What do you guys run for a pump? I have the entire rearend out of my car so it is a good time to think of up grading.

 

walbro 340m high pressure.....good for about 500rwhp or so

add a boost a pump and it will give you 30% more fuel.....so about 650rwhp with a boost a pump

or you could do dual intank walbros and never run out of fuel

 

I just ordered the walbro 340 with the hot wire harness for 170. I hade ordered a 255 lph pump, but it just isn't gonna be enough with the supercharger. Where do I get a boost pump from? Does it install inline of the fuel feed line? Is it on all the time, or can you just toggle it on when you hit the go-go juice or get the boost way up?

 

Here's the place I bought the Walbro
Walbro F body

 

The 340 would be better for me than a 304? I am only ruuning 6-7lbs of boost. I have the inline pump from the kit and 8to1 FMU . Should i keep all that stuf too?

 

so......you were going to buy a 255 walbro pump and then decided not to because it wont keep up with the blower? then you go and buy the same pump from jack for the blower?

you are confusing me

ONE walbro 340m (which is a 255 pump) will support around 500rwhp and 2 probably close to 900-1000

i know of a buick regal going 8.30s with a single -6 feed and dual intanks

 

Well if the the 340 does what it advertises with the hotwire set up, it flows more fuel than a standard 255lpm pump running on the factory harness. I was considering adding an auxilary pump inline just in case I see the air/fuel meter go to the lean side.

I am sorry to confuse you. I guess what I am asking is this. Too run two pumps are you looking at two feed lines with two pumps on each line, or a pump in the tank and another pump "in line" pulling more fuel to fuel rail. I am picturing the second choice. One pump pushing the fuel from tank and an optional pump to pull the fuel out on demand. I am sure it has been done this way, if not please correct me.

Bad things happen when that A/F gauge is reading lean. I just want to make sure she is not thirsty.

 

oh ok...i get it now. You are talking about Jacks hotwire harness. It is a very nice harness and what it does is "boost" the voltage to the fuel pump making it flow more. The walbros from what jack and everyone else has told me are VERY voltage sensitive.....meaning the like voltage to flow good. But you are correct, your pump with his "hotwire" harness (which is just a good relay and heavier wiring bypassing the stock wiring) will flow more fuel that if you just threw the same pump in the tank and did nothing with the wiring

Well, you are getting the idea. I'll tell you a few ways you could run with 2 pumps.

1) you could run both of the pumps IN the tank. What you do is modify your hanger bracket to fit both pumps. Then you "y" them together to use the stock feed line. You use 2 separate fuel pump relays and use an adjustable hobbs (pressure) switch to turn on the second pump when needed. Jack can and will do this setup for you.....he was going to charge me about $500 for it. I finally figured out how i am going to modify my own bracket and do this system myself. i already have started on it and have the fuel pumps ordered. I have a few pictures already.......

2)you could run one of the pumps in the tank and the other pump "in line". But the 340m isn't designed to be used "in line" it is designed to be used in the tank so if you use it "in line" you will most likely burn it up. So you would use the walbro 392 ( i believe thats the number) for the inline pump. The problem is you couldn't run "just" the intank because you would burn out both pumps quickly because you cant have the pump in the take trying to push through another pump........So that means you would run them both all the time

3)You do the same setup as above but you use a checkvalve that bypasses the in line pump and modify it somehow so that the intank flows around the inline until you need it. I'm not sure how to explain this but i've seen it done.

---lastly, the reason why i said (in the first choice) you cant run both of the fuel pumps at the same time all the time is because the return line cant handle all the flow all the time. It is a restriction and you will have fuel pressure problems. That is why you use the hobbs switch to turn it on when it is needed. Here are some pictures that i have right now....when i get my pumps tomorrow i'll trial fit them both and start to modify my hanger more to use both of them:

 

Kind of a related question, but what would be the Mechanical Pump of choice for a carbed application, with a referencedsignal to the pump?

Something on the lines of a big holley with a regulator, or without?

Kind of a general type question i know, I was thinking in terms of a 350 and a smallish rootes blower, like a 144.

If it's too general of a question just disregard it.

 

If your car is an older carbed car a really nice inline from magnaflow, BG, or one of the volumax billet housing holly pumps (not the blue one) would be nice.

 

So that's a no on recomendations of Standard type pumps.

I've shyed away from the Aftermarket fuel pumps because of woefull reliability problems i've seen first hand. The worst ones for reliabilty are the holley blues as far as i've seen/am concerned they are just not meant to be run for time periods longer than running round at a track

 

First thing I am going to do is run the 340 and the hotwire and see if how she is. They say it is good up to 500hp and I should be somewhere close to that. The only concerns I have is when I turn the 100 shot of NOS on, which I don't plan on using often at all.

If I need more fuel then I think I will just run an auxilary pump to help suck what's already being pushed.

Is all that modification of fuel pumps going to fit in the wee-bitty hole in the top of the gas tank?

Thanks for your feedback and pics ProCharged. If I ever put a pump and sender on my carpet....my wife would whoop my ***!

Hank O.

 

actually that pump is good for about 500 REAR wheel horsepower....so that is close to 600 or so at the flywheel and jack has told me that a single 340m is good for about 700flywheel horsepower so i think you'll be ok with one pump

thats fine, just remember it will be on all the time unless you run somekind of checkvalve and byass around it

it should, all i did was bend the one bracket flat and going to modify a side bracket for it....shouldn't be a problem

LOL, well my sender is clean and totally dry and the pump has been sitting on the shelf for 2 years....so all the gas has evaporated

 

340M is a stout pump.It has been documented taking cars in the 10s on the 340M and stock lines.Im now a dealer for Walbro and Here is my site: www.darrensperformance.com

I can also set up a gp for it if I can get enough people interested.Thanks



Joe,nice to see you again, Email me or call me,Ill set you up.