[cosmicdebris48059]

Posted this on general F30 but got no response. Does anyone know if this is necessary? I've seen many diy videos and no one is removing the rear bumper to install a normal rear diffuser. I ordered an AK style carbon fiber diffuser back in the spring and it was clearly not going to fit due to the sevear bow it had. The vendor argued with me that it needed to be taken to a professional shop (which it was) and the bumper had to be removed in order to be installed correctly. The shop said there was no way it was going to fit. It wasn't till I sent them a pic of the diffuser held up to the car showing how bowed it was that they agreed to accept a return but they still insisted it would fit properly by removing the bumper. I addressed this issue with a different vendor, they informed me that the vendor I ordered from in the spring supplies them with their diffusers and they made the same suggestion about removing the bumper. I understand the bumper cover is more flexible when it's off, but removing it to install a carbon fiber diffuser makes no sense to me since the bottom of it and the diffuser has to be bolted to the frame of the car which is straight. Carbon fiber does not bend and trying to force it in place by bolting it on will cause damage to the diffuser itself. I really want the AK style carbon fiber diffuser as opposed to the black plastic one to match the rest of the carbon fiber on the car but cannot seem to get past this obstacle. Any help would be greatly appreciated. Thanks in advance!

[roll_the_dice]

When I had my e90, it was easy to swap out the diffuser and the bumper did not have to be removed. However with my F30, I went through this same thing. I ended up buying and returning 2 CF diffusers because they would not fit correctly without taking the bumper off. I was told the bumper had to be removed which I did once and it still didn't fit properly. The CF diffusers for the F30 unless really expensive just do not fit well, IME. I ended up finding 1 CF diffuser that fit without removing the bumper...it took 30 minutes to remove OEM and install the CF and I love the look. Although I haven't found the right quad tips yet, I still love the look of the diffuser.

[MONSTAR]

Originally Posted by cosmicdebris48059

Posted this on general F30 but got no response. Does anyone know if this is necessary? I've seen many diy videos and no one is removing the rear bumper to install a normal rear diffuser. I ordered an AK style carbon fiber diffuser back in the spring and it was clearly not going to fit due to the sevear bow it had. The vendor argued with me that it needed to be taken to a professional shop (which it was) and the bumper had to be removed in order to be installed correctly. The shop said there was no way it was going to fit. It wasn't till I sent them a pic of the diffuser held up to the car showing how bowed it was that they agreed to accept a return but they still insisted it would fit properly by removing the bumper. I addressed this issue with a different vendor, they informed me that the vendor I ordered from in the spring supplies them with their diffusers and they made the same suggestion about removing the bumper. I understand the bumper cover is more flexible when it's off, but removing it to install a carbon fiber diffuser makes no sense to me since the bottom of it and the diffuser has to be bolted to the frame of the car which is straight. Carbon fiber does not bend and trying to force it in place by bolting it on will cause damage to the diffuser itself. I really want the AK style carbon fiber diffuser as opposed to the black plastic one to match the rest of the carbon fiber on the car but cannot seem to get past this obstacle. Any help would be greatly appreciated. Thanks in advance!

The one I have required the bumper to come off. It has bendable metal tabs that insert in the holes along the perimeter of the bumper. You have to put them through the holes, then bend them down to hold it in place. It also had holes on the bottom to mount, however, they did not line up at all. You could either drill new holes, use double sided tape, or just let it be. Mine is held on very securely just with the metal tabs

[cosmicdebris48059]

Originally Posted by MONSTAR

The one I have required the bumper to come off. It has bendable metal tabs that insert in the holes along the perimeter of the bumper. You have to put them through the holes, then bend them down to hold it in place. It also had holes on the bottom to mount, however, they did not line up at all. You could either drill new holes, use double sided tape, or just let it be. Mine is held on very securely just with the metal tabs

Do you have the stock exhaust? I recently learned that is the biggest issue and why most recommend removing the bumper cover. Stock muffler does not have enough room to allow you to pull down the heat shield and reach up in there.

[cosmicdebris48059]

Originally Posted by roll_the_dice

When I had my e90, it was easy to swap out the diffuser and the bumper did not have to be removed. However with my F30, I went through this same thing. I ended up buying and returning 2 CF diffusers because they would not fit correctly without taking the bumper off. I was told the bumper had to be removed which I did once and it still didn't fit properly. The CF diffusers for the F30 unless really expensive just do not fit well, IME. I ended up finding 1 CF diffuser that fit without removing the bumper...it took 30 minutes to remove OEM and install the CF and I love the look. Although I haven't found the right quad tips yet, I still love the look of the diffuser.

Love it! Do you have any side shots of the rear corner splitters? I'm interested in getting some splitters but not sure which ones.

[MONSTAR]

Originally Posted by cosmicdebris48059

Do you have the stock exhaust? I recently learned that is the biggest issue and why most recommend removing the bumper cover. Stock muffler does not have enough room to allow you to pull down the heat shield and reach up in there.

Well, yes and no. I got my carbon diffuser at the same time that I did an msport conversion to the rear. I installed the rear bumper but left the diffuser off, went and got a muffler delete out to 2 tips, and half-way installed the diffuser while the car was still on a lift. I didnt try to bend the heat shield back or anything. I just went home, took the bumper off and installed the diffuser 100% (or 90%, minus the bottom bolts)

EDIT:
https://f30.bimmerpost.com/forums/sh...postcount=1631
https://f30.bimmerpost.com/forums/sh...postcount=1645