Replace or Remove Splash Shields?

[VikAry]

While driving my 2012 M3 ZCP the other day, I heard a lot of scraping coming from the front bumper. After inspecting behind the splitters, I noticed these two black felt things that worn torn badly and hanging off of the body.

I'm wondering whether it makes sense to replace these parts since they are made of felt (really?) and will most likely tear again and again and again. I have read that they might help aerodynamics and keep debit out of the engine but not sure how much of that is true. Is there a high performance alternative (e.g. carbon fiber, plastic) that might actually last?

I didn't think BMW could made a design error worse than the cupholders in this car but I think we have a new winner.

M3 Splash Shield-Under Engine Side Cover Left 51757896419
M3 Splash Shield-Under Engine Side Cover Right 51757896420

[pseto]

I don't remember seeing anything that would be an upgrade. if mine were to come off, I would replace.

[VikAry]

Thanks Paul - It's about $190 to replace both sides. I've read in a bunch of forums that this is a common problem, particularly if you car is lowered. The only saving grace I have is that I don't drive my car very much but I'm having a hard time justifying the spend because I know that I will have to keep replacing them.

[John in VA]

Wow! $84.16 each at BMW of Silver Spring.

[VikAry]

I found a local welder who thinks he could make them from aluminum but would charge about $300 for the pair. Of course, BMW would not give me a straight answer as to why I even need them and they seem to think that a flimsy piece of plastic covered in felt is just fine to put underneath what is considered a street legal race car; German Engineering at its finest, eh?

There is not "high performance" version of this part, just the crappy BMW OEM plastic pieces. During my next oil change, I'm going to have a good look and try to figure out whether these guards are really guarding anything sensitive. Having said what I did about German Engineering, I have to still assume that they serve some purpose and if significant, then maybe I do invest in an expensive, custom version of the part.

[JamesAustin]

I found a local welder who thinks he could make them from aluminum but would charge about $300 for the pair.

Schmiedmann has the left-hand part for $56.08 and the right-hand part for $54.65, expected in stock in 5 working days.

As far as what the darn things do, I have no idea, but I notice that the parts' official name is Engine Bay EMI Insulation Tip. I don't speak German and don't know what BMW's engineers think when they hear "E.M.I." but I'm an I.T. guy and I think "Electro-Magnetic Interference" which suggests to me that this part either keeps interference OUT to protect your car's computer(s) or keeps interference IN to protect other cars' computers.

[VikAry]

Thanks James,

I will certainly keep this in mind when, undoubtedly I will have to replace them again in the near future.

Your assumption regarding what EMI means is certainly reasonable and I have to put some faith in BMW Engineers and assume that this part has some functional significance, despite its poor design. If indeed, I'm able to confirm its importance, then I will try and find a more durable alternative knowing that it will most likely cost more but also will have a longer shelf life.

[JamesAustin]

Your assumption regarding what EMI means is certainly reasonable and I have to put some faith in BMW Engineers and assume that this part has some functional significance, despite its poor design. If indeed, I'm able to confirm its importance, then I will try and find a more durable alternative knowing that it will most likely cost more but also will have a longer shelf life.

I Googled "BMW ENGINE BAY EMI INSULATION TIP" and found this thread where someone says "Helps direct and smooth airflow under the car for high speed driving. ...you can feel the difference over about 80 and it's very noticeable over 100" after someone else said "Be careful driving at speed until you replace it. The part behind the missing area is flexible and can act like a sail, especially at freeway speeds. As it scoops in more air, it gets pressed down, the sides weaken and eventually rip, and soon you could be scraping up all the road debris with it... ask me how I know. If you can't replace it soon, I would recommend thinking about taking it off, otherwise it will probably break at the most inopportune time."

But they may be talking about the entire middle section and not just the edge bits like you are.

I really can't figure out how EMI in or out could be a problem at the corners of the bottom of the bumper... But then again I'm not a BMW engineer...

[VikAry]

I read that thread also and like you, thought that the writer was referring to the middle plastic piece. Talking with a couple of guys who race a lot more than me, I was told that I really don't need those side pieces (I wouldn't expect race guys to say anything different, haha). I'll have a better sense of what these side pieces are doing when I have the car up on the lift later today and will report my findings because I'm assuming that this group might need to replace this part on your cars at some point.

[1996 328ti]

Race car?

[JamesAustin]

Talking with a couple of guys who race a lot more than me, I was told that I really don't need those side pieces (I wouldn't expect race guys to say anything different, haha). I'll have a better sense of what these side pieces are doing when I have the car up on the lift later today and will report my findings because I'm assuming that this group might need to replace this part on your cars at some point.

What did you end up doing?

[VikAry]

What did you end up doing?

Bought a new pair.