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  1. #11
    Join Date
    Feb 2014
    Posts
    4,493
    I use one I have saved on the computer but this ones pretty accurate

    http://www.wallaceracing.com/et-hp-mph.php

    2014 HSV GenF-GTS fitted with a Forced Induction Interchiller
    http://www.facebook.com/ForcedInductionInterchillers
    Australia's outright Fastest VF GTS & Fastest 6.2L 1900LSA with a stock bottom end
    9.700 @145.22mph 21/June/2017
    V-Box Results 0-100km/h in 2.47sec

    Looking for colder IAT's? we have achieved 11c IAT2 on a 41c day and -8c during winter.
    We have proven cabin AC vent temps are better than GM spec, both IAT2's and vent temps are all on video with nothing to hide.

  2. #12
    Join Date
    Jun 2013
    Location
    Sth West Syd ��
    Posts
    1,302
    Quote Originally Posted by GenF-GTS View Post
    I use one I have saved on the computer but this ones pretty accurate

    http://www.wallaceracing.com/et-hp-mph.php
    Just typed mine in all three and it tells me there is plenty of driver error!!
    Weight/HP = 11.3
    Mph/Weight = 623rwhp
    ET/Weight = 465rwhp



    Sent from my iPhone using Tapatalk

  3. #13
    Join Date
    Apr 2013
    Location
    Melbourne
    Posts
    1,315
    Quote Originally Posted by white_lie View Post
    I've always said rwhp is close to flywheel kW. If you run up a car in standard form, it's generally pretty close
    I've heard this from many sources and agree with the method

    OP; working backwards, what did you car run up stock at the rear wheels?

    Racing... Because football, rugby, basketball & golf only require one ball

  4. #14
    Join Date
    Jan 2004
    Location
    Perth, WA
    Posts
    6,768
    Quote Originally Posted by Nath View Post
    I've heard this from many sources and agree with the method

    Working backwards; what did you car run up stock at the rear wheels?
    If you ran it up in stock form, I'd agree with Jake's theory in looking at the difference and adding that on to the original factory rating. Would have to be close?

  5. #15
    Join Date
    Feb 2014
    Posts
    4,493
    Given that every dyno is different any back and forth calculations when using a dyno number is going to give you a number purely related to that initial dyno number.

    Dyno's can so easily be messed with, some messed with intentionally and some are just setup differently with different correction factors loaded into the software of the dyno. I was having a look at correction factors on a dyno recently and it was showing by how much it was correcting the HP figure based on the ambient conditions. So this literally will vary dyno to dyno, whilst also there in the setup it showed different options for choosing different correction factors, so even though the temp sensor isn't being played with etc the actual percentage of correction can be played with versus temp/humidity conditions.

    Unless we are all using the exact same correction factors on the same brand of dyno then numbers are going to be different.

    The only true cheap method of determining engine HP is at the drag strip, this does have a degree of variation eg going full throttle immediately and getting a good launch.

    Some people say regardless of wheel spin you will run the same mph this I disagree with as I have time slips which tell otherwise. But in general if you get a decent launch and go full throttle your mph and weight including driver and fuel will tell you how much HP you are making at the engine.

    I've seen plenty of cars that claim big HP numbers from a chassis dyno and many of them dont have the mph to match the dyno sheet.

    Like they say lets see what your dyno sheet traps.

    2014 HSV GenF-GTS fitted with a Forced Induction Interchiller
    http://www.facebook.com/ForcedInductionInterchillers
    Australia's outright Fastest VF GTS & Fastest 6.2L 1900LSA with a stock bottom end
    9.700 @145.22mph 21/June/2017
    V-Box Results 0-100km/h in 2.47sec

    Looking for colder IAT's? we have achieved 11c IAT2 on a 41c day and -8c during winter.
    We have proven cabin AC vent temps are better than GM spec, both IAT2's and vent temps are all on video with nothing to hide.

  6. #16
    Join Date
    Apr 2016
    Location
    Liverpool Sydney
    Posts
    448
    Quote Originally Posted by GenF-GTS View Post
    Given that every dyno is different any back and forth calculations when using a dyno number is going to give you a number purely related to that initial dyno number.

    Dyno's can so easily be messed with, some messed with intentionally and some are just setup differently with different correction factors loaded into the software of the dyno. I was having a look at correction factors on a dyno recently and it was showing by how much it was correcting the HP figure based on the ambient conditions. So this literally will vary dyno to dyno, whilst also there in the setup it showed different options for choosing different correction factors, so even though the temp sensor isn't being played with etc the actual percentage of correction can be played with versus temp/humidity conditions.

    Unless we are all using the exact same correction factors on the same brand of dyno then numbers are going to be different.

    The only true cheap method of determining engine HP is at the drag strip, this does have a degree of variation eg going full throttle immediately and getting a good launch.

    Some people say regardless of wheel spin you will run the same mph this I disagree with as I have time slips which tell otherwise. But in general if you get a decent launch and go full throttle your mph and weight including driver and fuel will tell you how much HP you are making at the engine.

    I've seen plenty of cars that claim big HP numbers from a chassis dyno and many of them dont have the mph to match the dyno sheet.

    Like they say lets see what your dyno sheet traps.
    Totally agree with Kirk.
    Dyno readouts are an indication and all dynos are different.
    The 1320 never lies
    The mph is a reflection on the engine and running gear - the ET on the car setup ( chassis, suspension, aero dynamics etc )

    LS2 V3 Vortech Supercharged
    607rwhp

  7. #17
    Join Date
    Jun 2015
    Posts
    176
    IMHO there are way too many variations to have a definitive answer to what an engines “peak power” is based on its ET/MPH/Weight from the Track. You could assume a power figure and that's all it will be, “an assumption”. In reality it is about the engines power “curve” and how it all comes together at the track in the particular operating conditions at the track and how the “tune” is influencing the engines operating conditions.

    Examples;

    Is the car auto or manual ?

    If manual, driver talent will have an influence on both the ET and MPH (more so on the ET and to a lesser degree the MPH but will still have an influence on the MPH). Based on the “drivers skill”, your calculated peak HP will vary and not be a true representation of the engines “actual” power curve.

    If auto, has the Tuner “dialled in the gear box tune” ? As in, if the engine makes peak power at 7,000rpm, what is the g’box calibrated to shift at in each gear ? 6,000rpm, 6,500rpm etc etc ? This will also have an influence on the cars ET and MPH as the shift point may or may not be optimizing the engines power “curve”.

    Speaking of an engines power “curve”.
    If you had two identical cars, one naturally aspirated and the other with a PD S/charger both making the same “peak” power figure, do you really think they are both going to ET/MPH the same ? Obviously not, yet based on the ET/MPH/Weight you’re saying you can definitively work out the power both engines are making yet they have drastically different power curves but the same peak figure?

    If you want to go even deeper, What were the conditions that the engine was tuned at on the dyno vs the operating conditions at the track and how the tune is being effected at the track ? Most tuners try and net the customer the highest “peak” figure so they;
    A) Look good,
    and
    B) Keep the customer happy.

    This generally means that the dyno fan is on full till between runs to cool down air temps, coolant temps etc to net the best peak figure, not only that, the rate at which the power run is “ramped” at on the dyno can effect how aggressive the ignition curve can/can’t be before engine knock comes into play, at the drag strip 4 th gear doesn't “rev out” as fast as 1 st gear does it ? You have a different situation at the drag strip. The cars are idling with their bonnets closed in the staging lanes, they do the burn out with no large amounts of airflow like on the dyno so in effect, the “operating conditions” from dyno to Track are different. At this stage, its all the tables in the back ground that will also influence the engines power out put over the 1/4 mile, for example Intake air temp corrections etc. Further more, this is dynamic, as in it will be changing inversely between a N/A engine and a FI engine as the cars run down the track with the N/A engine indicating cooler air temps as it goes down the track and a FI car increasing air temps as it goes down the track. At this point the correction tables will be coming into play effecting the cars ET/MPH and not representing the “actual power curve/output of the engine”. Anyone can make a peak figure on the dyno however it certainly doesn't mean that based on a ET and MPH you or any online calculator is going to be able to work out all the variable to give a definitive answer to an engines peak power figure. It will still only be an “assumption”..... a yard stick if you will and nothing more.

  8. #18
    Join Date
    Apr 2013
    Location
    Melbourne
    Posts
    1,315
    Quote Originally Posted by GenF-GTS View Post
    I use one I have saved on the computer but this ones pretty accurate

    http://www.wallaceracing.com/et-hp-mph.php
    4070 pounds Vs 119MPH = 11.5 on the above.. Best i could pull was 12.1 in manual, perhaps i should have dropped the clutch after all...

    Racing... Because football, rugby, basketball & golf only require one ball

  9. #19
    Join Date
    Jun 2016
    Posts
    41
    My Dyno Sheets


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