|
|
10-08-2008, 01:12 PM | #155 | |
Colonel
99
Rep 2,000
Posts |
Quote:
When you and I last went around about this, you were convinced that the GT-R was quite noticeably underrated, and I took the position that the jury was still out. Now, with full U.S. data available, it's pretty clear that the car is rated about 10% low, based on quarter mile trap speeds and chassis dyno data. There's also the tidbit that, as far as I know, the power for the GT-R isn't SAE Certified, in spite of Nissan's previously stated policy of certifiying all of their U.S. cars. A note on quarter mile trap speeds: If you throw out the obvious sick cars (or, as Nissan stated to C & D, those in less-than-final states of tune), and attribute the 124+ trap speed example to inappropriate meteorological adjustment, then the U.S. spec cars seem to be coming in at around 120 mph, which is consistent with a rating around 10% low. So I'm pretty well satisfied that the U.S.-spec cars are rated low, except I'd like to reintroduce a tantalizing (though perhaps far-fetched) possibility that we lightly discussed before. We know that Nissan has an indistinguishable-from-magic launch control algorithm. We also know that it is doing equally fascinating things in terms of power apportioning while cornering at speed. What if it's doing equally cool stuff down the straights? I've read that the car can apply up to 98% of full torque to the rear wheels, so what if it does that under full acceleration (assuming near-zero wheelslip) whenever it's not pulling lateral Gs? If that is the case, the car's roughly 410-420 HP dyno numbers come up closer to the factory number when corrected for a normal 2wd factor of 85%. It would also be quicker down any and all straights than one would otherwise suppose - including the drag strip. That, combined with the ability to mat the throttle at or before each apex, would help explain those extraordinary track times. Bruce |
|
Appreciate
0
|
10-08-2008, 05:11 PM | #156 |
Brigadier General
529
Rep 4,021
Posts
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals
|
Nissan Responds
http://www.autoblog.com/2008/10/03/n...t-r-ring-time/ Kudos to Nissan for taking the highroad and not responding to Porsche's whining. Earth to Porsche - build a better 911
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
|
Appreciate
0
|
10-08-2008, 05:13 PM | #157 |
Major General
1072
Rep 8,008
Posts
Drives: i4M50
Join Date: Oct 2007
Location: No where fast
|
Bruce,
As always........ well almost always, we are in total agreement about the GTR and it's incredible achievements, both on the dragstrip and around the track. The figure of 10% under rated is roughly my estimates as I see it as 480PS and my 525hp (not PS) is roughly about this percentage. On the ability of the awd system to shift it's power about, normally what happens is the system looks to shift as much as 45% over the front wheels (where most of the weight is) for the for the briefest of times (a tenth or two), to help get the ball rolling and then steadily shifting more towards to the rear as the weight tranfers rearward due the effects caused by the acceleration, whether it's able to shift the entire amount to the rear is something I know little about, usually this only happens when total grip is lost at either axle (i.e. ICE). |
Appreciate
0
|
10-08-2008, 07:21 PM | #158 |
Brigadier General
3639
Rep 3,241
Posts |
Honestly there is nothing special about the GT-R on a dragstrip. A stock Z06 beats it from a roll and dig. Around the track is a different story.
|
Appreciate
0
|
10-08-2008, 09:06 PM | #159 | |
Colonel
99
Rep 2,000
Posts |
Quote:
From a dig, the Z06's superior power to weight means it'll pull on the GT-R, and of course that's also why the Z06 has better trap speeds. Makes better noises, too. Bruce |
|
Appreciate
0
|
10-08-2008, 09:25 PM | #160 | |
Captain
15
Rep 645
Posts |
Quote:
I want to see a GT-R throw down with an M6 from a roll. That should be a good race.
__________________
2013 Audi S6, Ibis White
2008 E90 M3, Jerez Black, Black Nappa, Brushed Aluminium, 6-speed, Premium, Tech, Cold Weather *sold* |
|
Appreciate
0
|
10-08-2008, 09:57 PM | #161 | |
Colonel
99
Rep 2,000
Posts |
Quote:
Bruce |
|
Appreciate
0
|
10-08-2008, 10:28 PM | #162 |
Lieutenant Colonel
48
Rep 1,664
Posts |
Just wait until the new M6 rolls out...
__________________
2008 E92 M3 Jerez Black,DCT,Fox Red ext,Prem,Tech,19", ipod/usb, CF roof and trim
2010 E91 328i Space Gray,Black int, M sport, most options 2007 Montego Blue 335i (retired) |
Appreciate
0
|
10-08-2008, 10:36 PM | #163 | |
Captain
15
Rep 645
Posts |
Quote:
So put yourself in the shoes of a GT-R owner. You've just plunked down at least $80K of your hard earned dollars for your twin turbo terror. Do you risk voiding your warranty to out launch that Z06? Remember, if anything goes wrong down the road with your trick DCT transmission, you stand the risk of paying out of pocket.
__________________
2013 Audi S6, Ibis White
2008 E90 M3, Jerez Black, Black Nappa, Brushed Aluminium, 6-speed, Premium, Tech, Cold Weather *sold* |
|
Appreciate
0
|
10-08-2008, 11:23 PM | #164 |
Captain
15
Rep 645
Posts |
What powerplant are they cookin' up for the new beastie? Something with forced induction?
__________________
2013 Audi S6, Ibis White
2008 E90 M3, Jerez Black, Black Nappa, Brushed Aluminium, 6-speed, Premium, Tech, Cold Weather *sold* |
Appreciate
0
|
10-08-2008, 11:32 PM | #165 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
I not only think it could do this fairly simple thing on the straights but I suspect it is likely that it is doing so. I don't know much about the pre face lifted AWD Porsches. Before the 2008 variant the AWD system was an in house designed twin wet clutch system. It is certainly capable of shifting power F to R and L to R but the devil is in the details as to how much power can go where, how quickly it can be adjusted and how often it is adjusted. There were rumors that they would be switching to a Haldex AWD system, perhaps to improve one or more of these specific features. Either way the AWD Porsches certainly can send more power rearwards as can most modern AWD systems from Audi to Subaru and from BMW to Mitsubishi. Such a system that can essentially make the car into a RWD system would certainly give you some advantage in that it would exhibit less drivetrain losses than a antiquated system with a constant 50:50 F:R power split. However, 5% (roughly 20%-15%) of 480 does not come very close to the 1.4:1 or 2:1 power to weight (weight/power technically) advantage that I brought up, nowhere close. |
|
Appreciate
0
|
10-09-2008, 03:22 AM | #166 | |
Brigadier General
3639
Rep 3,241
Posts |
Quote:
The Z06 killed the GTR from roll and dig, multiple runs. Both fully stock vehicles. And the ZR-1 that kills both vehicles in a straight line. The GTR is nothing special in a straight line. |
|
Appreciate
0
|
10-09-2008, 07:29 AM | #167 | |
Colonel
755
Rep 2,736
Posts |
Quote:
Secondly, Nissan must not have much faith in their transmission if they don't offer at least a limited number of launches within a timed period; let alone even one. It appears to me that Nissan wants to be king of the 911tt, Z06, Lambo, F-car hill so badly that they have resorted to exaggerating tmies and offering a basically useless option. If you can't use it once without risking blowing something and voiding your warranty, it should not be offered nor advertised. |
|
Appreciate
0
|
10-09-2008, 07:33 AM | #168 | |
Colonel
755
Rep 2,736
Posts |
Quote:
I love how the media has focuses so much on track times, yet basically ignores that 997tts, Z06s, etc, will just walk the GTR in any straight line run. Put all the data out there and let the consumer decide. |
|
Appreciate
0
|
10-09-2008, 04:45 PM | #169 | |
Colonel
99
Rep 2,000
Posts |
Quote:
Bruce |
|
Appreciate
0
|
10-09-2008, 05:49 PM | #170 |
Major General
1072
Rep 8,008
Posts
Drives: i4M50
Join Date: Oct 2007
Location: No where fast
|
We will have to wait until the car is sold in Europe before we will know if this is solely a US problem. Memories of the American M5 SMG cars spring to mind, maybe it's the warranty claims expected or the lengthy warranties given in the US that has sparked Nissan's reasoning.
Though I would reckon it was be a hard case to win for the manufacturer is it went to court. The judge would argue and rightly so that to offer it means it was there to be used. |
Appreciate
0
|
10-09-2008, 07:08 PM | #171 | |
Colonel
99
Rep 2,000
Posts |
Quote:
Too bad about the LC nonsense, though, and I don't know what the hell Nissan was thinking when they let all those magazine testers run in the 11.6 - 11.8 range with launch control when just folks can only do that at their peril. Bruce |
|
Appreciate
0
|
10-09-2008, 08:03 PM | #172 | |
Colonel
99
Rep 2,000
Posts |
Quote:
Having said that, however, and assuming I'm not screwing it up, lucid's formula predicts that the GT-R needs about 1,000 HP to get under a 7:30 at the 'Ring, and even the Porsche Turbo needs about 700 HP to get that 7:38. So for me, that formula falls down, at least when attempting to predict 'Ring times for cars at this level of performance. Bottom line: I believe the 7:29 was done with a bone stock, roughly 525 HP GT-R. Bruce |
|
Appreciate
0
|
10-10-2008, 01:25 AM | #173 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
What makes sense about cars with a 1.4-2.0 times better power to weight achieving lap times in the same neighborhood? We keep seem to be going back to the point that the car is somehow "magic" and can defy the laws of physics. It is good but not that good. |
|
Appreciate
0
|
10-10-2008, 04:46 AM | #174 |
Major General
1072
Rep 8,008
Posts
Drives: i4M50
Join Date: Oct 2007
Location: No where fast
|
By the way Horst originally tested the R8 on the ring and got a time of 8:04, recently he retested one and got that down to 7:56~58 (not sure which).
That is one hell of a drop for basically the same car. The bottom line is the ring can't use this type of formula. |
Appreciate
0
|
10-10-2008, 11:30 AM | #175 |
Brigadier General
529
Rep 4,021
Posts
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals
|
Have fun reading the bullshit that Nissan is trying to pull off with warranties....
http://www.e90post.com/forums/showthread.php?t=177088 http://www.m3post.com/forums/showthread.php?t=176138 Anyone know if there is any truth to the rumor that in Japan, the GTR uses the GPS system to see if the car went to a race track. If it did and was driven at the track, you had to bring it in for mandatory service for about $4,000 or your warranty would be voided? Anyone hear of this?
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
|
Appreciate
0
|
10-10-2008, 11:58 AM | #176 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
The bottom line is any metric subject to a large pool of systematic and random effects can use regression for prediction, almost all will demonstrate the obvious trends based on simple physics. There will always be variability and the models will cover that. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|