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  1. #26
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    Well... they're just different aspects of the engine design. Keep in mind these are the sorts of things even the OEMs sweat over and spend millions of dollars researching to optimize. There's no Excel spreadsheet out there that will tell you the exact best stroke or CR to run for X psi boost on your N54 nor any other engine. There's no easy way to explain this all in an internet forum post. Either you learn by experiment, or you can try to use some very deep calculus to predict behavior.

    There are all sorts of things to consider here. We could start talking about combustion chamber shape, quench and squish, etc. People pursue doctorates in this kind of stuff...

    Those very interested might start reading a few books. I'd start with something like Maximum Boost to get started, then read A. Graham Bell's Four Stroke Performance or Forced Induction Performance. If you want more, you can search around you can then find some post-grad level books on it. I've got several feet thick of books on engine design and control theory if you need recommendations. Forgot his name, but a guy even did his doctoral thesis on the effects of wall-wetting (fuel left over on intake port walls from port fuel injection) and propositions on how to deal with it in the engine management system. There's a whitepaper out there you can download on it...

  2. #27
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    A well designed lower compression piston will also have deeper valve grooves allowing for higher valve lift.

    However, an overall reduction of compression, results in reduced thermal efficiency which in turn results in increased fuel consumption. An internal combustion engine, is nothing more than a heat pump after all.
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  3. #28
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    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    and I HIGHLY recommend NOT using a thicker head gasket, but replacing pistons.
    lifting the head KILLS quench.
    there's an OEM one on offer though, a very tiny bit thicker. which is why i suggested it. it's a relatively cheap modification at least, that can be implemented/reverted with some (relatively small) effort at least?

    it's not optimal, but it's how we could experiment with compression, without having to change pistons, i guess?

    someone could do back to back runs/tune for tune/optimised tune same day, 10.2:1 vs 10.2:1 with a thicker gasket

    i think it'd be awesome if someone were to do this, i mean, seriously useful stuff!

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    No it isn't. The compression ratio stuff is kind of an old school approach these days. Weistec boosts the stock compression ratio even with their built motors. From what I understand managing cylinder temps is more important. If your internals are strong and you tune well, you want higher compression as you will make more power per pound of boost plus spool faster and have greater volumetric efficiency.

    That's why the m3 is so strong with just a little boost. Plus, the less air your have to compress the less heat.

    It isn't a question of race gas. 10.2:1 with direct injection is more than low enough. As stated, there are other problem areas with the N54 to address well before this.
    DI may increase the knock threshold, but compression is still compression.

    yes, high comp is more power at a given level, and more efficient... but it's also easier to tune with a drop... and a drop is a good starting point, even like i said above, with the stock pistons and thicker head gasket, as a relatively cheap experiment for proof of concept?

    i don't see how dropping compression slightly to AVOID the fuelling issue by being able to run more power (with less risk) on pump, is a bad idea.. the only major issue the N54 has right now is said fuelling.. and it's only really an issue on ethanol fuels...

    as i said, there's a way it can be tested on the N54 without having to redo the bottom end, or making other changes at least.


    say i'm planning on only running 98/100RON day to day with not readily available ethanol, i'd personally seriously look into what compression is the best for my specific application (where i'm going for all out max power lol)

    besides the fact the N54 can't currently run Ethanol fuels at high power levels with the HPFP as is..?

    ED: just checked even - nearest E70 station is.. 46km from home, 23km from work..
    neared E85 is 67km from home... 43km from work...

    that's a good percentage of a tank just getting a fill, would need a boot full of 25L jerry cans to last a couple of weeks haha... OTOH, it's on the way to 1 of the 2 local tracks (the safer one lol) + the local strip.

    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    Well, if you want custom pistons for anything let me know. I can get JE or weisco pistons for anything.
    what sorta price would you be looking at? a little cheaper than CP?

    options available?

    rods too? (and same question as above haha)

    Click here to enlarge Originally Posted by vasillalov Click here to enlarge
    However, an overall reduction of compression, results in reduced thermal efficiency which in turn results in increased fuel consumption. An internal combustion engine, is nothing more than a heat pump after all.
    but theoretically then raise boost/etc. slightly which increases VE in turn?
    boop

  4. #29
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    Click here to enlarge Originally Posted by 135idct Click here to enlarge
    What's the relation between lower CR and destroke?
    Stroke and compression ratio are two different things.
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  5. #30
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    Click here to enlarge Originally Posted by Freon Click here to enlarge
    Those very interested might start reading a few books. I'd start with something like Maximum Boost to get started, then read A. Graham Bell's Four Stroke Performance or Forced Induction Performance.
    Do you know if these are available electronically?
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  6. #31
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    DI may increase the knock threshold, but compression is still compression.
    Doesn't octane increase the knock threshold?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    i don't see how dropping compression slightly to AVOID the fuelling issue by being able to run more power (with less risk) on pump, is a bad idea.. the only major issue the N54 has right now is said fuelling.. and it's only really an issue on ethanol fuels...
    Why is dropping the compression avoiding the fueling issue when reaching X amount of power you will need Y amount of fuel? You can reach X at lower or higher compression.
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  7. #32
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    there's an OEM one on offer though, a very tiny bit thicker. which is why i suggested it. it's a relatively cheap modification at least, that can be implemented/reverted with some (relatively small) effort at least?

    it's not optimal, but it's how we could experiment with compression, without having to change pistons, i guess?

    someone could do back to back runs/tune for tune/optimised tune same day, 10.2:1 vs 10.2:1 with a thicker gasket

    i think it'd be awesome if someone were to do this, i mean, seriously useful stuff!
    .7mm isn't going to ANYTHING really. It *may* lower the compression *maybe* less than a tenth of a point. No use doing all that work.

    you pay for it, I'd be happy to rip engines apart/dyno/rip engines apart/dyno

    Click here to enlarge Originally Posted by flinchy
    what sorta price would you be looking at? a little cheaper than CP?

    options available?

    rods too? (and same question as above haha)


    but theoretically then raise boost/etc. slightly which increases VE in turn?

    wait till tomorrow. Click here to enlarge
    I was gonna do it tonight when I got home, but I forgot my price list Click here to enlarge


    ill have a thread on some stuff I've been working on......Click here to enlarge
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  8. #33
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Doesn't octane increase the knock threshold?



    Why is dropping the compression avoiding the fueling issue when reaching X amount of power you will need Y amount of fuel? You can reach X at lower or higher compression.
    yes, but DI vs PI, you can run a bit more boost/timing/whatever on a given octane on DI.

    it's avoiding the fuelling issue, because we're hitting octane limits on 93AKI, not fuelling.. we can supply more fuel, but not more boost/timing without detonation.

    drop compression, and that limit goes away (and eventually should become fuelling of course)


    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    .7mm isn't going to ANYTHING really. It *may* lower the compression *maybe* less than a tenth of a point. No use doing all that work.

    you pay for it, I'd be happy to rip engines apart/dyno/rip engines apart/dyno

    months ago in another thread it was calculated to be ~ .3 compression drop, which is a fair bit more than .1?.. .3 is significant... hold on i'll give it a google haha.

    http://www.kb-silvolite.com/calc.php?action=comp - if anyone has the specific figures for the N54 to plug in?

    having a search around this forum though, 0.3 is the number that keeps coming up for this motor? maybe someone got it wrong right at the start? haha


    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    wait till tomorrow. Click here to enlarge
    I was gonna do it tonight when I got home, but I forgot my price list Click here to enlarge


    ill have a thread on some stuff I've been working on......Click here to enlarge
    sweeeet! Click here to enlarge. awesome stuff.
    boop

  9. #34
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    .3 is nothing in the grand scheme of things.

    i was purely guessing on the .1 statement
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  10. #35
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Do you know if these are available electronically?
    Not in ebook form, no, but they're not that expensive in dead tree edition off Amazon.

  11. #36
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    yes, but DI vs PI, you can run a bit more boost/timing/whatever on a given octane on DI.
    Yes but the point is you can raise octane so compression being compression and with the advantage of DI namely at lower octane levels why do you want to lower compression when you can up octane?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    it's avoiding the fuelling issue, because we're hitting octane limits on 93AKI, not fuelling.. we can supply more fuel, but not more boost/timing without detonation.
    How does this help when going for higher power levels? If you drop compression you will need MORE boost to hit the same power levels. Fuel limitation at higher power levels will still be fuel limitation at higher power levels low compression or high compression. One would want higher compression in this case as the turbos get maxed anyway. If you want more power why even bother with 93 then? The goal isn't who can make the most power on 93 octane.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    drop compression, and that limit goes away (and eventually should become fuelling of course)
    It doesn't go away it always exists all you are doing is lowering the potential knock threshold for 93 octane pump gas which you can do on the stock compression with meth while having better spool, power per psi of boost, and at less heat than you would with lower compression.
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  12. #37
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    Click here to enlarge Originally Posted by Freon Click here to enlarge
    Not in ebook form, no, but they're not that expensive in dead tree edition off Amazon.
    I hate paper. I also hate waiting. I want this now.
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    Click here to enlarge Originally Posted by alex@ABRhouston Click here to enlarge
    .3 is nothing in the grand scheme of things.

    i was purely guessing on the .1 statement
    10.2 > 9.9 (if that's accurate) would give quantifiable changes one way or the other.... it may not be enough to make it a 'do this if xyz' mod, but it would at least give credence to those wanting to try lower compression pistons?
    boop

  14. #39
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Yes but the point is you can raise octane so compression being compression and with the advantage of DI namely at lower octane levels why do you want to lower compression when you can up octane?
    if the highest octane you have access to (or want to run) is 93AKI, then no, you can't raise octane (and if you don't want to run meth, which many don't)

    you may not be able to, or don't want to, raise the octane, if you're already at the highest on pump.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    How does this help when going for higher power levels? If you drop compression you will need MORE boost to hit the same power levels. Fuel limitation at higher power levels will still be fuel limitation at higher power levels low compression or high compression. One would want higher compression in this case as the turbos get maxed anyway. If you want more power why even bother with 93 then? The goal isn't who can make the most power on 93 octane.
    because you can advance timing further. boost isn't the only aspect of tuning to increase power, as you are aware.

    you can get more power out of the same boost/fuel... raise the compression further and want to keep the same boost? pull more timing, net same/similar peak peak power best case scenario, you'd only increase power in the low/midrange, that is, assuming you're octane limited at the peak.

    one post i remember on a WRX forum, (nasioc?) someone raised their compression to 9.x and lost peak power, because they could no longer run the same boost/timing on the octane they were using.

    why wouldn't you want to make the most power on 93AKI? it's an entirely admirable and acceptable goal to have, 'record pump gas whp' is a fine record to hold.

    or if you run 93 99% of the time, and ethanol 1% of the time, maybe you'd rather have that 'more power' 99% of the time.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    It doesn't go away it always exists all you are doing is lowering the potential knock threshold for 93 octane pump gas which you can do on the stock compression with meth while having better spool, power per psi of boost, and at less heat than you would with lower compression.
    some people (many people) including myself, either can't or don't want to run meth

    myself for 'cant' be bothered with another thing/expense' and also wanting to track in a couple of classes where meth isn't allowed (ethanol is though). (including local drag strip/national ANDRA rules for many of the street/lower classes)

    and if the fuelling doesn't get fixed soon, it's simply physically impossible to get as much power on ethanol as on pump (and not wanting to run race gas)

    there are many situations where 93AKI is simply the only/best choice for some people.
    Last edited by Flinchy; 07-23-2013 at 10:01 PM.
    boop

  15. #40
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    if the highest octane you have access to (or want to run) is 93AKI, then no, you can't raise octane (and if you don't want to run meth, which many don't)
    So you're asking to run pump and make big power? Who doesn't have access to meth or race gas? Why would anyone compromise a build around 93 pump? Why make the car worse? Who cares about pump gas, really?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    because you can advance timing further. boost isn't the only aspect of tuning to increase power, as you are aware.
    And you can advance timing further with E85 on the stock compression than you could by dropping the compression on 93. So you essentially don't need to waste money then dropping the compression as you get more power, better response, and better spool by using the proper fuel for the goal don't you?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    you can get more power out of the same boost/fuel... raise the compression further and want to keep the same boost? pull more timing, net same/similar peak peak power best case scenario, you'd only increase power in the low/midrange, that is, assuming you're octane limited at the peak.
    Once again you don't have to be octane limited. I don't understand why you are handicapping a car.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    why wouldn't you want to make the most power on 93AKI? it's an entirely admirable and acceptable goal to have, 'record pump gas whp' is a fine record to hold.
    I guess. Until you run into someone at stock compression on E85 who blows by you and you say, wow, what a waste that was.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    there are many situations where 93AKI is simply the only/best choice for some people.
    I honestly don't know of them but I guess sure if someone wants to build around this fuel by all means. It just isn't even utilizing the strength of the options out there correctly.

    I'm not building my cars kill mode for 93 octane I can tell you that. And also, meth is cheaper than a whole engine rebuild to drop compression.
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  16. #41
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    So you're asking to run pump and make big power? Who doesn't have access to meth or race gas? Why would anyone compromise a build around 93 pump? Why make the car worse? Who cares about pump gas, really?
    people may not all want to run meth (or can't for their application). Again, me.

    race gas is about $70/gallon

    i'm not sure if you're just trying to continue a debate or not with that last question haha

    ok, what if you're not out to go for max power to the moon, you just want a reliable, easy to obtain, fairly high number. you don't have the ability to run E85 like on the N54, so all you can do is 93-94AKI... fill up the car at any station, plant your right foot, enjoy.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    And you can advance timing further with E85 on the stock compression than you could by dropping the compression on 93. So you essentially don't need to waste money then dropping the compression as you get more power, better response, and better spool by using the proper fuel for the goal don't you?
    Again, the N54 can't run E85 at the power levels you can even reach on 93AKI. Yet.... Hopefully haha.. and again, not everyone can access E85/E70

    so this argument is moot.

    and so far, the stock frame turbo record is held on 94AKI+Meth, some of which was likely helped along by the thicker head gasket (in theory)... heck, there was probably room for even more timing even on E85, were it possible to run it... no one, not anyone on this forum can say one way or another than even a slight compression drop is 100% a terrible idea, and no one should even try it under any circumstance.

    by your logic, why not raise compression even higher? 10.5:1 say? maybe it'll come out in the future that 10.5:1 on E85 is the best idea?

    but really, until the N54 can run 100% E85 with either a better upgraded HPFP setup, or supplementary DI, the power records will be pump/pump+meth.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Once again you don't have to be octane limited. I don't understand why you are handicapping a car.
    some people simply are as a matter of fact. Not a choice.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I guess. Until you run into someone at stock compression on E85 who blows by you and you say, wow, what a waste that was.
    yeah, but it doesn't really count because it won't be another N54 powered car. well. maybe in the future, in which case this discussion is moot, you're right and i'm wrong in THAT situation.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I honestly don't know of them but I guess sure if someone wants to build around this fuel by all means. It just isn't even utilizing the strength of the options out there correctly.

    I'm not building my cars kill mode for 93 octane I can tell you that. And also, meth is cheaper than a whole engine rebuild to drop compression.
    the people who don't have access to anything other than unleaded (or don't want to/can't afford hundreds on a weekend of C16).

    or own an N54, and are physically unable to run E85 in a powerful setup.

    or take it to the track and aren't allowed to turn meth on.

    i understand records overall will be (at least eventually) held on E85, and E85 alone (well, maybe FTW purple lol), i'm not debating that.

    But i'm saying there are situations, and builds, where a static comp drop is the way to go.

    E85>93/94 pump... when we can run it. i'm not bothering denying that.

    if there is an upgraded fuel pump that will let me run 100% E85 when i get mine in. i'll buy some jerry cans and run E85 on stock compression lol.

    otherwise? ehh i'd really have to consider lowering the compression. fun now > fun later.
    boop

  17. #42
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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    people may not all want to run meth (or can't for their application). Again, me.

    race gas is about $70/gallon

    i'm not sure if you're just trying to continue a debate or not with that last question haha

    ok, what if you're not out to go for max power to the moon, you just want a reliable, easy to obtain, fairly high number. you don't have the ability to run E85 like on the N54, so all you can do is 93-94AKI... fill up the car at any station, plant your right foot, enjoy.
    Usually when trying to get the most power you want to... get the most power. Knowing there are fuels out there that can up your octane and allow you to make more power without changing your internals makes it seem pointless to drop compression for pump gas. How much peak power gain are you really going to see on 93 octane? Anything to make it worth the cost and time? How much will you advance timing? You could just run a different map with E85 when you want more power and have even more power. I mean it just seems logical doesn't it?

    Race gas is $70 a gallon? WTF?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    Again, the N54 can't run E85 at the power levels you can even reach on 93AKI. Yet.... Hopefully haha.. and again, not everyone can access E85/E70
    I don't know we've seen higher levels on E85 than 93 haven't we? Or maybe the pump is maxed? Anway, E85 will still allow you to increase timing more than 93 octane even if you drop the compression. How much are you going to drop it or 93 octane?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    and so far, the stock frame turbo record is held on 94AKI+Meth, some of which was likely helped along by the thicker head gasket (in theory)... heck, there was probably room for even more timing even on E85, were it possible to run it... no one, not anyone on this forum can say one way or another than even a slight compression drop is 100% a terrible idea, and no one should even try it under any circumstance.
    That makes sense to me. I'd run meth then.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    by your logic, why not raise compression even higher? 10.5:1 say? maybe it'll come out in the future that 10.5:1 on E85 is the best idea?
    Now you're thinking. If you're building the motor I say go for big power not pump gas power. Raising compression considering turbo limitations makes sense. Definitely for road course guys. If someone was using stock turbos or upgraded stock housings higher compression with race gas will likely make for an N54 with some much better drivability.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    some people simply are as a matter of fact. Not a choice.
    Do you have access to meth? Water? Ethanol? Anything? Do you live in the arctic circle?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    yeah, but it doesn't really count because it won't be another N54 powered car. well. maybe in the future, in which case this discussion is moot, you're right and i'm wrong in THAT situation.
    Let's just assume that situation will be feasible but yes it works in that situation.

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    the people who don't have access to anything other than unleaded (or don't want to/can't afford hundreds on a weekend of C16).

    or own an N54, and are physically unable to run E85 in a powerful setup.

    or take it to the track and aren't allowed to turn meth on.
    What track forces people to track pump gas?

    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    i understand records overall will be (at least eventually) held on E85, and E85 alone (well, maybe FTW purple lol), i'm not debating that.

    But i'm saying there are situations, and builds, where a static comp drop is the way to go.

    E85>93/94 pump... when we can run it. i'm not bothering denying that.

    if there is an upgraded fuel pump that will let me run 100% E85 when i get mine in. i'll buy some jerry cans and run E85 on stock compression lol.

    otherwise? ehh i'd really have to consider lowering the compression. fun now > fun later.
    I totally get your 93 octane point I guess I'm not a person who would compromise potential based on pump gas. I mean what turbo cars ever hit their potential on pump gas anyway? The one thing that is really nice about turbos in my opinion is adjusting boost based and tunes based on fuel quality.
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Usually when trying to get the most power you want to... get the most power. Knowing there are fuels out there that can up your octane and allow you to make more power without changing your internals makes it seem pointless to drop compression for pump gas. How much peak power gain are you really going to see on 93 octane? Anything to make it worth the cost and time? How much will you advance timing? You could just run a different map with E85 when you want more power and have even more power. I mean it just seems logical doesn't it?

    Race gas is $70 a gallon? WTF?
    cheapest local is $182/20L.. so $35/gal at bulk order... for C16.

    sorry, $70/gal was the first link i found. should have kept looking. my bad.

    i'd have to do some google on other cars, where they go from 10:1 to 9.5:1 on NA-T conversions.. thicker head gaskets.. like S2k's, they at massive head gaskets for boost.

    i guess it's a balancing act, but as far as i understand, don't have more compression than you can run as much timing as possible on, if your turbo is pretty well maxed out already?

    again, you can't run E85 on the N54 properly? yet.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I don't know we've seen higher levels on E85 than 93 haven't we? Or maybe the pump is maxed? Anway, E85 will still allow you to increase timing more than 93 octane even if you drop the compression. How much are you going to drop it or 93 octane?
    vargas 725 run i believe was 93+meth... dzenno's 55xhp run was 94?+meth

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    That makes sense to me. I'd run meth then.
    i don't want to myself, and again, not allowed to for some drag/timeattack classes here.

    i understand some people do want to, and it ups the octane a ton. but not for everyone for a variety of reasons.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Now you're thinking. If you're building the motor I say go for big power not pump gas power. Raising compression considering turbo limitations makes sense. Definitely for road course guys. If someone was using stock turbos or upgraded stock housings higher compression with race gas will likely make for an N54 with some much better drivability.
    yeah, if the N54 can handle E85 in the near future Click here to enlarge. If you autocross your car, high comp ftw, as you'll be in the low revs often... road course being normal track? ehh depends... but yes, if you run E85, can run E85, have access to it easily. higher comp is worth looking into for an experiment at least, yes.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Do you have access to meth? Water? Ethanol? Anything? Do you live in the arctic circle?
    meth? with some difficulty

    eth? some distance away as already posted. it's inconvenient lol.

    P100RON is right near my home though.
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Let's just assume that situation will be feasible but yes it works in that situation.
    then yes, it may be a fools errand lowering compression, still can't be sure. i mean, it's always going to be safer tuning with a dropped CR over stock/raised.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    What track forces people to track pump gas?
    i said 'can't run meth injection' not 'can't run ethanol fuel'

    some safety issue blah blah i guess. *shrug* rules are rules.

    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    I totally get your 93 octane point I guess I'm not a person who would compromise potential based on pump gas. I mean what turbo cars ever hit their potential on pump gas anyway? The one thing that is really nice about turbos in my opinion is adjusting boost based and tunes based on fuel quality.
    yeah i understand and agree haha... what if you have a big turbo with big boost though? 6466/6766/GTX35/GT37/40/GTX42 or something like that? adding boost is pretty much the same as adding static compression in terms of knock effects.. don't want to be limited in how much boost you can run in that situation either?
    boop

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    Click here to enlarge Originally Posted by Flinchy Click here to enlarge
    but theoretically then raise boost/etc. slightly which increases VE in turn?
    Yeah, that's the trade off, but fuel consumption will suffer. Why do you think all the car makers are pushing out all those high-compression engines? Its for increased thermal efficiency, which leads to improved fuel economy and also reduced emissions.
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    Click here to enlarge

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    3 out of 3 members liked this post. Reputation: Yes | No
    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Do you know if these are available electronically?

    Ask and you shall receive:
    http://vasillalov.com/Maximum_Boost-Corky_Bell.pdf

    P.S.: I think this deserves a rep point, no?
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    Click here to enlarge Originally Posted by vasillalov Click here to enlarge
    Yeah, that's the trade off, but fuel consumption will suffer. Why do you think all the car makers are pushing out all those high-compression engines? Its for increased thermal efficiency, which leads to improved fuel economy and also reduced emissions.
    haha true

    I mean, fuel consumption isn't much of a worry in this discussion, it's all about the power Click here to enlarge

    it's a good discussion to have, 10.2:1 may be perfect for every situation for the N54

    9.5:1, or 10.5:1 or 9.7:1, also could have their applications.. and one of them will eventually hold the peak power on E85 with a massive turbo record.

    we won't know what sucks and what doesn't until it gets tried.

    Click here to enlarge Originally Posted by vasillalov Click here to enlarge
    Ask and you shall receive:
    http://vasillalov.com/Maximum_Boost-Corky_Bell.pdf

    P.S.: I think this deserves a rep point, no?
    awesome!

    good for some light reading when i get home Click here to enlarge

    and just your luck, for once it's not 'you must spread reputation' when i click the thumb haha
    boop

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    changing the head gasket is NOT an easy modification.... you need special tools to remove the chain .
    07 335i AT - MOTIV 750 - MHD BMS E85 - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade
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    You don't need special tools for the chain Click here to enlarge

    you need special tools to reset the cam trays and timing Click here to enlarge
    Click here to enlarge
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    Click here to enlarge Originally Posted by vasillalov Click here to enlarge
    Ask and you shall receive:
    http://vasillalov.com/Maximum_Boost-Corky_Bell.pdf

    P.S.: I think this deserves a rep point, no?
    Nice, Repped!
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