[DBU]

We have two X4's: a '17 M40i and a '15 2.8. The 2.8 has sound insulation on both sides in the engine compartment near the fenders and the firewall.

When I look up the part numbers imprinted on these thick black rubber pieces, I find the exact same part number also applies to the X4 M40i (and the X3's), but as you can see from the attached photos, these rubber parts are missing on my X4 M40i.

So I have a favor to ask any owner of an X4 M40i: Does your car have these sound insulation bits in them?

Two top pictures are from the X4 2.8i (with the rubber bits). Bottom two pictures are from the X4 M40i

[Duke I]

Nope. Are you inclined to retrofit? Is it described as a sound insulating part in the catalog?

Could it be that BMW wants more m40i engine sound in the cabin with this omission?

[DBU]

Originally Posted by Duke I

Nope. Are you inclined to retrofit? Is it described as a sound insulating part in the catalog?

Could it be that BMW wants more m40i engine sound in the cabin with this omission?

Thanks Duke. Have a look at part #51487278060 or 51487278059 as examples. I believe there are actually two pieces on each side - a lower and upper. The lower one goes way down and out of sight... I looked at realoem.com and those part numbers are listed as sound insulation on all X3's and all variants of the X4. So why were they not installed on our X4 M40's?

You may be right about BMW wanting more engine sound in the cabin. I actually prefer the engine sound on the 2.8 over the M40. It seems more refined. The exhaust sound is a different story... BTW, the 2.8 has a big fat form-fitting piece of foam rubber between the actual valve cover and the plastic you see when you open the hood.

Each of the "missing" pieces are listing at about $45, so I may try and find a wrecked X3 in a junk yard and get the pieces there. Just a fun project.