Hi all, I have a few questions for yall....

first, I want to install (permanently) a boost gauge in my car. Should I tee it into the wastegate line, at the manifold banjo fitting, or at the alda itself?

second, I think I might do away with the stock airfilter, go with a cone style. I WONT go with a K&N filter, way to dirty. I basically want a filter that does as good a job or better than the STP-brand OEM-style I am running now. Extra airflow isn't what I'm after, good under hood looks are what I want. What is recommended to fit this bill?

third, I tweaked my alda. Right now I am 1.0 turn CCW from stock. It was a virgin alda (had plastic cap intact) but it only has 1.25 turns of adjustment in it, so I am basically maxed out already. Does this sound right?

fourth, I want to install a boost controller, If my boost gauge shows that I am at less than stock boost levels. I know that the wastegate can be tuned, but I like the idea of the quicker spool times with the boost controller. I was thinking along the lines of the mechanical type that don't cost a fortune. If I over boost at all, it will only be by 1-2 psi max.

fifth, If the alda is designed to meter more fuel with more boost, why do you have to tweak it when upping boost pressure? Shouldn't the increase in pressure alone be enough to increase your fuel delivery?


Thanks in advance for the help. Sorry for so many questions.

__________________
-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

With regard to the permanent boost gauge, it's probably best, and easiest, to T it into the line from the overboost valve to the ALDA. You then are monitoring the exact pressure that the ALDA sees.

The stock air filter provides excellent filtering capability with little restriction and the housing provides a proper cyclone drain for the excess oil in the blowby airstream. If you eliminate it, in favor of good looks, you must deal with a filtering system with reduced capability and then you must attempt to cobble up some sort of device to return the oil to the crankcase. You certainly don't want it all over the road, correct?

One turn should provide a measurable improvement in the feel of the vehicle at part throttle conditions. You might very well be at the end of the travel at 1.25 turns. If necessary, the ALDA can be shimmed higher to provide increased fuel.

The boost controller is a fine idea. But, don't exceed stock boost levels without a pyrometer installed. You are gambling with a very expensive engine.

There is a limit as to the additional fuel that the ALDA can provide. Somewhere around the spec for maximum boost (about 12 psi IIRC) is the limit of the capability of the ALDA. You could turn up the turbo to 15 psi and the vehicle won't go any faster, but you will cause a dramatic increase in exhaust temperatures because of the increased temperatures of the charge. What needs to be adjusted is the maximum load screw on the injection pump. This allows the pump to put more fuel into the cylinders at full rack. There are several threads on this procedure and it's currently being evolved as we speak. Adjusting the max load on a 617 IP is not for the faint of heart. It has effects on the idle if the screw is increased too much.

You don't tweak the ALDA when you adjust the boost pressure. You tweak the ALDA to add additional fuel throughout the operating range because the engine is operating too lean. This adds fuel prior to, and after, the turbo comes on line. If the turbo is operating below spec, the boost controller will raise it back to spec and the ALDA will provide commesurately more fuel, without further adjustment.

The air in the engine compartment is pretty hot. Are you sure looks takes priority over getting the coolest, densest air charge to the engine?

Sixto
95 S420
87 300SDL

Good point, I forgot that the air filter had that "snorkle" hose to the front of the radiator.

As for the boost gauge, although it makes sense to tee in after the overboost regulator, If you put it there, you will never be able to tell if you are overboosting in short intervals because the overboost valve will dump it. Wouldn't putting boost gauge before the valve be better?

__________________
-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

Depends what you are looking for. If you put it before the valve, and the valve dumps it, AFAIK, the boost gauge will still read nominal boost pressure, but, the ALDA won't get any. I don't believe that the overboost valve opens up a line from the manifold directly to atmosphere when it closes, but, I'm not certain.

If you put it after the valve, and the valve dumps it, you know it immediately because the gauge heads south in a hurry.

There are dead spots in the dash warning light strip. Wire one of the segments to light when the overboost protection switch closes the switchover valve.

Sixto
95 S420
87 300SDL

Sixto, do you know if the switchover valve seals the manifold connection when the valve closes? Does it connect the ALDA to atmosphere and seal the manifold connection? I would think that it must.

It definitely closes the line between the manifold and the ALDA. I don't know for sure if it vents the ALDA but I imagine it should or there's not much point to closing the line. There's a little breather atop the switchover valve so that must be the vent.

Sixto
95 S420
87 300SDL

Thanks, that's what I thought.

Positive ventilation of the aneroid capsule is essential to the proper operation of the overboost protection system.

You will know. The gauge will drop to zero.
Plus, the overload protection switch does not close until 1.1 bar. You have already overboosted significantly by the time that occurs. Don't think of the overboost protection system as a "regulator." It's more like a safety valve. Boost regulation is the function of the wastegate controller.

Ok, those are good points. But, If I am going to cut a line to install a boost controller, wouldn't it by smart to tee the gauge into the supply side of that? That way I am only cutting one boost line in the system. Plus, that line comes directly out of the turbo outlet neck, so that should show exactly how much boost is developing.


I guess what worries me is the possibility of the alda line getting clogged and having no, or incorrect boost readings. Under certain conditions it could be disastrous.

Additionally, that ALDA line is really hard, a real pain to get put back on the banjo fitting.

Just my thought on it.....

__________________
-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

It'll be a PITA to T into the line for the boost controller. The controller takes much larger hose and you'll have to jury rig something to get down to the size of hose required for the gauge.

Don't cut the hard plastic ALDA line. There is a rubber connector at overboost valve end of this line so that it can attach to the overboost valve. It's a simple T with a readily available fitting to attach the line for the gauge.

BTW, you can't get the hard plastic lines off the banjo fittings. They are sold from the dealer already attached. I recently broke the line to the overboost valve due to it's age. A new one comes witht the fitting to the banjo already in place.

If a clogged ALDA line was disasterous, the roads would be littered with disabled Mercedes turbo diesels. The best chance for a disaster occuring is when a car with a clogged line pulls out in front of another car.

If the ALDA line clogged while adjusting boost, it could be disastrous as your boost readings wouldn't be right and you could be overboosting without knowing it.

As far as getting the banjo fitting off, I got mine off, had a heck of a time getting it back on, but I did successfully get it back on without destroying the line.

__________________
-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com