my z4m rear custom diffuser

He said it would be £150 to each address

His exact words were -

No problem - I have no issues shipping to UK :)

We will ship using USPS, just add $20 bucks so $230 shipped per diffuser if going to different addresses.

So if we can get 5 together

TomScott
Ranski
BigT

So far.
 
exdos said:
Don't forget to factor into the cost Import VAT and the "Clearance Fee".
Click to expand...
Exactamondo! Was going to post the same. What are we looking at, £200 all in perhaps?
 
£50 for import tax etc?

I bought a £800 Airsoft gun from Japan last year and only paid about £40 on-top






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I bought stuff from us before,and it was $80..paid £22 in taxes,etc. so maybe worth checking out;could well be upto/around £50.
£200 isnt too bad though,as said,looks good and cheaper than anything else around
and agree with tomscott-would look even better wrapped in some lovely carbon-fibre :D
 
Beedub said:
The fit is very neat... I like that it uses existing mount points a well.... Very nice.
Click to expand...


Thanks. The piece comes without any holes. So you can drill and install however you like. I just chose to use existing holes and mounting points with only 2 drilled at the far back at each corner
 
The part that you've fitted appears to block off the exit of the two channels in the OEM black plastic undertray which will prevent the smooth flow of air on the underside of the car, particularly in the region where smooth flow is most important. :roll:



dubdiff.jpg
 
dubsed, just wondering, if this is only attached by the two rear screws, the leading edge towards the front of the car whats stopping air being trapped under their and lifting the item at high speed, as we all know air at speed is a different beast all together!!! i think this needs to be attached at the front edges as well, also i didnt realise this is placed ontop of function ducts, you are disturbing meaningful airflow by placing this piece like this..... shame though as it looks really good imo!!!
 
Good point, although looking at the image don't the groves lead airflow to exit through the grill



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ranski said:
Good point, although looking at the image don't the groves lead airflow to exit through the grill
Click to expand...

The OEM black plastic undertray directs the air in the centre, which flows ABOVE the flat part, so that it cools the differential and that's the air that exits through the grille. All the air that flows UNDER the undertray must flow around the rear bumper and this "diffuser" part appears to occlude that flow.

One thing that I've noticed after driving my Z4MC in the rain is how few dirty streaks remain on the bodywork when its dry and how relatively clean the back end remains, which I think shows the relatively smooth airflow over the entire car. In comparison, the rear end of my Z3MC gets filthy in no time.
 
ranski said:
Good point, although looking at the image don't the groves lead airflow to exit through the grill



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Click to expand...

Exactly. The diffuser doesn't block any airflow. The oem diffuser venting is guided towards the grille between the bottom of the bumper upwards. The bottom of the diffuser is tight to the bottom portion of the plastic diffuser, so I don't see how it blocks air? And beedub, the piece is secure at all four corners, it's just difficult to see the screws. The piece is rigid and doesn't shift at any speed.
 
dubsesd said:
The diffuser doesn't block any airflow.
Click to expand...


Here's a photo of the OEM rear undertray attached to the rear bumper on which I've highlighted the right-hand side channel with the white dotted line. From the line where the tunnel finishes to the edge of the rear bumper under the grille it measures a total of 7 inches. You say that the part you've fitted is 8 inches deep, therefore it seems to me that the front edge of your part MUST lie over the end of the channels, and if it does, as it appears to do in your photo, then it will occlude airflow exiting the chanels.

Z4reardiffuser.jpg
 
mine just come past the diffuser section by 1". my measurments were just estimates. if it really bothers someone, they could easily trim that bit of plastic. i think your overanalysing it a bit. i havnt noticed any ill effect under any type of driving. the ac schnitzer diffuser blocks all cooling from the differential and i havnt read any negative reviews on that yet
 
dubsesd said:
mine just come past the diffuser section by 1". my measurments were just estimates. if it really bothers someone, they could easily trim that bit of plastic. i think your overanalysing it a bit. i havnt noticed any ill effect under any type of driving. the ac schnitzer diffuser blocks all cooling from the differential and i havnt read any negative reviews on that yet
Click to expand...

Your piece comes right up to where the indentations are for the two bolts showing in the middle, between the right and left air passages. it also sits flush with the underside. From what I can see in your pics, the two OEM air channels seem to line up between the outer two fins on either side. The most I can see happening is the exiting air has a slight bump at the very end of it's travel when it hits your add on diffuser ....... and your piece is what, a 1/4 inch thick at that point? As long as the inside edge under the car is tight and flush against the OEM area, doesn't seem to be an isue to me. The last inch could also be trimmed if it was a concern so the piece stops at the point where the bumper and factory air channel meet (yellow and black area in the pic)

John
 
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