does lid airbox stay closed with cold temperature?

[dave1]

noise regs

[SpineOnABap]

exactly

[Mark CSL]

Originally Posted by houlbt

Why do so many sports cars have exhaust valves these days?

I still think there is more to it than that.
But i do no mine stopped working and i put a new pontomoter on it
and all is good now.

[BMsport.com]

Finally, some one understands the flap is there for noise reasons. It has no bearing on the fuelling. The amount of air entering the engine is controlled by the throttle valves, not the flap and monitored by a MAP sensor. There are many CSLs out there with and without the flap. If it caused rich or weak running then the emission light would illuminate on the dash board. To say it must have a reason as it was fitted by BMW Motorsport is correct, noise. For the same reason the exhaust is quiet.

[M3_CSL]

probably someone should make an exhaust with a valve for the CSL too... while the exhaust valve is closed, the exhaust flow is like the original CSL exhaust... and when the sport button is depressed, both intake and exhaust valves will be opened for full race noise..

I used to use an electronic exhaust flap on my highly tuned N/A 350Z (revved to 8200rpm with full engine rebuilt and MoTeC), that car was quite loud with its exhaust, so a flap was needed to go around the suburban streets and i couldn't believe how much difference it made.... but with the flap closed, power loss was substantial and also the engine didn't like it at all

just a wild thought...

cheers,

richie

[englebert]

Someone should buy a Kreis-Seig... best sounding out there, goes from a normal exhaust to completely straight through at a touch of a button!

As said before, BMSport removed my flap. Went from their lowest peforming CSLs to one of the best!

[NZ_M3]

Originally Posted by BMsport.com

The amount of air entering the engine is controlled by the throttle valves, not the flap and monitored by a MAP sensor.

Kindly explain how does an individual throttle intake system operate on a MAP sensor without an intake manifold (to measure manifold absolute pressure??) - better still point to me an actual MAP sensor BMW part number on the CSL (I've yet to find one on realoem.com - and no not the one on the idle regulator lines - that controls idle). As far as I am aware the car runs without a MAF or MAP sensor - basically Alpha N tune on throttle position and air temp sensors.

Actually, if you can throw up a dyno graph showing that there's no torque loss without the flap operating in comparison to one with the flap operating.

[BMsport.com]

Map sensor part no. 13 62 7 833 561. It fits to the air rail so feeds from each throttle body, part no. 13 41 7 833 597.

[NZ_M3]

Originally Posted by BMsport.com

Map sensor part no. 13 62 7 833 561. It fits to the air rail so feeds from each throttle body, part no. 13 41 7 833 597.

That one's for idle control ... unless I am mistaken ...

[BMsport.com]

And even if it was alpha n, the air flow would still be controlled by the throttle valves, not the flap.