Hi all - so my 4.2 supercharged only plays nicely on gas until about 4000rpm so we have it switch over then which seems ok.

After that the power goes weird about 5000rpm sporadic and bouncing up and down hence switching now at 4K

Anyway looking at something entirely different today and I notice the vacuum feed for the aeb map sensor is drilled into and then the hose connected to the right hand air cooler.

I may be sounding like I don’t know what I’m talking about here but whilst doing some other bits on the car and having issues it occurred to me that this is not always vacuum and at around 4000rpm+ it would have switched from being vacuum to being boost - which I am assuming is not what the map sensor is looking for?

Am I right or wrong? If I’m right where do you get your true vacuum feed from?

Thanks!

Hi Dan

Looking like your installer up and thats leading to your issues, that section will be under boost pressure, last time I messed about with the map sensor on mine the vacuum line line looked as if it tied into the inlet side of the throttle body, but I didn't trace it all the way to the tie in point tbh

Hth

Thanks I think that it should T into the bypass actuator looking at it I think if I buy a brass T and just move it I should be good although it will likely need a retune and that part blanking off Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF