I'm pretty sure I've heard of people doing this but couldnt find much info on it. I've got a 255 in the tank but need more fuel. I wanted to do the fullblown twin pumps but I was curious if it would be possible to do an inline 255 added to the intank pump? If so it would be cheaper but obviously I would only do it if it will work.
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Looking for rc1000s-1200s and a fullblown twin pump setup, PM me if you have either.
SCT tuned by AGP!
Yes you can do it and it will work fine. I would have them both run at the same time.
I'm tuning with an sct so base pressure is 50 psi, rises from there. I planned to run both at the same time. Thanks for the input, I'ma check that link out.
This seems to be exactly what you are looking for.
Thats nice and probably works real well but if I wanted to spend that much money Id go with the fullblown twin intank pumps. What I'm after is keeping the intank 255 and doing the bottleneck mod while adding an inline 255 on the feedline from the tank to the rail. Will this be functional working that way?
yeah it will work, if you only need a little more fuel dropping the base down will buy you some room. So 10psi drop in pressure buys you about 60HP(crank HP) worth of fuel on a Walbro 255
yeah it will work, if you only need a little more fuel dropping the base down will buy you some room. So 10psi drop in pressure buys you about 60HP(crank HP) worth of fuel on a Walbro 255
How is dropping the base pressure going to richen the car up? That would lessen the amount of fuel unless I'm somehow thinking wrong, don't see how though. I run 50 psi base because thats what Kevin told me to for the flash. I need more than a little bit of fuel. I'm pretty much out of fuel at 20 psi and I plan to run 30+.
I know the link I sent was more than you want to spend, but that answers your question on whether or not it's possible. What exactly do you have in mind?
How is dropping the base pressure going to richen the car up? That would lessen the amount of fuel unless I'm somehow thinking wrong, don't see how though. I run 50 psi base because thats what Kevin told me to for the flash. I need more than a little bit of fuel. I'm pretty much out of fuel at 20 psi and I plan to run 30+.
If you have a walbro 255 and are running out of fuel at 70psi total fuel pressure, its not your pump! At 20psi I doubt your maxing the pump. Unless the voltage at the pump is weak or there are restrictions in the lines, like sharp 90 deg bends or small diameter fuel lines.
Just because it goes lean doesn't mean that you need more pump. But I'm not saying that at 80psi the pump will flow enough to support your setup on 30psi of boost.
Whats your duty cycle?(this will tell you if you need more injector) Is the fuel pressure dropping? (this would tell you if its a supply issue with the pump, voltage)
I think you need to do whatever bottleneck mods and rewire the pump also if you have not already. Then if its still lean and your FP is not dropping and your duty is not maxed then your calibration needs more work.
heres a chart of an external Walbro 255 pump,
what I was trying to tell you is that if your maxing your fuel pump but still have injector duty to work with then you can lower the base to flow more fuel. Of course you would need to retune for it.
Last edited by SpeedEuphoria : 05-20-2008 at 09:08 PM.
I'll be doing injectors as I said. Right now I'm on 750s. I've got a larger -8an line from the Boomba rail to the regulator, -6 an returnline, -8an feed from the firewall to the rail. The changes I planned to make at once ( for now), was to do the bottleneck mod and pump rewire, while also adding in an inline pump and run the -8an line from there to the firewall, or probably all the way to the rail. Basically what I'm getting at here is this. Regardless if I do the bottleneck mod and pump rewire, then add the 1000-1200cc injectors that I'll eventually be getting, I still dont see having enough fuel for 30-35 psi on a single 255, which is why I wanted to find out about adding in an inline pump, something that could be done while doing the bottleneck mod and rewire.
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