Dennis5374

for guys who went too small with their first fuel pump, why couldn't you use two different sized fuel pumps but have one kick on with a Hobbs switch? For example, Iln my 98 z28 i have a racetronix Hotwire setup with a 255lph pump. I just recently purchased an aeromotive 340lph stealth. Why couldn't they be ran together and successfully add more fuel together? I'm no expert on these cars "obviously " but the only issue I could see is one pump being overworked more so than the other . The same switch that engages my boost a pump, could be used to engage the 340lph pump once pressure drops so many psi , and allow me to make more power. Idk just food for thought as I'm sure a lot of people like me have wasted money on pumps like the 255lph and just assume when we upgrade it's useless unless running a dual 255lph setup .

pdxmotorhead

Just my very humble opinion,,, but I've spent a lot of time a the track, I have a lot of friends that road race and I'm pretty good at keeping a car on track. Three things have cause more DNF's for me than any other.

1. Dual Fuel Pumps.
2. Crappy/Cheezy/sloppy electrical wiring.
3. Waiting till the last minute to prep the car (IE at the track on race day)

I really prefer a bigger single pump, bigger lines and a full return regulator. Electric high pressure pumps heat the fuel a lot. And the less time it spends in the lines in the engine bay the better. One problem is that with hydraulics the pump with the most power can dead head the other pump until demand get high enough that the head pressure equalizes on the output side of the pumps.

Your Mileage may vary...

Dennis5374

Most of the high powered cars in my area runna dual setup and a lot of them run dual baps "mostly cobras , Shelby and roush. It was just an idea so that people who didn't do t right first can still benefit from their old pump. I may attempt it and run it off of the bap switch , to engage the bap and a second pump .

gametech

iTrader: (1)

Damn, I wish more people understood the simple truth in your post. Dual pumps are actually MORE than twice as likely to fail than a single pump, bad wiring is the devil, and if you're lucky, last minute prep only ruins your day. It could easily blow a motor or kill you.

pdxmotorhead

I once had a guy show up at an 12 hour enduro, with a camaro with a regular NA small-block when he was backing it out of the trailer it was running like total crap,
When I asked him what was up he said, "Burnt Valve" , insert me looking like "WTF!" He says "we have a couple hours I figured we'd just change the valve"..

Now I could pull a head and replace the head in 2 hours with good help if there were $$$$ on the line but Do a valve? Possibly needing a grind and lord knows what in that motor when the head came off? Afraid I walked off into the sunset on that deal... They also forgot their rain tires and it was sprinkling at the track..

sweet99ss

iTrader: (41)

Why are dual pumps more then twice as likely to fail??? My single Walbro 255 had been going strong since 07 and worked great when pulled. Why would the dual 255's be MORE then twice as likely to fail?

truckdoug

iTrader: (25)

its not anything mechanical...just simple killing-floor statistics.

say your pump has a 1% chance to fail. add another pump. now each pump has a 1% chance to fail. add those together and it's 2%


i think the point he's making has to do with the installs rather than the pumps themselves.

truckdoug

iTrader: (25)

for my money ($100) drop a walbro 450 in the tank and call it a day.

sweet99ss

iTrader: (41)

Right I wanted to do that but the stock regulator wont handle the pressure. So then you have to do aftermarket regulator, lines, and fuel rails.. Which gets pricey.

ScottyBG

You can do an aftermarket regulator and still use the stock feed line, and rails. You could just run either a return, or run a -8 feed and use your stock feed line as a return. You can do it for a couple hundred bucks.

sweet99ss

iTrader: (41)

Probably what I should have done, but to late now lol. I took the car out and I haven't wired the second pump yet, but my a/f is perfect with the one new walbro 255 and I'm around 570rwhp or so. I'm thinking the second pump on stock lines should get me 750rwhp. My limiter now is the 60lb injectors. From research they run out somewhere in the 700-750 range.

I'm hooking the second pump to come on when the boost pressure switch sees 4lbs of boost. The only thing I don't like about that is like mentioned above there is a lot more room for error. Wiring, boost pressure switch failure, leak to boost pressure switch, ect ect. I watch the A/F gauge pretty closely, but I still would like to set a fail safe up somehow so if the a/f gauge goes lean it will warn me..

gametech

iTrader: (1)

Simple component failure addition. You need components for a twin setup that you don't need for a single, in addition to the single components. Every added component has a certain percentage chance of failure. Sometimes the chances are worth it, sometimes not.

sweet99ss

iTrader: (41)

I watch my a/f like I hawk so hopefully all will be good

truckdoug

iTrader: (25)

i ran a 450 on the stock regulator, no problems