What is stock boost for 84 300D - PeachParts Mercedes-Benz Forum

mbzkid · #1 06-12-2006, 08:38 PM

What is the official spec for turbo boost on the 617? I have a FSM, but it is for non-turbo engines.

The car is currently at 9.5 psi, and I believe it should be around 10-12, but I do NOT want to take a wild guess.

#2 06-12-2006, 10:34 PM

0.7-0.9bar or 10.15-13.05psi. Most came from the factory with 7-9psi boost. Why? Reliability, economy, emissions, mistake? Nobody will know why unless we can get one of the builders/engineers to tell us.

mbzkid · #3 06-12-2006, 10:51 PM

.7-.9 bar is what MB has published?

It doesn't make sense for the manufacturer to have a spec of 10-13 psi, yet have the cars leave the factory at 7-9 psi. I'd say either MB didn't want owners destroying cars from high EGTs, or, emissions regulations demanded less fuel and therefore less boost. I would still go with the boost setting that MB designed the engine for.

#4 06-12-2006, 11:02 PM

Quote:

Originally Posted by mbzkid

.7-.9 bar is what MB has published?

Dang it, now you made my break out my FSM.

It's .7-.8 bar. So I was 1.45psi over...

Brian Carlton · #5 06-12-2006, 11:23 PM

Quote:

Originally Posted by ForcedInduction

0.7-0.9bar or 10.15-13.05psi. Most came from the factory with 7-9psi boost. Why? Reliability, economy, emissions, mistake? Nobody will know why unless we can get one of the builders/engineers to tell us.

I've got the SD set to 13.5 psi and, my guess is that it's too high.

Why, you say?

I don't think the ALDA has sufficient range to accept 13.5 psi of boost and the engine does not get anymore fuel above.......say.........11 psi or so.

I definitely see a temperature rise on the gauge........everytime I use maximum boost for more than 10 seconds or so. The 617 would never exhibit such behavior........more common to the fussy 603.

So, before I run the a/c for the summer, I'm thinking of dropping it back to 11 psi. I'll do another 0-60 time after I reset it.........it's currently at 12.7.......but........I'll bet that I don't lose any time.

However, the drop of 2.5 psi will definitely cause lower charge temperatures and lessen the rejected heat loading.

#6 06-12-2006, 11:38 PM

Quote:

Originally Posted by Brian Carlton

I don't think the ALDA has sufficient range to accept 13.5 psi of boost and the engine does not get anymore fuel above.......say.........11 psi or so.

I don't know about that. I've got my ALDA at the max (No guts inside it) and at 14psi boost, I still get a bit of black haze at WOT. It may be just the turbo heating up the air but I'm not going to give it more boost to find out.

Brian Carlton · #7 06-12-2006, 11:43 PM

Quote:

Originally Posted by ForcedInduction

I don't know about that. I've got my ALDA at the max (No guts inside it) and at 14psi boost, I still get a bit of black haze at WOT. It may be just the turbo heating up the air but I'm not going to give it more boost to find out.

That's interesting. I can't get this 617 to smoke at anytime.......under any condition.

You might be right on the ALDA.........I'll have to reduce the boost and do another performance check. I don't think I can manage 13.5 psi during the summer with the a/c running and dealing with the CT hills.