350SD top end - PeachParts Mercedes-Benz Forum

DslBnz · #1 05-24-2003, 07:59 PM

I was just wondering. Does the 350SDL engine have some type of restrictor on the engine? I had an encounter with a real jerk who was trying to cut me out. I went as fast as 115 mph(and I beat him). However there was a pullback in the engine that started at around 108 mph. It felt like the engine was holding back it's power. The engine looked like it was turning at 4250 rpm at 115 mph. Is this the overspeed governor on the engine? I don't have a manual so I don't know if it is the redline.

wbain5280 · #2 05-24-2003, 08:08 PM

You can get killed doing that.

DslBnz · #3 05-24-2003, 08:33 PM

Car felt very stable at speed. You would never know you were going 115.

sixto · #4 05-25-2003, 04:22 AM

I believe the governor is set closer to 5000rpm. See how high you can get the revs in the lower gears.

Sixto
91 300SE
87 300SDL
83 300SD

#5 05-25-2003, 04:47 AM

If you can get killed doing that then I should be dead already.

sixto · #6 05-25-2003, 05:17 AM

I see Warren's point. "Officer, I went 115 to avoid getting cut off" probably won't go over too well.

Sixto
91 300SE
87 300SDL
83 300SD

wbain5280 · #7 05-25-2003, 11:39 AM

Quote:

Originally posted by sixto
I see Warren's point. "Officer, I went 115 to avoid getting cut off" probably won't go over too well.

Sixto
91 300SE
87 300SDL
83 300SD

Thanks!

There were several people who were killed in the D.C. area a few years ago who were driving at high speed after one cut the other off. One car crossed over the median strip and killed some people.

The instigator is in jail for a very long time. The judge said he wanted to send a message.

Don't let your lower level brain hijack your higher level brain just for a little road space.

Regards

DslBnz · #8 05-25-2003, 02:21 PM

The highway was wide open, 2 lanes of travel. I shouldn't have gone so fast, but the way this guy drove; everytime I went to pass him normally, he cut over to my lane so I couldn't. I got sick of this, so I floored my 350 cut to the right lane(of course there wasn't any traffic, I took notice beforehand))and had to go up to 115 to get past him. (He was maxxed out)

His speed in the passing lane when I was behind him was about 54 mph in a 65 mph zone. On a wide open road!

The RPM limiter in my 300SDL is about 5300 - 5450.

I tried keeping the 350 in '2' up to 50 mph, and it would not go above 4250! I think I found the limiter.

P.E.Haiges · #9 05-25-2003, 02:52 PM

DslBnz,

Could be a fuel filter just starting to plug.

P E H

psfred · #10 05-25-2003, 05:36 PM

I would second PEH -- my 300D easily hits 4600 rpm (I've never tried to see how fast it would go!) and 115 is well below what I would expect to see in a 350 SDL -- more like 130 for the top end.

Change your fuel filters and check that the boost control system is working properly -- it may be venting boost off prematurely because the switch is bad. This will limit power substantially -- feels like you lifted your foot.

And do what I do with tailgaters -- find a place to turn off and let them by. DO NOT just pull to the side of a highway, they are usually some nut looking for an excuse to "prove" themselves. Take a short trip down a side road and leave them to hassle someone else. Keeps your blood pressure down and prevents accidents.

Peter

#11 05-26-2003, 12:42 PM

"If you can get killed doing that then I should be dead already."

You remind me of a friend who used to own a 18 wheeler. Give yersrlf some time, you'll be dead in no time. He just decided to run over some dihard like you. Smushed em all up, guts everywheretoo.

#12 05-26-2003, 03:21 PM

He decided to run someone over? How can I prevent that?

oldsouth · #13 05-27-2003, 10:28 AM

The S-350 does have a govenor. It is not a speed limiter just a rpm limiter. Mine stops accelerating at an indicated 121 mph which is actually 118 mph. I could definately feel it when the car was new, it would pull to just over redline and hold that speed even going up and down slight hills. I have lost some of that power now as it is hard to reach the govenor (about 116-117 mph top end now). I guess over 220,000 miles will do that.

DslBnz · #14 05-27-2003, 08:31 PM

Awesome, nice speedo pic(150 bhp, who would've believed it?). Thanks.

So the stop I am hitting is the engine RPM overspeed sensor. But how come mine is limited at 4250, and yours has an indicated redline at 4400?

*Also, at those speeds you are getting 12.5 mpg, eh? That's not bad at all considering the weight you are pulling and the fact that the engine is redlining. Hmmm,... I wonder what a 1992 W140 600SEL would be getting at redline? Is it measured miles per gallon, or gallons per mile?

turbodiesel, somebody told me once that they saw pictures of a 300SDL doing better than 140 + mph on the NJ turnpike on the web. The guy had pictures of the speedometer and everything! It was just nearing redline. You wouldn't happen to know where those pics are online would you? Was it your 300SDL?

oldsouth · #15 05-27-2003, 11:39 PM

When you floor the car from a standstill and let it do full throttle upshifts, does it upshift at 4250 rpm? Mine upshifts at the redline and will go to almost 4500 rpm's in top gear. In the photo, I was quickly closing in on a curve and had to take the shot and let off. I have been meaning to take a more recent photo but after the chewing I received from my wife on this one, I have decided to wait.

edit -- LOOK my 350 post!