Engine/Transmission (1998.5 - 2002) What does the VP44 have on the P7100?

[sparks57]

It seems as though the P7100 injection pump has superior fuel moving abilities, including GPH and pressure.



But what is superior about the VP44? The only thing I know is that it has variable timing. What does this do? Also, what else is different?



Thanks.

 

[Snow man]

I know it is also quieter ,and robs a lot less HP off the engine to turn it. i think there around a 35 Hp difference in parasitic HP loss that the VP trucks do not have to get over. Theres also the automatic RPM control,it idles the correct speed hot or cold,starts faster colds,and with no throttle needed. unlike the P7100,which stalls cold of you set it to idle at 800 hot(below freezing). I am able to remote start my 2000,never could with my 96 unless it was plugged in every night below 45,the 2000 will remote start at zero even if its not plugged in.

 

[sparks57]

Quieter??? I thought most engine noise was acutally pump noise, and the 24v trucks are a lot louder!



Or am I misinformed?



Thanks a lot for the info Snow man!

 

[Forrest Nearing]

quieter = NO WAY! my neighbor across the alley and 7 houses down had a 24v, and it would WAKE ME UP when he started it!!!

 

[ToolManTimTaylor]

Don't forget the $$$'s LOL!

 

[sparks57]

The $$$'s in what? The p7100 or the vp44?

 

[Gary - K7GLD]

SUPERIOR?



How about the ability to INSTANTLY, on the fly, adjust fuel volume and timing to match vehicle speed and load - allowing excellent low-demand economy, yet excellent power when the need arises...



What do you have to do with older pumps to get that - what do you give up in low demand economy to obtain high demand power? I can easily get better than half again the power and torque out of my engine for less than $600 - and STILL have the above TOTAL flexibility at an instant touch of a button, from the drivers seat - what similar can be done with a P7100 - and at what cost to even come close?

 

[sparks57]

Can't you do that with your right foot?

 

[Gary - K7GLD]

NO, as a matter of fact, you CAN'T, not with a modded P7100 modded to the levels obtainable with a Comp/VP-44! You gotta make a sacrifice at ONE ond of the scale or the other - with P7100, you can have decent economy, or power, but not likely BOTH at the same time - Hell, where do you think so many of the smoke stories come from - guys who have turned up their pumps...



Smoke at significant points of engine load = reduced fuel economy and poor efficiency at low demand, PERIOD!



There ain't NO free lunch - but the *adjustability* and computer control of the VP-44 come close! IF you could do THAT with a P7100, you'd REALLY have something...



With my truck, I get the power displayed in my sig, still get 22-24 MPG empty at 60 MPH - OR can tow a GCWR of about 14,000 at 80 MPH over the steepest Sierra grade I've traveled - In Overdrive! Wanna try that, both economy AND power with a P7100?

 

[sparks57]

I see. Thanks for the valuable information!

 

[ToolManTimTaylor]

The Question Read:

Originally posted by CB_Parker

The $$$'s in what? The p7100 or the vp44?

What does the VP44 have on the P7100? MORE DOLLARS

 

[sparks57]

OK!

 

[ToolManTimTaylor]

Originally posted by CB_Parker

OK!

LOL

 

[Joseph Donnelly]

My P7100 retained good mpg even hopped up. Mileage was highly dependent on the right foot

The VP44 is smaller and lighter, so it is easy to change, which you have to do often

 

[sparks57]

:-laf



I feel mighty priveliged to be graced by the presence of such a diesel guru!

 

[Gary - K7GLD]

HEY Joe - define "good MPG" in layman's terms...



Like, what is the best MPG you can see at a steady 60 MPH fer instance - and then, when towing that slippery lightweight Airstream down the pike at similar speeds - or do ya ever keep under the speed of sound...

 

[Cummins Cowboy]

The 24v trucks are definatly way louder, Also and I would like to hear what Joe D. thinks of this. It seems like the 24v trucks have way too advanced timing when starting up especilly during cold weather starting. When I start up my truck on a cold morning it seems like the engine is just hammering inside, I would think retared timing would help this a bunch. This would also explain why the engines seem much louder than the mechanical motors. It would also explain why the off idle torque of the 24v is alot less than the mechanical engines, sometimes I start off in the wrong gear and my new truck sure is alot easier to stall out than my old first gen was. Could this all be a result of timing too advanced at idle and lower speeds. It seemed like my first gen was a brute at idle. However I will say my 24v just seems to come alive at 80+mph it pulls like it has reached its second wind the mechanical engines where running out of steam at these speeds, again this could be do to advanced timing that is finally helping at this speed. maybe this even further helps the noise factor with the 3rd gen motors ideal idle timing then crank it up when the rpms go up

 

[Huff N Puff]

Please correct me if I'm wrong

The VP44 can shut of fuel while coasting. I'm assuming this, cause the engine goes almost silent while coasting down hill,and EGTs drop to almost 200deg. Just as you start to come to a stop you can hear the engine fire backup,and EGTs jump to 400deg. I'm sure that saves alot fo fuel,for the every day driver. I dont think the P7100 can do that.

 

[Hohn]

The VP has higher injection pressure than the P-pump. IRC, the difference is along the lines of 26KSI vs 18-20 KSI for the p-pump.



The real killer is the HPCR.



Justin

 

[Snow man]

None of the trucks ive worked on,locally or mine has ever needed a VP44 replaced, theres quite a few of us running them most with comp boxes. I dont know how much harder you could run one than im running mine,and its fine. I know they fail,but on here people make it sound like they change them like they change the oil. I tend to think the failure rate is exaggerated sometimes,or we have all good ones out here.