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The mkiv Supra Owners Club

Fueling; Single pump vs Twin pump


Noz

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Can't find a huge amount of information on this. Even outside the forum.

 

I've seen discussion on various issues, but never seen anywhere that collated information has been listed for benefits of setups against each other.

 

I've currently got a walbro 255, and looking to upgrade.

 

At this time I'm unsure where I'm heading, so for now just doing research on my current setup. Just thought it would be useful to have a thread relating directly to the benefits of each, IF there even is any.

 

Also, would an improved pressure regulator be recommended with the increase in flow to the rail.

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why pay for two when you can do it with one , statisticly two have twice the amount of failure but you may not pick it up until high boost and by then its too late

 

my 255 run my 524 bhp okay on the limit but still good, then i went for the walbro lp400 slightly bigger fits perfictly in the hanger and delivers alot more fule great pump

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The benefit of Single Pumps is simply that you are less likely to suffer unexpected detonation because if the pump dies the car doesn't run. With 2 pumps you can still run, and then unbeknown to you the second pump has failed and doesn't supply the extra fuel when demanded at high rpm/boost. You go lean & detonate...unless you have some very sophisticated fail safes.

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What about using the stock with the 255? Saves having to buy a new pump assuming the original works well but i suppose that's a bit budget.

 

but that would still be 2 pumps one new and one thats 20 years old , i cant even think of a worse combination

edit: 2x 20 year old pumps

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What about using the stock with the 255? Saves having to buy a new pump assuming the original works well but i suppose that's a bit budget.

 

what sort of power are you pushing and what are the flow requirements for the setup?

 

If its anything less than 600bhp then its a pointless thread.

 

imi

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Guest Budz86

I tend to think of fuel pumps like injectors; the lower duty you run them at, the better. 044's may be expensive, but they will be more than enough for 90% of builds. I'm only BPU++ but will be chucking in a 044 when I overhaul the rest of the fuel system (I've only done injectors so far).

 

Noz, with regards to your original question, I'm not sure what the benefits or more than one pump are, but I'm assuming it's something along the lines of 'lower duty, more longevity'. Also, if running something like a Syvecs that can detect a drop in fuel pressure, if one pump dies, the ECU can go into limp mode and prevent a total loss of fuel (instead of the engine just cutting out completely) which could be extremely dangerous depending on the situation you are in at the time!

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+1

 

I will replace my twin Walbro by twin 044.

 

In case of a twin setup, you normally run 1 of the 2 pumps and the second one kicks in if needed.

 

Please correct me if I'm wrong but that depends on how you do your twin setup (Parallel or series set-up)

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Guest Budz86
Please correct me if I'm wrong but that depends on how you do your twin setup (Parallel or series set-up)

 

Correct, but this seems the logical way to set them up when you need large amounts of fuel :)

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My target power value is all dependent itself on the components required.

 

I would rather set a budget value and modify depending on what I'm willing to spend than set a bhp target. Thus carrying out research and component investigation to give me an idea of whats possible and within easy reach.

 

Realistically, I want a few changes within my Ultimate Emanages capabilities. I'm not going for a target bhp until I've changed ECU's at least.

 

From what I've read, the Bosch 044 will be what I'm looking for at this time.

 

I was also interested in the pump selection on comparison of single vs twin. There doesn't seem a difference from peoples experience, just depends on what the user selects by the look of things.

 

Perhaps introducing a smaller pump would help an over heating pump working close to its limit would be a prevention measure, rather than a direct benefit (i.e. OEM pump). I think it's safer to run with a single pump for now.

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from what i can gather , the pumps will always run at full chat unless modified , ie the fuel ecu in the rear panel 9v idle and then 12 with any boost , this was done to stop the fuel heating in the tank , adding 2 or 3 pumps vs 1 larger pump , i gues the smaller pumps may not get as hot but may have some more surface area ,

best way to test maybe get some old stockers and the bosch 044 put them each in a bucket with water and a 12v feed for 20minutes and see how hot they get or the actual water gets

 

how hot each pump gets would depend on windings and friction

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My target power value is all dependent itself on the components required.

 

I would rather set a budget value and modify depending on what I'm willing to spend than set a bhp target. Thus carrying out research and component investigation to give me an idea of whats possible and within easy reach.

 

Realistically, I want a few changes within my Ultimate Emanages capabilities. I'm not going for a target bhp until I've changed ECU's at least.

 

From what I've read, the Bosch 044 will be what I'm looking for at this time.

 

I was also interested in the pump selection on comparison of single vs twin. There doesn't seem a difference from peoples experience, just depends on what the user selects by the look of things.

 

Perhaps introducing a smaller pump would help an over heating pump working close to its limit would be a prevention measure, rather than a direct benefit (i.e. OEM pump). I think it's safer to run with a single pump for now.

 

Go for a Bosch 044 pump mate. You can run these for 700-750 bhp without a problem. They are very good.

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