What advantage does it have to hook up the line from the "banjo" fitting directly to the ALDA. I noticed this on the 1985 300SD I got from a friend.

No advantage but you lose the overboost protection circuit. It didn't leave the factory that way.

Sixto
87 300D

.


Sixto is right on the money.

but in theory only advantage is in case that your overboost device is
totally restricted and your ALDA because of it is not supplied enough.

you can easily put factory setup back to establish proper order....


mine is direct also and I inspected this setup but can not find any
reference in actual world that someone has hurt in due this setup.
most of the times we have issues with low boost

however,if I could I would bring my setup back to factory's one.


.

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w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

I have the line (CD) directly to the ALDA, bought it that way, no problems.

__________________
83 SD

84 CD

What ALDA?

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I have been considering removing the ALDA on my 85 California SD. The main reason I am going to leave it on (and adjust it instead) is so I can keep the overboost protection.

So the engine doesn't "run away" if you were pulling a load hard through the alps (or something like that). I don't really understand but I think it's the cautious approach.

Definitely. If you're not making a racecar, and you don't have a boost gauge, then the overboost is a good idea.

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I installed a boost gauge and after 300,000 noticed I was never in danger of over boosting.

So the overboost protection came out while I was testing for why I had low
boost readings.

I go straight from banjo on manifold to ALDA .

I did install a manual boost regulator on the turbo and this helped
my weak wastegate and now boost is up from almost zero.

But at 9lbs I still do not worry about overboost.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250

It's not a question of how much boost the turbo can produce with a functioning wastegate, it's a question of how much boost the engine can survive if the wastegate actuator fails. To quote from Selling or parting 350SD

The quote is condensed for dramatic effect. Hopefully the engine is fine. If not, hopefully overboost protection limited the damage.

Umm... no. The simple overboost protection solenoid was unneccessary because EDS had at MAP sensor input and vacuum control of the wastegate actuator. With vacuum control, EDS can and does limit boost under other conditions than just overboost some which have nothing to do with safe engine operation. Disconnect the vacuum line to the EGR valve actuator and see how much boost EDS allows.

Most of us know our cars and have the sense to realize that a sudden burst of power can be as much a problem as a sudden loss of power. It's your car and you'll do what you want but do so in an informed manner.

Sixto
87 300D

Atmosphärische LadeDruckAnpassung LOL!

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

ALDA = Absolut messender Ladedruckanschlag

A Lousy Diesel Adjuster

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Bypassing the overboost switch has not caused me any problems. It has been this way for a few months. I have not been able to boost over 10Lbs under any condition, so you should be fine, too. I would rather have a boost gauge than a switch that could fail and cause me issues.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

Engine overload protection was eliminated in early 90s on 60x engines.
http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Engine/602_603/Tech_Mods/comb3.pdf#page=2

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CENSORED due to not family friendly words

I have, on occasion, pinched the wastegate line with vise-grips to see how much the turbo can produce. On my 1978 300SD, with the early 617.950 engine, the overboost circuit still works, even though it has been sitting, most likely dormant, for the better part of 34 years.

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership