Aftermarket Fuel Pump = Less Fuel Capacity?

[scotty nm35]

So why post the thread? You were warned...

[sonicz]

So why post the thread? You were warned...

I dont understand what you mean? Warned of what?

[battery]

http://www.supraforums.com/forum/showthread.php?683983-Fuel-Pump-Comparison-Bosch-044-vs.-Walbro-416lph-vs.-Walbro-255lph-vs.-Supra-Denso

[sonicz]

http://www.supraforums.com/forum/showthread.php?683983-Fuel-Pump-Comparison-Bosch-044-vs.-Walbro-416lph-vs.-Walbro-255lph-vs.-Supra-Denso

Is that supra denso the same pump that came with some of the r33 skylines?

Mine is a Jecs.

So according to that the walbro 255 flows less than the stock pump?

Edited May 8, 2013 by sonicz

[battery]

Is that supra denso the same pump that came with some of the r33 skylines?

Mine is a Jecs.

So according to that the walbro 255 flows less than the stock pump?

Not the same pump.

Forget about which flows more, the stock pump is 20 years old, pick the pump which will supply enough fuel for your application. If your running stock injectors then a 255lph @ battery voltage will.

[discoPumpkin]

op dunno what youre concerned about, i only ever fill up to half a tank cuz it saves weight = more power

[Ben C34]

op dunno what youre concerned about, i only ever fill up to half a tank cuz it saves weight = more power

what???

It still fits in the same amount of fuel its just that the intake was higher so couldn't use it. That would mean your awesome method of going fast (light weight) would mean you can only access 1/4 of a tank.

And sorry to burst your bubble, but a 50kg weight saving is worth 0.1 seconds at the drags. You might as well fill your tank up man.

[discoPumpkin]

And sorry to burst your bubble, but a 50kg weight saving is worth 0.1 seconds at the drags. You might as well fill your tank up man.

Do u know

Thats over 400 metres only, on a race track that would be a second slower a lap, and a second is a HUGE difference, a second a lap slower then anyone else would have u almost being lapped at the sned of the race.

But youre right doesnt make much of a difference, hell might aswell throw in barbell plates and dumbells for even more weight gain...wait wot

[sonicz]

op dunno what youre concerned about, i only ever fill up to half a tank cuz it saves weight = more power

Lol. The only way that would make any sense is if gravity worked upside down just in the petrol tank.

Moving on, I have a quick question hopefully can be answered here without starting a new thread.

Is it at all possible to run a dual walbro setup with the stock wiring and piping?

BY this I mean just splice in power to the second walbo 255 from the wiring going to the 1st then fit both pumps into a "Y" piece in tank.

Its ok if the voltage drops off a bit because there will be 2 pumps pumping.

Edited May 9, 2013 by sonicz

[discoPumpkin]

Lol. The only way that would make any sense is if gravity worked upside down just in the petrol tank.

If u fill youre car only half full VS full tank, which do u think is gona make the go go faster? C if u can work that equation out lol

ps i don't know how u brought gravity into this.

If he really wants extra fuel capacity, might as well make it duel fuel tanks like my dads Hilux, again pointless tho i mean its hardly a 500hp fuelaholic rotary were talkin about here. So many mods for so little gain.. but its you're ride

[Ben C34]

Lol. The only way that would make any sense is if gravity worked upside down just in the petrol tank.

Moving on, I have a quick question hopefully can be answered here without starting a new thread.

Is it at all possible to run a dual walbro setup with the stock wiring and piping?

BY this I mean just splice in power to the second walbo 255 from the wiring going to the 1st then fit both pumps into a "Y" piece in tank.

Its ok if the voltage drops off a bit because there will be 2 pumps pumping.

No, you will melt your wiring.

http://www.skylinesaustralia.com/forums/topic/423664-melted-connector-plug-due-to-larger-in-tank-pump-pics/?fromsearch=1

[sonicz]

No, you will melt your wiring.

http://www.skylinesaustralia.com/forums/topic/423664-melted-connector-plug-due-to-larger-in-tank-pump-pics/?fromsearch=1

Hmm well thats a walbro 460 not 2x 255s. The walbro 255s take about 7-9 amps, and these guys are saying the 460 takes 25A? Its possible the stock wiring could handle 2x 7-9amps ?

Furthermore this guy did the direct battery feed mod, which would raise the volage above the stock 12v, further drawing more amps than my setup would.

[scotty nm35]

You need to learn some electronics basics, raising the voltage will lower the current draw, which is why the Walbro's fail at the low cruise voltage. That stalling your car is doing while idling and cruising is the pump stalling out, bad news for the pump.

[Ben C34]

You need to learn some electronics basics, raising the voltage will lower the current draw, which is why the Walbro's fail at the low cruise voltage. That stalling your car is doing while idling and cruising is the pump stalling out, bad news for the pump.

+1

watts=volts x amps

watts are constant. higher volts = less amp draw.

[sonicz]

According to this the the amp draw is higher as the voltage increases

http://www.roadraceengineering.com/fuelpumpflowrates.htm

[mad082]

I understand the walbro is not designed to run at 9v, but its still just a DC motor in there just like the stock pump which runs at 9v like a champ.

Are people actually saying when both pumps are at 9v, the walbro flows hugely less than the stock, so little in fact my car almost stalls, but when both pumps are at 12v suddenly the 255 overtakes the stock pump and flows more?

of course a pump designed to run at 12v may not run that well. hell, a big turbo that is designed to run on large capacity engine isn't going to spool up like a champ when bolted into corolla. it's all about effeciency. sure the stock pump may run fine at 9v, but that is probably because of it's design. 9v might be enough to have it work efficiently. but something designed to work at only 12v may have more resistance in the internals to allow it to flow more, but that means that at 9v it isn't able to overcome this, so it doesn't work very well.

[GTRsean]

I wouldn't be using rubber items such as radiator hose in the tank. The rubber breaks down. You can only use butyl rubber fuel hose inside the tank (inner and outer layers are butyl rubber, $100 a metre roughly) as it is designed to be immeresed in fuel.

Even efi fuel hose, not to be used in the tank, just outside.

It will break down and harden and clog shit.. My 2cents...

[sonicz]

I wouldn't be using rubber items such as radiator hose in the tank. The rubber breaks down. You can only use butyl rubber fuel hose inside the tank (inner and outer layers are butyl rubber, $100 a metre roughly) as it is designed to be immeresed in fuel.

Even efi fuel hose, not to be used in the tank, just outside.

It will break down and harden and clog shit.. My 2cents...

Yes i agree, this is an important issue.

I too, had the same concern before i went out and bought a radiator hose for my second fitting attempt.

I went ahead and fitted it because I figured, if the fuel is strong enough to dissolve the hose at the source, It will be strong enough to keep any of the dissolved debris from building up or clogging anything. Worst case scenario I will be burning small amounts of dissolved rubber in the combustion chamber mixed in with the fuel.

I would appreciate your thoughts on this reasoning.

I plan to check the state of the rubbers after a few weeks.

Edited May 10, 2013 by sonicz

[Ben C34]

Yes i agree, this is an important issue.

I too, had the same concern before i went out and bought a radiator hose for my second fitting attempt.

I went ahead and fitted it because I figured, if the fuel is strong enough to dissolve the hose at the source, It will be strong enough to keep any of the dissolved debris from building up or clogging anything. Worst case scenario I will be burning small amounts of dissolved rubber in the combustion chamber mixed in with the fuel.

I would appreciate your thoughts on this reasoning.

I plan to check the state of the rubbers after a few weeks.

not sure on your thoughts there man, radiator hose has fibres reinforcing it,i doubt the petrol would dissolve them.

Also, that is some freaky stuff with the current draw getting higher with more voltage, really can't get my head around that....

Edited May 14, 2013 by superben

[suwidji]

Just the thread i was after!!

I mounted my walbro in the exact location as the stock one, but I was provided with a vertical strainer/filter, but it's still about an inch shorter than the stock.

I didn't realise i had to install it lower, and therefore my car would just crank and try and try and try to start up, but just wouldn't fire up when I got down to about 1/4 tank.

I was supplied with a black sock that i didn't know what i needed it for, but now I'm assuming it's to cover the pump. I'm not exactly sure what material it is though, and I don't want it to dissolve or whatnot in my fuel. I may have a go at just lowering it without the sock, and just maybe try my luck at using just one hose clamp? :\

Can anyone tell me what size hose clamp is needed to tighten the pump onto the cradle thing? Also, will I need to cut off the metal round thing on the cradle where the stock pump used to sit on the rubber mount?