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12-30-2008, 07:05 PM | #1 | |
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MotorTrend says Nissan not lying about GT-R horsepower:
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12-30-2008, 08:03 PM | #2 | |
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Funny Nissan hasn't wanted to back that time up with 1 or 2 other production GT-Rs. The GT-R's engine seems to be so finicky though. Some seem to run strong enough to trap 120-121 mph, others only 115-116 mph and the average seems to be in the 118-119 mph range. That seems like a good 50 hp difference between the production cars. |
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12-30-2008, 08:15 PM | #3 | |
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Exactly, very insightful IMHO. +1 on the post just above as well. This is the crux - the GT-R's have shown a very large variation, track and strip especially. Do you have any more information? The quote does not indicate the test method (very curious how they got this without disassembly). Did they mention the total drivetrain loss figures? Wouldn't it be reaonable to assume a near RWD type effect from the advanced transmisson lowering losses during hard acceleration? |
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12-30-2008, 11:26 PM | #4 | |
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Here's more info from MotorAuthority.
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12-31-2008, 03:04 AM | #5 |
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^ Thanks. Idiot magazine guys, Motortrend says "significant" losses and MotorAuthority says they are "quite good" for an AWD car. I say if they peak at 17% (100 mph is very close to redline so they should peak there) that is pretty darn good. However, I question the ability of this "coasting method" to properly track losses under WOT acceleration and the control of front/rear power bias through the ATESSA system (as mentioned above).
FYI original Motortrend article here. Seems there is a small error in their math as well. They claim the losses range from 88 to 93 hp. The graph I saw showed a maximum loss of 98-99 hp. With their actual drive shaft power measurements the losses compute out at 20% (max loss/max hp - not taken at the same rpm). However, at peak hp (about 6k rpm) the losses were 87-89 hp or 18%. Since the cars peak hp is not at peak rpm this distinction matters. Either way I am not sure how they come up with 17%. I'd say 18% is the best figure. |
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12-31-2008, 05:00 AM | #6 |
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I'm not a gambling man but I'd put my money on it that Nissan probably destroyed the 7:29 car after its monumental run.
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12-31-2008, 07:53 AM | #7 |
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I bet the 7:29 car is sitting in Nissan's HQ for all to see. Though this does not mean anyone will ever get to test these theories out.
I won't get into a debate on dyno figures with awd cars, needless to say I have ever agreed with any figures produced. Though due to their differing designs I would reckon you couldn't standardize the lose figures in to same way as can be done with either fwd or rwd cars, best to look at the performance results like what swamp has done and guesstimate the HP/weight. Also best to disregard the 1/4mile figures and look at ingear figures, say 30~130mph to gauge any PTW figures, this way traction is taken out of the mix which will blur figuring cars like the GTR. BTW, as an example of how different results can be a (stock)GTR has been dynoed at an estimated 560hp in Japan. |
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12-31-2008, 10:28 AM | #8 | |
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12-31-2008, 12:44 PM | #9 | |
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MT like many others are stabbing in the dark at guessing the true output of the GTR by using the dyno approach. |
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01-01-2009, 12:39 PM | #10 | |
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In fact all negative comments directed towards the GTR always happen when the car is equipped with Bridgestones and might explain why in the UK at least all 2009 GTRs will be equipped as standard with Dunlop rubber. |
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01-01-2009, 05:18 PM | #11 | |
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I can understand grip off the line (therefore the ET's may very be a couple tenths) and certainly in handling variations with different rubber but unless one of the tires is like glue and the other spit, road friction differences would be minimal and I would suspect so would tire weight. Therefore trap speeds should by minimally affected by the tire choice. Any car will have a slight variation between each that will affect trap speeds by say 1-2% but the GT-R's trap speeds seem to fluctuate by as much as 5+% on stock cars. That's got to be mostly because of power variations between each car. Don't get me wrong, I know the GT-R is fast (I did some canyon runs with them and they could easily lose me as my 335i just wasn't up to the handling task of those cars, nor the straight line speed) but I'd be ticked if I bought a GT-R and got one that couldn't do better than 12.0 @ 115-116 mph when others are doing 11.6-11.7 @ 121 mph. |
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01-02-2009, 03:57 AM | #13 |
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Driver72,
I understand what you are saying but when you actually view the tests that have been done, all the slow ones with the one exception have been on Bridgestone rubber. In fact it was commented by one of the magazine (can't recall which) that the second GTR tested was a full 5mph slower and that one was on Bridgestones instead of the Dunlops and they found excessive wheel spin in comparison to the Dunlops. There may be more to this than first meets the eye, especially as the GTRs incredible times are believed to be the work of it's launch control. |
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01-31-2009, 12:30 AM | #15 | |
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