dual pumps (which combination)
 

Alright right now i have a walbro fuel pump and am looking at upgrading to dual pumps. I was going to go with the dual supra tt pumps.

From coopers website i would prob be fine with the walbro and supra tt pump combo, yet ive heard of walbro pumps burning up.

any thoughts on this at all?

injectors are 1680 and 850.

Also is it better to Y the pumps together inside the tank or outside?

I know some people have had some disasters with them being Y'ed in tank, but this is just hearsay from what i know.

Thanks for your help guys.

I think you can get away with cramming two NipponDenso Supra pumps into your tank on the factory FD sending unit. Might be worth trying.

When I built mine, I Y'd them together just outside of the tank. I added a bulkhead to the top of the sending unit and ran an additional -6AN line out, Y'd them together to a single -8AN hardline, and ran it all the way up to the filter.

One note -- I don't recommend running both pumps full time as you run the risk of overloading the FPR and the return line at low operations such as idle and very low throttle where IDC's are very low. You can stagger the secondary pump off of some sort of load by relaying it to a boost-sensing source to activate when manifold pressure hits a certain psi.

B

thanks brian. Do you happen to have a picture of this at all. i think i get the concept, but im visual guy myself thanks.

On my old setup i first ran dual stock fd pumps then dual walbro 255s. I teed them inside with a welded -6 outlet on the lid. Ditto with brian on running a switch for the 2nd pump. Thats alot of fuel at idle and cruise.


Heres an example of a stockers and a walbro. not the prettiest but you get the point.

I run 2 Walbro in tank y'd together in tank with stock feed and stock return lines.

You won’t overload the return but Brian’s right about overloading the fuel reg at low engine speeds. I over came this by running dual stock regs on my fc, we have done the same on a friends fd,

a second stock reg can fit on the primary rail upside down on fd. We were running premix and not using the oil injectors on the fd block, The second fuel reg gets close to this so it may not be possible if your not running pre mix.

Sorry I don’t have pics of the fd situation only memories.

heres my set up used a fuel block to y them togeter outside the tank





http://img410.imageshack.us/img410/7...s001rh5.th.jpg

I herd using the T you used in your setup will burn the pumps up because the fuel is fighting together. I don't know just saying what I herd I spent the extra money to buy a fuel block

A tee is pretty much worthless in a fuel system. it acts againest each other. that will only flow a little above the one pump. A Y will be a little better around 1.65 times the amount of one pump.

I just added an additional 3/8 tube brazed on the inside of pump cover and run two supply and stock return lines. The tube i used was brake line it brazes well and bends easy. I then used rubber gromets for the extra wiring and seald it with good silicone.

That's about how I did mine, as well. I couldn't figure out a "slick" way of joining the pumps together short of zip ties, unfortunately.

http://bdc.cyberosity.com/v/ProjectCars/BDC/FuelSystem/

B

Good stuff BDC...

i understand you could overload the fpr but are you talking stock or aftermarket FPR it seems that if you used one large pump it would still overload the fpr the same as the twin set up. the reason i ask is im still debating the twin walbro set up or running intank walbro 0psi to surge tank to like an a1000 aeromotive then to the aeromotive FPR. so again the question is is this overloading on stock, aftermarket, or both FPR?
later
z

Two walbros will be plenty sufficient for the most part. Delslow made 531whp on two walbros. He did burn one pump up though. DO NOT RUN THE WALBRO OUT OF FUEL. INSTANT CARNAGE. Delslow ran out of gas, and it ate a pump up. Reinstalled another walbro, cranked the boost, put down 531.

Jackson

yeah those walbros are proving to be quite the little bad asses. I know I say this alot but with one jrat is making 490rwhp.

I have a A-spec 500r turbo and iam running 2 nippons in tank without any problems. I would not Y them together before they feed the rails because you will loose about 25 to30% effi. Iam running 1600pri 1000sec and iam at about 65to 70% injector duty cycle at 18Psi. about 460whp

I just got done doing my dual pump setup. I drilled holes in the top, ran new 3/8 line off the pumps to just under the car. The holes were sealed with gromets, and silicone. The two lines were run out of tank, and used a NOS Y under the car, and then continued the larger fuel line to the front. I found, at least when using the NOS Y that there wasn't enough room for the pumps to sit above the float, so they would sit on the bottom of the baffle. I also added an inline fuel filter, because the stock fuel filter location sucks my balls.

This is what i am planning on doing in the next few weeks when i upgrade the fuel system on my baby

I am going to be running two walbro intank pumps, but the differnce is that I am NOT going to Y them together, I am going to run two new 6AN SS lines to feed each rail then into the FPR and return in the stock return line.

I do like the idea about using a boost activated switch on the second fuel pump

I will be running 850Pri and 1600sec

Any information reguarding the boost switch for the one pump would be appreciated... Also, would it be hard to run (in addition to the 6an feed from the pumps) a 6an return? I know running it isn't the problem but how am I going to get it back into the tank? modify the cover???