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I Found Out How To Make My Turbo Whistle Louder!

Started by Squiggle Dog, 19 May 2011, 09:40 PM

Squiggle Dog

My last 300SD gave a turbo whistle upon accelerating, which I thought was normal. It was a fast car, too. My current 300SD was sluggish when I purchased it and I immediately noticed that I couldn't hear the turbo. This lead me to believe that the turbo was dead. 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.

I was still unhappy with the fact that I couldn't hear the turbo and I wanted to know if it was working. Today I removed the exhaust and drove the car. Wow, my turbo works for sure! I could hear it spool up and hear the waste gate open. I was turning heads and got a smile from a guy with a Ford Powerstroke. The engine was louder, but it wasn't annoying at all, it actually sounded good, like a big truck.

When I removed the exhaust I had to remove the flex pipe that goes between the turbo and the exhaust. There was a pipe inside of the flex pipe. Out of curiosity I did not put this pipe back in when I installed the flex pipe.

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. 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. Someone local gave me a used exhaust system but it did not have that pipe that fits inside the flex pipe. So, there you go. If you want to hear your turbo, remove the pipe inside the flex 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. 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. In any case my exhaust is sealed.

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. I may remove the muffler while retaining the resonator if that will help make the turbo louder. The engine is loud enough for me; I just want turbo noise.

This was totally worth the hour spent removing the inner pipe. Imma firin' mah turbo! WOOO WOOO! :o

Below are some pictures of the pipe on a spare engine I have. 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.


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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

Big_Richard

is it possible on the 300sd to stuff around with the waste gate to increase boost pressure ?

Thats something i would be trying if you want a bit more power  8)

Squiggle Dog

Yes, the waste gate spring can be tightened for more boost. I plan on doing this after I find out what my current boost pressure is and how high I can safely go.
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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

BWalker82

In another post, I recalled reading something about "good" turbos being quiet.  Closer inspection after reading your article revealed a relatively newer, rebuilt turbo on my 300SD. 

I'm guessing whatever I read was bs cause I can hear that puppy clear. It's still shiny and even the exhaust side is nice 'n clean up next to the old exhaust components.  I see smoke sometimes during prolonged idle.  I'm thinking I must have a leaking injector, instead of the spent turbo I originally feared.

Would a valve job minimize any unburned diesel/smoke? 

Squiggle Dog

All turbos make a whistling noise, however the sound is silenced by the exhaust system. A bad turbo can make grinding noises, and this is bad. The pipe inside of the flex pipe works as a silencer for the turbo, though it most likely has other purposes. By removing this pipe it allows some sound to come out.

A valve job can indeed minimize smoking. It might not be the cause of the smoking, but it's a good idea to do one every year or two. I do them myself with the special bent wrench kit from http://www.mercedessource.com/node/715. The first time I did the job with normal wrenches, but I had the fuel injectors out.
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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

Big_Richard

Quote from: Squiggle Dog on 20 May 2011, 09:13 AM
Yes, the waste gate spring can be tightened for more boost. I plan on doing this after I find out what my current boost pressure is and how high I can safely go.

I dont know anything about diesels but you will obviously need to increase the amount of fuel injected if you increase the boost too.

Ive seen videos of that very engine in a car doing burnouts at speed and going sideways around corners. theres clearly alot of potential  8)

Squiggle Dog

I've already increased the fuel delivery at lower RPMS by backing out the ALDA screw completely on the injection pump. I'm confident that I will have enough fuel delivery at maximum boost. However, if I were to do anything like install a larger turbo or intercooler then I'd have to have the pump altered to deliver more fuel.

As it is, my car is fast enough for me, but I want to get as much power as possible out of it with it being mostly stock and with efficient fuel mileage. After turning up the boost I am not sure if there is much more I plan on doing to the engine.

You can get maybe 300 horsepower out of one of these engines with a bit of tweaking and around 500 horsepower with some additional work. That's a lot of power considering the amount of torque produced and that they are already peppy even at 122 horsepower.
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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

thysonsacclaim

Interesting...

I may be installing turbos on my car soon (2 x 2.2 litres), and this bit is good to know. I wonder if there is a pipe inside of the flex pipe on my driver's side exhaust? The passenger side does not have one.

There were extras laying around in the shed from Shelby Daytonas.

Big_Richard

A twin turbo 450 would be very nice and the US/AU version low compression engines are perfect for such an accessory  8)

thysonsacclaim

The trick is the exhaust.

On the passenger side I believe, the out pipe goes towards the back. On the drivers side theres flex pipe and the out pipe is in the middle.

I'm planning on swapping the manifolds side to side and flipped upside down (maybe, if measures are right). I am hoping the RHD version of the car has no flex pipe on the passenger side, so I can use that. That way, both turbos will sit up front, towards the radiator, and the turbo out will curve back down and under the manifold to the exhaust.

Squiggle Dog

Yeah, I once saw a twin turbo 6.9 but the guy crashed it in short order. Not surprising! I've also seen people put twin turbos on the OM617 turbodiesels to turn them into OMG617s.
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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

thysonsacclaim

QuoteYeah, I once saw a twin turbo 6.9 but the guy crashed it in short order. Not surprising! I've also seen people put twin turbos on the OM617 turbodiesels to turn them into OMG617s.


Haha. Yeah somewhere on here I thought was a twin turbo 6.9 R107 or similar model. Not sure whose it was.


I don't plan on going crazy with it! I'm interested in seeing if it will affect the fuel economy at all. I'll probably start at around 5 pounds of boost and see where it goes from there. I don't want to risk melting holes in pistons or anything crazy...

Squiggle Dog

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've since rebuilt the turbo and reinstalled the tube that goes inside the coupler. So, I don't recommend removing the tube inside.

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. I also don't want to put any holes in the exhaust.

It's interesting that my previous 300SD had such a loud turbo whistle. It's possible it had a leak somewhere after the turbo that was letting out the sound. I noticed it had some strange large round metal gasket at the housing that I haven't seen on other Mercedes turbos.

At some point I may delete the muffler and resonator. I have a hole in the muffler, anyway. 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. 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.

P.S. People on this forum are a lot more civil than those on PeachParts Shop Forum!


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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+