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Thread: Brad Barnhill's Virtual Dyno with HP Tuners

  1. #21
    Senior Tuner 5_Liter_Eater's Avatar
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    I got that when I tried to cut out parts of a log file. I took another log that only contained the pull and it worked. Well it's off by about 100 on the HP and TQ but it looks decent. Then again maybe I need to do a 4th gear pull. Traction in 3rd gear is not gauranteed. I just don't have anywhere with enough room to comfortably do a 4th gear pull to redline with >700 RWHP.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
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  2. #22
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    You I dont have enough room to do a 4th gear pull to redline and I'm only sitting in the mid 200 area. And I think if I ever plan to go that fast again I'm going to have to take my wipers off in advance.
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  3. #23
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    I've tried 3rd gear pulls, and 4th gear and it's not even close.

  4. #24
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    Quote Originally Posted by SargeZ06 View Post
    Here you go vette guys.
    <?xml version="1.0" standalone="yes"?>
    <CarDataset xmlns="http://tempuri.org/CarDataset.xsd">
    <CarParameters>
    <CarMake>Chevy</CarMake>
    <CarModel>Corvette C5 97-04 (Manual)</CarModel>
    <Weight>3300</Weight>
    <TransGear3>1.30</TransGear3>
    <TransGear4>1.00</TransGear4>
    <FinalGearRatio>3.42</FinalGearRatio>
    <DragCoefficient>0.31</DragCoefficient>
    <FrontalArea>20.7</FrontalArea>
    <TireDiameter>26</TireDiameter>
    </CarParameters>
    </CarDataset>

  5. #25
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    Quote Originally Posted by Brice View Post
    <?xml version="1.0" standalone="yes"?>
    <CarDataset xmlns="http://tempuri.org/CarDataset.xsd">
    <CarParameters>
    <CarMake>Chevy</CarMake>
    <CarModel>Corvette C5 97-04 (Manual)</CarModel>
    <Weight>3300</Weight>
    <TransGear3>1.30</TransGear3>
    <TransGear4>1.00</TransGear4>
    <FinalGearRatio>3.42</FinalGearRatio>
    <DragCoefficient>0.31</DragCoefficient>
    <FrontalArea>20.7</FrontalArea>
    <TireDiameter>26</TireDiameter>
    </CarParameters>
    </CarDataset>
    C5Z is not 1.30 in 3rd gear. It's 1.43. C6Z is 1.30.

  6. #26
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    And still crazy high numbers with your data Brice.

  7. #27
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    Quote Originally Posted by SargeZ06 View Post
    C5Z is not 1.30 in 3rd gear. It's 1.43. C6Z is 1.30.
    it's for a C5 coupe MN6 (not C5Z).

    I will try tomorrow with my C5. I've tried on previous logs : crazy high numbers !

  8. #28
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    Quote Originally Posted by Brice View Post
    it's for a C5 coupe MN6 (not C5Z).

    I will try tomorrow with my C5. I've tried on previous logs : crazy high numbers !
    What numbers did you get?

  9. #29
    ill have to check i out

  10. #30
    Advanced Tuner jakebdb56's Avatar
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    Quote Originally Posted by 5_Liter_Eater View Post
    I don't see anywhere where it tells me what PIDs I have to log for it to work. And if it's using delivered engine torque I'm out of luck as it pegs at 640 foot #'s.
    It'll just read "too much powa" for you, lol
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  11. #31
    Advanced Tuner bbarnhill's Avatar
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    Hi Im the developer of Virtual Dyno (VD ... not the itchy kind).

    If anyone has a couple of logs from say a Vette or other GM branded wagon let me know. I need a couple as Ive only tested this with Cobalt logs, and one guys at that. I was rushed to get HP tuners support in there. So please forgive me if its not perfect, but I wanted to get it supported and ask forgiveness later. So if you have any unmodified logs, send a couple to: bradbarnhill at hotmail com

    Thanks guys and bare with me as I try to support the HP Tuner crowd as well. I know I own an Evo X and I know its only got 4 cyl., but ... I had a Pontiac GTO right before it. So Im a GM guy at heart.
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  12. #32
    I couldnt get it to retreive the scanned information from HPT

  13. #33
    It would be best to allow people to input their own gear ratio, tire size, weight etc as it can fluctuate so much.

    FSAE_Junkie did this in excel a few years ago and it has proven accurate within a few HP.
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  14. #34
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    Quote Originally Posted by ArthurJGuy View Post
    It would be best to allow people to input their own gear ratio, tire size, weight etc as it can fluctuate so much.

    FSAE_Junkie did this in excel a few years ago and it has proven accurate within a few HP.
    Where is that spreadsheet?

  15. #35
    Senior Tuner 5_Liter_Eater's Avatar
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    Quote Originally Posted by bbarnhill View Post
    If anyone has a couple of logs from say a Vette or other GM branded wagon let me know.
    Here is a 3rd gear pull from my vette and here are the parameters I came up with for it. When I tell it 3rd gear and 200# for the driver weight I get >800 HP and TQ.

    <CarParameters>
    <CarMake>Chevrolet</CarMake>
    <CarModel>2005 Corvette Z51 (6 Speed)</CarModel>
    <Weight>3175</Weight>
    <TransGear3>1.43</TransGear3>
    <TransGear4>1.00</TransGear4>
    <FinalGearRatio>3.42</FinalGearRatio>
    <DragCoefficient>0.29</DragCoefficient>
    <FrontalArea>21</FrontalArea>
    <TireDiameter>26.85</TireDiameter>
    </CarParameters>
    Last edited by 5_Liter_Eater; 02-13-2011 at 08:04 AM.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
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  16. #36
    Advanced Tuner TiredGXP's Avatar
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    Hey 5LE,

    I ran your data through a spreadsheet that I also use. Here's the results:



    Is this remotely like what you would have expected to see?
    2005 Grand Prix GXP - 5.3 LS4 - HP Tuned, MF catback, 1.8 rockers, K&N, Some day I'll finish putting the LS6 intake on

  17. #37
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    TiredGXP, what spread sheet are you using? Ran my car thru the program and it says 226hp and 182tq, I knew those DynoJet dynos lied

  18. #38
    Senior Tuner 5_Liter_Eater's Avatar
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    Quote Originally Posted by TiredGXP View Post
    Hey 5LE,

    I ran your data through a spreadsheet that I also use. Here's the results:



    Is this remotely like what you would have expected to see?
    Thats on the low side now but I'm curious why you ended up with different numbers.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
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  19. #39
    Advanced Tuner TiredGXP's Avatar
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    I don't know the ins and outs of Brad's calculations, so can only speculate.

    The spreadsheet I use calculates the force required to accelerate the vehicle based on the rpm and the time stamp in the log. It also calculates the forces required to overcome tire rolling resistence and aerodynamic drag. The spreadsheet uses a lot of smoothing - as you know, raw data logs have a lot of "jitter" because the logged items are not necessarily the value at the same instant as the time stamp.

    Rolling resistence is kind of a "plugged" item because it is difficult to get actual data on individual tires. I just use a mid-range number that I pulled off the web for all calculations.

    Aero drag is heavily influenced by the temperature at the time that the log was taken - in the graph above I believe that I took the lowest number from you IAT data - the actual temperature was probably lower, which would have increased air density, and the calculated power required to push through it. I don't think Brad's program takes ambient temperature into account when calculating aero drag.

    The other issues are wind and whether the road is perfectly flat - it's best to do back-to-back pulls in each direction and average the results to compensate for these variables. A head wind or an uphill pull will definitely decrease the calculated hp/tq.

    The other thing I noticed was that some aero testing on the C6 vette shows a Cd of .333, not .29 (See - http://www.corvettefever.com/techart...own_chart.html ) This would add maybe another 10 hp/tq to what I calculated before.

    2005 Grand Prix GXP - 5.3 LS4 - HP Tuned, MF catback, 1.8 rockers, K&N, Some day I'll finish putting the LS6 intake on

  20. #40
    Senior Tuner 5_Liter_Eater's Avatar
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    Well my IAT's were skewed because of the meth.

    I've seen a few different numbers thrown around for the C6 from .27 to .33 so it's hard to say who's right.

    I have Mickeys so I'm sure my rolling resistance is high.

    Well in any case it may prove to be worthwhile in comparing mods or tune changes on performance. I tried doing that with delivered TQ but again it tops out at 640 so I couldn't use it.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game