Benefits of running THE flap?

[0-60motorsports]

My Flaps surrounding rubber seal that seals the intake when the flap is closed has fallen off and rotted away. I would love to keep the flap as we are in a hot country ad it helps with driveability here in summers, but i have to figure out what to replace that material with in order to seal it when in the closed position.

[M3glaubiger]

The flap acts as another throttle; its not just about noise control. Frank at TTFS knows a good bit about the function and design.

There is an easy way to connect everything in a functional manner:
The driver's side brake duct (#4) serves as the intake for the factory system. That's the starting point.
In the diagram, #20 tube gets cut down by an inch or two. Orient the tube so it fits back in the duct hole by 180 degrees from factory (its cut on an angle, you want to install with the long end towards rear of the car so as to catch the air). I think you'll need to grind down a plastic locating key.
Squeeze the upper portion in your hand to fit over the triangular portion of the snorkel. The bottom portion fits back in the hole of the duct.
On the duct, there is a bulbous protrusion designed to direct clean air into the factory system. Its not visible in the diagram. Cut the end of the bulb off you have another side duct, essentially.
Get 3" neoprene air duct (single layer) from Pegasus Racing meant for brake cooling. 3 ft length is needed. Connect air duct to your newly formed "side duct," and the other end to the intake of the CSL airbox, the intake downstream from the flap. You'll want to cut away the wire of the air duct for a good seal. 2.75" air duct would be perfect but I didn't find any in that size.
With the factory powersteering lines, you aren't going to have much room to run that 3" duct so be prepared to smush it, tie it away, etc. Interference with the alternator pulley is likely. I did away with the factory lines so it fits well.

For those to whom its applies: some vehicles have blanking plates on the rear of the factory brake ducts (visible from the wheel wells). My driver's side came with a partially closed blank and passenger side with a full blank (nothing can pass through). You can swap plates to direct maximum air into the driver's duct which feeds your airbox.

I want to do this exact procedure you are describing. I cant locate my blanking plates from the factory brake ducts though. I had taken them off like 10 years ago Are those plastic blank plates orderable? Can't seem to locate them anywhere. Also if not, what would be an alternative ?

[heinzboehmer]

I want to do this exact procedure you are describing. I cant locate my blanking plates from the factory brake ducts though. I had taken them off like 10 years ago Are those plastic blank plates orderable? Can't seem to locate them anywhere. Also if not, what would be an alternative ?

https://www.realoem.com/bmw/enUS/showparts?id=BL93-USA-04-2002-E46-BMW-M3&diagId=51_3278

Wow they're incredibly expensive. ~$80 for each side. If you weren't so far I would ship you mine, I've got no use for them.

[M3glaubiger]

https://www.realoem.com/bmw/enUS/showparts?id=BL93-USA-04-2002-E46-BMW-M3&diagId=51_3278

Wow they're incredibly expensive. ~$80 for each side. If you weren't so far I would ship you mine, I've got no use for them.

I think it's #9 on the diagram...and those are like 4 bucks at least I found the part. Thanks.

[heinzboehmer]

I think it's #9 on the diagram...and those are like 4 bucks at least I found the part. Thanks.

Cheapest I found them for is $45 on Schmiedmann

https://www.schmiedmann.com/en/product/1988110-new?product=51-71-7-894-515

They're about $80 on ECS and FCP.

https://www.ecstuning.com/b-genuine-bmw-parts/covering/51717894515/

[M3glaubiger]

Cheapest I found them for is $45 on Schmiedmann

https://www.schmiedmann.com/en/product/1988110-new?product=51-71-7-894-515

They're about $80 on ECS and FCP.

https://www.ecstuning.com/b-genuine-...g/51717894515/

Never mind my last post. Those were old prices i guess. That is insane for a piece of plastic. It's like 45€ per side here in Germany 😮

[jbfrancis3]

Pfftttt you can get the whole fender liner section with the blanking plate for $71...
https://www.ecstuning.com/b-genuine-...t/51712695664/

[heinzboehmer]

Pfftttt you can get the whole fender liner section with the blanking plate for $71...
https://www.ecstuning.com/b-genuine-...t/51712695664/

Lol that's hilarious.

[terra]

Sure, though you'll have to get crafty-- there's no product sold to do it.

A black piece of PCV piping down in the brake duct would be pretty subtle and completely functional.

I've been tempted to make something akin to your 3d printed brake duct to hook up to the flap intake... but I'm not good enough at designing crap to do that.

[Cubieman]

Its getting real!

[0-60motorsports]

Does anyone have a spare flap they want to sell me? maybe someone who doesnt their car with the flap. PM Me if you have only the flap for sale, i am not looking for the complete snorkel. Thanks.

[Obioban]

Does anyone have a spare flap they want to sell me? maybe someone who doesnt their car with the flap. PM Me if you have only the flap for sale, i am not looking for the complete snorkel. Thanks.

Have you asked on cslregister? Many of them removed their flap.

[0-60motorsports]

Have you asked on cslregister? Many of them removed their flap.

I will now. Thanks bud.

[Cubieman]

Have you asked on cslregister? Many of them removed their flap.

Oh wow, did not know about this place. Awesome.

[Cubieman]

Assuming you've already got an H bridge how involved is the wiring to make the flap work? Can it be done in such a way to as to reverse the wiring "mods" cleanly?