those tests are both of external pumps, the difference between the in-tank units shows the same general trend.

the 040's and 044's share extremely similar flow numbers.....

if your over 20psi map then your at/over your 80psi "limit" per say, a high quality injector will survive all day long at that pressure....its truly not even that "much" we run cars much higher then that with little to no issue....and even when an issue arises its mostly due to low fuel levels causing aeration.

when your looking at two pumps (the bosh and walbero) that are just about the same dam price, why not get the pump thats clearly superior?

i know sean, and he knows i'm not bashing him on this, i'm simply stating that if your going to spend money on a pump, why not get the best of the bunch?(per that price bracket)

 

re-read my post above i think i edited while you were posting. i would rather run bigger injectors then over 80psi anyday.most injectors arent rated for that kind of pressure and even if they are you gotta admit higher fuel pressure is more wear and tear on the whole system.

I am offically calling BS on the graph now. If you go to jayracing.com and go under the 044 pump you can click on comparison to see the graph, but if you read the writing it also says the pump only flows 200lph at 72.5 psi and that graph doesnt show it dipping below 250lph. I know you know my brother and I realize this is all a discussion and your not bashing.

 

i've got flow tests from kinsler i'm trying to dig up.....

as for the twin 255's....not a bad idea but i cant see it fitting

edit-

found it!
sorry for the bad MS paint skills, its the quickest i could get something together with our sending the whole PDF.

 

60's and the walbro gss342 with a return style fuel system should do the job for me IMO

 

the 70+ psi range is all that matters.

and your "bigger injector" idea is cute, but no matter the size of the injector, if the fuel pressure isnt there to push it into the cylinder against the boosted air charge, it does you no good. agreed?

with our car at 58-61psi base, +20psi MAP (less then 20psi boost at our elevation) that 80psi mark is quickly crossed.

According to Scott at Kinsler this is what he says....

"please tell them that the walbro pump numbers represent an average of at least a half dozen tested pumps, when I first started on this document I noticed HUGE (multiple GPH) difference between the same PN 255 pumps directly from walbro, I had to contact them and get there OK on producing the document using averages. one pump would flow 130lph at 100psi and the next would flow 90lph. to big of a difference for us to recommend them to people who need flow at a pressure more then just flow, the Bosh units were all fairly close across the 8 we tested, +/- .8lph"

i'm not trying to sell/push an 044 on you, simply showing that the 255 leaves much to be deisired. i see your using areomotive parts thus far, so you obviously haven't cheeped out on things, why do so with a pump?

 

i agree you need some fuel pressure but anything over 80 is over kill. if all we needed was pressure everyone would still be on stock injectors and they'd be running 200psi. lol

some pics of dual walbro gss340's in a stock fuel bucket.(the bottom of the bucket would need to be cut and the pickup socks would need to go out the bottom which would lower the pumps about 1.5 inchs from the pics. it wont bolt right up but it can work.

 

that, in theory would work.

the higher the pressure, the more flow the injector has, but resolution suffers.

we are an example of that as-is. our beloved "60's" are much more then that, they are rated at 65lb/hr an 42psi (industry standard) with our min of 58psi we are 28% over that 65lb an hour mark.

i have all the conversion factors if you want to see them.

 

Does anyone actually know how much the stock fuel pump can put out?

 

Its just a single hole man. Trust me, my stock rail has been inspected in and out. All you need to do to make a return line, is take the two bolts out of the end of the rail, and tap the hole in the end.

 

your both correct in a way. there is a tube but its only about a 1/2 inch long and it only covers the number one injector hole. the fuel rail is also tapered on the inside. its about a inch in diameter at number one and about 1/2 inch at number 4

 

thats why i thought it was tapped to allow all cylinders to get the same amount...

 

i have the conversion factors to. were only going to run a base of 50 and prob a max of 75. the reason i dont like to run such a high pressure, is that its rough on injectors and the pumps start to loose flow. i like to use a good combination of both flow and pressure.

 

We did a flow analysis on the rail with that pipe that covers number one. At 58 psi, flowing 188 lph, with all 4 injectors (60/lbs hr) wide open at the same time there was even flow through all 4 cylinders, because its pressurized. If it was lower pressure, it might be different, but at 58 psi it was even flow, and there was still flow going out the return end.

We've also decided on a max pressure of 78 psi. I'm using dual walbero 255's (or comparable pumps) with a pressure regulator, and 83 lbs/hr injectors. Should be more than enough for whatever I throw at it.

 

so u did the same as above? the end of the rail?

 

I have a custom rail. My stock rail is collecting dust somewhere

 

id like to see pics if you dont mind. i bought some fuel rail stock but i would've had to weld it up and i just decided to say screw it and use the stock rail

 

whats wrong with using the stock rail tapped?

 

Just in case anyone hasn't noticed, we are now taking orders for the first batch of HTV1320-LSJ's.

New thread here

https://www.cobaltss.net/forums/showthread.php?t=105295

 

I'll see if I can get some pics after work.

Probably nothing.... but hey everything else on my car is custom so I said "**** it!"

 

lol