Ferrari manipulation or manipulation for even all manufacturers?

Discussion in 'Tech Talk' started by F40 LeMans, Mar 9, 2012.

  1. F40 LeMans Active Member

    Backtraking? No, I explained mafalda the role concerning conditions. I start by the point that the published data (acceleration and 1/4 mile) are correct, data factors for the correction are mistaken (also written by hand). C/D published them for 3 times, two times in the article and one in the data sheet written by hand. So acceleration data/quarter mile are surely corrected. Then, we have the air conditions to evaluate and coming back to the uncorrected time, and conditions doesn't explain so hard "back" correction... or you are trying to say that the article is completely a fake? lol
    If that the Pobst's mule is not so fast is because they probably not apply so hard data in their ECU... we can't know, I not exclude about that situation..
  2. Guibo Well-Known Member

    That's my point: The published figures are corrected. From the correction factors, we know that they made the ET faster and the trap speed higher than what they actually were (and by what factor for each).
    I'm saying the test was badly corrected. It doesn't mean everything in it is fake. From what we know of turbochargers (which I explained a long time ago), from what we know of the Motor Trend test, we can see that their correction method was wrong. What, you think C&D didn't benefit financially from publishing those numbers? I bet you they did. And edmunds has a guess why most of the industry uses SAEJ1349, which has been around since 1995 and revised since 2004, while others use the older standard (which C&D admits to using as late as 2008):
    "Some publications still use J607, ostensibly because they don't want to lose the ability to make comparisons to their library of past data. (Sure, the 0.3-second advantage they get in quarter-mile times has nothing to do with it.)" (That is meant ironically, BTW.)

    No, I'm saying the Pobst car was a production-spec press car. Not a mule. Pobst would have had limited time in setting a fast lap in the GT-R and as we've seen from Motor Trend's tests there, they tend to apply wrong tire pressures (whereas Nissan's crew would know the ideal pressure for a fast lap). Yet Pobst is only 0.8s behind. Perhaps it's ECU-related, but why not allow that Pobst's inexperience with the car and non-ideal pressures could have led to the very minor time discrepancy? Indeed, with more practice, instead of having to share time with 9 other cars, plus prime tires and pressures it's not outlandish to think that Pobst could have found that 8/10ths easily. Ferrari's 458 found 1.0s at Donington with just a tire swap. See, you are again focusing on ECU. It might be, but it doesn't have to be. Nor is it even probable. Do you honestly think the 997 Turbo production car that Nissan bought and used as reference has harder ECU than a for-sure blueprinted press car?
    Nissan's production 997.1 Turbo - 1:39.89
    Pobst (professional Porsche racer) in press 997.1 Turbo - 1:42.507

    You were backtracking because you explained to mafalda that C&D's correction was not right (concerning air temps) and then you reverted back to your flawed calculations using incorrect and missing data (123.5 mph). If the car actually went 123.5 mph and the published data is 124 mph, then they would have applied a correction that is opposite to MT's: they made the car faster when they should have made it slower, if any correction is to be made at all.
  3. F40 LeMans Active Member

    Yes, and my point is the other one, starting by the acceleration published and coming back...

    I explained to mafalda that correction writen by hand was not right, not the acceleration published. They applied that opposite correction because of the balance between humidity and slightly colder temperature than the normal can occur. C/D temperature was just slightly lower than 60 F degrees as correction claim and the addition of humidity was a perfect opposite greater role of balancing. M/T temperature was colder, the % humidity was not enough to balance, for this reason they applied the other side of correction. This is why in uncorrected condition the car was faster.
  4. Guibo Well-Known Member

    Wait, you're losing me here. Are you saying the published data is the raw, uncorrected performance? You seem to be saying that when claiming the car, if corrected like Motor Trend, would be faster than 11.5 @ 124.
    Humidity was pretty much the same between C&D and Motor Trend, only 3% difference. And as I've already explained, some humidity in some cases can be better than standard of 0%. Of the factors listed between the two tests, that leaves temperature and pressure. Pressure, we already know, should not be corrected in turbocharged cars; Motor Trend's test of 29.75 in-Hg would have been so close to SAE1349 standard of 29.234 anyway and what minor difference is consistent with applying a slowing-down factor to that GT-R (if any correction should be made), since the measured air was denser than standard. That leaves, then, temperature: Motor Trend were right to apply a slowing-down factor (for a measured 66.9°F vs SAE J1349 standard of 77°F). So C&D should likewise have applied a slowing-down factor (if any correction is to be made) for a 52°F measurement vs 60°F SAE J607 standard. So why would C&D then publish (and in all likelihood use) a correction factor of 1.041103 for speed and .96084 for ET?? If you still don't think they used it, why would they publish it as such?

    C&D's temperature was even colder by 14.9°F and % humidity was close. Shouldn't they both have been on the same side of correction?
  5. F40 LeMans Active Member

    Again. C/D temperature was 52 F degrees and it's just lower than the standard by 8. Humidity here has the higher role in balancing the correction. The 33% is enough to over compensate the difference by the temperature. Even more explained if humidity was 55% as verified. This is why correction should be much closer to 1 than the writen by the driver. And indeed it seems he lost a pair of main decimals.
  6. Guibo Well-Known Member

    But it's still lower and the simple fact is their SAE standard is lower than that of Motor Trend's anyway.
    How do you know for a fact that humidity should have the higher role in balancing the correction? As I've said (and which you have thus far not refuted), some humidity in the air can be good for advanced ignition timing. Road & Track even said as much in comparing their Infiniti M45 0-60 test numbers, taken from the same car but at different times:

    100 deg F, 23% humidity: 6.7s
    68 deg F, 65% humidity: 6.1s

    Much greater humidity, yet 0.6s faster in 0-60.
    Even if humidity has a higher role, you can't know that the 3% is enough to knock the correction onto the other side and by those factors that make a 119 mph car into a 124 mph one. All you can say is that the slowing-down correction might be a little less; instead of 1% or whatever MT used, it might be 0.5%. In other words, both on the same side. A turbocharged car, if it senses less oxygen due to an increase in water vapor, still has the means to increase boost until it meets some predetermined parameter for air density.

    Look at their recent Z06 vs GT-R vs 991 test, where temperature was similar (53.9 deg F) but humidity was much higher (71%): no correction noted to the data.
    http://media.caranddriver.com/files/2012-porsche-911-carrera-s.pdf

    You can't know they lost a pair of main decimals. You arrived at that flawed conclusion using incomplete and misinterpreted data. The simple fact is, we can reasonably assume that those are the correction factors they used (you've provided no evidence that those are not the numbers) and their published data is after corrections are applied. It's not the raw data as you claimed. You can no less refute the factors anymore than you can pull correction factors from another test and arbitrarily apply them here; it would sort of undermine the whole point of even recording things like humidity, temperature, pressure, etc, for each individual test.
  7. Guibo Well-Known Member

    Let's put this theory into its grave by using the calculator that C&D did use. They've published it online, available here:
    Correcting for Weather - Feature - Car and Driver

    Input the data from the GT-R test and follow their directions for finding the vapor pressure. You'll get these results:
    [IMG]

    Here's their correction for the 997.1 Turbo:
    [IMG]
    Note the "1/2" correction note. The published correction value is indeed halfway between the specified values of the spreadsheet, which further supports my case that the published values are after corrections are made.

    From this, we can conclude:
    1) C&D didn't even use the same online correction calculator that you used
    2) C&D's calculator didn't even take into account for humidity so your "balancing in weight of humidity" theory appears to be false
    3) C&D applied a full correction to the GT-R data in contrast to their practice of using 1/2 correction for the Turbo; in the 458 vs MP4-12C vs GT2 RS test, only the Ferrari was given the full correction while both turbocharged cars got only 1/2 correction
    4) C&D's calculations didn't "lose a pair of main decimals" as you claimed
    5) C&D's calculation seems heavily dependent on not humidity, but temperature (as I've stated) and heavily slanted toward pressure, as a correction for temperature should have made the GT-R slower, not faster as their own weather correction page says
    6) From this we can see that the mule indeed did record a 1/4 mile time of 11.97 @ 119 mph before corrections, which is no faster than many customer cars (it's slower, actually) or production-spec press vehicles (like Motor Trend's 11.51 @ 120.71 uncorrected).

    It's becoming even more clear now that your agenda to make this GT-R faster than it really was has been based on missing data, misinterpreted data, and data that was incorrectly manipulated by C&D in a manner that is inconsistent with what we know about turbocharged cars. C&D's factor that pushed the GT-R from a condition of being faster than it really was (compared to the opposite correction method by Motor Trend) seemed heavily dependent on the reduced pressure which is likely the result of the high altitude testing. But by their nature, modern turbocharged cars can compensate for this pressure difference. And that is not even taking into account the cold, dense air that both naturally aspirated and turbocharged cars can benefit from.
  8. Mafalda Active Member

    nice, unfortunally... it doesn't work
    "A car will run faster on a cool day than it will on a hot day because cooler air is denser and contains more oxygen, allowing the engine to burn more fuel. Similarly, high barometric pressure produces more power than low pressure, and dry air has more oxygen than moist air. So how do you know if a quicker run was due to the new exhaust or more favorable weather?"

    ok, in general agree, but:
    1. the difference between 11.5s @ 124mph and 12.0s @ 119 mph cannot be explained with a nice day of spring;
    2. Not all engines react in the same way, and modern fuel Inj can give and hand...;
    3. why this is the only test so fast? all other GT-Rs were tested when full summer? ;)
    4. according with (2), I can also send many examples of identical tests under different wheather conditions
    - 430 Scuderia (the same unit) tested by QR @ 12.c, and Auto @ 29-30.c: same performances ;
    - F40 tested by QR (32.6°C) and Auto (also tested in summer) , by Ruoteclassiche in winter: 0-260 20s all!! I can continue....
    5. if this GT-R was tested at zero degrees.. perormances? 11.0s @ 130 Mph?!?!? 10.5s @ 140 mph isf -8.C?!?!!?!??
    6. Why you never speak about C.F. and / or weather conditions, when we talk about Ferrari?

    6 points, just one reason and, as usual, two meters and two measures
  9. Guibo Well-Known Member

    Exhaust? I didn't see the GT-R test where they ran it stock then ran it with a changed exhaust. Quit clouding the issue and stay on topic.

    1. In which test did a GT-R actually run 11.5s @ 124 mph? I think you still don't understand: the C&D mule never actually went that fast. Those figures are after correction. 11.5 @ 124 mph vs 12.0 @ 119 mph can be explained by the correction factor they used and published in the test. Nobody here is saying that mule was fast because of spring weather; that mule was never fast to begin with, only made fast after a correction that doesn't make any sense.
    2. Modern fuel injection is not going to increase intake manifold pressure without some kind of forced induction or other power adder. (See where you come up short when talking about barometric pressure in your quote, as it relates to turbocharged engines.)
    3. This test isn't so fast. Look at uncorrected C&D vs uncorrected Motor Trend (Motor Trend was faster). I've already posted up customer cars that were faster uncorrected and that's not even taking into account that a dragstrip timing light records speed averaged over the final 60'; true 1/4 speed as verified by GPS would be even higher
    4. So what are you saying...naturally aspirated cars can't take advantage of weather? ;) In any case, you don't have other cars in test to measure. For example, in the QR F430 test, we have a Gallardo to compare and in the Motor Trend test we have customer LP560-4 and F430 tested on same day in likely very similar conditions...
    Simply showing two tests done in two conditions recording similar performances is not proof that engines (both NA and turbocharged) can't take advantage of cooler, denser air. That kind of theory has about as much relevance as a broken clock (which can actually be right at least once a day)
    5. I don't have to say that at all. There may be an upper limit to the parameter to ensure safety of the engine, but where that is neither you nor I can say. Stay on topic: We need only look at the published figures and the correction factors to derive the actual speed of this GT-R.
    With regard to C&D's correction factors, if you choose a high enough elevation (and treat the GT-R with a full correction like you would with a naturally aspirated engine), a 130 mph trap is possible even with 32 deg F input temp. It all depends on how you've manipulated the raw figures. It doesn't mean that the car actually went that fast.
    6. Is there some test of a Ferrari that is in doubt due to correction factors? Autocar doesn't use correction factors.

    Wrong. Come back to me when you can find a suspicious Ferrari test with poor corrections. Then we will talk about two measures and why you should apologize for calling me a "pathetic liar" when you clearly said 0.01 (not 0.1). Instead of incorrectly flaming me, address the topics on hand. Like your response (thus far still missing) as to why you do not defend McLaren/Mercedes/Dodge/TVR/etc when they too have been called out for test processes on various forums.

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