[MOTK]

Originally Posted by Vanne

thanks for the pics MOTK, , i appreciate them, see the stock z4m intake size that comes through the nose wall, It's about a 1/3 of that size of the headlight intake in your picture.

Don't worry about the pictures mate, I've had a glance or two at the intake over the last 3 years as have I seen the M3 racecar in the shop i use which uses a similar arrangement. There's really not that much of a difference in size of the intake hole, I can take some better pictures of it if that helps you.
In any case what I was trying to say is that the initial entry size of the hole is not that important, indeed when the car was last on the dyno and made 383bhp it still had the restrictive oem scoop rather than the rpi I have now, the tuner was clear that there was no issue with enough air flowing to the box.. I've noticed no difference since fitting the rpi unsurprisingly to me.

Originally Posted by Vanne

And that's not even talking about the 90 degree corners it takes as it goes from the scoop (if you even have a scoop) to the exit through the the nose wall. I have some pics somewhere I should dig up.

Bit confused about this statement as both air intakes from the bumper and the grill also have similar 90 degree corners in the original CSL application?

As I said though I am no flow dynamisist, I'd love to know the calculations you used for this statement...?

Originally Posted by Vanne

Btw, the OEM CSL snork flap is closed only at idle/below 3k rpm, and yeah oem Z4 air hole at that rpm that will provide enough flow at this stage.

Originally Posted by Vanne

Edit: not meaning to say its useless, just less than optimal, and if your getting one of these intakes, i would imagine your going with optimal, otherwise you might as well have stayed with your OEM intake, which as FD3S correctly pointed out is very nicely optimised by the BMW M factory to provide an excellent intake source for the MAF requirements of those maps, which our CSL intakes don't have.

In my opinion if you really want to be running this intake 'optimally' as you say, you'd be better off figuring out how to run the box with correct CSL map sensor rather than the bodge we currently have of using alpha-n, a very flawed approach unfortunately. Certainly more important than worrying about increasing the size of the intake hole by an inch or so. Just my 2c.
As I'm not sure if that's possible I have concentrated on what I know to be important for getting alpha-n to work well which is to have a good supply of cold air and making sure the IAT probe reports this air temperature accurately (i.e. not suffering from any heatsoak to give false readings for the table).
I look forward to seeing your headlight/carbon tube mod and the results you see from it...