So I have a Walbro 255 and hotwire kit and 47lbs Bosch injectors (from the GT500--so 60 @ 4-bar). I know it won't support 600+ to the tire. It might be close. Injectors are probably fine, but I may look at going to a 52lbs ZR1 or even the 60lbs Siemens.

The stock lines are fine to 700 boosted... where do they tap out NA?

And the fuel pump... going to a dual 255 setup wouldn't work as there would be no trigger for the Hobbs switch. So I'm looking at either a Stealth 320lph or a Walbro 450 pump.

WS6Store has the C5 Regulator for use with the 320... so that might be the cheaper option. But if I go with the Walbro 450, I'd have to remove the in-tank regulator and run at least an -8 AN line (using stock feed as the return) and setup an adjustable regulator that isn't 1:1 boost referenced. I guess it would be vacuum referenced in this application.

What would you guys do?

 

will you be running pump gas or e85?

 

Are those the Bosh 0 280 158 117 ?

 

Pump gas...

And yeah, that's the injectors. I think they are probably okay. 60lbs @ 4-bar... but I worry about the 255LPH pump.

 

IMO, the simplest way is to run a dual pump setup with a Racetronic dual wire harness for each pump with it's own relay. The primary pump will handle up to about 500 rwhp. When you need the second pump is when you want to play. Just can't see running a 450 where you are recycling the fuel 5-6 timee per hour when 99 percent of the time in normal driving all you need is a single 255.

If you can't find a pressure switch that activates on negative manifold pressure, you could just turn the second pump on and off with a toggle switch.

The great thing about the Racetronix duel harness for each pump is that each harness end terminates in the engine bay. So if you want to switch pumps periodically it takes less then 2 minutes to switch the end plugs on each harness. The kit include a short harness that typically is connected to a Hobbs positive pressure switch. So it's just a simple matter of switching the harness from time to time if desired from the primary to the secondary or vise versa so each pump runs about the same amount of hours.

Want you want to go prowling, flip the toggle to on so both pumps run when you leave the garage. Both pumps will run. When the night is over, flip to toggle switch off and just run on the primary and take it back to the garage.

See pic. The first pic show where each harness terminates. One plug end completes the circuit for harness one - primary pump. The second harness connects to the Hobbs switch that controls the secondary pump coming on from 1-2 lbs of boost up to 5-7 lbs of boost. Switching the plugs ends can't get much easier. In your case the short harness connects to a negative pressure switch or to a toggle on-off switch.

 

That is a good idea.

And you're right. One 255 is all I need most of the time. And every few months switch so the pumps take turns being the primary...

And that's the Racetronix Dual Pump harness? It's such a clean install and the price is great.

 

Forgot to mention. The Hobbs switch harness is about 3 ft long, so obviously you will have to extend it so it reaches into the cabin to the toggle switch.

Both ends are plug in so easy to make an extension without having to cut off the plug that connects to the Hobbs switch. The ends are weather/metri-pack.

Have you contacted Lonnie to see if he has a negative pressure switch for those that make big power NA and still want to run dual pumps?