Most hp on return less system

phunk

The RRP is based on a single 255 walbro as its primary full time pump. It can either be plumbed into the factory filter and regulator housing to use with an otherwise stock fuel system, or you can get pretty wild with it by adding a secondary pump inside it, and if you need to, bypass the factory filter and regulator (requires a return kit as well).

Now I tell everyone that I really prefer the primary pump remain the 255 that it comes with, because its a special version of the 255 that has a siphon in it that is being used to help fill the RRP and enhance its starvation eliminating qualities, while helping the stock pump live longer by creating extra surge can overflow back to the stock pump to help it stay wet and recover from fuel slosh. That said, it might work just fine without that special primary pump, and perhaps it would do fine on its own with a 340 or 400 or 485 as its only single pump. However, it was not intended to run this way, and hasnt been tested this way. If someone wanted to experiment with it like that, I would support the testing and give a little discount to the customer... however, this is not in the cards for most guys. This year, I will be personally testing it that way... but its still winter here.

If it works that way, it will make everyone's life easier as it will allow a cleaner and easier way to support boosted Z's, rather than having to run two pumps in the RRP, which requires secondary pump activation through a hobbs boost pressure switch, and extra complicated plumbing inside the tank to accomodate. I would really love it if the RRP still performs well with a 485 as the primary pump. I am going to try a 340 in the stock pump, with a 485 in the RRP. I THINK it will work... but it might not be as ideal for hardcore track use as it wont be doing anything to help the stock pump from starving... but that isnt a problem for street cars like mine.

What would also be awesome about that configuration, is that when I swap in the built motor, I will use the special 255 as the secondary pump in there, and then when the secondary pump is activated, it will also start up the siphon pulling fuel from under the RRP to help make sure it stays full! That would be a really trick configuration.

Anyhow, I am just talking about the RRP and boosted cars in general here, and not exactly answering your question clearly. With the standard configuration of the RRP that I sell as a full kit, you are based on a 255 pump which is a good pump but cannot supply as much fuel for the power a VQ37VHR is capable of... so it depends on how hard the customer wants to push it. On top of that, it depends on what other fuel system upgrades are done. If the car also has my Stage 2 fuel system on there, that will help get more out of that 255 pump than if all the plumbing outside the tank is still stock.

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