Whatever it is, it’ll be enjoyable to discover the modifications you need to make your exhaust louder. Do you wish to launch flames out of the exhaust? Set off vehicle alarms when idling at a cold start? With enough rattles, bangs, and booms, you could even create the soundtrack for an ongoing combat zone in your calm neighborhood. It’s possible to increase the volume and depth of your exhaust system so that you can genuinely hear natural power dwelling inside your car’s engine. If your ride’s exhaust system doesn’t seem loud enough to meet your preferences, a few modifications are waiting for you. P.S.You must be among the numerous car person who loves the sound of an impressive-sounding car despite its loudness. I tightened up the wastegate spring until I was out of threads, but the most boost I am getting is 12 psi, barely above stock specifications. Like I said, I don't want the engine to be louder, I just like turbos when they spool up, like on every other brand of diesel. At some point I may delete the muffler and resonator. I noticed it had some strange large round metal gasket at the housing that I haven't seen on other Mercedes turbos. It's possible it had a leak somewhere after the turbo that was letting out the sound. It's interesting that my previous 300SD had such a loud turbo whistle. I also don't want to put any holes in the exhaust. When I ran the engine with the air cleaner off after installing the turbo, I could not hear any turbo noise when revving the engine, so I don't think that anything before the turbo is going to help with making the whistle heard. So, I don't recommend removing the tube inside. I've since rebuilt the turbo and reinstalled the tube that goes inside the coupler. This is a late update, but the ridges of the turbo-to-exhaust coupler filled up with carbon in short order and the faint whistle shortly went away. I was tempted to use the damaged flex pipe in the last picture to get more sound out, but then I don't want the exhaust escaping, either. Imma firin' mah turbo! WOOO WOOO! Below are some pictures of the pipe on a spare engine I have. This was totally worth the hour spent removing the inner pipe. The engine is loud enough for me I just want turbo noise. I may remove the muffler while retaining the resonator if that will help make the turbo louder. I am considering having a custom exhaust downpipe made out of thinner metal that will transfer sound so that the turbo noise can come through it. Though, I wonder if I could sleeve one so that it's open and allows the sound to escape while routing the exhaust down the pipe. I was tempted to make some holes in the flex pipe to allow more sound to come out, but I don't want the engine compartment filling up with smoke and soot. If you want to hear your turbo, remove the pipe inside the flex pipe. Someone local gave me a used exhaust system but it did not have that pipe that fits inside the flex pipe. It sounds like a jet and I love it! Now that I think of it, my last 300SD had no exhaust when I purchased it. I drove the car again, and though the engine was back to being quiet as before I removed the exhaust, I could now hear the turbo with the exhaust attached! It's not as loud as without exhaust, but the engine is quiet and the turbo is audible over the engine when accelerating, just like my last 300SD. Out of curiosity I did not put this pipe back in when I installed the flex pipe. There was a pipe inside of the flex pipe. When I removed the exhaust I had to remove the flex pipe that goes between the turbo and the exhaust. The engine was louder, but it wasn't annoying at all, it actually sounded good, like a big truck. I was turning heads and got a smile from a guy with a Ford Powerstroke. Wow, my turbo works for sure! I could hear it spool up and hear the waste gate open. Today I removed the exhaust and drove the car. I was still unhappy with the fact that I couldn't hear the turbo and I wanted to know if it was working. After doing routine filter and fluid changes, adjusting valves, and backing the ALDA off completely I got a lot more power out of the vehicle. This lead me to believe that the turbo was dead. My current 300SD was sluggish when I purchased it and I immediately noticed that I couldn't hear the turbo. My last 300SD gave a turbo whistle upon accelerating, which I thought was normal.