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Thread: Compressor Map Calculator

  1. #1
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    Default Compressor Map Calculator

    Hi Everyone,

    I'm bored at work and have been reviewing compressor maps for when I move on from the 16g. Punching a calculator got really annoying very fast so I put everything into a spread sheet and thought I would share in case it can help someone else.

    I'm not able to upload files so I hope a link to the calculator on ECMLink forums is ok: http://dsmlink.com/forums/showthread.php?t=55071. If not can someone please remove the link and I will email it for anyone interested. I won't be able to edit this when it's posted.

    All you have to do is fill in the green cells with your values and it will do the work. There are also two converters for the compressor maps that are in M^3/Sec.

    Let me know what you think.

    Thanks!

    Greg

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    I haven't opened your link yet but for what it's worth, Borg Warner has the most detailed turbo calculator I've seen anywhere on it's web site. Here is the link.
    1995 GSX
    9.99 at 140.59

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    Wow, that's much more detailed than the one I put together. Thank you for the link!

  4. #4
    6mmXC
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    None of that matters much, unless you Went Large or Went Pussy Boost majority of you run it so far off the published map it would make your head explode.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

  5. #5
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    I have to agree, unless your doing something that no one has ever done before. But there is a TON of info around of what numbers people are putting down with what turbo

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    Thanks for the feedback guys.

    I do agree that in certain situations the information doesn't really mean much. I just use this to give me an idea of how a given turbo will perform under certain conditions before I buy it and find out it's not going to do what I want it to.

    It's just like any purchase. I like to go in with as much information as possible, and since there aren't any turbo department stores, I use this as my "salesman."

    But there is a TON of info around of what numbers people are putting down with what turbo
    I appreciate your point. I have a hard time trust alot of the information that's out there unless it comes from credible sources though. I've been pissing around with these cars since '97 but only recently have been active on forums since '06. I'm not saying all the information out there is bad it's just personal preference.

    unless your doing something that no one has ever done before.
    For a couple years I have been experimenting with the 16g compressor cover to try and increase inlet pressure. I'm not saying I'm the only one to do that but I've used the calculator to help me plot on it's map of where I might fall if the design actually works. Unfortunately, I haven't been able to log any numbers quite yet. Life happens. But this spring I will be able to get out and give it a whirl.

    http://i539.photobucket.com/albums/f...6-cfm25psi.gif
    http://i539.photobucket.com/albums/f...6-cfm30psi.jpg

  7. #7
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    http://i539.photobucket.com/albums/f...6-cfm30psi.jpg

    That isn't the way things work. You will hit max shaft speed then the operating line will follow the RPM line almost vertically down in PR and stay about the same in mass flow.

    Like I said, most of you run it off the published maps so all that stuff is USELESS.

    Max shaft speed for that sized compressor is ~ 20K higher than that maps highest RPM line. Where is it? They don't publish "out of normal operating range" data.

    It appears you are calculating PR incorrectly, remember ABSOLUTE pressure out divided by ABSOLUTE pressure in. 1 kpa a = .145 PSI.

    Looks like an EVO, best way to help a 16G6 is here- http://store.forcedperformance.net/m...Lancer-TurboHW

    Worth 2-6 lb/min depending on inlet density.
    Last edited by Artie Effem; 2011-01-11 at 20:56:58.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

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    Thanks for the information! Please don't misunderstand this as me trying to argue the facts you provided, far from it. The values I plotted on that map were just a part of an experiment using only engine flow to see how much of a change inlet pressure would have on flow for me to learn that aspect before going further with the ideal gas law, intercooling, etc. I definately don't expect the compressor to perform like that.

    The milling I did to the compressor cover is similar to the most basic idea behind the FP cover as well, as in a larger inlet to increase absolute inlet pressure. It's not near as advanced as the FP cover but it's just something I've been messing with. If it helps great, if not that's okay too. I'm eventually upgrading to something that will flow in the 60lb/min range at some point. This is just for fun in the mean time.
    http://i539.photobucket.com/albums/f...wee1882/32.jpg
    http://i539.photobucket.com/albums/f...wee1882/33.jpg

    The PR's I calculated using what I "guesstimated" inlet vacuum gauge pressure in inches of mercury to be on a DSM running "X" amount of boost (-2inHg, -1inHg, -.5inHg, etc). I've never logged what actual inlet vacuum is but will be in the spring when I get to try this out.

    After accounting for altitude, absolute pressure at the local track would be roughly 28.856inHg (http://www.sensorsone.co.uk/altitude...onversion.html). I then calculated absolute inlet pressure by adding the values I estimated and atmospheric pressure. That value I converted to PSIA and then took absolute outlet pressure, adjusted for altitude as well, and divided it by the absolute inlet pressure I calculated.

    IE (30psig +14.173psiatm)/((-2inHgg+28.856inHGatm)/2.036) = 3.35PR. Is that incorrect?

    Thanks again for your feedback! Greg

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    In order to get an accurate PR figure you CANNOT measure engine manifold (boost) pressure and assume that is P2, and use baro in an airbox and assume that is P1. P1 needs to be as close to the inlet as possible and several ports (120 deg to 45 deg radial spacing) need to be sampled as there is a big-time pressure gradient due to upstream effects, unless it is an open inlet with nothing within several inches (including radiant heat). Comp outlet is usually fairly uniform. Use abs sensors in kpa A then convert. Its easier.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

  10. #10
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    Quote Originally Posted by Artie Effem View Post
    ...and several ports (120 deg to 45 deg radial spacing) need to be sampled as there is a big-time pressure gradient due to upstream effects
    Your static pressure changes due to geometry influence near bends or transitions so that is what you're observing. The only way to do it with one measurement point is to use a piezo ring.
    I love Ty Pham and you can too and in just 3 easy payments of $9.95!

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    The boost reference port for measuring P2 is tapped at the little threaded hole that is already on the compressor outlet. I drilled a .0625" hole at the bottom of it and threaded a vacuum nipple there. I was going to use it for the wastegate but went downstream a little bit instead for that.

    I wasn't aware that P1 would be that difficult to measure, thank you both for the explanation. I can try adding two more ports spaced 120* around the intake tube.

    For measuring inlet pressure I planned to use a 1 BAR GM MAP sensor and compare logged voltages to a chart. I will use the kPa values as suggested.

    For outlet pressure I was going to use a 3 BAR GM MAP sensor also comparing voltages to a chart, or logging in ECMLink.

    For outlet temperature I was going to use a GM IAT sensor approximately 6" away from the compressor outlet. Iím still working on finding a voltage chart to see if this will even read high enough though.

    I was even considering putting another GM IAT sensor 6" after the intercooler outlet. I just have to figure out a way to log all these values first.

    Thanks again! Greg

  12. #12
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    Otto- Not sure what a piezo ring is, the old-timey NACA/NASA/SAE multiple sharp edge orifices is about all I can muster. 3 orifices 120 radial deg apart is pushing it, they recommend at least 4 for round tubes.

    Neither the GM pressure sensors nor the GM NTC thermistors will cut the mustard, terrible drift, inconsistent between sensors etc. Use more modern pressure sensors, and calibrate to local pressure. While an NTC thermistor can be made to work at 200C plus, getting the pullup resistor correct to get the curve shifted for your area of concern is tricky, and the sensor calibration is tricky, better off with low mass TC's, you can get to within +/- 2C without any real effort. Getting to +/- 2C with a thermistor across the range you need is a non-trivial effort.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

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    Is there a specific pressure sensor you'd recommend? I was going to use the GM sensors because I have a bunch laying around, but I'd rather go with something that will be accurate. I don't want to do all this and end up with crappy data.

    Just double checking that I understand your abbreviation; by low mass TC's I assume you mean thermocouples?

    I really appreciate you helping me out with this! Greg

  14. #14
    6mmXC
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    Yes fine wire gauge thermocouples, down to 30g wire.

    These work awesome, have 4 in a box and they all read exactly the same-

    http://www.mouser.com/ProductDetail/...KK7Hfr3J2E0%3d

    4 bar board mount, alcohol vapor resistant. Quick connect 1/8" (oring) fittings fit the nipple. They are tiny and difficult to work with, need SSOP adapter boards.

    Easier to work with are the older Freescale/Motorola units, MPX4115 (1.1bar), MPX5250 (2.5 bar), MPX5500 (5bar), MPX5700 (7bar) but often require individual calibration.

    many are available in differential pressure versions with two ports, you can directly measure pressure drops on one input.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

  15. #15
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    These pressure sensors are all rated to 125 C only. Is that rating referring to ambient temps on the IC, or will a pressure reading on a hot gas cause a problem as well?

    How far away are you mounting these from the compressor outlet?

  16. #16
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    No flow = minimal heat transfer.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

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    Thank you Artie! I will look into trying to make those sensors you linked work for me.
    Quote Originally Posted by Brad S. View Post
    How far away are you mounting these from the compressor outlet?
    The outlet sensor port is tapped directly at the outlet flange on the compressor cover. Heat at the outlet is a concern of mine as well, but if air doesn't travel through the sensors it should be okay.

    Greg

  18. #18
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    Thumbs up

    There is good information on this thread, I just used some links and info to ball park a turbo for my car for which i was overlooking. Ill just bump this so all the limited access newbies like me will read it hopefully more then once.

  19. #19
    6mmXC
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    I'd still recommend a SS body isolated type transducer for exhaust, just because of the ton of water vapor, formaldehyde etc. As long as you isolate the heat via tubing you won't have temp issues.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

  20. #20
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    Long story short, I'm hoping to have the car with the SSOP sensors recommended above and thermocouples ready to do some testing within the next couple weeks. Unfortunately, I just can't seem to source the 1/8" quick connect fittings and tubing that will work with these sensors. I hate to ask to be spoonfed for this stuff, again, but I'm out of options. These are the last pieces I need to get things ready. I appreciate any help anyone can offer. Thanks!

    Greg

  21. #21
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    Push-to-connect, instant tube, etc. Looks like this-

    http://www.mcmaster.com/#cadinlnord/5779k21/=ds019c

    Teflon tube will work fine for non- heat apps or inside the box from sensor to bulkhead.
    Last edited by Artie Effem; 2011-08-25 at 17:57:53.
    "A democracy cannot exist as a permanent form of government. It can only exist until the majority discovers it can vote itself largess out of the public treasury. After that, the majority always votes for the candidate promising the most benefits with the result the democracy collapses because of the loose fiscal policy ensuing, always to be followed by a dictatorship, then a monarchy." - Alexander Fraser Tytler

    "The historical cycle (of democracy) seems to be: From bondage to spiritual faith; from spiritual faith to courage; from courage to liberty; from liberty to abundance; from abundance to selfishness; from selfishness to apathy; from apathy to dependency; and from dependency back to bondage once more." - Henning Webb Prentis, Jr.

    "This year (1935) will go down in history! For the first time, a civilized nation has full gun registration! Our streets will be safer, our police more efficient, and the world will follow our lead into the future!"

    - Adolf Hitler

  22. #22
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    Thank you, sir!

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