Boost Control Install!! - PeachParts Mercedes-Benz Forum

#1 05-06-2002, 11:15 PM

I just finished installing a boost controller that I bought from Dawes. I heard about them here and I came in yesterday. Everything needed to install it I got from Home Depot. I also got an Autometer Boost Gauge that I installed in the Glove Box area. I got the idea from 'speedy300d'. I took it one step further though. I made some templets out of cardboard for a panel. I then took the templets to TAP Plastics and they cut out a panel out of ABS plastic. It is textured so it looks like a dash board is supposed to. I also put a power output next to it. I left the ashtray door frame attached and just removed the ashtray itself. Like you do when you empty it. (I don't smoke, BTW

) Then I just got some industrial velcro and atachet the panel on the sides so no screws are needed or showing. I'll try to get a picture posted. If I don't say so myself, it looks good. I set the boost at 13psi and adjusted the alda about half a turn out and WOW! what a difference. I originally was at 7.5 psi max. No, it just flys at high speed. I highly recomend this mod.

adiaw83 · #2 05-07-2002, 12:00 AM

do you think a mod like this would be applicable for my 83 300Sd. Please get those pictures up becuase I am very curious.

DieselHead · #3 05-07-2002, 12:19 PM

Congrats on the install. They are pretty neat devices. For my gauge install, I used a VDO 0-15psi gauge (I like to see the needle sweep the entire range) and used industrial velcro to attach it to the instrument cluster right above the front left speaker. The wires for the gauge illumination and the tubing that sends the boost all were routed up from under the speaker grille. I thought it was easiest to see placed here, I didn't want to get rid of my ash tray, and I thought that putting it near my right knee would be inconvenient.

Alex

#4 05-07-2002, 08:34 PM

adiaw83,

I don't see why you can't do it to 300SD. You need to get your self a boost gauge. That is very important. You don't need anything more than a 20psi gauge. I used an old 2 5/8 autometer gauge that I got from someone with a supercharged mustang. It has a vacum side that doesn't get used in a diesel. I plan on changing it out for just a boost gauge. I will try and locate a digital camera because my scanner quit. Those pictures should be up soon. I got a question for you guys, how much boost can these things handle? I'm not planning on any more but, it be fun to know. thanks.

adiaw83 · #5 05-07-2002, 08:45 PM

cool after I see the pics I might give it a try. It would make for a good summer project.

DieselHead · #6 05-07-2002, 09:02 PM

roadracer,
regarding the max boost you can apply to the engine, people will tell you different numbers and give all sorts of different reasoning. I'm not sure what the safe proper number is but I have mine maxed out at just below 14psi. It seems to work well and it sounds like it's within the realm of normality. Oh, and besides, if you over boost it too much, there is a safety valve that will release all the pressure to keep the engine from blowing up.

Alex

#7 05-07-2002, 09:07 PM

Dieselhead,

How much did you adjust the ALDA to get max performance at 14 psi? I turned it about 1/2 a turn out and get slight smoke going uphill at full throttle at 4000 rpm. I've heard that this amount of smoking is right. I'm gonna try about 14 psi too and see what happens.

gsxr · #8 05-07-2002, 11:36 PM

FYI, the ALDA setting is totally separate from the boost pressure setting. Set the boost first, then mess with the ALDA. Factory spec is 0.85-0.95 bar (12.75-14.25 psi). So, if set at 14psi, you should be fine. The overboost safety switch is rated at 1.1 bar +/- 0.15 bar, to give you an idea of the maximum setting. I wouldn't mess with much past 1.1 bar or you could end up with a melted engine (the pistons are the weak point). For some reason (emissions?) the later W123.133 came from the factory with very low boost settings, usually 7-9psi. Upping this to 12-14 makes a BIG difference. However, increasing the boost on my 1987 300D from 13 to 15 psi made no perceptible difference.

Adjusting the ALDA screw increases the minimum fuel setting, which increases power off idle. I *think* that it will NOT affect top-end power (under boost), only off-idle. However I'm not 100% sure on that and I haven't heard any concrete evidence to prove that it does improve power under boost. Anyway, most cars usually need 0.5-1.5 turns CCW. A little smoke is normal at full load, as seen on a SUNNY DAY (not at night!) in the rear view mirror.

If you unscrew the ALDA even more, and don't see any more smoke, either the ALDA is not enriching the mixture under load (which supports my theory), or it's just not as visible and your MPG will suffer.

Best regards,

DieselHead · #9 05-08-2002, 12:11 AM

racer,
I turned my ALDA out 360 degrees and am thinking about screwing it in just 90 degrees. GSXR is correct though, it should only affect power off the line. It sounds like you've adjusted it just fine though so I if you still want to play around with it, I would only turn the screw a quarter or an eighth of a turn at a time.

Alex