Has anyone dynoed before and after removing the intake flap
 

Recently a good number of members with CSL (and replica) air boxes have been retrofitting the full CSL ecu tune (and associated wiring changes), and basing their custom tunes on that instead of the stock M3 tune.

Some of them have started retrofitting the intake flap as well, under the assumption that it has a DISA like effect in addition to noise control.

e.g. http://www.m3forum.net/m3forum/showt...p?p=1066740021

From reading this forum over the years, I've always been under the impression that the flap was for sound control only. But, seems like that might not be the case? Have any of you done before and after dynos after removing the flap?

It will NOT effect any power that you will use to make you faster.
It might effect power low down where a standard CSL tune may think it's closed, but I highly doubt that, and the power effected low down won't be noticeable and when driving fast you will NEVER be in the low rpm range anyway.

I wouldn't bother with the CF air box flap on a CSL clone as it can rob you of about 30 BHP when it (and it's friend the potentiometer) decides not to open when they should :banghead: ... don't ask me how I know :smt022
Sufic to say I've been flap-less since 2010 :thumbs:

Do you recall what rev range /gear you noticed this Matt?

Not exactly but it was well into the rev range, say 4000 RPM and above :banghead: irrespective of which gear I was in.
It felt like I left the hand brake On ... and Yes I did have a quick looky down :) to make sure it was Off while on a flying lap @ the Ring.