I often hear about the wonderful performance boost as a result of adjustments made to the ALDA. I realize that often other adjustments must be made as well, specifically wastegate tuning. My 300D's ALDA looks as if it has never been "tapped," and thus its boost is most likely at factory specs. What I want to know is: how does one (like myself, a decent DIY-er) remove what appears to be a non-user-serviceable part on my ALDA? Also, if I make an adjustment for increased boost pressure, will I only see improvement starting around 2300 RPM, and not from a standstill?

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Matt
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1995 E300 Diesel (Die Blau Frau)

Greetings,

I have already tried to get the Techs to respond to my post on altitude compensator adjustments to no preveiling response except those that said that turning it out causes a rich mixture and tampering with such a EPA sensitive item would either get it broke during the adjustment stage, or to leave it alone altogether. If yours is still sealed I'd leave it be, it's factory set to perform as designed. Mine on the other hand has no seal that is visable, and I was simply wanting to set it back to factory specs. No point in trying to hot rod a diesel, buy a gasoline driven if that's what you have in mind.

Charles

Zoonhollis,

I was interested in doing the boost adjustment as well. But with a car of this age, I figured that the cost of a new engine and/or transmission isn't worth getting to 60 a few seconds more quickly. Additionally, I didn't buy the 300D to be a speed demon It's not like a Toyota Supra, in which you can crank up the boost to crazy levels and get 600HP on stock internals. But thats a WHOLE different story.

Zoonhollis, I installed a boost gauge last November just for kicks. However, I searched on this site and learned what the proper boost spec should be at a given rpm. I noticed the boost was too low in my car at that rpm and adjusted the wastegate so that it was set close to the highest limit of the factory spec. I did not adjust the ALDA for fear of breaking it. I noticed the car was quicker off the line and I get more boost when driving below 45mph. I'm no expert, but I think that if you adjust the wastegate to the upper limit of the factory specs, you can leave the ALDA alone (factory setting) and still get some performnce out of the engine. But if you want to go beyond that and turn up the juice, you will have to start monitoring the EGT's so that you don't melt your pistons.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

Thanks for the responses all. I simply want a little more punch off the line; I'm not looking to make a hot rod out of this car. SW seems to have had good results with wastegate tuning. Perhaps that's all I need to mess with.

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Matt
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1995 E300 Diesel (Die Blau Frau)

After reading the ominous warnings about the ALDA failing due to adjustment I was unwilling to try it without a spare on hand. after a close examination of several ALDAs I think they are more robust than you might think. In short make your boost adjustment ( it was designed to run boost at the spec without ill effects ) They were delivered under spec to help meet Nox levels and the spring looses tension over time. check to see if you have slight smoke with the engine at temp under full power under load at 4000rpm. turn out to richen in to lean a little at a time. If you break your ALDA let me know I have several spares I'll part with cheaply.

Bob D.

I adjusted the ALDA on my old '84 300D. I really liked the
effect made by the adjustment. Rather than being dog slow
off the line and coming on boost in the 2100-2500RPM
range, the car no longer felt turbocharged. It just pulled
smoothly and evenly straight off idle. I never hooked up
a boost guage to verify what changed, but I strongly
suspect after the adjustment it began building boost at
1000RPM, and increased smoothly from there.

The car was a lot nicer to drive after the adjustment.
It picked up so much torque in the 1000-2000RPM range
that it could just stroll along with traffic without
breaking a sweat. It was also easier to drive smoothly -
the engine lost that binary on the power/off the power
feeling it had before adjusting the ALDA.

As for consequences, I understand adjusting the ALDA can
cause it to fail. It's apparently expensive to replace.
It's been three or four years since I made the adjustment,
so far there have been no negative consequences. (I sold
the car to a friend; it's still driven daily.) I don't
think fuel milage changed either. If you are a serious
leadfoot I think the ALDA tweak could cost you one MPG
or so.

I haven't done this tweak to my '87 300TDT yet, simply
because the ALDA is quite well hidden under the intake
manifold. It's too difficult to get at, so I've not
put the effort into it. My '98 E300D doesn't have an
ALDA, so no tweaking there.

- Jim

Thanks JC and others for your replies. JC, I know what you mean about the "binary" fashion in which these underpowered diesels operate. In city driving, it must be hell on the transmission, especially in traffic jams...which are de riguer here in Dallas...

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Matt
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1995 E300 Diesel (Die Blau Frau)