Very interesting Heinz. Do you think it's possible that simply relocating the maf sensor would have the greatest impact?
Nick
I tried the standard 57 mm tube with the added maf sensor plastic tube mounted directly to the throttle body. The result was not so good, but I think, that was because of the additional length of total tube and also because it seems that the maf sensor neither works not at best too far away nor mounted directly to the TB. I don't know why, possibly the sensor itsself adds turbulences just in front of the TB because it is "in the way" or possible as well it seems to be better if the ecu has a little bit of time to make it's calculations when the maf sensor is a little farer away but not too far giving incongruent results to what the TB "sees" in terms of temperature etc.
To sum up, the slightly wider diameter of my new intake tube makes sense in cooperation with the sport manifold which also has wider diameter tubes.
I'm pretty shure that in team with the standard manifold a relocated maf sensor mounted at the standard 57 mm tube at the position more or less where my maf sensor is placed should improve the throttle behave significantly. Remember I know no other car of any brand where the maf sensor is so far away from the TB as on a 4/4 Sigma.
If you like to keep the standard system it could be an improvement to change the accordion rubber hose mounted at the filterbox for a smooth one, but then you have to take one which has 60mm diameter at the box side and 57 mm at the tube side.
