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I have been expecting 7:20 out of the Spec V, at very least low 7:20s. I have been feeling that the Spec V will be, at least for a while, the fastest factory production car. Nissan wants to time the release of the lap times with .... something.
 

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Yes I read that too from the same place. Apparently the spec-v has a time that's unknown. Way back in testing I was told it was doing about 7:25 is but those were not idea conditions. Nissan plans to go back for a faster time and kris re confirmed this info since he talked to the man himself in japan (gtrblog kris). The previous info was posted on my old blog which the google cache doesn't work anymore :(
 

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7:25 was also an alleged spy shot time from many months ago. I'm expecting the time to be much better than that.
 

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Left side of chart looks like it's comparing power to weight ratios of various cars.

On the same website there are some more graphs down the page. These look like charts showing the additional torque values with the over-boost feature.

Someone on the forum has to know Japanese so they can translate. We are all dying to know!
 

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Discussion Starter · #8 ·
Another slide shows they're going back to 'Nur in April '09.. so we have a couple months left to speculate!
I saw that too...

Either their going back in April or their releasing the time in April...I also suspect they are very concerned about the timing of releasing the Nurburgring time. Maybe a US release date set in April????
 

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Just translated some of this no mention of the ring time but these are interesting:

next year is "M Spec" out of the V Spec special some segments the "performance oriented version appeared. Mr. Mizuno, next is also GT-R show the evolution of M Spec version out to say it is what version, or were not disclosed.

357 kW (485 PS) and 588 Nm (60 kgm) to generate specially tuned VR 38 DETT. The steering wheel and high gear Harvard boost switch is pressed, about eighty seconds with a torque 608 Nm(62 kgm). overtook switch for the use of ascents higher gear used to be in the fuel economy improvements says
 

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To get close to 7:20 this car must be making 550 horsepower...Looking at the exhaust system for the Spec V, plus the overboost feature this car has to be making over 500 horsepower. The overboost button is good for 15 pound feet of torque only, which seems like a very low addition. The 997 TT also has an overboost function which raises torque by 45 pound feet. Perhaps Nissan is being a little coy about the actual power numbers? How much extra boost is the Spec V getting for the overboost?
 

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To get close to 7:20 this car must be making 550 horsepower...Looking at the exhaust system for the Spec V, plus the overboost feature this car has to be making over 500 horsepower. The overboost button is good for 15 pound feet of torque only, which seems like a very low addition. The 997 TT also has an overboost function which raises torque by 45 pound feet. Perhaps Nissan is being a little coy about the actual power numbers? How much extra boost is the Spec V getting for the overboost?
Although I am almost always in agreement with you, I don't think you can accurately calculate the estimated power levels of the Spec V going by lap times, especially considering all of the other improvements done to the Spec V. Nissan claims the CCB's are capable of producing another .6 g's more than the regular steel brakes, which is substantial difference at such high speeds seen at the ring. Added to the fact that the rotors reduce rotational and usprung weight, as do the lighter rim/tire combo, WHP figures could be up by as much as ~3% just from the reduced rotational mass. The reduced curb weight will help the car in all performance aspects as well. The tuned springs, dampers, and swaybars will likely be worth a couple of seconds. The increased midrange torque will help corner exit speeds a good amount, which is an advantage carried all the way down a straightaway.
 

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If I were to guess it would be max of 1.1bar or 16psi. But knowing nissan its probably less. Cobb also mentioned the max boost of the actuator is about 16psi. For 80 seconds that's not bad. Btw how much boost will make 62kgm of torque? That would be a better guess.
 

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Judging by the increased TQ of the V-spec (when the overboost button is pressed), I would venture to guess that the boost tapers off toward redline, to a level identical to that of a stock GT-R. Peak boost in the mid rpms was probably only raised a pound or two.
 

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Remember back a few months ago, during the controversial 7:29 lap, attained by the base model: --such time was achieved mostly by only changing the subframe bushings and factory tire options. Now with the Spec V's myriad tweaks to suspension, it is possible to connect the dots: Nissan doesn't need 550hp to achieve near 7:20 times.

They wouldn't affix carbon brakes to a GT-R for looks only. The GT-R is a form-follows-function surgical speed knife. Those are there because the car goes faster.
 

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Although I am almost always in agreement with you, I don't think you can accurately calculate the estimated power levels of the Spec V going by lap times, especially considering all of the other improvements done to the Spec V. Nissan claims the CCB's are capable of producing another .6 g's more than the regular steel brakes, which is substantial difference at such high speeds seen at the ring. Added to the fact that the rotors reduce rotational and usprung weight, as do the lighter rim/tire combo, WHP figures could be up by as much as ~3% just from the reduced rotational mass. The reduced curb weight will help the car in all performance aspects as well. The tuned springs, dampers, and swaybars will likely be worth a couple of seconds. The increased midrange torque will help corner exit speeds a good amount, which is an advantage carried all the way down a straightaway.
I agree with your post that it is not accurate to say a certain time at the Ring equates to X horsepower. But from studying the GT-R's well documented 7:29 lap time against the Zr1 and Viper ACR videos it is apparent that particular car had more ponies under the hood then a regular GT-R. To go 9 seconds faster again this car will need at least that power level, or more to achieve it. The carbon brakes, suspension upgrades and perhaps most important of all the reduced unsprung mass along with improved mid range grunt will all add up on a 13 mile lap. I hope Nissan hits that number and does a video documentary of the attempt to dispel any internet bench racing....
 

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Im sure the Spec v has a 20 or 19 in it but the acr has that in it as well. Its posted time was done on a half day track rental with the driver missing two shifts. Just something to think about before you call it the fastest production car on the ring. And lets not even get into that the spec v is almost 60 grand more.
 

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But from studying the GT-R's well documented 7:29 lap time against the Zr1 and Viper ACR videos it is apparent that particular car had more ponies under the hood then a regular GT-R.
Studying? What kind of computer modeling software did you use? Were you able to include parameters for the difference in spring rates, suspension geometry response, bushing movement, 3D Aero dynamic flows, drag, lift, downforce, gear ratios, chassis rigidity, time varying tire to ground pressures, load spikes, tarmac surface attributes and variations, stability, AWD algorithms or lack thereof, driver confidence etc.?

I hope your model was not limited to a youtube click and drag approach and subsequent power/weight ratio comparison.

Some notable prior anomolies of the "p/w ratio is all that matters" approach:

996GT3RS - 276hp/tonne, 272km/h nurb top speed
C6 Z06 - 350hp/tonne, 270km/h nurb top speed

997 GT2 - 360hp/tonne, 293km/h nurb top speed
C6 zr1 - 425hp/tonne, 280km/h nurb top speed

The Viper ACR's not using 5th gear also resulted in a rev limiter
governed 4th gear top speed of 160mph at the nurb.

You might want to read Edmunds attempt at a top speed run in the ACR
at Bonneville for a great lesson in how just two simple variables
like drag and gear ratio can have devastaing effects on what seems like a great
p/w ratio. They hit a top speed of 173mph........at Bonneville.
 

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When they go back to the ring someone mail them an accessport!!
 

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The first ring time was done not in idea conditions. That and the slight upgrades and tires in better conditions is what made the time better the second time for 7:29 lap.
 
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