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Discussion Starter #1
Where does the stock intake get its' air from? I've looked under the car, but I don't see any openings. I saw a channel in the front wheel well, but I think that directs air to the brakes.

Also, why does the front grill have only have holes in solid part of the drivers side and not the passengers' side?

Thanks
 

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sublimaze said:
I saw a channel in the front wheel well, but I think that directs air to the brakes.

Also, why does the front grill have only have holes in solid part of the drivers side and not the passengers' side?

Thanks
sublimaze-

Sounds like someone started to put the brake air ducts on the car but only got to one side.
 

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The stock air intakes are exactly behind the front bumper, you cannot see them from the outside!

The holes on the grill have no relevance except for making their removal easier by using your fingers!!! Thats all!
 

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Discussion Starter #4
kcdoyle said:
sublimaze-

Sounds like someone started to put the brake air ducts on the car but only got to one side.
I don't think that's the case, the car is completely stock( for now) and CPO'd when I bought her.
 

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Discussion Starter #5
Ahmed said:
The stock air intakes are exactly behind the front bumper, you cannot see them from the outside!

Again, so how does the air get in behind the bumper? Could I just drill some holes through the fog light cover to increase airflow?

I've read other posts where people, Elevens and NAVYBO come to mind, have made a DIY CAI by removing the fog light covers and replacing them with mesh to allow more air to flow through. But then they also had to cut part of the stock air intake hose. That's the part I did not understand. Can't you just make the openings and forget about it?
 

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with the hood open, try to look below the headlamps, and you should see the air intakes. Opening the foglamp surrounds will do nothing with the intakes in the stock position, too far away. You would have to cut or remove the intake snorkles from the airbox. I had my snorkles off and open foglamp surrounds for a while. It should allow more air when the car is at speed, but hard to feel any difference. in theory, this would make the front fenderwell area (behind the foglamps) a large air plenum, that could see some positive air pressure at high speeds, which would feed into the stock airboxes.
Mike

sublimaze said:
Again, so how does the air get in behind the bumper? Could I just drill some holes through the fog light cover to increase airflow?

I've read other posts where people, Elevens and NAVYBO come to mind, have made a DIY CAI by removing the fog light covers and replacing them with mesh to allow more air to flow through. But then they also had to cut part of the stock air intake hose. That's the part I did not understand. Can't you just make the openings and forget about it?
 
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i've looked into this as well. seems like you can connect a flex hose from the stock air intakes to the either the front grill or the bottom grill providing it is protected from water.also looked at drilling holes in the plastic front grill and connecting a flex hose to the brake system in the wheel well.but all this sounds good in theory but will it do any good.????????
 

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gilmores m5 said:
i've looked into this as well. seems like you can connect a flex hose from the stock air intakes to the either the front grill or the bottom grill providing it is protected from water.also looked at drilling holes in the plastic front grill and connecting a flex hose to the brake system in the wheel well.but all this sounds good in theory but will it do any good.????????
The people at actve autowerks feel it's worth 25hp! Hard to believe, but there's been good feedback on their system.

As a side note, your don't really need to worry too much about water ingestion, the stock airboxe, i believe the passenger side (for US spec car) has an extra intake pipe that goes into the top of the fenderwell area to avoid water ingestion.
Mike
 

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When I put my brake ducts in I took a long hard look at the way that air gets into the engine. The two main snorkels open into the enclosed space behind the front bumper. On the right side (looking from the driver's position and facing forward), there's a second branch to the snorkel that goes to an opening in the fender well, presumably to fetch cold air from there. On the left side, the row of holes at the top of the lower grill provides what appears to be the only cold-air inlet to the space where the snorkel is.

That's it - there's no magic and no access from the snorkels to the outside air, except for that little row of holes on the left side. Of course the space is not sealed, although it is baffled, so apparently enough air gets in there to make 400 horsepower. At speed of course, that row of half-inch holes lets lots of cold air in, I'm sure.

When I installed my factory M-Sport grill insert (with the splitter) I drilled a row of holes across the top of both brake duct tubes (left and right) to fulfil the function of the lost holes in the stock grill insert. I'm not sure that breathing would be inhibited without the row of holes, but it's the only source of outside air for the intake snorkels.

Cheers
JJ
 

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BKH said:
JJ - Were you driving down Denman a few days ago?
BKH - except for the last couple of weeks, I go through there pretty much every day. My office is in North Van, and I live in Dunbar, so I go against the traffic. It was probably me, if you saw a CB beast masquerading as a 540i Sport!

JJ
 

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How does the design of the M-Tech bumper work to provide air to the stock M5 intakes?

When I put my brake ducts in I took a long hard look at the way that air gets into the engine. The two main snorkels open into the enclosed space behind the front bumper. On the right side (looking from the driver's position and facing forward), there's a second branch to the snorkel that goes to an opening in the fender well, presumably to fetch cold air from there. On the left side, the row of holes at the top of the lower grill provides what appears to be the only cold-air inlet to the space where the snorkel is.

That's it - there's no magic and no access from the snorkels to the outside air, except for that little row of holes on the left side. Of course the space is not sealed, although it is baffled, so apparently enough air gets in there to make 400 horsepower. At speed of course, that row of half-inch holes lets lots of cold air in, I'm sure.

When I installed my factory M-Sport grill insert (with the splitter) I drilled a row of holes across the top of both brake duct tubes (left and right) to fulfil the function of the lost holes in the stock grill insert. I'm not sure that breathing would be inhibited without the row of holes, but it's the only source of outside air for the intake snorkels.

Cheers
JJ
Well I'm not sure that resurrecting a 3 year old thread is the best way to join the party, buy what the heck. Hello everyone!

I started visiting here to learn more about the E39 M5, which I guess I consider to be the big brother of my "baby beast" '03 540i M Sport. While there are certainly a world of differences between the two models, there's still enough that the two have in common to make it worthwhile to know more about the M5.

With the front bumper cover of my 540 being painted, I've also recently had the opportunity to contemplate the design reasoning behind the placement of the intake trumpets on the M5 and how they might be fed by the air flow that may (or may not) occur inside the bumper cover and behind the bumper support. As has been covered many times in other threads here, the 525, 530 and 540 all take their air from a rear-facing duct that attaches to the cover on the front side of the air-conditioner condenser coil, the radiator looking thing in-front of the actual main cooling radiator. On the other hand, the M5 utilizes open horns that pull their supply from any air that could reach them through the back of the metal bumper support as directed by the shape of the inside of the bumper cover and the insides of the wheel wells, behind the foglamps. The ports on the condenser cover that supply the intakes of the other models are blocked by covers.

So with the understanding that the 540 functioned as designed well before the cosmetic addition of the M technic bumper (which had been primary to the M5 during the entire run of the e39 platform), and after looking long and hard at the design of the bumper cover and the placement of the intakes on the M5, I started to think that maybe one of the design considerations for the M bumper cover was to provide a distribution channel for cooler air intake air flow to the trumpet openings.

But, the more I look at the component and the design, I'm starting to think that I'm either crazy or that my theory may have been true at one part of the design and development, but then became obsolete due to other design or mechanical considerations that superseded the air flow issue.

Take a look at the large rectangular holes in the bumper support just inside and under the high beams. This is exactly where the openings of the trumpets are, which also happen to be directly above the brake ducts/intake ports on the the euro M5 and the 540i lower grill. Yes, this is where the PDC sensors go, but they're pretty large for just a sensor. Was this for put here for a reason that went away? A bumper intake? Maybe some venting from the ducts in the lower grill?

So in addition to the 6 holes in the blocked portion of left side only of the lower grill, the only sources of fresh air I can find on the US M5 are the few vent slots in bottom of the left side wheel well liner (which are being replaced by the way). Here's a shot. I wonder if these function to remove water or to introduce air into the enclosed area behind the bumper?

JJ, I also had the idea of providing a little air by punching through the brake duct, but I thought I'd just cut a flap and fold it into the duct to force a little air up toward the right side M5 horn I'll be installing in my 540.

Anyway, I'd love some other opinions on this if anybody has any... or if anybody cares. Thanks for letting me ramble!

Ti
 

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