I'm getting sick of tired of my punk @33 friends makin fun of my 300sd. I used to find it humurous because they drive tauruss and saturns and really have no respect for the amazing engineering that went into my car. Are there any little things I can check or do to improve my acceleration. thanks a lot PS I have my service manual on CD on its way from ebay. I'm excited. my spring break is coming up this week so I will be devoting a lot of time to the car. Also how hard is it to do minor body work on the car?

Yes, there are many things you can do to optimize performance on your 300SD. Start with the Search feature and dive into ALDA, aneroid compensator, turbo adjustments, and boost pressure. That will give you tremendous amounts of information on making your car perform like it was designed to perform. Now it may not perform like V-8 Otto cycle but then again its an S class, full size, luxury Benz! What more do you need!!

Basically, it is what it is.

An old 5cyl 3.0L 120HP Turbodiesel. Absolutely nothing wrong with that in my book, but its not a V8.

Yeah, by messing up factory adjustments you can squeek another 5HP out of it, but is it worth it?

If you want performance, buy a 420SEL or 560SEL. If you want reliability, economy and longevity, stick with your slow 300SD.

I didn't know that it actually has 120hp... I think just for fun I'm gonna dyno my 300CD...

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2008 BMW 335i Coupe

Yep. off the top of my head:

240D: 67HP
300D: 89HP
300D Turbo: 120HP
300SDL Turbo (6cyl): 148HP

turbo diesel: is it really 120 hp? not trying to be a smart @ss or anything. that is what i have read on a lot of sites too. but i got a book (official) on the w116 body, and the specifications are as following:

110hp @4200rpm
168 lb ft torque @2400 rpm

this is for the 617.950 engine and i am wondering if other engines put out more please correct me if i am wrong

If you have not already done so, you can disconnect the EGR vacuum hoses, including the two white vacuum switches located inside the "black box" on top of the valve cover. Disconnect the two hoses at the rubber connectors closest to the main vacuum line near the inner fire wall. Plug the rubber connector with (your choice) golf tee, drip irrigator hose plug, etc. This may not directly give you greater acceleration, but it will eliminate a lot of potential vacuum leakage.

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Jeff Naumann
Torrance, California
1972 220D 138k miles (sold)
1982 300SD 263k miles
1989 BMW 750iL 183k miles
1993 Dodge D250 Cummins 5.9 202k Miles

txbill: now i am confused i thought the w126 have a 6 cylinder turbo diesels.. i need to do more research..

From 1981 to 1985 The 300SD (126) had the 617.952 Turbodiesel, 5cyl.
From 1986 to 1987 the 300SDL (126) Had the 603.9?? Turbodiesel, 6cyl 3.0L.
From 1990 to 1991 the 350SD/SDL (126) Had the 603.9?? Turbodiesel, 6cyl 3.5L.

Hope this clears things up.

PS: Thought the W116 turbo motor was slightly different, I thought it had 115HP or 118HP, rather than 110.

Just to really confuse the issue, don't forget that the California cars give up 5-10 HP to various emission devices that you 49 staters don't have. I recall my '85 300 turbo being about 95 HP.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

My 85 300D with a 617.952 has, according to the owners manual 123net-bph. The Calif version has 118net-bph @4350 rpm.

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Gary
85 300D Ivory, 202,000
Beatus exsisto Jesu, verus et Deus verus Vir

To fill in the blanks from a previous post:

From 1986 to 1987 the 300SDL (126) Had the 603.961 Turbodiesel, 6cyl 3.0L.
From 1990 to 1991 the 350SD/SDL (126) Had the 603.970 Turbodiesel, 6cyl 3.5L.
From 1992 to 1995 the 300SD/SDL (140) Had the 603.971 Turbodiesel, 6cyl 3.5L. (I think...)
(The 603.960 was used in the 1987 300D, W124.)

Back to the original question, it's very likely that the motor in your car is not putting out the original ~120hp that Mercedes intended. You're not going to get much more than the original spec out of it, as "turbodiesel" said, maybe 5hp if you're lucky. However, getting it back to 120hp should be a big improvement! The ALDA adjustment helps a lot if the car is slow off the line. To increase top end power make sure the boost is up to spec (0.85-0.95 bar), and that the lines from the intake to switchover valve and valve to ALDA are clean. Those are the main power robbing items (along with the EGR, if not disabled.)


Regards,

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I haven't really don much engine work on my car so I'm not as familiar with it as I should be. If you guys could provide some very specific directions or diagrams as to what I can do I would be grateful. And I think I have a vacum problem because my power locks don't work and there is this weird substance in these little resevoir type things on the vacum hoses.

Keep in mind that I haven't yet had a good look at the mechanics of an M-B diesel, and am in the process of learning about these specific engines (although I'm not new to diesels as a whole).

How well's the intake and exhaust set up? A suggestion would be to pull your muffler and make sure there aren't any clogs. Granted these cars aren't worked as hard as a Ford diesel, but there have been numerous reports of a guy pulling the muffler off his Ford and finding it so packed in with soot that the exhaust was almost pinched off There are other things you can do, but that's partially a question of how badly you want a "hot rod diesel" versus wanting to maintain the comfort of the luxury sedan you currently have. If having a noisier hot rod's more to your liking, you could go to a larger exhaust pipe size or put a free-flowing muffler or even, if it's legal where you live, eliminate the muffler and run it straight-piped. G@$$ers need some restriction in the exhaust, but diesels are happiest with no restriction whatsoever. Keep in mind that, depending on your state/county laws, your turbo can count as a muffler.

The other thing is intake. I don't know if this'll affect noise any, and again, I don't know the current setup, but some sort of ram-air would be best. A guy with a 6.9l Ford took the air cleaner and ran a piece of heater ducting to a hole he cut in the radiator support bracket. Even with no screen to speak of, he hasn't had any problem with injesting anything or having anything caught in the air cleaner, and his power levels went up a fair margin. I plan on doing that mod to my F-250 when I have the time...

Just a couple ideas for relatively inexpensive mods that won't put any strain on the engine...in fact, the engine'll be happier for 'em. And, if you really wanted to, if you did these and installed an EGT gauge, you could probably tuen the fuel up a little bit and be safe about it...but if you do that, watch your EGT's!!! Propane injection could also work, but, again, an EGT gauge and careful monitoring is imperative. A general rule of thumb is to not let the EGT get above 900°F is the sensor's mounted post-turbo, and 1200° if the sensor's mounted pre-turbo.

Hope that helps some...good luck!

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

Holson,

If you dyno test the engine throught he trans, you will get only 60-70% it's rated horsepower. To get the Mfgr rated power, the engine must be reoved, and run w/o any accssories. If you dyno test the engine throught he wheels, multiply the results by (1/.7) to get an approximate rep of the engine's true Hp.

ATLD