Z4-forum.com

Started this thread as I didn't want to hijack someone else's. I've done a search and can't find anything.

I ordered the carbon rear diffuser at the weekend and it is now at the dealers. I'll pick it up later this week.

Anyone actually finished fitting one of these yet?

I was wondering if it is possible to fit it without removing the rear bumper cover?
I think you could do the cut out on the car but I'm not sure you would get to the bolts holding the diffuser in place.

Are there any instructions on the net for removing the rear bumper cover? I've had a quick look but can't find anything?

Thanks in advance.

Hi - thanks to the wonder of mobile internet while sat in the shop getting my geo set up I can give some thoughts:

Firstly there is one member who has fitted on as I hijacked his photo for my research thread.

When you collect it ask for the instructions. They'll print off from their system as they are not in the box.

Having had mine on the bench for a week I see no way it can be fitted in situ:
1) there's a lot of plastic cutting and a possibility of cutting into other goodies from hanging down PDC cables. etc.
2) the top edge is held on by 9pan head bolts, 4 of which are so awkward that they come with wires welded to the top that are used to hold them in position while nuts are fixed. They are then tin snipped off.
3) OEM instructions specify removing it.

Removing the bumper will be in the TIS but to me it looks like remove the trim along the boot lip, undo some torx there. Unclip the wheel arch mounting pins and then 4 or 5 bolts underneath. Should just then unclip from the sides behind the wheel from the rear quarter, similar to the front.
I can find the section and email you tonight if needed.

Thanks. I think I realise it can't be done on the car to be honest!

That Email would be handy if you have time.

On the OEM fitting instructions, does it give an estimated fitting time?

em, what OEM carbon rear diffuser is that? any pics? that's the kind of expensive mod i like! More details on cost etc would also be appreciated.

Check this thread: http://www.z4-forum.com/forum/viewtopic.php?f=2&t=9267

By the way, BMW don't do one for the M!

BMW install instructions quote 2 hours for the post 2006 carbon diffuser. Times quoted are assuming no paintwork (which I can't see whay it would unless the existing is damaged by them... and 'depends upon equipment fitted'. Guess that means £240 basic at the dealer to do it plus VAT.

2 hours!! Are they laying up the carbon fibre as well!!

Yeah right....I agree, but that's BMW for you.

Here's a scan of bumper removal on a roadster FYI. As suggested earlier it's a real quick job:

I think the coupe has another row of clips under the bootlid trim, but you can check that

Thanks for that.

Looking on real OEM there are some screws under the top trim.

Breaker wrote:Thanks for that.

Looking on real OEM there are some screws under the top trim.

Yep - as per my post. clips, screws, whatever. Located on the roadster under a black trim cover. For some reason not mentioned on the TIS page

I'm picking the diffuser up Friday afternoon (it's at the dealers now) so I just need to pluck up the courage to take off the bumper and cut it out!!

Unfortunately it probably won't be for a few weeks yet as I have a very busy calender for the next 2 months!!

I work for a commercial vehicle body building company (IT and office bound now) so they have loads of tools I can borrow. The one tool is a small circular saw designed for cutting out glass fibre. It has a very fine toothed blade. Beauty of that is there is no sawing action so the paint shouldn't chip. The only problem can be heat build up though.

I may even get the shop floor guys to cut it out for me yet!

I too am stopped in my tracks due to work and other car issues to sort out....

Nice to have a bodyshop on hand. My plan will be to run a fine dremmel line along the final cut line to isolate any paint splinter. In fact aside the curves over the exhaust there is a lot of remaining material to work with so shoudl not be too bad.

I'd fit mine soon except the bigger job of battery moving needs doing and I don't want to drive around for weeks with dual outlet and single exhaust - too Corsa/ Saxo

I'll try and get some pics when I install it including the bumber removal (if I have time!!).

If it works, I'll post them, if it doesn't I'll be homeless so wont have access to a computer (the misses has threatened to kick me out if I mess up the Z4!!!........and it's my car!!!).

cj10jeeper wrote:

Breaker wrote:Thanks for that.

Looking on real OEM there are some screws under the top trim.

Yep - as per my post. clips, screws, whatever. Located on the roadster under a black trim cover. For some reason not mentioned on the TIS page

Actually, looking at the RealOEM picture I think the top fixing (item 5) is a push fit clip, not screwed in. The screws on the picture are to secure the holder.