Posted by Cliff Robb on January 29, 1999 at 10:52:54:
In Reply to: Re: exhaust posted by Troy Rudolph on January 29, 1999 at 09:03:05:
The system that Wietse described is the exact make up of the Metric Mechanic System 300 that I paid way too much for before I knew better. It does sound good though. I also went for the MM "ported" dual exhaust manifolds that I believe come from either a 535 or a Bavaria. The porting amounts to nothing more than opening up the inlets of the manifolds to a round shape so that they are purposely larger than the exhaust ports on the head. This is claimed to have an anti-reversionary effect. The euro downpipes are 2"(50mm) as opposed to the stock single 40mm. As far as the O2 sensor, MM recommended just putting the bung in one of the downpipes. They supplied my down pipes with the bung on the front pipe. I was a little skeptical at first, but I checked into how O2 sensors work. Since they sense % of O2, not total quantity, if the engine is healthy & running right having the O2 sensor installed like that does not pose a problem. My car runs well set up this way, and my gas mileage as well as my O2 sensor readings (450MV avg.) are correct. You could probably do the system cheaper if you had the downpipes modified with a 2 to 1 collector, & then just get a hi-flow 2.5" cat. You have room in the stock muffler location for all different kinds of performance mufflers. This style of system will drop about 40lb. from the stock system. Deleting the resonator gives you that cool James Bond exhaust resonation sound as you go from about 2000 to 3000 rpm. I like it. Find out which muffler guy the hot rodders use in your town. He could probably bend you up a really nice system including custom downpipes and hi-flow cat. for $500 or less. If I had to do it again this is what I would do.
: Your idea sounds pretty good. Where would you install the oxygen sensor?