All,

I let the cat soak in a citrus wash bath (mildly acidic). I gave it 3 treatments and the backpressure is down to <2 psi when loaded from a small compressor set to 150 psi to start. My compressor drops quickly at that pressure loading the cat. The acid in theory should cause a reaction to release the soot and free the clog. Based on the soot released and the huge drop in backpressure it seems to have worked. I'm about to put the pipe back on the car.

Some questions:

1. Does anyone know what the bp should be?
2. I was thinking of drilling a 3/8" hole straight through. I'm hoping this would solve the problem long term and at least leave some of the emissions reduction of the cat. Does anyone have any thoughts on this plan?
3. I was also thinking of just putting it on (without holes or a pipe) and seeing if the citrus wash worked according to theory. Has anyone done this before? Does it work? How long does it work for? Anyone else curious?
4. Any other thoughts on exhaust? I'll be moving to fuel next.

Thanks for all of the help so far,
Hugh

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94 E320c
87 300D

All,

Citrus Bath Cleans Cat (for those who were curious like me)

I put the exhaust system on the car back together. Boost drop was minimal. Bath seems to have worked. Almost no particulates when the car is warm. Diesel odor dropped significantly. I'm hoping to get the emissions done tomorrow. Looks like it will pass with flying colors. With the emissions report I'll have a better idea how far I can take it. After that I'll start playing with fuel and timing.

Thanks everyone for the help so far.

Hugh

__________________
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94 E320c
87 300D

I guess it's 2 then. Haven't been down there in a while. The resonator and muffler have baffles but nothing that can clog... unless the car was down for a while and rodents built a nest. I don't know if psi is the way to test for a clog. Seems like cfm is the way to go.

Sixto
87 300D^2

Sixto,

The clean out seems to have worked. Car is running fabulously. I'm going to play with it more after I do the emissions test. Fun to know my boost should be nearly twice as high. It's the same now as with no exhaust hooked up but still only 6 under load.

Q
What is cfm?

Thanks,
Hugh

__________________
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94 E320c
87 300D

Cubic feet per minute. It's how they measure the flow through a carburetor or cylinder head port.

Sixto
87 300D^2

Sixto,

Found a reference in the benz bulletins that backpressure should be <2psi at the exhaust bolt. I'll test this when I get a moment.


Q
Does having the cat working do anything bad? It certainly seems to help low end power...

Cheers,
Hugh

__________________
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94 E320c
87 300D

Are you measuring 2psi at the #1 exhaust runner test port? I read it as you charged one end of the downpipe with 150psi, hence the compressor, and you read 148 psi at the far end.

Sixto
87 300D^2