the OEM box. Regardless, OEM boxes flow fairly excellently as has been proven time and again by objective testing, but shade-tree'ers won't ever be convinced otherwise. Weee it makes more noise so I am sure it is +7.93 hp on the butt dyno!

On that we fully agree.
I didn't like your reference to my character and your instantaneous assumption that I didn't have experience or training in the automotive industry and probably didn't know what i was talking about. I simply volunteered observed documented results and took offense at your comeback.

Right here:
From their website:
Billet 3-Angle Adaptor: A billet 3-angle adaptor is used to speed up the air flow for improved performance and throttle response.
Now whether or not that works, I don't know. At least they tried.
https://afepower.com/afe-power-51-10...-intake-system

I can't argue with the evidence. You found one. Interesting that it comes after the air filter rather than before it as in the 6 cylinder OEM airbox. As you yourself state, its an attempt - bit too short to have any real effect but may be like the 540i box mentioned earlier in that its enough to prevent any idle stumble and surging they may have experienced when prototyping it.
Wonder if a short trumpet on the airbox inline and immediately in front of the MAF would show even better results on a dyno or such? But so far I haven't experienced any ill effects - only a much improved air intake temp.

[JimLev]

Right here:

Screen Shot 2017-10-22 at 10.15.05 AM.jpg

From their website:
Billet 3-Angle Adaptor: A billet 3-angle adaptor is used to speed up the air flow for improved performance and throttle response.

Now whether or not that works, I don't know. At least they tried.

https://afepower.com/afe-power-51-10...-intake-system

70% flow increase and a 20HP increase......HaaaaaHaaaa. I have some swamp land in Florida for you.

[computiNATEor]

70% flow increase and a 20HP increase......HaaaaaHaaaa. I have some swamp land in Florida for you.

Seriously. The numbers for the other E39s are reasonable, but those are absurd.

[fullthrottle540]

What is the hot-climate radiator? I don't recall reading about that before.

E39 gulf cooling system, made for middle east E39's

All the part numbers used to be on realoem but they are gone now

[R Shaffner]

Rarely seen such a contentious thread, but I'm willing to wade in with a question anyway.

I have an '02 540-6, with a non-TU intake and stock air box. Planning to get a DUDMD tune. Don't know whether to get one for the stock MAF and throttle body, or add $$ and effort for the tune for the 4" version (4" MAF and N62 throttle).

As I ponder this question, what CAI should I also consider? DUDMD said that the stock air box would be fine with the stock MAF and throttle. But what about the 4" mod? Would the stock box then be too restrictive and limit the benefit from the 4" additions?

Reasonable comments welcome.

P.S. I live in NC, and for us heat is a real problem. I've watched my IAT climb pretty high around town in the summer. Sure it cools down on the highway. But starting up from a light in the summer is noticeably slower when the car in hot and the IAT is high. I've also been wondering how to bring that down (for next summer).

[R Shaffner]

The primary reason for the trumpet in the 540i airbox is that the MAF connects directly to the airbox. Without the trumpet the air tumbles over the lower edge of the MAF intake and creates turbulence through the MAF. It can create some stumbling at idle and possibly some minor surging at speed. One method is to remove the tube from below the airbox to the radiator pulling the intake air from behind the foglight. I know it has been done but do not recall anyone actually reporting the results.

I've removed the snorkel on two different 540-6's (1997 and 2002). Personally, I like the differences. First, it sounds better. Reminiscent of of the carburetor honk I used to hear on my Honda 4-cylinder bike.

Second, the WOT throttle response feels better, more crisp, at low-to-middle rpm. Bear with me. I'm talking about driving around town. Like being in second or third gear around a corner at 1500 rpm and opening the throttle all the way, letting the displacement and that low-end torque pull the car back up to speed. (People driving automatics in auto mode won't ever experience this because the car will downshift at WOT. I experience it every time I drive, and love it.)

Do I have data to prove this? No. No one has dyno runs on this, or ever will. Dyno runs are for WOT focusing on higher rpms.

In retrospect, perhaps I could have looked at the OBD II data with and without the snorkel, at WOT in the low-to-middle rpm ranges. But it's not worth it to me to put the snorkel back on to do the tests. I'm confident this isn't any worse and it feels better. No reason to go back.

Do I have a plausible reason for thinking removing the snorkel might actually help? Sure. The snorkel narrows down at one point. That's always somewhat restrictive. (Please think before telling me that the air flow speeds up when it's narrowed down. Yes it does, through that narrow section, relative to the speed in a wider section. But adding a narrow section is ALWAYS somewhat restrictive. Imagine inhaling through a straw while running at full speed.) (Intake runners are different of course, more complex because of the cylinder pulses.)

The snorkel is also pretty long. That can't help air flow when the throttle is first opened. Might not matter on the Autobahn at 200 kph. Seems to matter where and how I drive.

And finally, the snorkel pulls air from right in front of the radiator. That's a high pressure area when the car is moving at high speed. Probably better for Autobahn driving. But from a stop and at low speed it can't be, especially when the electric fans are running. (I wish I did a lot of 100+ MPH driving to make that a concern. Sadly I don't, so it isn't.)

[JimLev]

And finally, the snorkel pulls air from right in front of the radiator. That's a high pressure area when the car is moving at high speed. Probably better for Autobahn driving. But from a stop and at low speed it can't be, especially when the electric fans are running. (I wish I did a lot of 100+ MPH driving to make that a concern. Sadly I don't, so it isn't.)

I'd go 4". Have you seen how the snorkel gets restrictive where it passes by the pass side bumper support? It necks down to ~2" x 2".
Before I had the Dinan CF CAI I cut the snorkel and removed the section that passes over the bumper support.


CAI_Tube.JPG

[Uturn540]

I've removed the snorkel on two different 540-6's (1997 and 2002). Personally, I like the differences. First, it sounds better. Reminiscent of of the carburetor honk I used to hear on my Honda 4-cylinder bike.

Second, the WOT throttle response feels better, more crisp, at low-to-middle rpm. Bear with me. I'm talking about driving around town. Like being in second or third gear around a corner at 1500 rpm and opening the throttle all the way, letting the displacement and that low-end torque pull the car back up to speed. (People driving automatics in auto mode won't ever experience this because the car will downshift at WOT. I experience it every time I drive, and love it.)

Do I have data to prove this? No. No one has dyno runs on this, or ever will. Dyno runs are for WOT focusing on higher rpms.

In retrospect, perhaps I could have looked at the OBD II data with and without the snorkel, at WOT in the low-to-middle rpm ranges. But it's not worth it to me to put the snorkel back on to do the tests. I'm confident this isn't any worse and it feels better. No reason to go back.

Do I have a plausible reason for thinking removing the snorkel might actually help? Sure. The snorkel narrows down at one point. That's always somewhat restrictive. (Please think before telling me that the air flow speeds up when it's narrowed down. Yes it does, through that narrow section, relative to the speed in a wider section. But adding a narrow section is ALWAYS somewhat restrictive. Imagine inhaling through a straw while running at full speed.) (Intake runners are different of course, more complex because of the cylinder pulses.)

The snorkel is also pretty long. That can't help air flow when the throttle is first opened. Might not matter on the Autobahn at 200 kph. Seems to matter where and how I drive.

And finally, the snorkel pulls air from right in front of the radiator. That's a high pressure area when the car is moving at high speed. Probably better for Autobahn driving. But from a stop and at low speed it can't be, especially when the electric fans are running. (I wish I did a lot of 100+ MPH driving to make that a concern. Sadly I don't, so it isn't.)

I believe we are talking about two different items. I am not referring to the snorkel from the airbox to the front of the radiator. I am referring to the removable trumpet in the airbox lid. I have contemplated removing or modifying the snorkel myself.20171024_132828.jpg

[R Shaffner]

Rather than launching into my automotive qualifications and experience of 52 years and turning this into a who's got the biggest d..k, I'll simply say that I am fully aware of the purpose and advantages of a trumpet and have utilised them in various ways over my 50+ years of automotive shop and race building. And stated as such earlier. (so I quite took offense at the shade boys comment!).

The evidence at the moment is quite a large intake temperature drop in removing the trumpet insert.
I have been observing this as being consistent over the last weeks worth of driving. For the first time in quite a few weeks we had another cool day with showers and the ambient temp dropped back to around 19 - 20 degrees. The intake temperature wandered between 29 - 37 degrees during my normal city and short freeway driving. Its a massive decrease over the higher intake temps I had been experiencing prior to the trumpets removal.

I cannot feel any appreciable difference in engine power or behavior. There is no difference in engine/intake noise. My fuel consumption is maintaining a 0.1 litre/100klm improvement - no big deal but never the less an observable improvement now that I've had a longer driving period.
I wont deny or argue that if I had access to a dyno and all things being equal I might observe a fraction of a horsepower decrease with the removal of the trumpet, but then my feeling is I'd be back up same or perhaps a tiny bit better with the significantly lowered intake air temperatures.

However, I do still maintain that the extension intake being placed low and near the radiators hot tank is affecting the air temp and I qualify this by being stuck in a line of traffic at traffic lights that took about three light changes before i eventually got through. Under these circumstances the cooling temp rose and sat at 97degrees and the intake air temp slowly rose to 63 - similar territory to prior of removing the trumpet. What was amazing to see was once through the lights and moving at only 5 - 10 klms per hour the intake temp plummeted to 49 degrees while the coolant dropped back to about 93 and then slowly settled back on 95 as I came back up to normal driving speeds and the intake temp continued to drop quickly to 37 and then much slower came down to 33.
ie: I still think the vicinity to the radiator and roadway is affecting the intake temp as shown by still air temp at the traffic lights and how quickly it dropped when moving again.

While originally I was thinking of some heat shielding, I'm now thinking relocating the intake much higher in the front of the car would be more beneficial. Trouble with the E39 is there isn't much space large enough above the front bumper bar. Cannot even pull air from behind the headlights due to the complete enclosed headlight design.
I'm pretty happy with the present improvements though and inner city freeway driving with an air intake temp only 10 - 15 degrees over ambient is very satisfying. Can't wait for the next country drive to see if it gets even closer to a 1:1 with ambient.

Wait. You're saying that you have cooler IAT just from removing the trumpet inside the air filter box? Forgive me, but that's hard to believe. My suspicion is that there's something wrong with the test. (Can you think of a plausible reason for why removing something from inside the air box would affect IAT one way or another? I can't. Something there doesn't make sense.)

Also, you said you were familiar with the benefits of velocity stacks, but are you really? Take a look at the attached graphic. Without the air horn, the effective working diameter of the exit tube from the air box might be reduced to 80% of its measured size. The air horn helps the air leave the box faster, in addition to smoothing the flow for the MAF.

[ss2115]

Wait. You're saying that you have cooler IAT just from removing the trumpet inside the air filter box? Forgive me, but that's hard to believe. My suspicion is that there's something wrong with the test. (Can you think of a plausible reason for why removing something from inside the air box would affect IAT one way or another? I can't. Something there doesn't make sense.)

Also, you said you were familiar with the benefits of velocity stacks, but are you really? Take a look at the attached graphic. Without the air horn, the effective working diameter of the exit tube from the air box might be reduced to 80% of its measured size. The air horn helps the air leave the box faster, in addition to smoothing the flow for the MAF.

I can only report on what I have observed.
Yesterday (Sat) I put the trumpet insert back in. It was a hot day as our summer is rolling in but friday and friday night had been raining, so humidity is involved also. My IAT started at almost ambient as it always does from a cold engine, but quickly shot to 10 degrees over what I have been experiencing without it and after 15 minutes of driving was back up at 73deg which is where I used to observe it prior to the trumpets removal. Unfortunately I didn't have time to remove it same day, but will be doing so later this morning (Sunday). Its expected to be a similar sort of day.

Explanation: From an engineering point of view I appreciate your diagram of the different air flows into containers so to speak. However, I don't think any of that is applicable to this situation simply because your diagrams and your argument are based on free open air entering a passage. You forget that in this case, the big round opening into the air box is already contained by the extension tube through the fender wall and down to under the front of the car - ie: the air flow is already laminar.

In regards to intake temperature, I can only postulate because I don't have the test gear, nor do i feel the need to find out because its working well anyway, but I'm thinking perhaps having the entire surface of the airbox interior now filled with moving air the box is staying approx 10degrees cooler? I know this idea is possibly full of holes because the heat has to go somewhere and the same heat is being applied to the outside of the airbox and doesn't magically disappear. I also think narrowing down the intake air to the diameter of the trumpet/snorkel and speeding the air up may impart some heat (but 10deg? Hmm - unlikely but not impossible). But it may be that slow or non-moving air in the box for the length of the long insert (its a closed tube 235mm long inside the front length of the airbox) is transferring heat into the air box and the entire inner surface now having air flow against it is reducing transfer?

The snorkel effect of the trumpet concentrating the air used by the engine into one spot center of the larger air filter I don't like at all whether that has anything to do with heat rise or not. I like the idea that the large volume of air is now being distributed over a much larger area of the filter - one assumes pretty much edge to edge now.
I haven't seen a 540i air box but from what has been described, the trumpet was proven necessary to smooth airflow into the MAF and I'm thinking the engineers have just carried it through as "a good idea". It may also be climate dictated as I proposed earlier in this thread. I don't find it necessary to be there.
I like the idea that I now have a hugely increased diameter entry into the air box of 93mm diameter versus 50mm diameter (despite the same volume of air passing but by being sped up) and the flow is still/already laminar. I like the idea that the full surface of my air filter is being utilized rather than a central round spot. I like that my intake temperature has decreased by 10 - 12 degrees on average. I like that I'm getting 0.1litres per 100klm consumption improvement however minuscule that be.