Supposedly these pumps suck better then they blow, so was hoping on putting it right near the filter housing, that is a possibility though.
Well.... here's a continuation of my Purolator rant I guess.
I was going to start a new thread of my recent install, but will do it here instead.
First off, I'd made an assumption these pumps were centrifugal based on inlet/outlet positions. However, the outlet is centered on the pump instead of on the side. Once the pump was running, I've guesstimated these are eccentric pumps.... basically a gear pump more along the lines of a rotary pump. I'm still guessing because there is no pump "type" description on any literature I've looked at.
Although many here have installed these pumps as puller pumps, they're rated to 10' of lift, Purolator themselves indicate they are "pusher" pumps on their FAQ's page.
Eccentric pumps are pushers too, not that they can't pull, it is their job to push fluids. Optimum performance for the pump.
What this means is, rail mounting is the best position for this pump, especially if one intends to add more filters in line.
Gandolf installed his on the rail with some coaching from Agnem. After reading as much as I could about the Purolator Dura-Lifts, including some failures and less than 100% fill of the pump mounted filter when installed further upstream, rail mounting is indeed the best location and I followed suit.
The pump was installed appx. 12" for the fuel tank selector. I used holes in the rail already there, mounted it to a jerry rigged u-channel( 2 90's bolted together), grounded in a free hole in the frame next to the pump, with a single 10ga hot lead to the GP relay ignition on/off.
The results were amazing.
Once I applied power, it took less than 15 seconds to fill the pump filter bowl and bleed my drained supply lines, until it literally shot out the main filter Schrader valve. When I started the truck, it started faster than off my mechanical pump, and this was first roll after severe air intrusion by working on the system.
On a test run, remember my mechanical lift pump was going bad-figured out all the excess fuel was coming from the pump's fuel dump(the safety feature on the factory lift to prevent fuel from filling the oil sump), my rpm's went down 150 at 55mph, and at 65mph my rpm's were only 100-200rpm's more than at 55.
Result's:
55mph- 1900rpm's
65mph- 2100rpm's
75mph- 2500rpm's
Since my mechanical pump was bad at purchase-although working- I have nothing to compare with in a healthy system, however, I can tell you what I was reading on a quasi-compromised system:
55mph- 2100rpm's
65mph- 2400rpm's
75mph- 2800rpm's
Add to this, the power output was much closer to neck bending. Punching it from a dead stop, the tire's almost broke free. There was that little skid sound for a half second before inertia didn't allow for more rubber to burn, although my tires are also brand new, maximum grab.
At my next top off of fuel, I'll start calculating my burn rate. At first, I was getting 16mpg's when I bought the truck, however, as the mechanical started giving up, it decreased to 14.5mpg.
I can only say this in conclusion, when you spend the time to research the pump itself, you can only come to the conclusion these are pusher pumps with some ability to pull. Optimum performance is as a pusher. Even burning other than diesel, such as WMO/WVO, it will work far better, possibly diluting less if mounted as a pusher pump.
No matter what pump is used for fluids, eccentric, circulating, diaphragm, vane, sliding vane....whatever, they all perform best closer to their source than further away.
Why do you think manufacturers now place lift pumps submerged in the fuel tank??
They perform better closer to the source. We only mount them outside for convenience.
I know, I know, we've all got opinions on where to mount, our own convenience desires and where we've already placed them.
For maximum performance of the pump, rail mounting is the best option because these are really pushers, not pullers.