sure, stroke would stay the same, but with the increased area, the volume will go up as well. just wondering what the stroke would be to calculate max volume...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I bet the stroke is longer too. Its a completely different pump.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Different from the M it was built from? Or different from the U.S. spec MW?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Volume is important and volume per degrees of crankshaft rotation is important.

The reason that the bore is increased is that you want more fuel, but you do not want to inject it over a longer period of time (more crankshaft degrees of rotation) because that will put the end of injection later in your combustion cycle, ... which will need to be compensated by increasing your advance at higher RPM and higher fueling, and that has its own issues.

Those of us with OE 5.5mm elements can increase the fuel amount by increasing max. fuel, but much of it will be wasted and create high EGTs because all that you're doing is allowing the injection event to continue longer. The larger elements will allow more fuel in a shorter (or same) time period.

Thus the way to go beyond with stock elements is a faster injection rate pump (cam with a higher rate of change, but not necessarily a higher lift/more stroke). This I believe exists in later pumps to create lower emissions (faster injection rate = shorter event = earlier end of injection and more complete burn), this is an assumption as my Caterpillar pumps had this change (a modified pump that I used for more power). Anyway, this is only a small incremental improvement within the design limitations of the pump. Another option is to increase the torque settings to allow more fuel at lower RPM, where the stroke can be maxed sooner and develop more torque and more power at lower RPMs, but still stay within the max. fuel at max. RPM. You can also turn up the high-idle (max. RPM) so that the mechanical governor is not starting to reduce max. fuel as you approach max. RPM, but you will then need to actually watch your tach.

It isn't as simple as it seems though, there is in a properly designed pump very specific injection profiles, which it appears some of the cheap Chinese elements do not consider, and therefore don't perform as smoothly as the higher-quality upgrades (dieselmenken video demonstrates this difference).

So the simple answer is that changing to larger elements (properly engineered) alone will allow almost a directly correlated increase in fuel supply without any negative impact on timing and injection event, and that is why this is the popular direction. A higher rate and lift cam has negatives in the limitations of the stroke, and the added side-load & wear between cam and elements, element bore, etc.

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Gone to the dark side

- Jeff

Back calculating the stroke: According to Dieselmeken, max fuel delivery is at 230 cc for his 3rd generation 8 mm pump elements. So 4.58 mm would be the max stoke [230 cc / (pi x16 sq. mm) = 4.5757 mm].

https://www.facebook.com/dieselmeken/videos/vb.200188306750341/589336234502211/?type=2&theater

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

That's what I was saying a few posts back. I've never heard of anyone reworking the pump cam though I suppose it IS possible, just like increasing the lift on a reground camshaft by reducing the base of the lobe. I don't know if it would be possible to readjust the lobe-to-plunger clearance to compensate for the regrind, having never been into one of these IP's.

Interesting thought, though..... This is what we Hot Rodders call "bench racing."

Dan

Just like calculating engine displacement:

Multiply the piston stroke by the square of the cylinder bore times 0.7854 (stroke x bore x bore x 0.7854) to calculate the displacement of 1 cylinder

Done.

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Current rolling stock:
2001 E55 183,000+ Newest member of the fleet.
2002 E320 83,000 - The "cream-puff"!
1992 500E 217,000+
1995 E300D 412,000+
1998 E300D 155,000+
2001 E320 227,000+
2001 E320 Wagon, 177,000+

Prior MBZ’s:
1952 220 Cab A
1966 300SE
1971 280SE
1973 350SLC (euro)
1980 450SLC
1980 450SLC (#2)
1978 450SLC 5.0
1984 300D ~243,000 & fondly remembered
1993 500E - sorely missed.
1975 VW Scirocco w/ slightly de-tuned Super-Vee engine - Sold after 30+ years.

Its why the RS numbers on the side of the pumps are different - think of the cam inside the pump like a camshaft of the engine actuating the valves. I think the 'best' pump in terms of lift is the RS203 pump.

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UK spec Mercedes W210 E300 Turbodiesel wagon - OM606.962 with 722.6 transmission - rust free!