Turbo and A.L.D.A. Service - PeachParts Mercedes-Benz Forum

Adriel · #1 01-19-2013, 11:15 PM

Tested the turbo today and makes 0,4 bar easily then struggles up to 0,6 bar. I shudder to think what it would do with the A.R.V. hooked up!

Cruising it is 0,2 bar so at least there is something, but think if it was higher get better mileage and response.

Turbo had cleaner run though in 2007 so doubt that be a reason. Then thought to check and see if the A.L.D.A. holds pressure and does not. Per this article it should: ALDA Repair . Could this be the reason for the struggle to produce 0,6 bar of pressure? Not finding any information on the Peach or anywhere else.

I was thinking the best plan would be fix the A.L.D.A. then re test and adjust the turbo as needed. Then once the A.L.D.A. is functioning properly and the turbo is maxing out at least 0,8 bar, then check the A.L.D.A. adjustment and correct if needed. Is this right?

Thank you in advance!

Brian Carlton · #2 01-20-2013, 10:26 AM

Quote:

Originally Posted by Adriel

Tested the turbo today and makes 0,4 bar easily then struggles up to 0,6 bar.

State the conditions for the test.

Adriel · #3 01-20-2013, 04:19 PM

Quote:

Originally Posted by Brian Carlton

State the conditions for the test.

Thank you for the reply!

Not sure what you are after, but will give it a shot.

Yesterday the A.R.V. was the only emission device disconnected. Temperatures yesterday and today are about 21 degrees Celsius. Been doing all types of driving, and today was romping it on the freeway up the hills we have. Not sure what the grade is, but not much.

Saw a mention of the E.G.R. having an affect and so figured why not try. It helped! Now boost is made easier and can get up to 0,7 bar. Plus, transmission is shifting softer. However, I do now have a vacuum leak...

All is plugged, so not sure what I did wrong.

Plan is today is pull the A.L.D.A. which requires moving some vacuum lines. So when I put it all back, will double check my work. Worse comes to worse, will hook the E.G.R. back up and know I will need to most likely add some boost.

dude99 · #4 01-20-2013, 04:54 PM

What he means in what grade the boost pressures were measured on and at how many rpm.

Adriel · #5 01-20-2013, 05:01 PM

Quote:

Originally Posted by dude99

What he means in what grade the boost pressures were measured on and at how many rpm.

Duh! Thank you for getting that into the meatloaf!

3.500 to 4.000 R.P.M., full load (i.e. romping up a good hill), is about 0,7 bar which is maximum P.S.I.. 2.000R.P.M. is about 0,2 bar and 2.500 R.P.M. to 2.700 is 0,4 to 0,6 bar. The latter is where I do most of my driving, so like to see it around 0,6 at 2.500 R.P.M. with partial load.

Skippy · #6 01-20-2013, 05:42 PM

EGR is only there for emissions.

Adriel · #7 01-20-2013, 08:46 PM

Quote:

Originally Posted by Skippy

EGR is only there for emissions.

Still affects vacuum, right?

Cleaned up the lines but can't try it until I figure out how to remove the A.L.D.A.. The instructions on here are lacking, probably because California 1985 model is different some how.

charmalu · #8 01-20-2013, 09:38 PM

The Calif 85 model ALDA is the same as the Federal ALDA.

Charlie

Adriel · #9 01-20-2013, 09:48 PM

Quote:

Originally Posted by charmalu

The Calif 85 model ALDA is the same as the Federal ALDA.

Charlie

Charlie, thank you so much for the help!

Then why is it stuck in the injector pump? I did give a good pull, but nothing. Too afraid to pull harder for fear to damage something...

charmalu · #10 01-20-2013, 10:15 PM

Quote:

Originally Posted by Adriel

Charlie, thank you so much for the help!

Then why is it stuck in the injector pump? I did give a good pull, but nothing. Too afraid to pull harder for fear to damage something...

The ALDA just unscrews from the pump. Don`t have the size of the 2 wrenches you need at the moment, but the ALDA turns left, and the big nut turn right. once you break the nut and ALDA free, just unscrew it to the left.

There is a rod that the ALDA sits on as I remember. maybe it is just stuck on the rod, wiggle it as you pull up. you do have it all the way unscrewed?

I have pulled a few in the Junk Yards and they all came right off.

Charlie

Adriel · #11 01-20-2013, 10:22 PM

Quote:

Originally Posted by charmalu

The ALDA just unscrews from the pump. Don`t have the size of the 2 wrenches you need at the moment, but the ALDA turns left, and the big nut turn right. once you break the nut and ALDA free, just unscrew it to the left.

There is a rod that the ALDA sits on as I remember. maybe it is just stuck on the rod, wiggle it as you pull up. you do have it all the way unscrewed?

I have pulled a few in the Junk Yards and they all came right off.

Charlie

Charlie, thank you so much!

Ah!

So it needs both the nuts to have wrenches on them! Well guess I need to patch things together and get another wrench. Guess my brain is more tired than I thought... I really should have observed the day of rest...

Brian Carlton · #12 01-21-2013, 01:05 AM

Quote:

Originally Posted by Adriel

Duh! Thank you for getting that into the meatloaf!

3.500 to 4.000 R.P.M., full load (i.e. romping up a good hill), is about 0,7 bar which is maximum P.S.I.. 2.000R.P.M. is about 0,2 bar and 2.500 R.P.M. to 2.700 is 0,4 to 0,6 bar. The latter is where I do most of my driving, so like to see it around 0,6 at 2.500 R.P.M. with partial load.

Those boost pressures are typical of most 617's. The wastegate can be adjusted so that you get the specified .8 bar, but it's probably not worth the effort unless the 0-60 time is very important to you.

You cannot get .8 at 2500 rpm, unfortunately due to the size of the turbo. If you need the performance, you must get the revs up to 2800 rpm or more, as your data shows.

If you can get more fuel at lower rpm's (by adjusting or removing the ALDA), you will get your boost numbers at slightly lower revs. However, you will not get more than the setpoint (currently .7 bar per your data) unless you adjust the wastegate.

Of course, if you have unlimited time and money, you can source a variable nozzle turbo and get full boost at 2000 rpm. That makes for a completely different vehicle.

Simpler=Better · #13 01-21-2013, 08:10 AM

Quote:

Originally Posted by Brian Carlton

Of course, if you have unlimited time and money, you can source a variable nozzle turbo and get full boost at 2000 rpm. That makes for a completely different vehicle.

Hit the nail on the head. expect to spend around $500 for a DIY VNT and some time tweaking it. The variable vane turbos "usually" take 1 second off your 0-60

Adriel · #14 01-21-2013, 10:30 AM

Thank you all!

Interesting! I would have thought turning up the boost 0,2 bar would affect the whole range, not just add to the top at higher R.P.M.. Meaning, cruise go from 0,4 to 0,6 bar.

Would a A.L.D.A. of an 1987 300D work? Bit of a drive and the place doesn't keep inventory all that well so don't know if it went to the crusher. If I do find it, any other parts that I should consider? Doubt it.

Adriel · #15 01-21-2013, 09:12 PM

A.L.D.A. is now removed. It was REALLY on there and required some gentle levering between the two wrenches. A lot of corrosion on the threads so will put some grease on them to make the next time easier. Too tired to mess with it so going to run without. Already ran with the vacuum lines disconnected and didn't get any smoke at all so doubt I will have any problems.