Today started out with me fixing the oil separator drain tube (it got disconnected at separator somehow and was making a wicked rattle), and ended up with me removing my exhaust system from where the downpipe bolts to the rest of the exhaust. I had been doing a lot of reading about ALDA adjustment today, and I have adjusted it before, but maybe just a quarter of a turn from stock. After reading that it should be turned until you see black smoke with a heavy foot below 2500 rpm - I kept turning it a quarter of a turn at a time, and eventually got to where it stops and still no black smoke - however off the line response is much better now. Then I finally did what I've been wanting to do for a while now, I removed the rear part of the exhaust.

All I can say about the sound is wow. I removed the exhaust in my single car garage, and first start up was thrilling. At idle the low rumble is very nice, then a blip of the throttle and I heard the song of the 5 cylinders of fury and its garrett assistance. Remind you all I have is the downpipe... that is it - I haven't devised a plan to get the exhaust to the side or back of the car yet.

I took it for a drive, got it up on the interstate - the sound at full throttle is pretty loud, I like it. I think I am going to stick with it for a while, but probably see myself adding a muffler down the road.

However, most say when they straightpipe they get more responsiveness at higher speeds, but when I was cruising at around 70 on the freeway, I got on it and didn't really notice much of a difference, if any. I am guessing that having just the downpipe isn't giving me enough backpressure? I know the turbo provides enough to act as a muffler, but will responsiveness improve if I routed the exhaust out of the side, or straight to the back (say where the stock location is), and can maybe get a little pressure from the force of the wind blowing across the pipe outlet? I might take it to the exhaust shop soon and just have them put some 2.5" pipe to the back with a downward pointing tip to have it look as stock as possible.

Another thing that might be causing it to be a little sluggish at speed is that I am not sure if my turbo is boosting to proper PSI. I have a gauge ordered and it will be here Friday, and I'm excited to see what she'll be running. If it is low I am going to be ordering a boost controller to dial it in correctly.

Lastly, I am considering doing some kind of intake set-up. I know it is a mixed bags of feelings on it here, but I really like the look of the clean engine compartment without the bulky housing.

Sorry for the long post... it ended up being longer than expected! Just wanna say thanks for all of the help I've received from this forum over the years! The search feature has definitely been my friend!

I ran with just the downpipe for a good while. I had fun hearing that turbo spool up and down. It was still remarkably quiet considering no mufflers.. but on the highway there was a ton of drone from 55-65 then at 70 it would get quiet.

I noticed no performance or fuel economy gain.

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1985 CA 300D Turbo , 213K mi

thats funny, I just hacked my exhaust on my CD over the weekend...


I started by removing the muffler and driving around w/ just the resonator... I could not tell any difference in sound, and perhaps a minor 'seat of the pants' improvment in acceleration.

then I chopped off the resonator, definately louder, but nothing like I expected (former gasser enthusiast) but it sure was sweet to hear the turbo spool @ both ends!!

I ended up installing a stainless steel diesel specific Aero turbine muffler, it is pretty much a str8 thru race muffler w/ no packing and 'noise canceling technology', tho you can still hear the turbo @ the tailpipe.

anyway I'm much happier w/ my deletion of the stock system... the new muffler sounds better and the car runs a little faster and a little cooler, plus I prolly removed 40 lbs from the car.

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Cheers,
Robert

Well I just ordered a boost controller off ebay - from what I read adjusting the wastegate on the garrett is a pain and a boost controller is the way to go. I picked one up for $13 shipped, has a lifetime warranty so I figured I can't go wrong.

Drove around some more tonight and the cooler night air (75 degrees as compared to 95 this afternoon when first testing the set up) - I could feel a little extra oomph.

boost controller.. ha.. Glad I have my KKK


I recommend you leave the intake alone..

Ditto.

The stock assembly, as bulky as it may be, is much better than most anything you can make or buy to replace it.

Yeah, the more I think about it and look at it, the more I think I am just going to leave it alone. It does work, an well. I don't think I'd be able to find a better spot to get air from than the stock location.

URL?

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

likewise would like to take a look at this..

http://www.aeroexhaust.com/diesel_muffler_4040.html

of course I bought the 2.5 inch version... not the 4 inch version

any way, Its an extremely solid unit, it lowers the timbre of the exhaust and makes it a bit louder, but not much. Yup, its shiny shiny stainless that you cannot see unless you are eye level w/ it.

it is NOT a 'fart can' I want to emphasize this fact.

heres a shot of it installed... for the tailpipe, I polished up a piece of 308 stainless tubing, cut a slash on it and stuck it in.

here is the result...



the wire used in this mockup pic has been replaced w/ 3/8" stainless round stock, it looks pretty sweet.


sorry 4 the hijack.

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Cheers,
Robert

Whoa - that is NICE! Looks like a high-quality product.

Nicely done. I like.

I have a 2.5" pipe from front to rear....it sounds pretty sweet. And I got it installed for free.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Just replaced the WHOLE system, including the cat ( I know - no more comments), . No difference in perf or milage. $450 ALL IN. Nice and quiet, although the cat has a "high whine" to it. Sounds like a turbo actually, in n/a car.

And unless one of you folks is a metallurgist and can explain the subtleties, there is very little differnce in diesel and non diesel cats/muff in term of contruction, as describd to me byt he muffler pros. In marketing terms, however, there's TONS of difference.

Car is brutally quiet. $450 all in. Nice job too. Might have used the stock muff ( $155 ) if I had known what a PITA it would be to custom fit one in there.

Very little smoke/soot, but I started using bio around the same time I had the new exhaust put on.

Been on straight pipe for years, engine runs cooler, turbo spools faster and engine feels way more responsive, not to mention it sounds much nicer, just a little more growl, thats all.

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99 Gurkha with OM616 IDI turbo

2015 Gurkha with OM616 DI turbo

2014 Rexton W with OM612 VGT

I did notice yesterday the engine is running maybe 5-10 degrees cooler. Also, what should I do about the bracket that is on the downpipe that was bolted to the bracket on the rest of the pipe? When I am sitting idling at a light I can hear it rattling around on the pipe and it is pretty annoying and sounds crappy. I tried to pull it off but there is like a lip on the downpipe that keeps it from coming off...