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Thread: Upgraded Valves/retainers/keepers/springs anyone?

              
  1. #26
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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
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    Stage 3 does come with upgraded springs, I believe. But they haven't received any yet.
    it doesn't list springs as an upgrade on the product page

    it could be planned by them though?
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
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    it doesn't list springs as an upgrade on the product page

    it could be planned by them though?
    I talked to them before about it. It is supposed to come with upgraded valves, but they haven't got them from the manufacturer yet. No telling when they will come in. I've heard different things. Apparently, upgraded springs for the N54 are a big challenge.

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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
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    I talked to them before about it. It is supposed to come with upgraded valves, but they haven't got them from the manufacturer yet. No telling when they will come in. I've heard different things. Apparently, upgraded springs for the N54 are a big challenge.
    hmmmm if it comes with more than they're stating... that may not be a bad price then...
    unless they plan on upping the price

    might sent them an email just in case

    wonder what's so hard about the springs, there's countless designs in other motors, all of which have solutions
    boop

  4. #29
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    Click here to enlarge Originally Posted by GeorgiaTech335Coupe Click here to enlarge
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    I talked to them before about it. It is supposed to come with upgraded valves, but they haven't got them from the manufacturer yet. No telling when they will come in. I've heard different things. Apparently, upgraded springs for the N54 are a big challenge.
    Ah, OK. I only spoke to them once and they mentioned they had them. Maybe they meant under development. What are you doing with yours? Forged pistons / head job?
    Burger Motorsports
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    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

  5. #30
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    The DI doesnt work at high rpm arguement is false. GDI has been winning in serious racing for nearly 10yrs.

    DI can inject a massive amount of fuel comared to a port injector. By design it is made to inject near TDC right before spark ignition and clearly does that just fine to a little over 7k right now in the n54 and over 8k in other production car engines.

    All one has to do is start the injection sooner or add multiple injection events and you're fine, in theory. You just lose some of the cooling and other less important benefits but fueling is still there.

    I think the block casting will have structural problems before we run out of injector.

  6. #31
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    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    The DI doesnt work at high rpm arguement is false.
    How is it false when the window gets smaller as rpm rises?

    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    All one has to do is start the injection sooner or add multiple injection events and you're fine, in theory.
    And how are you supposed to do that?

    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    GDI has been winning in serious racing for nearly 10yrs.
    In what series?

  7. #32
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    Super high fuel pressure = shorter injection duration required. I don't see how the RPM thing is an issue from a fueling perspective. Might be from a VE perspective, though.
    Burger Motorsports
    Home of the Worlds fastest N20s, N54s, N55s, N63s, S55s, and S63s!

    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

  8. #33
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
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    hmmmm if it comes with more than they're stating... that may not be a bad price then...
    unless they plan on upping the price

    might sent them an email just in case

    wonder what's so hard about the springs, there's countless designs in other motors, all of which have solutions
    It's just a question of resources etc. There's almost certainly an engine with similar springs. Some 4v heads have even used motorcycle parts.

    We really need a camshaft expert to plug in the valve weight, cam profile and desired rpm to see what the oem springs can do and if you can add rpm and/or profile intensity and still control the valve.

    Rpm is pretty hard on an engine though. I'd rather have 7200-7500rpm and boost the hell out of it than get 8200 and to worry about the bottom end concerns it will create.

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    We can do cams if you wish. Early adopters pay a lot of $$$ of course. We have cams/springs/retainers/valves etc for just about every BMW engine already in stock.... N54 def is in motion. Demand is very low at this point but I'm sure that will change in a year or 2.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    How is it false when the window gets smaller as rpm rises?

    Its false in the sense that its much harder or impossible for DI vs a decently sized port fuel injector. DI injectors have plenty of fuel overhead if you read the conti literature on them. About 500hp static flow per inector or enough fuel for about 3000hp in an N54- at stock fuel pressure. Yes you can't run them that hard but even at 1/3 dc, that's 1000hp. That's why I also said I'm more worried about block issues before running out of injector.

    And how are you supposed to do that?
    Code in the dme. Somewhere there is a table of injection start by CAD, rpm and prob several other factors. The dme at lower rpms and load uses multile injections already. Cake for proefi or equivalent when it arrives.

    In what series?
    24hr Le mans http://www.bosch-motorsport.de/conte.../html/4063.htm
    Ferrari has mentioned it wants to do gdi in it's F1 car if they go turbo. Lots of rumor re F1 and gdi, i havent kept up with all of it.
    Any oem gdi cars out there winning probably stand a good chance of still running gdi since there is factory and bosch etc support for it.

  11. #36
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    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    The DI doesnt work at high rpm arguement is false. GDI has been winning in serious racing for nearly 10yrs.

    DI can inject a massive amount of fuel comared to a port injector. By design it is made to inject near TDC right before spark ignition and clearly does that just fine to a little over 7k right now in the n54 and over 8k in other production car engines.

    All one has to do is start the injection sooner or add multiple injection events and you're fine, in theory. You just lose some of the cooling and other less important benefits but fueling is still there.

    I think the block casting will have structural problems before we run out of injector.
    N54 already operates in homogenous mode

    near TDC is stratified

    it's already 'started sooner' Click here to enlarge

    and it can inject x many times per cycle (it's in the tech data for the injectors)... 4 or something?
    boop

  12. #37
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    Click here to enlarge Originally Posted by Mike@VAC Click here to enlarge
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    We can do cams if you wish. Early adopters pay a lot of $$$ of course. We have cams/springs/retainers/valves etc for just about every BMW engine already in stock.... N54 def is in motion. Demand is very low at this point but I'm sure that will change in a year or 2.
    hehe, while i'd be entirely interested in some cams

    i don't QUITE have that budget if we're talking about THOUSANDS of dollars hahaha

    any idea on the time frame you're looking at for the valvetrain? aid year or two? or potential pricing?

    unfortunately i'm looking at sooner rather than later Click here to enlarge
    boop

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    Click here to enlarge Originally Posted by Terry@BMS Click here to enlarge
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    Super high fuel pressure = shorter injection duration required. I don't see how the RPM thing is an issue from a fueling perspective. Might be from a VE perspective, though.
    Because as the rpm increases the time to inject decreases since you can only inject at a certain point in the sequence. This window gets smaller and smaller as you raise the revs.

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    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    24hr Le mans http://www.bosch-motorsport.de/conte.../html/4063.htm
    Ferrari has mentioned it wants to do gdi in it's F1 car if they go turbo. Lots of rumor re F1 and gdi, i havent kept up with all of it.
    Any oem gdi cars out there winning probably stand a good chance of still running gdi since there is factory and bosch etc support for it.
    Ok this is a good example but if it's so dominating why was GDI ditched and no longer used by Audi in Le Mans?

    I really can't think of any racing series using direct injection especially with NA motors and high revs. The Audi motor was a twin turbo unit and Le Mans tends to emphasize efficiency more than raw power because the less pit stops the more distance you cover.

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    Click here to enlarge Originally Posted by V8Bait Click here to enlarge
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    Port fueled cars only inject into open valves under certain conditions with sequential injection setups. Batch fire port fuel cars rarely ever get an open valve. Even sequentially fueled cars puddle gas on the closed valve after a certain RPM due to the fuel demands. So port fueled cars have nearly 4 strokes of time to inject fuel, although you don't want to run the injectors over 80% duty cycle. FWIW- 100% duty cycle would be spraying 100% of the time, or for all 4 strokes. 80% is spraying for over 3 of the strokes. DI cannot do that, it can only spray for just over one stroke.
    @V8Bait

    Thanks, did not know this. I never made the connection between each 25% of injector duty cycle of a port injector = 1 stroke of a given piston.

    FWIW, 8k rpm means each one of the four strokes will take 3.75 ms. I would love to see some data on pressure vs. flow rate for the DI injectors. So I would expect this to be about the time available for a DI engine to inject fuel at 8k rpm. At 80% DC a port injector would have 12 ms at the same rpm.
    Eppur si muove.

  16. #41
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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
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    @V8Bait

    Thanks, did not know this. I never made the connection between each 25% of injector duty cycle of a port injector = 1 stroke of a given piston.

    FWIW, 8k rpm means each one of the four strokes will take 3.75 ms. I would love to see some data on pressure vs. flow rate for the DI injectors. So I would expect this to be about the time available for a DI engine to inject fuel at 8k rpm. At 80% DC a port injector would have 12 ms at the same rpm.
    3.75ms? 3.75ms/stroke would be 16000 RPM (1000/3.75*60), it's 7.5ms/stroke... and .. is it the bottom of the compression stroke or start of the intake stroke - i presume it CAN start injecting at the start of the intake stroke, so 15ms to inject fuel - not 3.75

    there's LOOSE data on the flow rates of the injectors at pressure given the manufacturer data - i know i managed to work out the best and worst possible case flow rates. it's... somewhere.
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
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    3.75ms? 3.75ms/stroke would be 16000 RPM (1000/3.75*60), it's 7.5ms/stroke... and .. is it the bottom of the compression stroke or start of the intake stroke - i presume it CAN start injecting at the start of the intake stroke, so 15ms to inject fuel - not 3.75
    You are right. I was off by a factor of 2, possibly due to lack of coffee. It's annoying me that I can't replicate the error I made though.

    I was also assuming it could not inject right at the start of the intake stroke due to lack of room in the cylinder, and I think the DI system can't inject during the entire compression stroke, only a portion, due to cylinder pressure. I was figuring a worst case of an injection event starting halfway through the intake stroke and ending halfway through the compression stroke.
    Eppur si muove.

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    Click here to enlarge Originally Posted by ajm8127 Click here to enlarge
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    You are right. I was off by a factor of 2, possibly due to lack of coffee. It's annoying me that I can't replicate the error I made though.

    I was also assuming it could not inject right at the start of the intake stroke due to lack of room in the cylinder, and I think the DI system can't inject during the entire compression stroke, only a portion, due to cylinder pressure. I was figuring a worst case of an injection event starting halfway through the intake stroke and ending halfway through the compression stroke.
    i'll re-read the last discussion on it in the morning after i turn my brain off for the night - i remember this was answered correctly..

    ED: a quick search says that homogeneous means it injects on the intake stroke, presumably intake stroke only? further googling later.

    ED:

    "a fuel injection control device that performs control such that the fuel injector performs a plurality of fuel injections to inject a necessary amount of fuel during an intake stroke, or from an intake stroke to a first half of a compression stroke so that homogeneous combustion is to be performe"

    so it can go UP TO the first half of the compression stroke, 1.5 strokes then?

    not sure if that'd be how the N54 does it though, could well be intake only.

    FINALED:

    In our earlier conversion, you mentioned that under high load the TI is about 2 ms ? Correct ?
    Yes maximum is 2 ms. Notice that the engine runs under homogenous mode and that means that the injection start in the intake phase. With this engine, it is no problem to keep injection into the compression phase, but not too long; it would be bad for emission. However, if the pressure of the HPFP is increased, this may not be needed.

    so yes the N54, going by that, does intake+half compression at most.
    Last edited by Flinchy; 05-17-2013 at 10:22 AM.
    boop

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    Ok, here's my take on why DI works and I wouldn't fear running out of injector for practical purposes on an N54 before I figure the block will split in half or the crank walks and grenades everything (about 1200HP? WAG):

    fig A Continental's Piezo Injector datasheet used in the N54 (takeaway: injector moves about 35 g/s of fuel and seems to scale practically linearly given the example of 14.5 mg/injection at .4ms PW)

    Click here to enlarge

    Fueling example using goal of 1150CHP/1000WHP at 6000rpm:

    6000rpm / 60sec = 100 Revs/sec

    12 grams/sec per injector fuel needed per injector to make about 1150CHP/1000WHP (http://www.rbracing-rsr.com/fuelinjectors.htm calc at bottom of page)

    12g/s / 100 revs/sec = .12g or 120 mg/s fuel required per injector

    injectors deliver about 35mg per 1ms

    120mg / 35mg = 3.4ms PW required which is about 122' of crank rotation @ 6000rpm


    Yes, you can fool around with BSFC numbers and argue that but remember, THIS IS ALL AT STOCK FUEL PRESSURE. The fuel delivery should increase with the square of with fuel pressure increases. So if you want to argue the BSFC is 10% too low for the above, going from a working pressure of say 1000psi to 1250psi would cover that.

    Port injectors are great in that they can spray over all 4 strokes vs the roughly 2 that DI can spray on but the most important thing to remember (this means you @Sticky) is...these DI injectors are about 10x higher flowing than an equivalent OEM port injector would be if used instead. They also open wicked fast. So you lose a little more than 1/2 the injection time but you're still waaaay ahead.

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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    Because as the rpm increases the time to inject decreases since you can only inject at a certain point in the sequence. This window gets smaller and smaller as you raise the revs.
    With 3000psi fuel pressure behind the injector you don't need much time to push a lot of fuel through. Once the high fuel pressure system is sorted I have a feeling RPM won't be an issue. But again it's a turbo motor. You can scale the turbo to whatever power band you want and the factory cams, etc, seem to give a nice broad 5500-7000rpm band as is.

    PS. @ajm8127 love your profile pic. Click here to enlarge
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
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    Ok this is a good example but if it's so dominating why was GDI ditched and no longer used by Audi in Le Mans?

    I really can't think of any racing series using direct injection especially with NA motors and high revs. The Audi motor was a twin turbo unit and Le Mans tends to emphasize efficiency more than raw power because the less pit stops the more distance you cover.
    What teams go with in racing 99% of the time has to do with what the current rulebook allows because everyone wants to win. We could speculate all day why Audi stopped as you say but honestly I don't follow it that closely and wouldn't know.

    I do agree that DI and it's efficiency gains are very important from a less pitstops is better perspective.

    I'm surprised you didn't mention F1 because DI is being discussed as the next big thing in a lot of the news articles and forum posts I was able to find on Google. Yes it's not used yet, but if teams like Ferrari are saying they would likely use it in F1, they probably have done their homework on it's limitations.

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    Click here to enlarge Originally Posted by BavarianBullet Click here to enlarge
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    Ok, here's my take on why DI works and I wouldn't fear running out of injector for practical purposes on an N54 before I figure the block will split in half or the crank walks and grenades everything (about 1200HP? WAG):

    fig A Continental's Piezo Injector datasheet used in the N54 (takeaway: injector moves about 35 g/s of fuel and seems to scale practically linearly given the example of 14.5 mg/injection at .4ms PW)

    Click here to enlarge

    Fueling example using goal of 1150CHP/1000WHP at 6000rpm:

    6000rpm / 60sec = 100 Revs/sec

    12 grams/sec per injector fuel needed per injector to make about 1150CHP/1000WHP (http://www.rbracing-rsr.com/fuelinjectors.htm calc at bottom of page)

    12g/s / 100 revs/sec = .12g or 120 mg/s fuel required per injector

    injectors deliver about 35mg per 1ms

    120mg / 35mg = 3.4ms PW required which is about 122' of crank rotation @ 6000rpm


    Yes, you can fool around with BSFC numbers and argue that but remember, THIS IS ALL AT STOCK FUEL PRESSURE. The fuel delivery should increase with the square of with fuel pressure increases. So if you want to argue the BSFC is 10% too low for the above, going from a working pressure of say 1000psi to 1250psi would cover that.

    Port injectors are great in that they can spray over all 4 strokes vs the roughly 2 that DI can spray on but the most important thing to remember (this means you @Sticky) is...these DI injectors are about 10x higher flowing than an equivalent OEM port injector would be if used instead. They also open wicked fast. So you lose a little more than 1/2 the injection time but you're still waaaay ahead.
    Good info. At high rpm DI has disadvantages to port fuel, but nothing sheer size, pressure and precise control can't counter of course. Nice specs, thanks!

    I think a bigger issue for our DI at high rpm would probably be air fuel mixing, injecting too late at high rpm also lowers the window for the mixture to, well, mix. That will probably manifest more in very high powered cars at high rpm than what we have so far, but something else to keep in mind. Personally I love DI, as the technology progresses these side notes seem to matter less and less, which is a good thing.

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    Click here to enlarge Originally Posted by V8Bait Click here to enlarge
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    Good info. At high rpm DI has disadvantages to port fuel, but nothing sheer size, pressure and precise control can't counter of course. Nice specs, thanks!

    I think a bigger issue for our DI at high rpm would probably be air fuel mixing, injecting too late at high rpm also lowers the window for the mixture to, well, mix. That will probably manifest more in very high powered cars at high rpm than what we have so far, but something else to keep in mind. Personally I love DI, as the technology progresses these side notes seem to matter less and less, which is a good thing.
    There is some data in research publications out there re DI (GDI) and RPM concerns. I've attached one which speaks to it and it's publish date was 2009.GDI droplet size.pdf

    To sum it up, there's a formula put forth in this paper that predicts max allowable droplet size to allow adequate time for evaporation, the thing a lot of people are concerned about. That formula is: 1291 / square root of RPM

    If you refer to my post above detailing the average droplet size of the Conti DI Piezo injectors, they state droplet size is around 15um at stock fuel pressure.

    So if you plug in 7500rpm to the formula, you get ~15um.

    What is not said is:
    1) Droplet size is affected by fuel pressure with droplets getting smaller as pressure goes up
    2) this is an OEM perspective which means the primary goals are likely to be fuel economy and emissions. It's not specifically stated what happens to droplets that don't completely evaporate prior to ignition but my guess is if you revved to 8500rpm and had droplet evaporation at 80% leaving 15-20% potential fuel deficit (affect usable A/F ratio, not actual A/F), you can probably just increase fuel flow for more droplets to bring you back to an ideal usable A/F ratio.
    3) This test was in a motorcycle engine, not a very hot turbocharged engine with very high dynamic compression ratio which probably speeds up evaporation because the increased heat present.

    In short, unless you're talking around 8000rpm or higher, I don't see too much concern re DI and evaporation based on what's available to read out there. Clearly other OEM engines with DI rev 8000+ RPM and are in production and doing just fine.

    It's clear GDI is the future. Port injection is headed to the same place as the carburetor. GDI isn't perfect and has fouling, cylinder wetting and other issues that require a lot more maintenance IMO, which is why I think some OEMs (Toyota) have shied away from it to a degree. But its benefits are inescapable. Luckily for us, one benefit so far is not having to change injectors to make some insane power.

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
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    N54 already operates in homogenous mode

    near TDC is stratified

    it's already 'started sooner' Click here to enlarge

    and it can inject x many times per cycle (it's in the tech data for the injectors)... 4 or something?
    You are correct. I was under the impression that the injection event was started really late but it's likely not. Homogenous is likely used as rumors persist that US NOx compliance and sulfur content of gasoline prohibit stratified mode. Tough to nail that one down though for BMW or any other OEM.

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    There's a paper that used a turbo DI gm engine and compared DI to PFI for all sorts of things from knock to flame progression with different DI injection timing with the incoming air. I think there was a section on droplet size and how heat from compression affects vaporization when they compared ethanol blend fuels. I'll see if I can dig it up. It was a big dissertation from a MIT guy with the head of sloan as corresponding author. I like reading things from sloan. But pretty much the same as what you're saying. Issues to keep in mind but not necessarily game breaking. Time will tell, though. Valve float and airflow from all components need addressed first.

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