DIY - BMW M Performance Front Lip and Rear Diffuser Install

[diesel733]

Originally Posted by Kzang

I had drilled holes and screws along with 3M double sided tape and it didn't hold after a while.

I ended up having the dealer use betalink adhesives to reinstall my lip. A friend of mine had his lip come off while driving damaging it beyond recognition.

Originally Posted by Kzang

I had drilled holes and screws along with 3M double sided tape and it didn't hold after a while.

I ended up having the dealer use betalink adhesives to reinstall my lip. A friend of mine had his lip come off while driving damaging it beyond recognition.

Thanks for the advice. I added 3M to the corners and to the underbelly of the lip as well. I drive 20 miles a day commuting going 75 mph. Still holding strong but in time we will see. I will keep an eye out on it. Fingers crossed. Thanks.

[spacegray_f15]

I screwed the bracket onto my bumper and used lots of vhb tape, let it sit for a few days to set. felt strong, about a week in it came off on the highway doing about 85. the tape just isn't strong enough to hold all that downforce. I had an RW lip by the way. just got my new lip in, goin with beta link and fabricating a middle support bracket.

[F15d_RN]

Originally Posted by euro-r

How much did you pay for both of them?
pick up locally or?

Let us know how it goes

So, I contacted JL for return because test fitment wasn't great.
Took them a day to get back at me for a installer suggestion and instructions for return.
In the meantime, I have brought my F15D to an accredited BMW body shop and asked them to install.
They did install using betalink adhesive as there was no way that the double sided tape will hold the diffuser because of the gaps.

The fit wasn't the greatest-I would say it's a good 90-92% satisfaction on my part to see it installed and turned out the way it did. I guess it's the trade-off for getting the aftermarket instead of the OEM.

I am not thinking of getting the front lip at this time though.

I don't think I can recommend the rear diffuser from JL though...

Maybe other aftermarket CF seller has a better fitment than theirs or maybe just stick to the OEM.

[mindcontrollerone]

Originally Posted by F15d_RN

So, I contacted JL for return because test fitment wasn't great.
Took them a day to get back at me for a installer suggestion and instructions for return.
In the meantime, I have brought my F15D to an accredited BMW body shop and asked them to install.
They did install using betalink adhesive as there was no way that the double sided tape will hold the diffuser because of the gaps.

The fit wasn't the greatest-I would say it's a good 90-92% satisfaction on my part to see it installed and turned out the way it did. I guess it's the trade-off for getting the aftermarket instead of the OEM.

I am not thinking of getting the front lip at this time though.

I don't think I can recommend the rear diffuser from JL though...

Maybe other aftermarket CF seller has a better fitment than theirs or maybe just stick to the OEM.

Pictures?

[Kzang]

Stick with OEM.... many people have already done the aftermarket and found the figment being off. Not to mention the quality of the weave deteriorating after a year or so.

[Alan l.]

Are you guys with the OEM lip properly prepping the back side of the carbon pieces and brackets where the VHB tape bonds to? I sanded mine down and wiped it with alcohol and my lip never flew off after putting 7K miles on it. Also heating the tape up also makes the bond alot more solid. I did my install on a hot summer day so I didn't have heat it up anymore but I've tried using the tape in colder weather and it definitely does not have nearly the same bite. Also removing the lip after initial contact will greatly reduce the tapes effectiveness. I've known people that has pulled the lip on and off trying to get the fitment perfect and that will certainly make the bond weaker.

No comment about those using afermarket because most don't even come with brackets and correct contour to fit the car so I can see why using the tape wouldn't be enough to keep it adhered to it.

[F15d_RN]

Originally Posted by mindcontrollerone

Pictures?

fit is ok but not flush.
if i can redo it, i will get oem.

[Installsplus]

Thanks for this great write up. Followed all ur instructions and couldn't be happier using 3m adhesive

[diesel733]

Originally Posted by Installsplus

Thanks for this great write up. Followed all ur instructions and couldn't be happier using 3m adhesive

Originally Posted by Installsplus

Thanks for this great write up. Followed all ur instructions and couldn't be happier using 3m adhesive

I did the same on the front with tons of vhb tape. Still holding strong after 4 months and 4000 miles.

[Russmov]

Originally Posted by Installsplus

Thanks for this great write up. Followed all ur instructions and couldn't be happier using 3m adhesive

Did you go OEM for that lip?

[Installsplus]

Originally Posted by Russmov

Did you go OEM for that lip?

Yes all OEM

[Installsplus]

Originally Posted by Russmov

Did you go OEM for that lip?

Let me know if ur interested the member I bought it from has another set. Front and rear. Great price and even better for you guys in the U.S

[Russmov]

Originally Posted by Installsplus

Let me know if ur interested the member I bought it from has another set. Front and rear. Great price and even better for you guys in the U.S

Ahh I'm in Canada, I also don't think I could justify oem prices lol.

[Installsplus]

Originally Posted by Russmov

Ahh I'm in Canada, I also don't think I could justify oem prices lol.

Pm u.

[Zwmack]

Originally Posted by Installsplus

Let me know if ur interested the member I bought it from has another set. Front and rear. Great price and even better for you guys in the U.S

Hey I'm very interested. I would rather get OEM than have an issue with the replica not fitting

[Zwmack]

I'm new here and I know it's been discussed, I realized the JL rear diffuser had difficulty with fitment, just curious about the RW front lip and rear diffuser. I'm going to be diy this project so I'm more likely to go OEM but just curious. Thanks guys!

[Zwmack]

Originally Posted by Alan l.

I installed both the front spoiler and the rear diffuser myself without using any betalink. This guide is meant to be used in conjunction with the factory installation instructions so you will notice I am going to skim through certain procedures while concentrating on the details where the manual is lacking

[COLOR="Red"]Refer to this post here for the factory installation manual. Thanks Cenix http://f15.bimmerpost.com/forums/sho...38;postcount=1[/color]

My reason for using 3M VHB tape instead is simply because I want to be able to remove the CF pieces if I need to. Granted I will still have holes in my bumper and these modifications are 'permanent' I still want to factor in the chance of some of the pieces getting damaged and will need to be replaced. Betalink is permanent. There are tons of stories about how much of a nightmare it is to remove this stuff. Bonds great but don't expect to be able to get it off your car without damaging your paint. 3M VHB is also very strong but it is possible to remove it with some heat and elbow grease which is why i went it instead. I've installed countless spoilers with this stuff and it has never failed me yet.

First thing you need to do is order some 3M VHB if you want to use my method without using betalink. I purchased it on Amazon and just be sure its VHB (stands for Very High Bond) version.



Rear Carbon Diffuser/Side Wing Installation

Now lets start with the rear diffuser first. Following the factor instructions it tells you to use sandpaper and scuff up the bracket so that the glue/tape will have more bite against it. This is what it looks like sanded down.



Now after the sanding is done, proceed to add some 3M VHB tape to the side where it will be against the rear bumper. Add only one layer of tape. If you double up on the tape it will raise it off the bumper and it will create a gap in between your CF diffuser and bumper.



Now follow the instructions on how to mount the bracket. The two T brackets is basically just a mounting guide so its pretty dummy proof. They screw into existing holes under the bumper so there is no way to get the position wrong. Keep in mind that you need to wipe down the area with some alcohol or degreaser so the tape has a good surface bond. You will also need to drill about a dozen self tapping screws into the bumper to hold the bracket. I did the VHB tape and drilled so its extra support. This is how it looks mounted to the bumper..

At this point the manual tells you to remove the screws on those two "T" shaped mounting guides and you can break them off. There is no more need for them and they were designed to be broken off easily by just bending them. There is a pre-cut line on the bracket where they would snap off.



Now its time to work with the gorgeous BMW Carbon Fiber pieces...



You need to also sand the back side of the CF diffuser to make sure the tape/betalink has a good bond. Follow the bmw instructions for this..

After sanding down the backside of the CF diffuser proceed to add the VHB tape in these areas that will come in contact with the frame you just installed as well as the lower bumper area.



Now peel off the tape backing and install to your bumper. There are a few screws from the bottom which holds up the diffuser. After installing use some painters tape to hold it in place for a few hours.



Now its time to move on to the rear side wings. Make sure your order contains a pre cut template so you know where to drill the holes. With this template its pretty much idiot proof imo. You remove one of your lower bumper screw so you can install the template then you can mark all of the holes you will need to drill. This template is key since you can precisely pinpoint where to drill and don't have to worry about it being straight or not in the right spot.



Once the holes are drilled...


Here it is mounted.






Front Carbon Spoiler Installation

The front spoiler is actually easier to install. Again follow the instruction guide and the concept is the same as the rear. You mount each bracket to the bumper with VHB tape/screws and then you attach the spoiler to the bracket using VHB tape plus bolts on the bottom.

Start off sanding both of the brackets so the tape will bond to the pieces stronger. After sanding apply some VHB tape to the areas where the bracket will come in contact with the bumper. Again, dont double upon the tape because it will raise the bracket away from the bumper and cause a gap between the spoiler and bumper.



Remove 4 of the bolts under the bumper, remove the backing for the VHB tape and attach the bracket to the bumper using the holes for the screws on the bottom as guides. Again this is pretty much dummy proof and very helpful to get the positioning perfect.



Once its attached you will need to drill the self taping screws into the bumper...



At this point you can snap off the mounting guides since they are no longer needed. Same as the rear they were designed to be snapped off simply by bending them. There is a slot where they will break off cleanly. Here they are broken off..



Now its time to install the L brackets that came with the spoiler. The manual doesn't show you how to really position these but here it is installed.



This is how it should look



At this point all you need to do is sand the back side of the CF spoiler and apply the VHB tape to the areas where it will come in contact with the bracket and bumper. Sorry I forgot to take pictures of the final steps but its pretty self explanatory. Sand, apply tape, install

The bolts you removed earlier under the bumper will screw back on holding the spoiler from underneath as well. It helps to have another set of hands to help you position the spoiler onto the bumper.

I've had it on my car for about a month now and everything is still holding perfect. If you choose to use betalink you can still use my guide and just substitute the VHB with betalink instead.



Hope this helps you guys.

Alan

Installing mine this week! Can't wait! Great post

[PanthersFX]

Just wanted to see how those with OEM lips VHP or 3M tape (no betalink)is holding up for the front lip/spoiler? I just received my OEM lip and debating betalink vs 3m Tape. How hard is the install to do myself? looks pretty straight forward based on the pictures and instructions.

[Russmov]

Originally Posted by PanthersFX

Just wanted to see how those with OEM lips VHP or 3M tape (no betalink)is holding up for the front lip/spoiler? I just received my OEM lip and debating betalink vs 3m Tape. How hard is the install to do myself? looks pretty straight forward based on the pictures and instructions.

While I didn't go OEM, I used a product called Sikaflex 221. It has a slight elasticity to it so it doesn't crack or shrink. My splitter is holding up very well, and hasn't budged. It was also much cheaper than betalink.

[Rotzy]

Originally Posted by PanthersFX

Just wanted to see how those with OEM lips VHP or 3M tape (no betalink)is holding up for the front lip/spoiler? I just received my OEM lip and debating betalink vs 3m Tape. How hard is the install to do myself? looks pretty straight forward based on the pictures and instructions.

My OEM lip is doing just fine with VHP and 3m adhesion promoter. But honestly, if it had to do it over again, I would use betalink so I never have to worry about the adhesive eventually failing.

[splitsensetam]

Originally Posted by PanthersFX

Just wanted to see how those with OEM lips VHP or 3M tape (no betalink)is holding up for the front lip/spoiler? I just received my OEM lip and debating betalink vs 3m Tape. How hard is the install to do myself? looks pretty straight forward based on the pictures and instructions.

I have the OEM splitter and only used 3m tape along with the existing screws from the bottom. I did not drill the brackets into the bumper and so far it's been holding up. My commute consist of 20 miles a day 80mph, I just did 4 hour this past weekend doing speeds of 80-100 and the splitter is holding up. However, it isn't as flush as I'd like it to be but I can live with it.

I know everyone mentions 3M VHB but I decided to go with 3M 06387 Auto Acrylic Plus Premium. According to 3m rep, this is the strongest auto tape they make and they recommend it over VHB. Unfortunately 06387 is hard to fine unless you buy bulk, but I was able to find a roll through the Internet.

Pics below

[monkiboy]

i did VHB and prepped really well. i do a good bit of highway driving and it just wasn't perfect. i'm a meticulous guy. i couldn't deal with the slight sags or it not being tight up against the body on the sides. did betalink and it allowed me to do it perfectly and sturdy as a steed. i know there are folks who say there's looks good with VHB but their standards may not be your own or perhaps it's just a matter of time, realistically. what you don't hear, are folks who did betalink and have had issues with separation or being unhappy with their decision other than the permanence of it.