If anyone here is still listening...
I've owned two e39 540i's. A '97 6-speed that lasted 230,000 miles before a pick-up truck bent the frame, and a 2002 6-speed that I just bought with half as many miles. (What can I say? Give me a practical, nice handling car with that sweet engine and gearbox and I'm happy.)
As for the cold air intake. Yes, all e39 540's have them. But that doesn't mean the set-up is optimized for performance. All manufacturers make trade-offs to try to balance multiple goals. (Even BMW cares about others things, like cost, reliability, efficiency, longevity, noise, etc.) So, if one asks whether one of those goals (like performance) can be increased with some modifications, the answer is always "Of course." The same can be said for improving efficiency (avoiding times at high rpms and full-throttle) , or longevity (by reducing peak performance in various ways).
With my '97 540, I took off the front bumper and saw the snorkel that was part of the factory CAI. Pulling in denser cold air makes perfect sense. But I can't figure out why BMW thought it made sense to choke-down the diameter of the snorkel, or to have it fight the AC fan for fresh air. (Perhaps it was noise reduction. Or perhaps it was because many European car companies care much more about highway acceleration that standing starts. With forward air flow, the snorkel's intake position in front of the radiator would have positive pressure, as opposed to the negative pressure it might have while stopped with the electric radiator fan running.
So all I did years ago was remove the snorkel and open of a path for fresh cold air to get around the right fog light. Even with the stock air box and filter, the positive effect was immediately noticeable. There is a little more throat in opening the throttle, especially at low rpms in any gear. I like that sound, frankly. More importantly, the torque increase is also easy to notice at all engine speeds with any significant increase in throttle.
(I should note that I use the V-8's strong low-end a lot around town, while in the middle gears. The open throttle response at lower rpms is truly great, and it revs so smoothly and quickly whenever I ask it to. I don't know why anyone would prefer to unnecessarily restrict the intake on such a nice engine.)
I have now made the same modification to the '02 540, with even better results. (The VANOS improves torque over a wide range, and my no-cost CAI improvement helps a lot. Throttle response is more than crisp. Immediate is the right word.)
So, I haven't dyno tested it, but I can tell it makes a difference. If you don't believe me, invest 30 minutes to take your snorkel off, and I think you'll change your mind.
Happy motoring!
Yes. Part number 13 is the snorkel. You have to remove the front bumper to get it off. I also removed some of the plastic beside the passenger side fog light, to give plenty of fresh air a way to get into the fender cavity in front of the front wheel. On the '97 I had to remove some plastic beside the fog light. My 2002 is an M sport with an M5 front bumper -- for that I just removed the plastic piece that goes around the fog light.
Here's another interesting way to look at it: The e39 M5 has 2 of these snorkels for the 5 liter V8, one on each side. So why should a 5 liter V8 have 2 snorkels and a 4.4 liter V8 only have 1? What sense does it make to give the 540 only 50% of the M5's intake air flow? It makes sense that the 4.4 liter engine would do better with an less restricted cold air intake, and in my experience it does.
(Sorry for the slow reply.)
You can also just remove the 5 inch or so coupling that connects the airbox to the snorkel
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FWIW: Removing the snorkel makes it a hot air intake because has to pull air from inside the engine bay. The shape and placement of the 'snorkel' was engineered to increase the velocity of the air and leverages the Venturi effect. Removing these components makes a larger opening but reduces the rate at which air is entering the air box. I am willing to bet a Dyno test won't show any improvement and, if the ambient temperature is high, it will show a loss, especially if the hood is closed.
Sorry, JaxPlanet, but you missed part of the explanation. With the snorkel removed and the stock air box in place, the air is still coming from outside the engine bay (from the front fender area, with cold air coming in from the front of the car). So we're not changing the source or temperature of the intake air from stock. It's still coming from outside. The point is that we've removed the restrictive snorkel.
Sometimes people make repairs and mods and think they see a difference. Haven't you done that? Have you ever replaced pugs or coils and noticed a difference, an improvement in performance? I know I have. Do you need to have your car dyno tested before you can believe that a new set of coils helps? I hope not, unless the all old coils were working just fine, of course. Sometimes, it's just not that hard to notice a difference.
This is free, easy, and protects the engine by using the stock air filter. I've only driven these cars 180,000 miles. As a sample of one, I'm telling you it makes a nice improvement, especially to the 6-speed version.
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Yes, but wouldn't that let hotter air from the engine bay enter the intake, especially at slow vehicle speeds? Seems so to me. I like the idea of bringing in nothing but fresh cooler air from the fender area.
Colder air fatter molecules more power. Warm air bad for power. Engines like to see air the is delivered to them, ram air, turbo or super charged, the last two benefit from intercoolers, ah dropping temperature of air. Engines are not sucking pumps. Why do you think super bike engines go to all the trouble of have massive sealed intake air boxes with the opening at the front of the fairing. Controlled air and free air charging at high speeds. Of course k/n flow air because the media is very thin, which I don't like, plus there covered with oil,bad for air mass sensor and there a major pain in the ass to clean. The air box on my e39 has great volume, is sealed and is fed cool air from the front of the car, excellent and the filter really filters the air. Save your money and spend it on maintance.
Plastic factory air boxes are engineered to be reliable, low-cost, quiet, and efficient. That's why an E39 factory plastic air box and snorkel looks exactly like one out of a Toyota Tacoma, or any other car from the 2000's. Plastic airbox with a snorkel - perfect for 99% of car owners. Out of sight, out of mind. I doubt that the BMW engineers focused primarily on air velocity and dyno numbers with the non-M E39 intakes. The E39 intake probably cost BMW $5 to produce, whereas the DINAN intake might cost $80 to produce. The DINAN intake makes more power, but it is a stupid choice for 99% of car buyers
Can you take a pic of inside where you have the cold air coming in from the fender?
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Thanks! The plastic shield where my temp sensor is already half missing so i'm already half way there!
Ran the afe pro dry first and it felt a little better and sounded nice. Installed the dinan cai and don't feel a difference but it sounds nice.
Sure. First, here's a picture of my '02 540 with the bumper removed and the snorkel still attached. It's that snake-looking tube coming out of the front passenger fender area (below the turn signal in this photo) to behind front bumper. (The air intake opening is actually facing backwards, toward the front of the radiator.)
IMG_2857.jpg
Also, note how the snorkel is choked-down where it snakes behind the bumper support. It would be hard to measure, but when you get the snorkel off you'll be amazed at how narrow that part is.
Here's a close up of where the snorkel attaches -- where the stock cold air comes from -- with the snorkel removed. So when the car is moving, cold air comes around the front bumper, hits the radiator and creates positive pressure. The engine is sucking air in through the snorkel making negative pressure. And this opening is where the two meet, where the outside air enters the snorkel. Not that big compared to the large diameter of most of the intake.
IMG_2858.jpg
It's worth noting that when the car is stopped and the front radiator fan is on (like when it's hot and the AC is running), the intake is fighting against the fan somewhat for cold air. I have trouble seeing the logic in that. Someone at BMW must have thought it was good enough. (I also know that no place in Germany gets as hot as the summers in NC, where I live. If the engineers lived here I bet they would have come up with a different design.)
And here's where the snorkel attaches at the other end. It goes into the fender cavity and enters the engine bay by going directly into the air box through this opening. (The air box was removed before this picture was taken.)
IMG_2859.jpg
There are several bolts that hold the snorkel in place. They are easy to remove. The snorkel attaches to a tube that feeds the air box with a circular clip that is also easy to remove. The hardest part is wiggling the snorkel out from behind the bumper bracket. (Actually, removing the bumper is the only hard part about this.)
On my '97 540i, I took the snorkel off and left the tube that enters the air box in place. On my '02 I decided to cut the snorkel off about 8 inches into the fender cavity. (That probably makes no difference.) If you're doing a test, you can remove the snorkel, try the car without it, and put it back on if you don't like it. My bet is you won't -- you'll like the little boost in sound and power, as I do.
I hope that helps.
Last edited by R Shaffner; 11-19-2016 at 07:28 AM.
On my 2002 530, I finally got tired of extracting the cold air intake to work on the car. Replaced the CAI resonator / silencer with an Oatey stopper from my local building supply store. Now much easier to pull the CAI. No noticeable change in sound or performance.
Cold air intake absolutely makes a difference on our cars, its one of the best things i did for my car. Dont believe the bs about the factory making the factory intake so good that no aftermarket intake will make a difference. That is not true. I actually gained power. You will gain even more power if you get the DME flashed. Dinan Stage 2 flash and cold air intake is a 20hp increase over stock.
Electric Fan conversion, 840Ci thermostat, Dinan style CAI,de-screened MAF, Dinan transmission chip, 255lph LS1 fuel pump, drilled slotted rotors, 3.15 differential, Bel rx65 radar (hard-wired). Hemi Killer!
Someone is smoking weed.
I have owned many 540i's and the factory intake system is NOT optimal. The dinan cold air intake absolutley makes a difference. There is a difference that can be felt when driving the car , especially at lower rpms, the torque difference is apparent. I can tell you this, its a 7 hp increase on its own and a 20 hp increase with their tune!
Electric Fan conversion, 840Ci thermostat, Dinan style CAI,de-screened MAF, Dinan transmission chip, 255lph LS1 fuel pump, drilled slotted rotors, 3.15 differential, Bel rx65 radar (hard-wired). Hemi Killer!
I've got the Dinan CAI, large bore MAF, and Dinan TB, and the non tu intake manifold, with Stage 5 tune.
10-15HP maybe. Definately wasn't worth the money. It does sound good when you floor it.
Jim, mine is a 97', already comes from factorty with the larger intake manifold, larger TB, larger MAF aka Euro MAF. The cold air intake def made a difference on my car, way zippier at low rpms and pulls harder,feels stronger at high rpms. Way more consistent than before. I would never go back.
Electric Fan conversion, 840Ci thermostat, Dinan style CAI,de-screened MAF, Dinan transmission chip, 255lph LS1 fuel pump, drilled slotted rotors, 3.15 differential, Bel rx65 radar (hard-wired). Hemi Killer!
2003 M3CicM6 TiAg
2002 540iT Sport Vortech S/C 6MT LSD TiAg
2008 Audi A3 2.0T DSG (the daily beater)
2014 BMW X1 xDrive28i (wifemobile)
Former:
1985 MB Euro graymarket 300SL
1995.5 Audi S6 Avant (utility/winter billetturbobattlewagen)
I put Dinsn cold air intake and nothing you can feel in the seat of your pants. The factory e39 intake is cold air intake. BTW, Dinan muffler also added nothing you could feel in the seat of your pants but sure sounds great.
The best thing for power was deleting cats. I would suspect that if you are driving on the street high flow cats would work equally well.
I hope this helps. The best modification would be a good stereo head unit upgrade and a better amp
Today's fake news
I installed a CAI and lost 30 pounds! I also sent $2500 to that Nigerian king and didn't loose my entire checking account! He sent me a casier's check for much much more that I am sure is good.
another great week....
Last edited by StephenVA; 01-18-2019 at 07:27 PM.
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Last edited by StephenVA; 01-18-2019 at 07:34 PM.
Current Garage Highlights
2003 525iT TiSilver
2002 M5 TiSilver
1998 528i KASCHMIRBEIGE METALLIC (301) (Goldie)
Former Garage Highlights
2005 X5 4.8is
2004 325iTs (2x)
1973 Pantera L
1971 Dodge Dart Swinger "Lite Package"
1970 Dodge Challenger T/A 340 Six Pack Alpine White
1970 Dodge Challenger T/A 340 Six Pack GoManGo Green
1969 Road Runner 383
1968 Barracuda Formula S 340 Sea Foam Green
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