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  1. #51
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Sooo.... a higher pressure high pressure fuel pump?
    Fuel pressure going into the HPFP makes zero difference (so long as there's no cavitation issues) because it's a positive displacement pump. Therefore each revolution will pump the same amount of fuel because positive displacement and physics (liquids are not compressible).

    What's needed for more flow through the pump is to spin the pump faster (like the shotgun does) or increase the displacement of the pump (which isn't likely from a money standpoint). The only solution that comes to mind for increasing displacement would be using a larger pump from another car, unfortunately I don't think such a pump exists.

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    Yes i agree with you that a better HPFP should be made too but our pump was designed to fuel an engine making approx 300HP and has calibrations set in the DME to make pump perform accordingly. The thing is, the DME has no way way of knowing it now needs to feed a motor making 900+HP, it only knows the parameters set for 300HP motor. When internal pressure is increased say by over spinning pump, the DME sees this pressure increase and dumps it.

  3. #53
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    I love that we're working on solutions for the HPFP, but out of curiosity what's the difference between being able to make power on DI vs PI? I thought the biggest difference was mpg?

  4. #54
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    Click here to enlarge Originally Posted by ayoustin Click here to enlarge
    Fuel pressure going into the HPFP makes zero difference (so long as there's no cavitation issues) because it's a positive displacement pump. Therefore each revolution will pump the same amount of fuel because positive displacement and physics (liquids are not compressible).

    What's needed for more flow through the pump is to spin the pump faster (like the shotgun does) or increase the displacement of the pump (which isn't likely from a money standpoint). The only solution that comes to mind for increasing displacement would be using a larger pump from another car, unfortunately I don't think such a pump exists.
    Right but essentially what you're asking for is more pressure from the pump. You can keep spinning the factory pump faster like the shotgun does but so what? That pump is already temperamental.

    It seems like to really upgrade the direct injection system as you state the injectors are not near maxed out is a better pump which would give you the fuel flow you're looking for.

  5. #55
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    Click here to enlarge Originally Posted by Fishayyy Click here to enlarge
    I love that we're working on solutions for the HPFP, but out of curiosity what's the difference between being able to make power on DI vs PI? I thought the biggest difference was mpg?
    What happened to all the DI is best for performance cars proponents once port injection options launched?

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    What happened to all the DI is best for performance cars proponents once port injection options launched?
    Oh man not this again haha

    All I'm asking is, if you're making your power goals I don't know why one is better than the other. That's all I'm asking. I remember a thread where I argued that same point a while back and nobody really had much to say other than DI is capable of getting better MPG and lower cylinder temps

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Right but essentially what you're asking for is more pressure from the pump. You can keep spinning the factory pump faster like the shotgun does but so what? That pump is already temperamental.

    It seems like to really upgrade the direct injection system as you state the injectors are not near maxed out is a better pump which would give you the fuel flow you're looking for.
    Pressure is not the sole determining factor of flow. The point is to make the HPFP less of a bottleneck, not increase pressure. Increasing pressure wouldn't be detrimental but it's pretty moot to waste your time on that. By increasing the flow through the pump, regardless of what pressure is on the other side (between HPFP and injectors), you will increase your overall fueling headroom. So long as pressure is sufficient, aka stock pressure can be held, that's what matters for pressure. What's needed is more flow.

    Another factor to consider is that since the pump is driven by the crank, as RPM rises, flow through the pump increasing exponentially. The biggest issues with fueling will be at lower RPMs and not higher RPMs.

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    I wouldn't be surprised if the HPFP is capable of much more once the DME allows it to exceed its normal operating parameters.

  9. #59
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    Click here to enlarge Originally Posted by Fishayyy Click here to enlarge
    Oh man not this again haha
    Just wanted to point out we are how many years in and the DI system is still a problem?

    There were people telling me oh watch all these cars with DI coming out that will solve everything. I forget which random moron it was that said the C7 LT1 would mean aftermarket fueling solutions for the N54 despite the fact the LT1 is a completely different motor with a different direct fuel injection system.

    Click here to enlarge Originally Posted by Fishayyy Click here to enlarge
    I remember a thread where I argued that same point a while back and nobody really had much to say other than DI is capable of getting better MPG and lower cylinder temps
    Because that's pretty much it. It also is capable of breaking pumps when you tax it or even in stock form. Ethanol showed us this and then some.

    Hopefully people do find a solution but with port injection here it's not the big deal it once was.

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    Click here to enlarge Originally Posted by ayoustin Click here to enlarge
    Pressure is not the sole determining factor of flow. The point is to make the HPFP less of a bottleneck, not increase pressure. Increasing pressure wouldn't be detrimental but it's pretty moot to waste your time on that. By increasing the flow through the pump, regardless of what pressure is on the other side (between HPFP and injectors), you will increase your overall fueling headroom. So long as pressure is sufficient, aka stock pressure can be held, that's what matters for pressure. What's needed is more flow.

    Another factor to consider is that since the pump is driven by the crank, as RPM rises, flow through the pump increasing exponentially. The biggest issues with fueling will be at lower RPMs and not higher RPMs.
    Definitely good points but like I was saying a new pump with a new design would be necessary to alleviate the issues, right?

    So how do you achieve your flow desire?

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    One key thing here, which I don't think has been brought up yet, will be the longevity of the injectors pumping all that ethanol. I've seen other research where vehicles have been fuelled on alcohol fuels by direct injection and the injectors wear out quicker. Replacing 6 of them isn't cheap.
    However direct injection of alcohols represents massive performance potentials.
    Best:11.79@119mph on stock turbos.
    11.74@129 on GCs.
    FBO+Meth Port injection, GC Turbos, custom bucketless stage2, JB4, Trebila flash.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Definitely good points but like I was saying a new pump with a new design would be necessary to alleviate the issues, right?

    So how do you achieve your flow desire?
    Essentially, yes. The N54 drew the short straw when it came to HPFP design. Ours is very weird and complex compared to most other systems out there. On other platforms it's almost always driven directly off the camshaft and it's simply a matter of replacing the guts of the pump with a larger one. It's a simple affair that anyone can do with basic tools and a bench vise.

    The N54 HPFP is a lot more complex and has more moving parts. I'm still trying to find some pictures of the guts of our HPFP because there is a slim chance that we could upgrade the guts of it to gain more flow. It wouldn't be to hard to get a company to machine out some parts that would do the job. Small improvements make a large difference too, going from an 8mm piston to a 9.8mm piston increases fuel flow by 40% through the HPFP in that other system I just mentioned.

  13. #63
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    Click here to enlarge Originally Posted by ayoustin Click here to enlarge
    Essentially, yes. The N54 drew the short straw when it came to HPFP design. Ours is very weird and complex compared to most other systems out there. On other platforms it's almost always driven directly off the camshaft and it's simply a matter of replacing the guts of the pump with a larger one. It's a simple affair that anyone can do with basic tools and a bench vise.
    I believe the technical and engineering term for this is BMW sucks dick.

    Guys on other platforms change their cam and get more power and more fuel flow with it. Changing the cam doesn't require a Bavarian engineering team either.

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I believe the technical and engineering term for this is BMW sucks dick.

    Guys on other platforms change their cam and get more power and more fuel flow with it. Changing the cam doesn't require a Bavarian engineering team either.
    What's comical is how backwards our fueling situation is compared to every other DI platform. Pretty much every other platform has a way to increase flow through the HPFP pretty easily, but the ultimate restriction is the injectors so people turn up the fuel pressure with little gains. Our situation is pretty much the polar opposite. Our injectors are plenty large, but we have next to no ways to increase flow through the HPFP.

    Does anyone know if the HPFP is driven off the timing chain or does it have it's own separate chain?
    Edit: Seems it's driven by the oil pump chain.

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    Click here to enlarge Originally Posted by Ericbh77 Click here to enlarge
    Thanks! Do you know of any real pictures though, it's hard to get a full understanding of the shapes and placement with a 2d picture. Pictures of what that document calls the fuel chamber (14), plungers (12) and the pendulum disc (10) would be very helpful. From the sound of it the pendulum disc is what provides the lift for the plungers. If that's true then something as simple as a higher lift pendulum disc would provide more flow through the HPFP.

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    The maximum pressure in the high-pressure area is limited to 245bar. If excessive pressure is encountered, the high-pressure circuit is relieved by apressure-limiting valve via the ports (8 and 5) leading to the low-pressure area.
    This is the part that stuck out to me. I would think you would have start with changing the pressure limiting valve.
    How much bar would one need ? Click here to enlarge

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    Sub'd for more info on how the pump is being controlled Click here to enlarge

  19. #69
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    Here are some pics of the internals, note these aren't my pics, just from the web.

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge
    H O O N

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    Aweome! Looks like the pendulum disc is connected to the sprocket so as the sprocket is spun the disc spins. As the disc spins it pushes the plungers one at a time in a circular order. It does look like there's room to increase the plunger size. That would definitely increase flow through the pump, and since there's 3 plungers that's even better.

    It's actually more simple than I thought it would be.

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    In for when they announce they found a high pressure accumulator that doesn't need any modifying of the fuel pump control. Click here to enlarge

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    Click here to enlarge Originally Posted by jyamona@motiv Click here to enlarge
    Sub'd for more info on how the pump is being controlled Click here to enlarge
    This is all i could find in the doc

    The fuel-supply control valve controls the fuel
    pressure in the rail. It is activated by the engine
    management system via a pulsewidth modulated
    (PWM) signal.
    Depending on the activation signal, a restrictor crosssection
    of varying size is opened and the fuel-mass
    flow required for the respective load point is set

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    Click here to enlarge Originally Posted by Optigrab Click here to enlarge
    This is all i could find in the doc
    There's more, read onClick here to enlarge That's why I suggested changing the set points in the DME that regulates at what pressure the pump bleeds excess off.

  24. #74
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    I believe Chris is asleep due to his late nights testing turbines. Sticky if you want this removed just go ahead. Since I designed the new set up, and made all the tables changes to the flash to accomplish this, I can speak on it with my one post a day.

    Basically I took the Double Barrel, and made some changes. These changes proved to be perfect in terms of the hardware side of the equation. Checked that off the list.

    Next I turned to the flash, not being a tuner, but having a decent knowledge of things, and having a suspicion of what people have been doing wrong on the fuel side forever. I went in, and made significant changes to some tables.

    At first it just plain didn't work, discouraging. Then it worked once perfectly, and not again. I went home defeated. I came in the next day fresh, and found that a wire had simply pulled out one of the pump plugs on the pull that worked. How ironic. I removed the plug, and crimped in a fresh factory plug. Next pull it has worked exactly as I hoped it would, and has every single run since then.

    On the fuel control side of things. DME has 100%, that is 100% control of the fuel, everything. This is why the trims, are so perfect, get the tables adjusted properly, and the DME does all the work, and keeps things right where they need to be. As I brought up power, I simply adjusted the tables I found for more fuel to be added. It worked like a charm. Full DME control of the DI system at 650+WHP, and no signs of the hitting any fueling limits.

    Next I tackled the pressure side of things, moving my targets around. I found we can control pressure targets to any level form stock, to riding the pressure relieve valves around 3600 psi. What I found lines up with what I already knew, and what someone up top has said. Pressure as a number means very little. Fueling will the same at 3600 psi, as it will be at 1800 psi. I found that flow is not effected until you get down around the 1500 psi mark, then you will see trims, and AFR's respond accordingly leaning the car out. I also found that running the high pressure targets around 3600 really, I mean really smooth things out. No more crazy LPFP spikes, etc, just very smooth signals from the LPFP sensor. When I target say 2000 psi at redline with factory targets in the low to midrange, the DME freaks for a second at the increased capabilities this system has, and it hunts up, and down, it always finds itself somewhere in the run, and grabs target, and holds it, but AFR, and LPFP are doing dances while it does. I believe there may be some traction to had as far as smoothness from the LPFP system. I will be doing some work on that tonight.

    All in all, there is no magic here, as some people are saying. It is nothing more than I improved upon the hardware I designed two years ago, and I figured out the tuning side of it. You cannot have this without doing both. Once I figured out the tuning, I was like $#@! maybe we don't need all these pumps. I unplugged one, and ran it. The results are common to what we normally see. HPFP cannot keep up as soon as fuel demand increases, and you max trims, and go lean. Plugged it back in, and away we go.

    I wanted to try to make this as thorough of a post as possible as I wont post again. Chris can tackle all the questions, but we have a LOT of testing to be done still. Proof of concept is complete, and it works, implementation, and public consumption is next.

    Also a side note, I filled the car up with E98 to do this testing, that is damn near 100% ethanol, and still have not found a ceiling, this means on E85 its much higher, on e70 even higher, on race gas, 30% higher. Its pretty cool stuff....Click here to enlarge

  25. #75
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    Uh uh, you know the deal.

    You may not post.

    Tony removed from the thread.

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