I'd like to implement the tweaked stock intake manifolds with crossovers from needwings.

The car is an unpullied SLK 32 AMG (SRT6-engine). I asked several tuners if an ecu-tune is neccessary for the new imf. They said all 'no' and 'you need only a tune, if you go pullied' - but I'm very skeptical.

MAP- and IAT-sensor are before the restriction (not after) - so an indicated boost drop possibly matters - especially on open loop. The boost drops with the imf by 3 psi at peak rpm on a stock (unpullied) car - but the air flowing through the engine is at least the same.

Think about this: you drive with stock!-imf trough the mountain - the boost drops because air pressure is lower (boost 11.5 psi). In this case in open loop - my thoughts - the ecu gives less fuel - and this is absolutely correct because you have less air. But if you drive on sea level with the crossover-imf (boost 11.5 psi) you possibly get lean.

Who knows it - are the tuners right - no tune neccessary - and how does the ecu work in this case?

 

Fuel is metered by EXHAUST. not boost. Woody

 

You are right on closed loop. But my thinking is not cruising but full throttle (open loop). Exhaust doesn’t know AFR because there is no wideband lambda sensor. Ecu needs an equivalent of air mass for the right amount of fuel – my thinking MAP- and IAT-sensor gives the input.