According to the factory specification, the 420er is lost by the cat 14hp, the 500er 21hp and the 560er 30hp (the higher compressed ECE engine I deliberately leave out). Questions: *Where does the loss of power (and also torque) come from? Compression and peripherals are the same, except for Kat and Lambdasonde. Is it only the increased counterpressure in the cat or are there any other changes like for example in full-ast enrichment or elsewhere? *why is the power loss in the larger lifting spaces so far exceeded This is why the kat-related power loss of the AKR engines (from 1987) is significantly smaller (only 7 to 21hp, depending on the engine capacity)? Were there other cats installed? *Sometimes someone made a measurement on a dynamometer? Although they have an R 107. However, since the engines are the same and the number of drivers in this forum is probably higher, I posted here (with a note in the SL forum).