Thinkin about converting. VP vs. P7100 MPGs?

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rockytopcummins

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I'm in the process of doing my homework on this swap. This question is for people who have actually done the swap, not the "I know a guy" crowd on hear say. Is the fuel mileage with you swapped trucks comparable to the VP? I just don't want to do this and have my fuel mileage drop like a rock. I know this depends on MANY MANY variables, but just generally speaking, how does it compare? Just to give you an idea, if and when I do the swap I plan on using a 180 pump setup to do about 500cc, and 35/HT3B or S475 twins with 150 or 200 horse sticks. Thanks for any advice anyone can offer. Oh, almost forgot, also plan on doing a Hamilton 181/210 cam at the time of the pump swap.
 
Just swapping from a HRVP to a 215 pump, nothing else changed, my mileage was up slightly. That was with 15 degrees timing. If I turned it up higher, I might have been able to get more.
 
18* of timing and stock 181dv's I was getting around 18mpg with the ppump vs. 14-15 with the VP. Now not so much but that's my fault.
 
I noticed that towing my mileage suffered, but unloaded I gained...

I did swap out injectors as well along with the swap.
 
Well thanks for everybody's input so far. What kinds of setups are you all using? Also, how hard was the swap to do? This will be my first venture into something this involved. Up until this point the deepest I've been was swapping my VP. I would be lieing if I said I wasn't a little nervous about getting the truck torn apart and getting lost LOL. The bit of encouragement I have is seeing and reading about how many people that have done this.
 
What pump did you use Roachie? What all was done to it? Was this your red pulling truck with the hood stack?
 
At the time it was still my DD, 275RV injectors, 4gsk, #4 plate, I think it still had the hx35 in it as well.

If memory serves right it was a 180 pump.
 
With a 160 pump 64/71 181s and 6x012s and 25*. Some how I got 22 on the highway doing 80-90. On the way home I did 75 or so and got 19. I have not come close to that since I put a 215 pump on and a 66/74.
 
CL2000 said:
With a 160 pump 64/71 181s and 6x012s and 25*. Some how I got 22 on the highway doing 80-90. On the way home I did 75 or so and got 19. I have not come close to that since I put a 215 pump on and a 66/74.
Click to expand...

How the hell does that happen? Are you sure you did your math right and was this the only instance you got such good fuel mileage?

Couple questions I forgot to take into the equation. What's your rearend ratio, tire size, and what were your RPMs? I know my truck is VERY sensitive. If I go below 1800 or much over 2k my fuel mileage starts to drop of FAST!!!
 
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I was getting mid teens with the VP around town, high teens on th highway.

after the swap I was getting mid teens around town and low twenties on the highway.

And a tank of below ten running it REALLY hard just for kicks. LOL
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rockytopcummins said:
How the hell does that happen? Are you sure you did your math right and was this the only instance you got such good fuel mileage?

Couple questions I forgot to take into the equation. What's your rearend ratio, tire size, and what were your RPMs? I know my truck is VERY sensitive. If I go below 1800 or much over 2k my fuel mileage starts to drop of FAST!!!
Click to expand...
At the time I had 35s and 355 gears. I thought my gauge was broken. I know that it is 330 mile trip to where I was going because I had drove it so much. I filled up befor getting on the freeway to head down and fueld up before I got on the freeway to come home.
 
My truck gets really good mileage around 75-80 mph too. Under 75 it doesn't like to run in od with the converter locked. I still get 18-19 mpg driving with it unlocked
 
Can anyone suggest the best DVs to use for driveability and MPG? Honestly, I don't even know what they are or what they do yet, but I've read enough to know it's a fairly important part of the setup.
 
my mileage has really been suffering, but I changed a ton of variables when I did the swap, at this point it could be the 215 pump, the leaking POS stainless lines(get mild steel instead), or the cut pistons.
 
Before i blew the motor, i was getting 15-17 on Comp DV's and 200 sticks. Who knows now with more fuel
 
cetanefreek said:
my mileage has really been suffering, but I changed a ton of variables when I did the swap, at this point it could be the 215 pump, the leaking POS stainless lines(get mild steel instead), or the cut pistons.
Click to expand...

I thought stainless was supposed to be the way to go? Did you have to cut the pistons because of the cam you used?
 
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