84 300sd performance
 

Any information on how I can increase the performance of my 84 300sd?

Make sure everything's to factory spec and see if you can do 0-60mph in about 15 seconds. If you get to that point, and it's not good enough for you, sell the SD and get a newer MB Diesel.

Sixto
91 300SE
87 300SDL
83 300SD

Yah, what sixto said.
Do a search. There's been alot of discussion here about that subject. I've not wanted to mess with mine as it runs great. But if your adventerous, there's a few things that can be done to perk up these engines I guess.

ALDA Adjustment is a tweek for improving the bottom end, but richening mixture also has environmental impacts. This is a tweek, not a performance boost.

If she's running good, leave her alone. If you suspect performance deficiency, inspect boost, waste gate and ALDA functions. I would spend a great amount of time studying these before trying to make any changes though. Improperly function or lack of function of ALDA will cost roughly 30% of optimum power, most notable by slow accelleration.

sixto, that's funny! you said about the same thing I did to the same question on the Performance Paddock forum. Great minds think alike, or something like that, huh? :D :D

Idiots think alike too so I wouldn't be too quick to fit myself into a category :)

Maybe it's just semantics but I think folks who've been here a while shudder at the thought of improving the performance of Diesels. The youngest 617s we deal with have 150K miles by now. I'll bet the average is closer to 200K miles. As such I'll bet most folks on this forum would be happy to RESTORE the performance of their cars. It would be an improvement over the current state, but that shouldn't imply that there is any intent to build a hot rod.

There's a guy who lives near me who's participated in the Silver State Classic (www.silverstateclassic.com) in his 84 SD a few times. His tech continuously tweaks the ALDA for top speed. His midpoint speed was something like 115mph the last time the SD was out. He came in .25mph under in the 105mph class. Without complex timing gear it's a PITA to hit the target speed on the money. He did as well as he did with a stopwatch. Check the May 2001 results.

Sixto
91 300SE
87 300SDL
83 300SD

Now THAT sounds like fun! My 124's rated top speed is 129mph (stock), and I've seen 125 on my GPS with fat 225/45/17 tires on 8-inch wheels. I suspect stock tires would boost the top end back to normal. One of these days I might enter that, not so much to compete & try to hit that stupidly accurate time frame, but just to drive legally at 100+ for a couple hours total! It would be one heckuva Italian tune-up. :) :)

And I agree completely, a lot of people want "more power" from their diesel, when in reality what they are asking for is to return it to stock power. That's why my initial reaction to every such post involves a stopwatch and preferably a GPS (people like to install bigger tires for some unknown reason, which screws up the speedo). :D :D


Regards,

GPS sounds like it would work great when running hard on a long, straight section of highway in the mid-west or west. What's it going to tell you if your running around Lowe's Motor Speedway?

using a GPS will confirm that your speedometer is accurate on plain old highways. My 1984 speedo is off by 2-3mph at 70mph, which also translates into nearly a half-second difference in 0-60 times (need to clock to an indicated 0-57 or 0-58). Oddly enough, it reads a little fast at 25mph, is dead-on around 45, and reads low above 55. My one 87 is dead on all the way to 100mph (haven't tested beyond that), and the other is 4% slow (due to larger tires). You don't need to buy one or have it in the car all the time, it's a one-time check to see how close your speedo is to reality. Find a friend who has one and borrow his for a weekend to play with.

Now for the Silver State Classic, that's a different story. A top-notch GPS is almost required for that kind of thing, unless youre just out there for the fun of driving fast legally (like I would be). :D :D

The first thing should be getting all the recomended service done, valve adjust, clean the boost sensor, etc. Then you could adjust the waste gate and the alda, but it will still be a dog.