Dual Fuel Pumps...yes? no?

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aj_johnson
no, one line to the rail, like so

So pressure back on the second pump wont adversly affect it at all?

And thanks, Jens I like the idea. Sounds like i'm going for reliability.

Shouldn't, however if it really bothers you put in a valve.

John here is the one I was talking about



Stock audi 80 fuel pump, found under the car and for 8 dollars at the local pick and pull.

original bosch part number 580-254-921 replacement p/n 580-254-910


Rated at 200 l/h at something like 72psi or so.

and yes it is a 14mm inlet (other side of above piccie)



Edited 2 time(s). Last edit at 10/25/2012 07:29PM by aj_johnson.

Quote
aj_johnson
Shouldn't, however if it really bothers you put in a valve.

John here is the one I was talking about



Stock audi 80 fuel pump, found under the car and for 8 dollars at the local pick and pull.

original bosch part number 580-254-921 replacement p/n 580-254-910


Rated at 200 l/h at something like 72psi or so.

and yes it is a 14mm inlet (other side of above piccie)

Yeah, that' the Juan.... cheap at Rally Car Spare Parts Storage Depots and I lurv the nice big fat 14mm hose inlet..... plunge one end of a hose into a bucket of methylated spirits, jumper it and listen, if it sounds good, then glo wif da schmo, kokomo.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
aj_johnson
Stock audi 80 fuel pump, found under the car and for 8 dollars at the local pick and pull.

If you can find 'em that easy, could you grab a couple for me and tack on whatever you want for the effort and shipping?

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

whats with the inverted banjoy thingy going on in the front of it?

---

First Rally: 2010 First RallyX: 2004 (a bunch)
Driver (0), Co-Driver (7)
Organizer (3), Volunteer (3)
Cars Built (2.5), Engines Blown (2) Cages Built (0) # of rotations (3.5)
Last Updated, Apr 9, 2023

Quote
Pete

Quote
aj_johnson
Stock audi 80 fuel pump, found under the car and for 8 dollars at the local pick and pull.

If you can find 'em that easy, could you grab a couple for me and tack on whatever you want for the effort and shipping?

Sure, headed to the junker on saturday. Shoot me a txt at 208 87one 688five and remind me on sat. There were a couple hanging around last I was there.

Quote
Gravity Fed
whats with the inverted banjoy thingy going on in the front of it?

Backflow or relief valve so AJ is going to make sure he gets the cap nut from the Audi..or in a pinch from other Bosch pumps.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Started on my two pump setup last night. Couple of T fittings and a bit more AN stuffs and it might work...

Quote
john vanlandingham
See? That's why we get along, you think..

By the way, don't know if you know it but I believe the reason they make a million injectors with different flow is cause they're happiest at a given range. Maybe yours are happy. But I have been warned against insane oversize because of droplet size when mondo injectors are run on the low end of their range...
Way back in last century Ford used a Bosch "Grey" injector for 420-480 range...so naturally every cossie good in UK wants to brag they're running "Greys" at the pub.... Ford themselves decided for better running to run 2 "803 Greens" better-er , cleaner at less than full throttle and all the fuel they want...
And you'd shit if i posted what Ford used for the various HP steps: about half what every Subie (keyboard) expert advises everybody.

Injectors are a subject near and dear to my heart, one which I can further clutter this thread with if anyone wants, or start a new thread, or forget we ever mentioned those pesky fuel squirters at all.

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

+1 on a new thread on fuel squirters.

Fuel injectors...
My favorite is the way most people decide on a size. It's almost always based on a broad generalization but more often seems to be based upon a case study of what someone else did.
I wouldn't think the mathematics involved to determine injector size would be all that complicated. I would think they have varying efficiencies depending upon spray pattern, pressure, and volume that would mean there IS an optimal size for every application and that like turbochargers, it's not always a bigger = better story.

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Grant Hughes

Quote
NoCoast
Fuel injectors...
My favorite is the way most people decide on a size. It's almost always based on a broad generalization but more often seems to be based upon a case study of what someone else did.
I wouldn't think the mathematics involved to determine injector size would be all that complicated. I would think they have varying efficiencies depending upon spray pattern, pressure, and volume that would mean there IS an optimal size for every application and that like turbochargers, it's not always a bigger = better story.

Sizing is easy, and having headroom is ideal (for more reasons than just the obvious). The real questions, and John alluded to these in his response to me, is what makes an injector TOO big? Why not just go with the internet and put the biggest fire hose nozzles in there you found for cheap on Ebay? I went way big on my Corolla, and I am ok with that. Why is this? A lot of knowledge growth has occurred in the last few years, to put real data to many issues that we stumbled through in the past. We knew of issues, but maybe we didn't know exactly what they were we just knew the bigger ones seemed to have worse issues. I will try and type up some stuff later today to try and make my point. Real work first..... LOL

Fuel pumps, size doesn't matter as long as your regulator can maintain proper pressure ratio at all operating conditions, and the pump can meet the flow demands of your setup at operating pressure. Just get what fits your car, your budget, or that you think looks cool.

The reason all of this is important, is so guys like me can then give you a tune that makes you smile all the time. If nobody really knows what is going on with the most critical support systems for your engine (sensors, air supply, fuel supply) then tuning it is like darts in the dark. You might hit the right stuff once in a while, the rest of the time you will probably just get pissed off or put someones eye out.

It was a little weird for me when I ran the Corolla at Oregon Trail with all the stock stuff in there. I am not used to not knowing. I didn't care, just put my foot down and hoped that there was still enough of what Toyota engineered in there working within an appropriate window that it wouldn't try and melt itself down. It worked out, but if it hadn't I wouldn't have a clue why unless there was a smoking gun. This is fine when you are talking about a probably $200 engine (which is why I really didn't care). But what if it is a $2000 engine or worse, and you DNF day one of a $800 entry fee plus whatever else you spent to be there? The devil is in the details then.........

---

John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

Quote
NoCoast
Fuel injectors...
My favorite is the way most people decide on a size. It's almost always based on a broad generalization but more often seems to be based upon a case study of what someone else did.

RX-7 guys are horrible for this. Stock injectors on a given car are staged 460cc. The ECU runs the engine pig rich, like 10:1 air/fuel. So what do guys do? They put a header on their car (with the airflow meter compensates for) and then they put 550cc injectors in the secondary side, and then either wonder why it runs even worse, or they never go over 3000rpm so they don't even know that they did something stupid.

Meanwhile the guys who have to run stock everything in certain road racing classes are busy trying to figure out how to pull fuel OUT, like modding the regulators to go down to 25-30psi instead of 42, because believe it or not engines run best when they aren't drowning in excessive fuel.

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

then you have turbo rotary guys with there 1600cc injectors everywhere!!

---

First Rally: 2010 First RallyX: 2004 (a bunch)
Driver (0), Co-Driver (7)
Organizer (3), Volunteer (3)
Cars Built (2.5), Engines Blown (2) Cages Built (0) # of rotations (3.5)
Last Updated, Apr 9, 2023

more

more

more!!!!!

Bigger is always better!!!!!
For the love of god BIGGER IS always.....

THINK of the CHILDREN!

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.