Several threads going on swapping differentials got me to wondering about power bands. How do you know what the power band is for a particular engine-transmission-rear end combination? I'm guessing this comes from a dyno, but is there a good resource where power bands can be looked up. I'm particularly interested in my 2.6L M103, A/T with 3.27/1 differential. TIA for educating me.

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1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

The power band for a particular engine is provided by its torque curve. The curve starts out very low at idle and climbs rather steeply toward 3000 rpm for most gassers. Somewhere near that figure it plateaus a bit and remains reasonably high and finally begins to fall off. Above a specific rpm, say 4500 or so..........the rate of fall increases significantly.

The "power band" is the area of the curve that is reasonably flat near the peak.

Some engine have a very high peak without a plateau. It requires a good driver and many gears to keep it near the peak.


The gearing for a particular engine/vehicle combination will utilize the power band to provide maximum acceleration for the vehicle. Unfortunately, in days gone by, fuel economy was not particularly important and the engine would run at higher rpm's than required under most conditions.

Thanks for the succinct explanation. Very helpful. According to the information I've seen, the maximum torque for the M103 2.6L engine is 162 ft.lbs @ 4600 rpm. I'm picturing a torque curve that rises up to a peak at 4600 rpm before falling above that. Is that the way to interpret that spec? And how does this relate to the maximum power of 158 bhp which isn't reached until 5800 rpm?

I would love to find a graph of the torque curve for the M103 2.6L. Haven't found anything so far on Google. Any suggestions?

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

I found this lurking on google; it's from a 190E, M103 3.0, so I figure it is similar.

http://i300.photobucket.com/albums/nn7/pete190/DSC05958.jpg

I also have no idea how to interpret these...


-Carlen

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1987 560SEL (210,000 miles)