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12-16-2007, 02:16 PM | #67 | |
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Just thinking of something not so witty ///M3 E92 '09 Jerez Black | 6MT | Ext Fox Red | Tech | Prem | 19s |Heated Seats | iPod |Smartphone | Euro Deliv June 09 Sold: 540iT / 530i / 323i |
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12-16-2007, 03:04 PM | #69 |
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I'm going to chill and wait for the CAR / EVO / C&D test
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Just thinking of something not so witty ///M3 E92 '09 Jerez Black | 6MT | Ext Fox Red | Tech | Prem | 19s |Heated Seats | iPod |Smartphone | Euro Deliv June 09 Sold: 540iT / 530i / 323i |
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12-16-2007, 04:59 PM | #70 |
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I KNOW the numbers are bogus...explain this...
nissans rating 480 hp @ 6,800 rpm... 430 lb-ft torque @ 3,200 - 5,200 rpm. 59.2 kilogram meter = 428.1944188307 pound foot isn't it a heck of a coincidence that the two dyno numbers match nissans ratings almost perfectly? 482 vs 480 HP and 428 vs 430 ft lb ...hmmmmmm also at 5250 HP = Torque, the lines cross... HP ~ 465 or so... T ~ at peak 426 or so... they don't match...hmmmmmmm but wait, they HAVE to match HP = rpm/5250 x T...at 5250, HP = T...period... they also state max torque of 430 from 3200 to 5200 peak T is only 4700 to 5200, well shy of the claimed oh yea, claimed HP peak is 6800, this is ~6100... it's off everywhere... rpm.....dyno T......dyno HP.....calculated HP 3000....130.............60...............74 4000....330............275.............251 5000....428............440.............408 6000....380............480.............434 the ratio window (4.660) should be 1.248 x 3.7 ~ 4.618...4th gear run... dyno speed at T peak 78 mph/5130 rpm...but calculated speed using the ratios is 91 dyno speed at HP peak 92 mph/6115 rpm...calculated is 108... this, and the HP/T mismatch at 5250 screams rigged... |
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12-16-2007, 05:35 PM | #72 |
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12-16-2007, 05:40 PM | #73 |
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Well sure if they were from different dyno runs that would make matters worse because it would be saying that Nissan quality control was out the window, two engine offering totally different results.
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12-16-2007, 06:01 PM | #74 | |
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why would they do that...even if they could... btw: the file number at the bottom is the same....and these aren't print-outs, it's a real time screen shot... iirc dynos CAN'T measure HP...they measure torque and covert it to HP... so which is right? the HP or the torque... they are BOTH wrong, I'm guessing torque is 10% high...and the HP curve is complete BS...the data was manipulated between the torque readings and HP calcs/display...don't ask how I deduced this...I'm pretty sure it's close... adjusted...less 10% T rpm.......T.......HP 3000....117.....67 4000....300.....226 5000.....385....367 6000.....380....391 this would give a power loss of (480-391)/480 x 100 = 18.5% that's a good number for an awd car with high drive rations (Fd = 3.7) that's the point... |
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12-16-2007, 06:41 PM | #75 |
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Blunt is fine, confused/mistaken is not. If you are still talking about shift times I say BS. You need to get over my appropriate criticism of your past speculation, keep that on that thread and stop tyring to simply turn the tables here. I provided lots of real and accurate actual data along with semi-subjective reviews from journalists about the "feel" of each tranmission, combined with my direct experience with SMG II which pretty much matches what everyone say/knows about that system. I would like a chance to address anything you believe to be speculation (I think I already have done so by the way, but if not, I will keep going).
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12-16-2007, 09:09 PM | #76 | |
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- I contend that the dyno test is an unknown quantity. We don't know about the dyno, we don't know about the particular car (chipped or not, for instance), and though I haven't glanced at the results myself yet, now it seems that there may be an issue with the validity of everything about that test. - The 'Ring test isn't indicative of anything I can think of other than it's a flyer. The car may be naturally fast (more on that in a minute), or in fact the car may be under-rated. - And for quarter mile times? I think they're pretty much spot on where they ought to be. When I simulated the GT-R and came up with results that were very close to spot on (according to Nissan's numbers), that was kind of interesting. When you reminded me of the drivetrain differences (properly, I thought), I ran the Porsche not to somehow validate the tool, but to find out how the Porsche simulation would also turn out. Obviously, if it too came out pretty much spot on (which it did), then looking at the compared results makes sense, since both cars have awd with the resulting penalties. Result? The Porsche was faster then the GT-R in the standing quarter mile (by a tenth and a single MPH), and if you do power to weight, it should've been two tenths and two mph faster. Wow! That's a whole tenth and one MPH those Nissan bastards aren't owning up to. But wait! The Nissan has the hot-damn trans and the Porsche (equipped with the "better" of its two inferior choices) has a damned torque-converter automatic, which we know (especially you) takes power to run. The fact that these cars are so close, with the Porsche being a little faster according to Car & Driver vs Nissan marketing, should give you pause, Swamp. On to the 'Ring. My contention is that the GT-R is a superior handler compared to the Porsche Turbo, and while everyone on the planet hasn't tested the GT-R yet, those who have think the handling is the best part about it, while we *know* what test drivers think of the Porsche at ten tenths. My favorite quote is "It takes three feet to driver a Porsche Turbo fast." OK, the current 911s are the best ever, but they still wield the threatening sword of physics at ten tenths. The Nissan is nearly as fast in a straight line (probably due to its transmission), but definitely quicker in the twisties. It turns out the Nissan is a little quicker around the 'Ring, and I'm guessing that while it was undoubtedly very exciting during those laps, it was very relaxed compared to the Porsche Turbo. My guess is that the legendary Rorhl ran up a dry cleaning bill during that 7:40 pass. Then there's the Edmunds article, which waxed poetic about GT-R handling, but declared the Porsche to be quicker in a straight line (out on the street) in side by side and follow the leader runs. The Porsche could not keep up in the twisties, but was the quicker car in a straight line. Swamp, why doesn't that give you pause. The Porsche should be mildly quicker in a straight line and apparently it is. As for your CarTest runs, I have trouble with giving them any credibility at all just yet. However, I'm betting that if you run the Porsche, it will be a bit ahead of the Nissan, just as in my simulations, but you'll also show the Porsche as being under-rated. Finally, there's that whole SAE thing. Almost certainly, the Nissan will show "correct" numbers on the dyno or the SAE will throw them out - and of course if you're correct then the GT-R will be a comparitive pig when our magazine guys give it a run. Won't happen, though. I'd bet quite a bit that the SAE numbers have already been run under current (SAE representative present) rules. Nissan is not only betting at least a couple of decades of legendary performance by past iterations of their baby, they're also betting that the car will be a worldwide legend, or the entire Japanese car industry loses face. Remember "The Usual Suspects"? "A legend isn't a legend if it doesn't die." Nope. The data points we've discussed collectively point to the fact that the jury is still out. Personally, I think the Nissan will be on the up and up, but we'll see. Bruce |
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12-16-2007, 09:32 PM | #77 |
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the 997TT never ran a 7:40...
Walter 7:49 7:54 --- 156.456 km/h -- Porsche 997 Turbo, 480 PS/1620 kg (sport auto 06/07) http://www.supercars.net/PitLane?vie...D=2&tID=126501 both on PSC's there is no way a car weighing 300 lbs more with 15% less torque on street tires can beat those times in the wet by 11 to 15 sec. as I have shown those dyno numbers can not be true...CAN NOT... T (lb ft) must equal HP (SAE) at 5250... MUST!!! yet T=428 and HP = 460... |
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12-17-2007, 02:52 AM | #78 | |||||||||
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One example of dyno runs I have seen for the 997 Turbo are here (just from a quick google). They give 429 hp/457 tq and if you believe the manufacturers claimed outputs this gives a drivetrain loss for hp at 11% and tq at a mere 4%. Possible or not, you tell me? I'd say this is some fairly good evidence of under-rating here as well, this would also be somewhat consistent with your QJ runs allowing for the higher drivetrain loss being balanced by the under-rating. Quote:
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You sure keep waffling on whether or not there is evidence here. I agree that the jury is out in that we can not say absolutely with no doubt that the car is under-rated. Perhaps the only way to settle that would be by removing the engine and putting it on a very accurate, factory quality engine dyno and that probably is not going to happen. I agreed that my thread title may have been a bit premature or aggressive but no way will I back from the claim that there is evidence and good evidence for an under-rating. |
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12-17-2007, 02:58 AM | #79 | |
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However, Art, the 20" Nitrogen filled Bridgestones (depsite being runflats) on the GT-R are probably just ast sticky as PSCs |
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12-17-2007, 05:32 AM | #80 | |
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It's easy to explain why SMG style gearboxes can be felt regardless of the speed of shift that's done but not DSG, sorry I can't understand what is going on that at all. So if you can explain it in a way that sound logical to me, please feel free. P.S. The more I think about it the more I believe Nissan's time between changes sounds about right and what you are feeling is the brief stop in acceleration that you don't get with DSG, admittedly all 0.2s of it. |
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12-17-2007, 08:15 AM | #81 |
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Now we have your real motive. Despite numerous videos and the close inspection of nearly every motorjournalist in the world, the 7:38 is not to be believed
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12-17-2007, 08:17 AM | #82 | |
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Try this...
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Try this... http://wheeltalk.fancal.net/?p=476 |
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12-17-2007, 12:37 PM | #84 | |
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Next more on the subjective side I suspect folks are comparing the GT-R box to the VW/Audi boxes and perhaps if the Nissan box shifts a bit rougher this is the source of those comments. It is not inconceivable that simply managing the much greater power and torque of the GT-R required shifts not quite as smooth as the VWs/Audis. Lastly there is the issue of software. As I have mentioned before the software component of a DSG/DCT is a critical part of the entire system. The entire nature of the shifts, their feel, the speeds and to some extent their smoothness and the quality of the downshift throttle blips will all be able to be tailored to some extent with software. We are talking about rates, ramping profiles, sequencing and next gear guessing all happening in millisecond resolution. To deny the importance of software for such systems is absurd. P.S. My favorite page that explains the mechanicals of all sorts of transmissions is here. It is really worth a look and read. Excellent web page. |
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12-17-2007, 12:53 PM | #85 | |
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5-10 seconds for each of these effects really adds up to a huge difference (25-50 seconds!). Furthermore since at least 3 of these factors are involved for sure, this makes the time simply much less special. A lot of folks are thinking along these lines. I am ignorant of points 1-3, 4 is "impossible" and the car is truly magical per point 5. This reasoning is seriously flawed, I don't see how anyone who knows anything about fast cars and lap times can argue along these lines. |
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12-17-2007, 01:14 PM | #86 | |
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I did think about the power difference between VAG DSG motors and this GTR but then remembered that the Veyron is basically using the same gearbox and it's got twice the power and torque of the GTR and yet it's shift is totally smooth, just like the same as in any other VAG with DSG. I might be down to the extra shafts involved in their awd system that aren't there in either VAG product. Frankly we could discuss this till the cows come home and still won't know the reason. |
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12-17-2007, 02:02 PM | #87 | |
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Yes, a combination of all those things and more are making the time possible, that is obvious on the face of it. Nothing about any of those factors makes this car less special. Is a Veyron less special because we can understand how slick aerodynamics and 1000+ bhp can make a 250+ mph capable car? |
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12-17-2007, 03:22 PM | #88 | |
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Last edited by swamp2; 12-17-2007 at 03:44 PM.. |
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