Diesel theory

[Archive]

Concerning the recent posts about the P7100 pump allowing the 12v engines to make lots more power: I, as some others, now have a first gen combo of the Bosch VE pump and HP injectors that gives outstanding performance and can make oodles of smoke, if adjusted to do so, even at high boost levels which implies the ability to deliver far more fuel than is needed. And, since the P7100 accomplishes better power without even that much smoke and at comparable boost levels, it seems that some other and very important factors come into play. What might they be? I'm guessing how quickly the fuel injection takes place and the engine camshaft timing are the main reasons. Is substantially more air getting into the cylinders of the 12v P7100 to make up for the added fuel that would just make a first gen smoke?

On another note I obtained a Railroad Atlas that has maps of every railroad ever in service in California and Nevada. I'm going to explore some abanoned railroad grades that do not appear on road maps. Time for some "lock and low' cruising with my new PW injectors.

Oh, BTW, drove normal again through a whole tank with my new injectors and pump timing. Mileage is UP to 14. 1 from 13. 5 the lifelong, never changing average before the injectors and positive stop timing. I knew the advance would help the mileage, I just couldn't tell while I was enjoying the new power!



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'93 W350 Club Cab, 5 sp. , Factory Options: LE, 4. 10, LS, 7600 lb. rear springs, tachometer, front stabilizer bar. Mods: Banks stinger plus, Linex bedliner, 25,000 lb gooseneck, 10,000 lb receiver, Tekonsha brake controller,
PW injectors.

 

[Archive]

Mark93 when the second gen's came out in 94 with the P7100 pumps they also had 12cm2 exhaust turbine housing. Maybe this is needed in the quest for more power!
Gene
92 350 4x4

 

[Archive]

Hello All: The VE 44 (rotary) is a fine precision injection pump, and can be made to perform "earnestly" by bench setting, adjusting the full fuel, delivery rate, and AFC. Too much will take it's toll on the pump thru wear if the injectors are stock sized, and the pump is "turned up" to excess. My experiences with the pump were favorable and it's reliability was without reserve.
The P7100 (inline) was added in '94 and actually is a higher injection pressure unit. You may well over fuel this pump without the results that would show up in the VE44. It's oil cooled, and has larger bearings. (the pump weighs about 50 lbs). This pump is a long life unit, and was used by Cummins in higher power level engines early on.
For what it's worth, BOTH pumps can be made to PERFORM as high power, efficient, reliable daily drivers. Both are capable of excessive smoke, and out of tune conditions.
The 12cm hot end turbo housing on the P pump trucks build boost sooner at the low end. This will reduce smoke. I'm not completely sure this is the trick setup for me and the '98, as my experience with my Big Medicine '92 with the non wastegated 16cm has shown.

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'98 2500, Cummins 12v, 5spd, 4wd, 3. 55, 300 injectors, JRE III power kit, 4" turbo to tail system, boost/pyro, did I mention 12 valves? GOT DIESEL?

 

[Archive]

Thanks Old School for the info on the pumps.


Had a GREAT day in the desolation of the Mojave desert. Even the 3" long dried scrubbrush shaft that stuck 2" into an outer rear and caused a leak didn't begin to stop the day. Got it fixed in China Lake. Followed the Trona Railroad from US 395 east to the chemical plant at Trona, CA. This place is near to Death Valley, CA.

"Accidentally" got on the side of a mountain on a motorcycle road that was steep (and I mean STEEP) and enjoyed how I could idle up in 1st gear High Range. Had to use some throttle to keep things progressing and not just sliding sideways along the cross grade. The Cummins is perfect for off road dry ground four wheelin. The clutch engagement torque is fantastic! No throttle ever needed to take off-even on a really steep grade or in sand.

On the way back I ran at nearly full load for about 50 miles total. Outside temp was about 101 F. I was against the wind and up grade much of the time. With cruise on and set at 70 mph, RPM held rock steady at 2500, boost varied from 17-21 psi, EGT got to
750 F (post turbo), coolant temp made a steady climb to about 205 F (a little past the the 3rd line on the temp guage's "normal" zone). There was still some pedal left to pass everything else on a long grade including, of all things, a MOPAR parts truck! Boost and speed topped out at 23 psi and 80 MPH (2750 RPM) respectively, in very short order.

Man that Cummins sings when it's working hard. For me, it's a pleasure to listen to; but it gives my wife a headache.