If a 110hp VW TDI is quite with no muffler, or my neighbor's turboDiesel Ford that no one notices any difference, then surely the 300D would be the same way.

Most people don't know that turbo's can be certified as mufflers on diesel engines, and I have seen said turbo's stamped as such. As a matterof fact I've seen a lot of the big Cat V8 twin t's running around with nothing but heat shields on the upper stacks.

When I was last out at the truck center I was looking a big Cat TT V8 over close and it had no mufflers, when the guy started it, all you could hear at idle was the turbo whine. When revved only thing heard was clatter of engine, not bad for 500+ HP and about 1000 lbs of tourqe. They had just completed some preformance mods on the engine, oil change and general service. Truck had little over 120, 000 mile on clock and was 14 months old.

I ask the owner/driver what kind of speed it had, and all he did was smile and said most cars can't keep up with him. I'll bet it would haul a#s with empty or light loaded trailor.

Funny thing was durring the conversation biodiesel came up, and he said at the moment he was running a 10% mix to clean fuel system. His brother who is a local farmer had put him on to B100 mixing for cleaning fuel systems and removing coking from pistons and rings. I was in hog heaven, to say the least. He also told me his brother and some other farmers are in the process of setting up a local plant to mfg biofuel. That would be just too cool, I would get in on that Co-op in a heart beat if allowed.

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'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.

Since these have TWO mufflers, the removal of ONE should do ZERO to increase sound, but would likely reduce at least some of the restriction. Most who say they've gone to straight pipes on these claims there is NO appreciable sound difference (turbo does most of the sound baffling as you stated.)

As for the BD, they CERTAINLY would let you "in" on the co-op if you helped them set it up, run it, X-port grease for it, etc., just tell them you're into BD and want to help them get the processor going and help run it, they WILL let you be part in that case.

We have a farmer here just outside of Boulder who is part of our group and let us use a 25x40 quanset for the processor and simple auto work (I'll still need a shop for the heavy stuff) just for trade for a percentage of the BD we make. Will be in there SOON, but not soon enough (still need to seal the cement floor and mount the end walls)!

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

I am running nothing after the s-shaped turndown after the turbo. If somebody says it's not "much" louder than a stock muffler, they are BSing you. It IS alot louder. It is within tolerance of most people, being diesel, it's quiet when you are not on the pedal. When you get full boost PSI there will be a fairly loud poping sound as some exhaust gets past the wastegate unrestricted.

As far as the legal issue, I live in a outer city/suburb area and have driven past many speed traps, cops on the highway, and cops at stoplights without no more than a glance at me. Since I am living here as a "student" I have not gone in for a Colorado inspection, so I don't know if they would fail me for it.
Oklahoma was no problem since they don't give a rats behind whats on the road, or what condition it's in.

.

On my SD I've made a couple of sequential changes to the exhaust which have improved throttle response and overall performance. First, I had the kidney-shaped resonators cut out and replaced with straight pipe. In addition to removing some weight from the car, the engine really woke up, even on a car with 300+k miles on it. The exhaust note was only very slightly louder but the engine was far more responsive. However, even though the car ran better I wasn't wild about the *sound* of the exhaust, so I had the rear muffler replaced with a straight-through Magnaflow muffler in the stock location with a simple turn down tip. I bought an aluminized muffler, not the stainless Magnaflow product, so the cost was quite modest. Since I have a 110 mile daily round trip commute I was not interested in anything loud, and I guarantee this setup is no louder than stock. However, the car runs so much better than with the stock system that I am now thinking about backing off of my ALDA adjustment and seeing if I can pick up some additional economy. As it is, the changes I made helped me gain a couple of mpg. One nice side benefit is that when pulling hard, such as up a long hill under sustained boost, the engine peak temperatures aren't quite as high (10-15 degrees cooler according to the guage) and on the downhill portion the engine cools off faster. In normal driving situations the thermostat controls engine temp and there is no change. Food for thought for those thinking about modifying their exhaust systems as a way to improve performance. And no, I did not do any GPS verified pre- and post-mod 0-60 or other tests--it's a 20 year old car with 325k miles; I'm not going to beat it, but rather just want to optimize its performance as the miles roll on.

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Richard Detoy
'84 300SD
'76 Moto Guzzi 850 Le Mans

After reading more of the posts regarding K&N filters and the like, it would seem their benefits apply more to gas engines than to turbo diesels.
There doesn't seem to be much dispute about the fact they will allow more air into your engine, and more particulates as well.
The questions for me really are, "can my turbo diesel use the additional air?", and "is allowing additional particulates into the engine cause for concern?"
On my 85 300SD (CA) the air filter is HUGE, probably almost twice the area of the non trap-ox car air filters on the same engine. Considering the engine displacement vs. the size of the filter, I don't believe air flow is a problem (assuming a clean filter). As stated in another thread on this subject, " The stock filtration is not the bottleneck here." Eliminating some of the constriction in the exhaust system seems like a more fertile ground for improving performance.
The additional particulates getting into the engine is a cause of concern on general principle. The MB manual suggests using leather to wipe off the oil dipstick instead of cloth to avoid lint or loose threads becoming engine contaminants. Maybe this is just German obsession with detail, but the message to me is pretty clear. You should do whatever you can to avoid allowing anything
into your engine that doesn't belong there.
As for me, I will continue to use the stock OEM paper filter. Shopping online for a better price, is the only savings I feel comfortable with. Thanks to all who helped me come to this conclusion!

__________________
1985 300SD CA (low miles 180k)
1977 300D (RIP)
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In theory, there is no difference between theory and practice. But in practice, there is.

When I first installed my K&N I had a horrible exhaust leak right next to it and this caused the filter to turn black instantly, but what disgusted me about this ordeal is that the inside of the turbo had a fine mist of the carbon in it. So if it lets the carbon through surely a fine sand and other stuff as well (think a foam cover would help at all?). On the other hand I notice the car has a good deal more pep and spools faster now than it did before but my biggest selling point was ridding of that @#$%ing stock airbox. I just bought a brand new filter, upgraded breather hose, new heat shields, mounts, and welded the broken bracket. After I got it back together around 1200rpoms it rattled, shortly after I ordered the K&N and stuck it right on the turbo. The turbo spool is much more distinct now whether that is good or bad is upto you, but I love the way turbos sound especially the ones on diesels.

Did I pick up fuel mileage? Probably not. Did I gain performance? Yes. Sound? Yes. Was it worth it? Probably. I bet the EGTs fell a little bit.

Somebody once tested our cars running with no mufflers and running with, either the times (1/4) were the same or worse without a muffler.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Peter T,

God love you if you can look under that bonnet and see that huge stock can sitting there. God help you too if you plan to buy one of those things! For me the choice was logical. I don't like to leave stuff alone. I never regretted doing it and don't think I ever will. I can tell you that the car WILL run better with all that tubing and junk off the car. Mine does. How much better? It is hard to say.

P.S. I still have the old CA em. air can with tubing and filter. I also have the CA turbo if anyone is interested.

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R

TomJ:
Regarding that air filter pix you posted, is there another filter element inside there to filter air coming from the cold air duct? From the pix it looks like it's just passing thru unfiltered.

I believe that is the style that has the filter on both the outside diameter and the inside diameter. I was actually looking at those for my 300D but it didn't seem like they came in the right size for it to stick right on the turbo like I wanted it.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Just as Boostnbenz states in reply, the filter has filter media in a cone-shape inside of it and is made to have a tube stuck into it (same mfg sells an intake tube for this purpose) for CAI.

And, just as BB stated, the mounting dim is too large for the stock turbo. Since the turbo I had to experiment with had been "chaffed" down at an angle from a loose intake elbow for many K miles (on another car), I had to machine a large 7075-T6 "ring" to go over the compressor intake that would be just the right size for this filter.

What a person could do is machine a ring that would be a location fit over the compressor intake flange with an OD that would be a press fit on the filter. Drill & tap for set screws every 120deg. to hold it on.

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1984 300D Turbo - 4-speed manual conversion, mid-level resto

1983 300D - parts car

1979 300TD Auto - Parts car.

1985 300D Auto - Wrecked/Parts.


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"If you don't know where you are going, any road will get you there". Lewis Carrol

Cool. That's what I figgured, but I've seen too many dumb things done to cars to just assume that was the case, so I had to ask. Good work!

I am hooked on K&N filters for everything, I saw a slight increase in MPG on the 300CD, but no real power increase. However living in a dusty enviornment, it is much better, and since the filters work better, the dirty'er they get, the better it is for me...

I'm not hooked on them anymore. Almost sick of them after seeing the stuff a brand new one will let through. I had an exhaust leak at first and a powdery carbon was coating the inside of the turbo, later I found about the same thing but with dust. That is just absurd. I've ran a K&N filter on practicaly every vehicle I've ever owned but I doubt I will on my next one. Make sure they are oiled well and let them get dirty, only chance we got!

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k