300SDL exhaust front pipe/cut out converter - PeachParts Mercedes-Benz Forum

MadtownDiesel · #1 07-30-2009, 08:58 PM

Hi all,
After 9.5 years I finally split/crushed the flex-pipe (has a braided cover) that is on the front pipe that runs down From Exhaust Manifold To Catalytic Converter coming out of a parking ramp laden down with camping equipment. The cabin is filling with fumes. My question, what happens if I just forgo the converter when replacing? Do I have to adjust anything?

In the pictures/diagrams I see of replacement front pipes, (attached) the pipe looks like it extents for another 12" or so after the bend with a flange. Mine is cut after the bend and a Catalytic Converter is welded on with a flange on the rear side. It looks like I can just pull out the old and hook up to the rear flange. I replaced the back half--everything past the converter 4 years ago--looked like the original 1 piecer, with the center and rear muffler.

Simpler=Better · #2 07-30-2009, 09:19 PM

That's probably a resonator, not a catalytic converter.

I'm running a straight pipe out the side, you may need to adjust your wastegate due to a decrease in back pressure(If you chop the muffler too)

Hit Man X · #3 07-30-2009, 09:34 PM

Quote:

Originally Posted by Simpler=Better

That's probably a resonator, not a catalytic converter.

I'm running a straight pipe out the side, you may need to adjust your wastegate due to a decrease in back pressure(If you chop the muffler too)

Go roll under one and see for yourself that it is infact NOT just a resonator, but a catalyst of some form.

I gutted mine as they plug up all the time and there was no need to adjust boost levels. The stock muffler is of a straight through design (same as the center resonator), nothing gained by removing it.

Brian Carlton · #4 07-30-2009, 09:44 PM

Quote:

Originally Posted by Hit Man X

I gutted mine as they plug up all the time

Details please............how do you get to it while it's in middle of the pipe?

Hit Man X · #5 07-30-2009, 10:00 PM

Quote:

Originally Posted by Brian Carlton

Details please............how do you get to it while it's in middle of the pipe?

I removed the three bolts at the turbocharger outlet, the two at the transmission bracket, and the three by the converter itself. I think that's it... it was a simple removal.

It was a struggle to free the pipe, but once free I just covered myself (eyes, breathing, etc) and pounded it out w/ a long piece of rebar. You will want some long pointed pliers to pull the large chunks of the cat body out and then proceed to shake it upside down. Repeat until it falls out (similar to gutting precats on a Z32 Nissan Twin Turbo). There is something similar to a screen door that secures the body of the cat to the body of its housing, just twist that around the pliers and yank it out. I would soak the cat body in some cheap motor oil before doing this again to keep the dust and such to a minimum.

I did this to my SDL and an '87 300D I was fixing for a locally (I should have purchased it, SUPER clean

). The 300D was an absolute turd after trying all the usual fixes... filters, banjo fittings, EGR delete, ALDA, etc. So I did the cat, and voila... ran great after the surgery.

TheDon · #6 07-30-2009, 10:08 PM

hmm I might have to do this to mine since I just noticed it today and wondered what the hell it was

daw_two · #7 07-30-2009, 10:27 PM

I've got a complete 300SDL exhaust on the parts car in case anyone messes theirs up with a hole thru the side of the pipe.

Hit Man X · #8 07-30-2009, 10:28 PM

Do it and remove/max out the ALDA... you'll be surprised how responsive the vehicle is to drive.

Tweaking the IP is simple on these too if you want to go in that far.

I blew my 300SEL off the road in a dead stop race (the SEL was sitting in first gear). I took it until about 45mph then the SEL pulled away due to the greater top end power. I love the SD and SDL for dorking around town, I'd love to have a 350SD... SWB and a 603.

babymog · #9 07-30-2009, 10:33 PM

Is the '91 350SDL exhaust any different than the '87 SDL exhaust? I have from the downpipe back, no cat on that one, pulled from my '91 before the crusher.

Hit Man X · #10 07-30-2009, 10:38 PM

Quote:

Originally Posted by babymog

Is the '91 350SDL exhaust any different than the '87 SDL exhaust? I have from the downpipe back, no cat on that one, pulled from my '91 before the crusher.

AFAIK no cat on those or the '86 SDL.

MadtownDiesel · #11 07-30-2009, 10:48 PM

Thanks much for the advice. Getting it ready for a run out to Yellowstone in 2 weeks.

Hit Man X · #12 07-30-2009, 10:56 PM

I can't figure out why we see piles of '87 cars and very few '86s, when more '86s were built.

TheDon · #13 07-30-2009, 11:02 PM

No idea.. I find an '86 SDL to be odd.. '87 just sounds better.

MadtownDiesel · #14 07-30-2009, 11:20 PM

Upon further review...The photo is what I have, the diagram (from the original post) is what I've been finding as a replacement. I assumed that was a catalytic converter at the end of the front section of what I have. Since the only thing bad with the front section was the braided resonator looking thing on the down pipe and the converter in question looks iffy age-rust-wise I was hoping to drop this and just use what is shown in the diagram and bolt to my newer back end.

87 sounds better for some reason.

Hit Man X · #15 07-31-2009, 12:32 AM

Just get the catless style pipe or gut your cat then replace the flex section. I think that piping is 2.25" so the joint can't be too spendy.

Mull over it with a beer then decide, or flip a coin and let fate decide your course of action.