Hello, I currently own a 81 300SD Turbo Diesel. I'm looking for any performance upgrades that I can do to the engine. Does anyone have any recommendations?

Thanks

I always thought I was different, trying to race a Mercedes but a "high performance" diesel is very different! Guess you should start with basics; valve adj, fresh filters & set basic injection pump timing. Also check basic cam timing (poss stretched timing chain). The real performance is "Turbo" output! Have the maximun boost pressure tested, this is where diesels can perform better.

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MERCEDES BENZ MASTER GUILD TECHNICIAN
ASE MASTER TECHNICIAN
27 YEARS M.B. TECH

Thanks for the tip, so far I've already adjusted the screw (altitude fuel adjustment) to provide more fuel to engine, but creates heavy smoke. This screw is located on top of injection pump, other than putting a strong or larger turbo, is there anything else? Would changing the exhaust help?

Thanks

GP

Too much fuel is just as bad as not enough, time to back off of adjustment. Excessive fuel will cause more blow-by & wear Expensive pistons & rings more quickly!! You might pick-up a HP or two with a more free-flowing exhaust, but I doubt whether it would be worth the cost.

Thanks again...

(Question #1)
I just had the valve adjust earlier today, also replacing all filters (oil,air,primary & secondary fuel filters), the mechanic also backed off on the altitude fuel adjustment screw. Now the car feels slower but not running under any stress or friction. Previously, the car was running with a stronger acceleration, more smoke, and if you would back off on the throttle the car would deccelerate rapidly. So to maintain speed you are always on the throttle. But since the adjustment this is no longer an issue.
Now to accelerate you would have to depress the pedal all the way down to get some movement, and inorder to force the car under hard acceleration you would have to depress the pedal until you hear a clicking sound (down shift mechanism). But to maintain speed a minimal amount of pedal pressure is required.

Is this normal after the valve adjust???

(Question #2)
The mechanic also adjusted the modulator valve on the transmission because the car was shifting with a hard kick (as if someone had rear-ended the car), enough to have the rear tires whine when shifting from 1st to 2nd. According to the mechanic he adjusted the modulator to the maximum, which has created a some-what a slightly softer kick, causing the rear tires to whine
from time to time, compared to all the time.
The mechanic states that being the modulator is at maximum a new valve body is required to fix the problem, and once it is replaced the car will shift through the gears unnoticeably.

Would changing the valve body fix this problem???

Thank you

GP

Valve adjustment should allow the engine to run better, unless the adjustment was already correct! The transmission adjustment is very crutial to performance, make sure that the control pressure cable & modulator are both in correct adjustment!!

If the modulator is at maximum and no longer can be adjusted to make the car shift softer, is it then necessary to change the valve body? Also recently I've noticed a delay in shifting from 3rd to 4th (3-5 second delay), what could cause this delay??
And would changing the valve body fix this too?

Thanks

The modulator isn't the only adjustment, there is also a vacuum control valve that regulates the amount of vacuum to the modulator. THE adjustment of this valve is important! The lower the modulator pressure the "softer" the shift. You have a serious problem if 3-4 shift takes more than 1 second!!! Soft shift means the modulator pressure is at min specs! not maximun!