Dear US colleagues, Do you run your cars with catalytic converters in the US? In a recent e-bay auction they had included a picture of an emission-standard plate, specifying catalytic converter for the auctioned 400i. The EU is soon implementing a ban for non-catalist cars in certain areas (and Switzerland will probably follw as usual). Therefore I'm thinking about such a conversion. It must be possible on technical grounds. Many Germans have modified their Mercedes 107 types with K-Jetronic fuel injection because they can save considerably on road tax. The questions are whether someone is offering a suitable conversion kit, what are the costs and how does it influence the performance. Peter
My 1983 400i has catalytic converters, which are required in the state of Connecticut. They were installed by Dick Fritz at Amerispec, who has converted many gray market cars for the US over the years. The cost of the two converters installed plus two "test pipes" (plain pipe sections that can be used in place of the cat sections for <ahem> track purposes) was about $1,900 in 1998. With these cats, the car passes CT emissions tests easily. John
Have never seen a conversion kit but the standard method was to cut out the front section muffler from the exhaust center section, weld appropriate flanges on the pipes and install the convertor between the header collectors and the now shortened center sections. Many conversion shops used the cheapest cats that would fit and the installs were often not that good so power loss was common. With modern high flow metallic cats there is no longer any reason to live with a power loss so you should be OK. One caveat though. 400's were never designed to have cats so I would fabricate some sort of heat shielding to install above it on the bottom side of the floor.
Thanks, Brian and John for your information. The way you are describing the conversion seems to me as if the cat used on the 400i is not a three way catalyst with lambda probe system to control the air fuel mixture although this should technically be possible with the K-jetronic fuel injection system. Peter