I am thinking about putting an exhaust on my OM603 powered car to help free up the exhaust flow. I was planning to put a free flowing muffler on it to keep it pretty quiet, but to give it a little bit of sound when you punch it. How do these engines sound with exhaust? Anyone have any sound clips?

You won't gain much from a custom exhaust, mostly more noise. Only use a straight through type muffler. Chambered types don't play nice with turbo engines.

I was planning to use something like a magnaflow or dynomax ultraflo. Chambered mufflers suck bad enough on NA gas engine...let alone a turbo diesel.

So there arent really any gains from upgrading the exhaust system?
Maybe I should just cut out the cat on the exhaust and leave the rest be.

Still though, how does the om603 sound with an exhaust?

The stock MB exhaust system is already a full straight-through flow system. You won't really gain anything but noise. I went straight pipe on my car because it cost almost nothing, while a full MB exhaust would have been $400.

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It already has an exhaust. If not, what happened to it?

That's incorrect. Dyno tests in gearhead magazines like Hot Rod have repeatedly shown that straight-through mufflers have more HP loss than chambered mufflers (whether they're "turbo" mufflers or baffled mufflers like Flowmasters). Additionally, glass-pack-style mufflers like Magnaflows are likely to get clogged with soot, so you might as well run a straight pipe.

Very funny...I knew that was going to happen.


Dyno tests performed by me on the same day on the same car repeatedly showed that straight-thru mufflers outperformed all other types. Turbo style mufflers are NOT straight thru.

Don't the exhausts for the diesel trucks use a similar style muffler to a magnaflow? I guess that the holes are just bigger

The Finns have done it, and I've seen video clips of the results somewhere. But they didn't just install tuned exhaust systems--they added bigger turbos, intercoolers, and I don't know what else. You can see some pix at 124performance.com/SuperTurbo

When I lived in Europe, I was on the lookout for a Euro style exhaust manifold without the egr attachment, but never tracked one down. Should've tried harder.

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Rob

Yeah, those euro manifolds look nice.

I have watched those clips...but I'm sure the turbo and extra boost makes them sound a lot different.

OK, you have more credibility than Hot Rod. In any case, I didn't say turbo-style mufflers were straight through, did I?

Credability to you...probably not and I really could care less.

Credability to me...yes. I know what I saw on the dyno and it is hard to tell me that it was a lie. This was also done with multiple runs and the differences were large enough and pricise enough to prove that it wasn't just a fluke. I, unlike magazine, do not have any advertisers buying space and giving me money. I would be willing to bet that if you piss off a sponsor of your magazine by running an article saying that their product is not the best that you would have a tought time getting them to continue advertising. Either way, I saw what I saw and I will continue to buy straight-thru mufflers instead of other types. In addition, I prefer the sound that they make, but not everyone must have the same opinion on that.

Pissing matches aside, ...

Your power on the stock turbodiesel Mercedes is limited quickly by the wastegate/boost control. Creating a better exhaust flow might improve your fuel efficiency or maybe even a slight improvement in your spool-up time, but ultimately the boost is limited/controlled and limits your power output.

If you were modifying your boost, increasing fuel flow to match, it could theoretically need more exhaust flow. Before that happens though you will probably want an aftercooler (which restricts flow).

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