HELP Gutting or Removing Precats on early 300E - PeachParts Mercedes-Benz Forum

FA22 · #1 08-30-2002, 06:39 PM

I am reworking the exhaust system on my 300E (remus muffler/ Y-pipe) and would like to find the easiest method of eliminating the precats. Euro Models don't have them and I should gain 10hp.

I know I have several options, gutting, replacing with Euro down pipes($$$) or somehow replacing with custom pipe. Living In CA with our tough emissions, I wouldn't be able to go to a shop have have this type of work done. I am not worried about emissions as the 92+ 300e don't have these precats(2 cans connecting to headers) . I believe gutting the precats would be my best option, but what is actually involved in this process? Anyone who has eliminated them or would be kind enough to explain how to gut the precats please share. ..

TIA!!!

Maddog · #2 09-01-2002, 12:17 PM

I did this on my 190E. Here is what you have to do. Remove the downpipe from the car. I believe it bolts up to the exhaust manifolds and right after the cat. I then took a large metal rod, stuck it down one pipe at a time, and just beat the living $hit out of the precats. After a couple of hours. My precats were gone. If you know how to weld...I would just cut the precats out and weld in a straight pipe.

#3 09-01-2002, 12:50 PM

You are not going to gain 10 HP from aliminating them. I doubt that you will gain more than a couple of horses which you will not be able to feel anyway. Plus, your car will not pass emissions.

But the best way to do that, is to cut down the cat canisters and weld straight pipes. You take out the header, cut the cats off and then take the header to someone to weld the pipes.

If you leave the canisters on and just brake off the material inside, you are not going to gain any horsepower because of the decreased exhaust gas flow velocity and turbulence that the empty canisters will provide. As a matter of fact, if you do that, you will probably loose a couple of horsepower.

Maddog · #4 09-01-2002, 01:15 PM

Here is what I experienced. I gutted my precats and cats. At high RPMs, my engine used to vibrate and I could never figure out why. But that is gone now...so I guess it was exhaust restriction. Damn US emissions. My exhaust system sounded a bit deeper and I like that a lot. I think I may have gained a few HP but nothign really noticable.