Tested on flat road 0-52mph (redline 2nd gear) in 12sec, pathetic. The car needs a lot of cosmetic work to keep me satisfied enough with the car to have the turbo and alda looked at. Anything I can do myself to speed up this gunboat? BTW just had a new fluids and filters installed.

Thank You

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Elliot Easton
1987 300D Turbo 151K
1996 C220 stock (Mom's car)

One of my books said your car should do 0-60 in 10.0 seconds.

A word of advice--don't rely on a stopwatch and speedometer. Stopwatches are difficult to trigger just right, and speedometers can lag in response, as can your attention.

Fortunately I have a G-Tech accelerometer which is an amazing little toy. It is also surprisingly accurate in its measurements--though nothing beats a drag strip and a dynomometer.

When testing 0-60 and 1/4 mile, you must "launch" your car. You can do this with a manual or automatic transmission, and it's even better with turbocharging. If you have an automatic, just power-brake then car until boost builds up a little, then simultaneously release the brake and floor the accelerator.


For tuning, I'd first check the boost pressure using the factory recommended procedure. If it is low, track down any possible causes such as a leak in the intake tract, a faulty EGR valve, a clogged exhaust, etc.

If everything is good, increase boost pressure manually. A factory manual is priceless here (not a Haynes book).

Your boost compensation (if adjustable) may not need any tweaking, save it until everything else is done.

A little disclaimer--I'm obviously not a Mercedes-Benz expert. However I am a technician with training for other car lines, and I am a speed-freak of sorts.

TurboD,

The factory spec for your vehicle from 0-62.4 mph is 11.9 seconds.

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Chris

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold

Lubricate throttle & turbo linkages! Made a HUMONGOUS difference on my '92 300D 2.5...even my wife noticed

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"If God had meant for us to walk, why did he give us feet that fit car pedals?" Sir Sterling Moss

Michael
2014 E63S Estate
2006 SLK55
1995 E500
1986 Porsche 944 turbo

Actually, factory specs for 0-62mph are:

10.9 sec - 300D (sedan)
11.9 sec - 300TD (wagon)

Yours is not "pathetic". When they run really bad they're 20+ seconds 0-60. Yours is probably ~15 seconds or so, based on what you said, which is workable. You need to check the pressure line from the intake manifold to the ALDA and also make sure the switchover valve is clear. This will make the biggest difference if it is not perfect. Other than that there are a bunch of little things that could be the cause, but check the ALDA circuit first - then time it 0-60 (not zero to 2nd gear redline) and get back to us!

Oh, btw - what elevation do you live at? Anything over ~3000ft causes a serious power loss off idle. And how "quick" does the car get off the line when you punch the pedal? If it's slow you can adjust the ALDA.

BTW - I just finished working on my second '87, which is now getting 0-60 in 10-11 seconds at sea level, checked with stopwatch and G-Tech Pro.


Regards,

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Dave
Boise, ID
Check out my website photos, documents, and movies!

I have driven my fair share of 300SDL's and I must say that some are slower than a non-turbo 300D (no lie) and some are as fast as a 300SEL. I think mine is the fastest 300SDL I've ever driven (not bragging!).

Whats the factory 0-60 for the SDL?

I've never seen an official spec for the SDL (W126), but I think it's about 13.0 seconds. And if one is slower than a non-turbo car, it's almost guaranteed to have a plugged ALDA line. (Or a bad turbo, or bad I/P, just not likely.)

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Tonight I did an un-offical 0-60 time with my 300SDL and its at 13.5 seconds, so I think I'm good as far as power goes.

I should have a 0-60 or 0-100 video shortly

There are several easy to fix things that can reduce power on this car.

The boost line must be clear from the manifold to the ALDA, including the overboost switchover valve.

There must not be any bad rubber connectors in the boost control system, including the transmission control system. I had to replace almost all the rubber bits.

The overboost protection switch must not operate at normal pressures.

The air bypass on the turbo has to work properly (I've dissconnected mine due to serious turbo lag problems -- made a big difference).

Injection timing has to be correct (check the chain for stretch & roll in a new one if out of spec).

You've already done fuel filters, but you can also get fuel leaks at the IP suction line -- this will reduce power and cause hard start problems.

Minor brake drag will cut performance and fuel economy, and you won't notice if the rear brakes are dragging.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!