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1984 300CD, 1983 240TD Euro
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I had read somewhere that the 85' models didn't have that "Turbo Lag" but I have been unable to recall where I read it. I'm sure someone knows about this. [8D]
 

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1982 300D Turbo
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cant do anything about it, thats how the turbo is made. The new turbos reduce lag because they have variable geometry turbos. the fins inside the turbo tilts to differnent pitches resulting in faster boost at lower rpms. Dont worry bout the lag, just b happy you got a black cloud of smoke behind you!
 

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karugs - 5/15/2005 12:53 AM

Schmohey - 5/14/2005 5:56 PM

By Turbo lag, how would you define it? Turbo not kicking in till xxxx RPM?
Exactly, mine kicks in at roughly 1800 rpm-- best estimate.
sounds like it kicks in very quickly! i think the normal is between 2200-2500 rpm's.

you can tweak the ALDA if you dare...
 

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W-1-2-3 Go!
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Discussion Starter #7
84300DTurbo - 5/15/2005 5:43 AM

karugs - 5/15/2005 12:53 AM

Schmohey - 5/14/2005 5:56 PM

By Turbo lag, how would you define it? Turbo not kicking in till xxxx RPM?
Exactly, mine kicks in at roughly 1800 rpm-- best estimate.
sounds like it kicks in very quickly! i think the normal is between 2200-2500 rpm's.

you can tweak the ALDA if you dare...
Already tweaked at 1 turn CCW. [:D] When I step on it, I feel a slight pause as it reaches that 1800 mark, then it will slowly pull! Like you're about to go over a crest on a roller coaster, then once over, there's no turning back!

Marsh, your explanation sounds good. I wonder now if anybody else has installed a different (newer, different boost, etc) turbo on our cars. [?]

On a side note, I don't have as much smoke as before after purging it. I didn't even use up a whole bottle! Wow! I saved the rest and stored it for future use (maybe when I get back from vacation)...
 

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83 300d turbo, 79 c123 AMG
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My car's turbo seems to kick in at about 1500 rpm. I tested it by slowly increasing the rpm in neutral and used my ears to identify it kicking in. When driving it seems to really add some power at 2000 rpm. Also my car doesn't seem to produce the coveted black cloud of smoke you all talk about. At night when I kick it in on the freeway I can clearly see the emissions but I have yet to produce the cloud commonly seen by the many Chevy, Ford and Dodge diesels. Is my engine just clean or is it a problem?

I've also heard that taking off the silencer and muffler can cut back on the lag because there is less blocking the air flow so it can kick in at a lower rpm.

In newer BMW diesels they have been using a 2 turbo system to eliminate the lag. The smaller turbo works from idle to 1500 then the larger turbo works with the smaller one from like 1500-2500 then its all the larger turbo. You probably could do it on your car but that goes against adding of modifying the car. It would also be pretty expensive and require a lot of understanding of the 2 turbo system.
 

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Discussion Starter #9
I have heard of the twin turbo set up with a mini turbo and main turbo to compensate for lag. Seems like a very clever set up, I just forgot where I read it (Pop Sci/Mechanics maybe).

When I count 1800rpm I base it on the surge, maybe it spools earlier, I can't tell because I sealed up my car's J tube pretty tight [:D]

I read that final gear ratios will also affect the pull, or maybe not at all related to the turbo but to the actual engine acceleration.
 

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Yea that makes sense. I think I read it in a road and track talking about the new age of diesel. Funny how they always mention the "old, loud, slow and smokey mercedes diesel's" from the 80s.
 

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Boardmonger - 5/17/2005 12:43 AM

My car's turbo seems to kick in at about 1500 rpm. I tested it by slowly increasing the rpm in neutral and used my ears to identify it kicking in. When driving it seems to really add some power at 2000 rpm. Also my car doesn't seem to produce the coveted black cloud of smoke you all talk about. At night when I kick it in on the freeway I can clearly see the emissions but I have yet to produce the cloud commonly seen by the many Chevy, Ford and Dodge diesels. Is my engine just clean or is it a problem?
I have read and heard before about other ways to adjust (something somewhere) in order to have less smoke (or more smoke). I know you can try to tweak the Alda for this, but isn’t there another way with the IP (or somewhere else) adjustments to lessen the smoke from the exhaust. My car doesn’t bellow out black smoke but there is consistent light smoke like most diesels have… I have owned 4 other W123’s before - all gas versions. This 300TD is my first turbodiesel W123, so there is a learning curve here for me also… but it is a good thing plenty of other W123 parts and components are interchangeable between gas & diesel cars. So are there any insights or suggestions on other adjustments in our diesel engines regarding smoke “control� etc…. etc…?
 

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thebenzbar - 5/17/2005 11:15 AM


I have read and heard before about other ways to adjust (something somewhere) in order to have less smoke (or more smoke). I know you can try to tweak the Alda for this, but isn’t there another way with the IP (or somewhere else) adjustments to lessen the smoke from the exhaust. My car doesn’t bellow out black smoke but there is consistent light smoke like most diesels have… I have owned 4 other W123’s before - all gas versions. This 300TD is my first turbodiesel W123, so there is a learning curve here for me also… but it is a good thing plenty of other W123 parts and components are interchangeable between gas & diesel cars. So are there any insights or suggestions on other adjustments in our diesel engines regarding smoke “control� etc…. etc…?
sure, you can do an italian tuneup.
take it to the bottom of a long hill and floor it! either in 'D' or even better in 'S'
 

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FYI, the KKK turbos will boost earlier than the Garretts. KKKs feel better in town but don't boost as well at highway RPMs. My turbo acts the same way as yours does Karugs, I have the Garrett.
If it matters that much to you, replace the turbo cartridge(basically everything inside the housing as a unit- cheaper than just buying a new/rebuilt unit and bascially the same as a new/rebuilt unit). The bearings inside may be wearing, albeit normally, and friction coefficients will increase resulting in some negligible lag. This is all because of age and use, nothing wrong with your turbo. If you choose to replace the cartridge, you will not see a night/day difference, just a noticeable one. Also, make sure you are boosting [email protected] 4krpm WOT. Your IP timing and valve adjustment should be confirmed before doing this.
I'm afraid I will have to say to you and all others that I have driven an '85 300D that drove the way it was intended from the factory, and this car had 83k on it. To be truthful, it drove like butta but it still wasn't very fast, no faster than mine just tighter in the response dept. which I attribute to slop in the accelerator linkage. Karugs your car is performing normally.
 

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Discussion Starter #14
How do you know if you have the Garrett or KKK turbo? I haven't looked hard enough when the air cleaner was out. Are there any immediately distinguishable differences between the two?

Perhaps I do have the Garrett...like you I feel the need to shift to S when in town to get the boost going. It's nothing really critical to me, I just want to know and learn more about the car (and perhaps have that spark of creativity one of these days).

When you check for boost, do you do it at speed? Or is idle enough (have somebody say when you're at 4000rpm and measure the Mity Vac reading)? You're lucky to have ridden in a rather "new" diesel W123. We second hand owners (or maybe the long time hard core original owners who have forgotten the feel of it) don't know how it feels like.
 

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the kkk turbo has the wastegate on the side and the garrett has the wastegate on the bottom. u got the garrett i think pat, and to check the boost you have to hook up a guage, some kind of gauge that you prefer and the car has to be under load, doesnt matter which gear as long as your at full throttle and high rpms, even mid rpms, the turbo should be boosting full.
 
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