Nother Question

[elshadow001]

Ok time for another dumb question!Has anyone ever put lift pumps in parallel and run them.I was just wondering how they would perform as far as pressure and volume

[ISX]

I think they might actually end up putting out too much pressure. I don't think the VP44 can withstand much more than 20psi, which 1 pump should be able to do that much. So you would have to put some sort of overflow valve in the line before it reaches the VP44 in order to limit it to 20psi. Sounds like doing that would yield you a very good setup, though costly. You must also make sure they are the same size pump, running different size pumps in parallel is seldom a good idea because the larger pump can throttle the smaller pump causing it to run too far off of its BEP (best efficiency point.) This can cause shaft deflection and possible premature bearing and seal failure.So now they both have to be Airdog 150's or the like so that the flow will remain between 10-20psi should one of the pumps fail. I assume you would want that kind of fall-back rather than having 2 smaller pumps that could not flow enough should one fail.

[Mopar1973Man]

Yeah I seen a few parallel setups and a few series the series setup will increase the pressure most time will beyond 20 PSI but the parallels were good at delievering good volume at the strongest pumps pressure. Problem... 2 Stock Carter pumps is more expensive that 1 single Raptor 150 GPH pump... Not to mention the Carter pumps typically have a 30 day warranty and the Raptor is lifetime... No it makes no sense to run a parallel setup...

[edcasey]

Ok time for another dumb question!

Has anyone ever put lift pumps in parallel and run them.

I was just wondering how they would perform as far as pressure and volume

It's not a dumb question at all. The science of fluid mechanics tells us running dual fuel pumps (assuming they are identical pumps) in parallel would not increase the fuel system fuel pressure compared to running a single pump but would potentially double the volume output of the fuel system. Realistically, in a closed system, fuel volume delivered to the injection pump would only increase if one pump had insufficient volume output to satisfy fuel requirements. It's very similar to electrical pressure (voltage). If you run two 12 volt batteries in parallel, voltage remains 12 volts but the capacity (amp hours) will double. If you run two 12 volt batteries in series, the voltage doubles but capacity remains the same as one battery.

Dual fuel pumps are very common in high performance gasoline applications that require high fuel volume and high fuel pressure. Many companies make dual fuel pump kits for these applications. However, on our trucks with relatively low pressure requirements, in most cases, it makes more sense use one high volume, low pressure pump. A complete Raptor kit will cost less than buying and plumbing two lower volume pumps (Carter, Holley,ect).

I'm probably one of the few people who has two fuel pumps plumbed in parallel in a CTD application. However, I only run one pump at a time because one pump provides more than enough fuel flow to supply the VP44. Running both pumps at once provides no advantage. The only reason I have two pumps in parallel is for redundancy. If one pump was to fail, I simply throw a toggle switch on the dash to change pumps. I use my truck to pick up wholesale campers all over the Northeast and a failed fuel pump can be very expensive (tow bill, lost time, hotel room ect...).

My fuel system: