CJM stage 2 full fuel return install

Originally Posted by phunk

The RRP has 2 pump positions.. one that can hold a standard diameter Walbro or similar shape, and one that can hold the larger 400/485 pumps.

It was designed and has only been tested using a special model 255 in the one position. This special Walbro 255 has a siphon to help the RRP fill itself with fuel from underneath it on the driver side of the tank.

I dont know yet how well it will perform without this special 255 in it. I have been suggesting people to supplement it with a secondary pump in the RRP that is triggered with a Hobbs switch.

However, I am starting to get more and more comfortable with the idea of the RRP not using the special 255 as its primary pump. There is no doubt in my mind that its surge protection will be at least slightly hurt... however with how everyone is telling me they are able to race down to an empty tank... it would seem it has some function to spare and still offer far superior surge protection than stock.

This siphon on the RRP that is built into that Walbro also serves to help transfer fuel back to the passenger side in attempt to extend the OEM fuel sending units pump life. Since we know its always starving badly even if the RRP is protecting the engine from starvation, I wanted it to have a secondary function of trying to protect the OEM pump. By having that siphon active in it, it will increase surge can overflow volume which overflows back to the passenger side.

So anyhow... nobody has tried the RRP without that special Walbro yet.



Just after shipping you your individual S2 fuel systems pieces, I than had to build another kit for a customer. He wanted the 485 in the factory sending unit. This mean cutting out the filter to fit it, which I think is best for a pump that large anyway, especially with E85 since the factory filter is paper and the paper filters are not supposed to be used with E85.

That said, coming up on 3 years my OEM paper filter hasnt given me any problems with my 340 pump.

While building that order, I built it as something I could duplicate as the "S2E Fuel System". The E for external filter. The rear of the 2 hardpipes from the standard S2 is replaced with the external filter setup.

To further enhance output potential, the S2E uses the factory quick connect outlet on the pump as the return inlet, and the added bulkhead is a -6 for the output. This setup bypasses the internal filter whether its been cut out or not. So it doesnt have to only be used with a 485 in the sending unit.

We can upgrade you to an S2E easily. I would make sure that it doesnt cost you any more had you just gone that route (had it existed when your parts shipped).

As for the RRP and S2E... I have already mapped out how to integrate the RRP with the S2 and S2E fuel systems. Having the RRP be a part of it doesnt change anything about the S2 or S2E since the RRP is all in-tank.

The S2E with 485 will do 700+ rwhp, no problem.

Originally Posted by O&G

Good deal! So from what I understand, I need the S2E rear hardpipe section w/ the filter, ditch the 340LPH and go with the 485 Wally in the main pump housing and just stick with your original design on the RRP setup? I'll get with you next week on it and give you some time to get everything together. I still need to break the motor and clutch in and I can do that with the current setup on pump gas.


Thanks for the response!