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Shiney bits
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498 Posts
Discussion Starter · #1 ·
I've Been reading a book called "Engine management and advanced tuning" and there's a section on fueling I've found very interesting in hindsight of Jamie.Ps issues with overheating fuel issues.
The part that rang bells was about having a returnless fuel system which would reduce fuel temps from engine bay heat etc.

Instead of the fuel pump running at 100% output all the time it is governed by the ECU depending on load/RPMs boost pressure etc. The pressure is monitored by a sensor directly in the rail so this would remove the need for a fuel pressure regulator in the engine bay also if I read article correctly.

What's you opinions on this??

Can a Bosch 044 be ran as a variable output pump??

I've seen speed control pumps on the market with variable output which I would imagine would if connected to the ECU (I'm running a Syvecs) could be controlled any way wished as it would just increase flow with a voltage increase generated by a speed signal.

So say with the issue Jamie had with his pumps overheating in traffic, the pump heat could be dramatically reduced if the pump was only running at say 10% output.

I am seriously considering giving this a go at the latter part of the year.

Opinions and views would be great.
Thanks
John
 

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SF.com Member #0000000023
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1,218 Posts
I'm very skeptical that this would help the fuel run cooler. In a variable pump scenario the fuel would sit in the rail much longer.......which is located a couple of inches off the cylinder head. That is also a lot of complexity to design, build and implement a pwm based fuel system vs a fuel cooler which is the simplest of devices. Another more common option is to have to second pump come on with boost or rpm.
 

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Engmaineer
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2,406 Posts
It would def be cooler, if you have a feedback loop system, you just keep varying the speed of the pump to maintain pressure on the rail. You need to do some tuning to hard program an idea or range of where the pump should be operating. You won't be heating up the fuel moving it around over and over.

But a simpler way would just get a Weldon, which has a high and low speed setting through the dial a flow. Low speed for out of boost, high speed for in boost, Then install fuel cooler (lookes like a mini radiator). You could install one on the feed and return if you wanted . . .
 

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Super Moderator
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An alternative would be to have the number of fuel pumps pumping ramping up based on throttle position?
This is precisely what most tuners will do on a setup using multiple 044's or other external pumps. On huge single external pumps, there are controllers available that will reduce the pumps' output.

Having worked on a few late-model Mustangs that utilize returnless fuel systems, they are a pain in the ass to tune, and it can only support so much power before you have to go to a return style fuel system.
 

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Registered
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...Instead of the fuel pump running at 100% output all the time it is governed by the ECU depending on load/RPMs boost pressure etc...
This is what the OEM fuel pump ECU does (in addition to the safety shutoff feature during a collision or turn-over). Of course some misguided people implement the "12V fuel pump mod" and negate the benefits of the fuel pump ECU. As is commonly done on many Supras, to avoid too high electrical currents you can use the fuel pump ECU to control multiple pumps by controlling relays vs direct pump control.
 

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Inline for the win
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Nick,

So I wonder if its worth while to get another fuel pump ECU to control the pump 2 in my system. IIRC, very few people have done this to maintain the 9v-12v operation.

DP
 

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Found E85 NOT in NJ!
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This is precisely what most tuners will do on a setup using multiple 044's or other external pumps. On huge single external pumps, there are controllers available that will reduce the pumps' output.

Having worked on a few late-model Mustangs that utilize returnless fuel systems, they are a pain in the ass to tune, and it can only support so much power before you have to go to a return style fuel system.
Good lord I was just thinking about tuning that and my head exploded.
 

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Nick,

So I wonder if its worth while to get another fuel pump ECU to control the pump 2 in my system. IIRC, very few people have done this to maintain the 9v-12v operation.

DP
Before I went with AEMv2 I always used the stock fuel pump ECU to stage my two Densos. Even now with AEM I'm sure my pumps are staged ...but I'm not sure if it's just thru AEM based on boost/throttle or still using the fuel pump ECU. I'd have to ask my tuner guy that question.
 

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This idea may seem elementary, but I had this thought of increasing feed and return lines sizes just slightly to combat temperature issues associated with the fuel pump, more specifically external/inline fuel pumps. Assuming that the entire fuel system has been upgraded (increased rail size, larger injectors, aftermarket FPR) would a larger line not only conduct heat transfer more efficiently while operating within the pump specifications, but also provide a small reservoir of fuel in the case of a lean condition??? I guess the only problem I see with this is that the entire fuel system must have no smaller ports than the line sizing you choose. 1/2 inch fuel line??? Am I crazy? I'm just working on the idea that any electric motor, regardless of application, likes to be run cold, at its desired rpm, and likes to stay running. The more fuel that passes by the pump the colder it will run, hopefully eliminating pump fatigue. Maybe eliminate the need for an external pump completley... Any thoughts or should I go back to sniffing glue....
 
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