Who has been brave enough... - PeachParts Mercedes-Benz Forum

BluEyes · #1 10-22-2005, 01:23 AM

... to set/check the max 'no-load' RPM?

I'd like to go through and make sure the governing settings are right on my engine, but the idea of dropping it into neutral and burying the pedal just doesn't make me feel good.

The manual is full of cautions not to let the engine hit 5000rpm for more than an instant lest bad things happen. How much of a risk is it to bring my little 220D up to 5000rpm?

Today I did check the maximum full load RPM, and she topped out at 4000rpm on level ground, so I know that I need to make some adjustments to the governor since I should have another 350rpm before it stops.
I do not plan to use the redline often (or ever) but it seems that if the governing RPM is too low, then I either need to have the IP set to inject more fuel, or loosen the full load screw to let the TB open a bit further, either of which would seem to affect power throughout the entire RPM scale.
The problem is that I do not know which adjustment is the proper one to get the engine back to proper MB specs without checking the no load max RPM...

P.E.Haiges · #2 10-22-2005, 05:53 AM

BluEyes,

Maybe 4000 is the maximum you engine will turn in high gear because of the air drag. Try running wide open in third gear and compare the full speed RPM to the RPM in high gear.

P E H

BluEyes · #3 10-22-2005, 11:20 PM

Well, you were right. In third, she actually pulled past 4350. My 'Tiny Tach' recorded a max 4435 rpm before I shifted into fourth, so the governor is actually at least 100rpm too high.

Dang, I thought she had more in her and would be able to pull max rpm in any gear. I guess I've found the limits of 60hp...

JimmyL · #4 10-22-2005, 11:29 PM

Quote:

Originally Posted by BluEyes

Well, you were right. In third, she actually pulled past 4350. My 'Tiny Tach' recorded a max 4435 rpm before I shifted into fourth, so the governor is actually at least 100rpm too high.

Dang, I thought she had more in her and would be able to pull max rpm in any gear. I guess I've found the limits of 60hp...

I think you're getting the most out of those 60hp!

BluEyes · #5 10-23-2005, 12:02 AM

Yeah, I guess I am.
Since switching engine and diff lube to Mobil 1, changing the tranny oil, and adjusting the valves the car has picked up noticably. I have had to lower the idle speed twice to keep it in the 700-800 rpm spec, and it will now idle smoothly under 800rpm when fully warm. I am also able to actually accelerate up several hills that I used to lose speed on.
I still never see any black soot at WOT like others talk about though, just a bit of blue/grey smoke is all. Guess I'll just have to live with the car being all polite and respectable that way

redly1 · #6 10-23-2005, 12:35 AM

just out of curiousity, what was your speed at top RPM in 4th?

BluEyes · #7 10-23-2005, 01:18 AM

Well, my speedometer reads a bunch low (bad magnent I think, odo is fine) so the speedo was only reading 60.
Doing the math based on 1:1 4th gear, 3.92 rearend, and 185/75R14 tires I was doing about 75.
Man, you had to go and make me check that...

Now I'm thinking I might have a few ponies still napping under the hood after all.

Nate · #8 10-23-2005, 04:10 PM

well if your spedo was working correctly the flux capicitator would kick in around 88ish, so something definetly holding your back

My 76 300d will do 90 WOT for a long time, but I dont know the ratios, but I think 100 would be maximum down a hill... without overrevving.

the 220 is a 2.2 liter 4 right? (I should know this... but dont), and 75 seems a bit slow. I suggest that you get your spedo fixed asap, but I know that time gets tight...

What I would do is fix the magnet, then retry

~Nate