Porsche accuses Nissan

[homeforsummer]

What Joey said. It's like deja-vu reading through this thread.

 

[Robin]

Well according to Clarkson all the engines are different so maybe the one used by Nissian was slightly more powerful.

Or Porsche needs to get themselves a better "expert" driver... Sour grapes indeed! Like they would really tell the world if they had managed an equal time in the GTR... they arnt that stupid!

Surely there is a vid of the record time which Porsche could look at a see that the car was stock for themselves. Nice to see this is what they are spending R&D money on... buying other competitors cars, that one more sale for Nissan!

Robin

 

[Joey D]

Meh every automaker buys and tests other cars constantly, GM probably buys hundreds of Toyota's a year.

 

[Jim Prower]

That's true, but I don't see GM claiming that the Malibu is faster around the 'ring than a Camry...although that may or may not be true. Typically, that's done to "Reverse Engineer" components to make your car better. CAT does it with Komatsu and other tractors: I've seen their proving grounds.

Porsche stacked the odds in their favor with their test, and, honestly, it doesn't surprise me. I'm most apt to believe that independent 7:50 than Nissan or Porsche's times...but aren't 'ring times overrated? There's less time to lose at places like Tsukuba.

 

[nissman]

If you look at the super gt cars in japan Nissan dominates the porsche.

 

[Jim Prower]

That's got nothing to do with anything: The cars are in completely different classifications. The Porsches run in GT300, while the Nissan GT-Rs in GT500. Besides, in GT300 this season, the Porsche GT3s have been consistently near the front; can't say that about the GT-Rs.

 

[daan]

If you look at the super gt cars in japan Nissan dominates the porsche.

If you must make a point, make sure its relevent. 💡

 

[speedemon08]

AHEM!

The GT-R engines are made in a special lab, not a factory floor for one. the next fact is that they don't all produce the same amount of power. One mag had one that was rated at 507 HP, and the One that Porsche Had was Rated at 480 hp.

And another thing, they don't realise that this car can corner so fast, that headlights that follow the steering cant keep up, DUE TO 4WD, and the Porsche ONLY HAS 2WD!

The Nissan Seems completly valid, as I Reckon the Porsche Drivers Drove the car as much as they think they could handle, but knowing the GT-R, The limit is Much faster than what people think. Top Gear said this is the car to be Judge on the Handling and Acceleration Side of things

 

[Leonidae]

AHEM!

The GT-R engines are made in a special lab, not a factory floor for one. the next fact is that they don't all produce the same amount of power. One mag had one that was rated at 507 HP, and the One that Porsche Had was Rated at 480 hp.

and that was due SAE correction and wrong drivetrain loss factor.

And another thing, they don't realise that this car can corner so fast, that headlights that follow the steering cant keep up, DUE TO 4WD, and the Porsche ONLY HAS 2WD!

Porsche 911 turbo is AWD, just like GT-R.. Though, Porsche's AWD isn't as intelligent. secondly, GT-R doesn't have turning headlights. next time, listen CLOSELY what Clarkson says..

The Nissan Seems completly valid, as I Reckon the Porsche Drivers Drove the car as much as they think they could handle, but knowing the GT-R, The limit is Much faster than what people think. Top Gear said this is the car to be Judge on the Handling and Acceleration Side of things

and they used a mere engineer instead of their best factory driver, Walter Röhrl who has set their lap records this far..

 

[speedemon08]

Porsche 911 turbo is AWD, just like GT-R.. Though, Porsche's AWD isn't as intelligent. secondly, GT-R doesn't have turning headlights. next time, listen CLOSELY what Clarkson says..

WRONG CAR! i thought it was the GT2. (Screw the Porsche range.....)

 

[the Interceptor]

Dear speedemon08,

please distinguish your personal preferences from your opinion from facts. You know that this "Nissan GT-R vs. the rest of the world" thing has gotten so hot because there were so many rumours presented as fact and so much false and misinterpreted information around, which is incredibly hard to put right.

Thanks mate! 👍

 

[Rusty*]

I as a basic idea agree that if you wish to pull the best lap possible or near to it that you can in any one car, then you must practice extensively in that car. So if these people who where driving the car have different skill levels and have had different amounts of practice...then isn;t it obvious that the lap times are going to be different and favor the driver with more skill and practice? Did Porsche honestly expect to match Toshio Suzuki's lap with a driver who has had far less experience in the GT-R? Come on... Mr. T Suzuki has been Driving Nissan GT-R's for a long time and was with the development team and testing team for the new GT-R every step of the way. When you have an unobjective look at the facts then it can be clearly observed that Porsche has come to a false and misleading conclusion, one they new would obviously spark controversy, that fact that Porsche have chosen to do all this does not speak highly of there Character.
Rusty*

 

[the Interceptor]

We don't even know how Porsche set up the GT-R. Did they put the drivetrain, the suspension and the traction control in race mode?

 

[Joey D]

We don't even know how Porsche set up the GT-R. Did they put the drivetrain, the suspension and the traction control in race mode?

I wouldn't doubt it, I mean I would assume they know what they are doing. But you are right, since there is no confirmation one way or another it's all speculation.

 

[nissan tuner]

So where's the video of Porsche's run with the GT-R?

 

[Danny]

AHEM!
And another thing, they don't realise that this car can corner so fast, that headlights that follow the steering cant keep up, DUE TO 4WD, and the Porsche ONLY HAS 2WD!

And in addition to this, the price of fish is increasing! Screw the Porsche range!

 

[niky]

So I don't have to post again:

https://www.gtplanet.net/forum/showpost.php?p=3174187&postcount=2731

https://www.gtplanet.net/forum/showpost.php?p=3130434&postcount=2682

Understandable, but what happens when more magazines run dyno tests and get the same results? Moreso, when other international magazines are starting to accept their tests as "proof" (points to Top Gear)?

It by no means makes it the final word, but when they've tested two different cars at different times of the year and get the same 500+ BHP rating, that tends to say that something is up. There isn't anything wrong with putting more power in the car, but it'd be nice to have Nissan be honest with us.

C&D has tested two of five cars to make 420 whp on the Mustang. Others have tested 400 flat on the Mustang... others have tested 415-420. Some even claim 500 whp from the Mustang with a GT-R. The only way to "prove" anything is to put a stock GT-R on the same dyno as a stock Porsche GT2 and show that it makes as much power at the wheels... or up against another Turbo and show more power, this time.

Of course, I've discussed dynos in-depth... and this quote from another forum is another suport for my argument on the futility of bench racing:

http://www.nagtroc.org/forums/index.php?showtopic=24253&st=0&p=347825&#entry347825

Twice now C&D have alluded to using "corrections" for their results but they
have made more than a concerted effort to hide their methods and the raw uncorrected figures
they obtaned.

Edmunds have also dyno tested a GT-R and produced a great write up about why the GT-R's dyno results
should NOT be corrected. The GT-R runs an absolute pressure controlled iterative system. For every RPM, Throttle
Position, etc. the ECU has a setpoint manifold absolute pressure. The boost is continuously adjusted up or down
to achieve the setpoint manifold pressure, which is fed back to the ECU via a manifold pressure sensor or similar device.

Since the system is governed by the absolute pressure, by default it automatically corrects for air density and air temperature
up to minimum air density/maximum air temperature combination. It is entirely unlikely that anyone will drive
a GT-R in conditions that overstep those maximum/minimum values.

This also means that comparing boost pressure is a pointless excercise as the boost is continually varied to
account for the ambient conditions. In this car the boost is just a means to an end (the required manifold pressure).

From edmunds,

SAE J1349, Section 5.5:

"... boosted engines with absolute pressure controls shall not be corrected for ambient barometric pressure."

And yet every GT-R dyno I've seen from other sources, so far, applies SAE correction.

I don't believe in SAE corrections. At all. I've seen gains of 10% or higher from SAE. I'll say it again... SAE corrections are pointless on a turbocharged engine.

The interesting argument at the moment is what the actual drivetrain loss is. Nissan claims a low drivetrain loss. In fact... 10%.

Given the raw numbers in the test... 430 whp... correct by 10%... what do you get? 470 bhp. We should actually be carping about how Nissan is over-rating the engine...

I don't know how people don't get how automotive technology moves over time... Let me reiterate: drivetrain losses are an estimate. It's not a law. That's why Honda Civics and Toyota Corollas regularly dyno higher than other cars with the same absolute horsepower... low losses. Many new cars, even with automatics, which traditionally have a 25% drivetrain loss compared to about 15-20% for manuals, actually dyno in the same region as manuals... lower drivetrain losses due to friction. It's my bane... automatics with the same bhp as my manual car dyno at the same whp because my drivetrain is an oily, rotating piece of prehistory.

Drivetrain losses are not a sliding scale, either... the extra weight of 20" wheels and extra driveshafts will not affect a Mustang Dyno. A load dyno will only be affected by drivetrain friction and wheel traction... too little traction will cause high readings as the tires slip creates more torque against the brake... which is why a Dynapack is a great measure of absolute no-BS power... except Dynapacks are calibrated very high compared to Mustangs, so the "traditional" 15-20% calculations don't apply there, either.

But the problem with load-dynos like the Mustang is inaccuracy (Again... 500 whp?) due to the aforementioned tire slip. Dynojets seemingly give the most consistent numbers... but you can't apply the 15-20% loss calculations there, either... because they read high, too... and there's a big question amongst tuners as to the accuracy (repeatability =/= accuracy) of the Dynojet... since changing tires or even changing a flywheel will affect your horsepower reading on the Jet.

Changing a flywheel doesn't make horsepower. It makes for less inertia, which is why a lightweight flywheel allows for faster 0-60 times, but it won't increase your top speed, which is reliant on absolute power.

In the end, C&D's tests show that there's some differences between GT-Rs in terms of track times (but given their reliance on weather-correction for track performance may throw these numbers off)... and that there are performance differences between ECU builds... but nothing more.

I love it when I don't have to re-type... ...basically, your regular automotive hack is just that... a hack... most people can't grasp the concept of how a dynamometer actually works, and think that "if X is so, then Y should also be so". I've had over two dozen dynos on my car at three different locations, with power varying a lot between locations and even on the same dyno at different times of the year, despite SAE corrections, so my expectations of what those particular dynos will read isn't as bizarrely tunnel-sighted as C&D's is. A dyno that is not done back-to-back on the same day in the same conditions as another car of the same aspiration and similar power is patently useless.

And if it all sounds too good to be true? Well... the GT-R's low-friction drivetrain apparently eats itself for lunch if you use the launch control too often... which probably explains why some GT-Rs run slower as the tranny fluid and gears eat themselves alive... oh... and the turbos, too. Apparently that much torque against that much weight equals a ton of stress on the components.

As for lap-times... how well attuned to a car a person is often dictates how far they're willing to push it. As stated in some reviews, the Nissan is just downright ornery when you pass its limits... which means that a driver more familiar with it can conceivably push it harder with more confidence than a driver not familiar with it. In most cases where the driver has equal experience in all cars in the test, the GT-R usually comes out between the GT2 and the Turbo in lap times on standard tires. Remember, however hard C&D holler, their own tests show that the GT-R is slower than the competition at high speeds, (despite the extra gears and low drag) so it's not a factor of engine power. And on the dyno, said "press" GT-R gets the same power as the 911 Turbo... so the discrepancy is definitely in the tires, AWD, transmission and suspension tuning.

I'm willing to believe those stock tires are extra sticky... (remember, Nissan admitted the second run was on the dry-weather only Dunlops, and not the Bridgestones). I'm also willing to believe that a non-test driver can only get 7:54 on the 911 Turbo and 7:50 on the GT-R, especially if they're not familiar with the ABS-tuning and the grip limits. What I'm not willing to believe is that the same driver can get such wildly varied times as Porsche is claiming, when all other independent testing evidence indicates otherwise.

And this from Chris Harris:

https://www.gtplanet.net/forum/showpost.php?p=3174384&postcount=2733

http://drivers-republic.com/first_l...fm?articleid=e4f2857514b74fd1abb770ddf45f0b2d

Chris' column - 2 October
02 October 2008

Hold on to your handbags –Porsche has announced that it now understands how the Nissan GT-R, with less power than a GT2 and 200kg tubbier, manages to lap the Nordschleife quicker than the fastest Porsche currently in production.

According to an interview on carsguide.com.au, August Achleitner, the boss of the regular 997 programme, the advantage was down to, er, rubber.

Now this is the age-old problem with Nurburgring lap-times. There is no parity, and until Euro NCAP comes-up with a standardised Nurburgring-test, there is unlikely to be a level playing field. The speed of the circuit itself seems to change on an hourly basis, so when manufacturers begin to extract lap times that will form the basis of a global media campaign, it’s not surprising that the list of ‘variables’ becomes extremely long -as they attempt to perfect their message.

Earlier this year, Nissan claimed a standard GT-R lapped the old circuit in 7min 29sec, and then posted a rather excellent video of Toshio Suzuki driving at some lick. Around this time, Porsche announced that Walter Rohrl had achieved 7min 32sec in a GT2 –but on the revised 997 launch earlier this summer, I struggled to get anyone from the company to talk on-the-record about the fact that a heavy Nissan was faster around Porsche’s home test track than its own scud-missile. This was before a Corvette ZR1 popped-in a 7min 22sec effort, but I don’t think anyone doubts the potential of a 600bhp plus, plastic bodied 2 seater. The GT-R’s time, however, has industry chins wagging.

Well, now Herr Achleitner has piped up with some new evidence. Apparently Porsche recently took a GT-R, a Turbo and a GT2 to the ‘Ring and whereas it managed to get very close to the claimed times for its own cars (7min38 and 7min34 respectively) the best its test driver could achieve in a showroom spec GT-R was a 7min 54sec. That’s 25sec slower than the claimed time.

Now before we consider what this might tell us about the state of Nissan’s definition of ‘standard’ or for that matter Porsche’s paranoia, we should probably ask a more pertinent, general question. Namely, does anyone really give a ****? I mean once you learn a bit about the place, and what a very, very fast lap requires, you quickly begin to understand that these are among the most random markers of absolute performance to have been perpetuated since the advent of the 0-60mph time. Yes, they give you a very good indication of the car’s complete performance potential, but the scope for naughty ‘infringements’ and the variability of drivers means they must be taken with a pinch of salt.

The Nissan deserves some manner of defence though. It is not possible to make any kind of accurate estimation of its actual performance by looking at its bare numbers, as our Silverstone lap on DR TV proves. Numbers mean nothing, it’s the net available and useable performance that counts and, plucking some completely arbitrary figures out of the ether by way of example, if a GT2 can deploy 75 percent of its potential over a given lap, the figure for the GT-R must be in the 90s. Furthermore, the ‘Ring isn’t especially hard on brakes, and that’s the one area in which –over multiple laps- the GT-R eventually comes unstuck.

What people really need to know about these published Nurburgring times, is that they are almost certainly not replicable by any normal human being. Nor, in light of everything discussed above, is a difference of under 5sec between two cars worthy of much discussion. The exercise is too loose, to unscientific for the numbers to be worthy of anything beyond public house pontificating. What we should recognise though, is some kind of outline benchmark scale for individual times.

By way of suggestion, it might go something like this:

BRISK
Under 8 minutes.

VERY BRISK
7min 50sec to 8min

GENUINELY FAST
7min 40sec to 7min 50sec

OUTRAGEOUSLY FAST
7min 30sec to 7min 40sec

SO FAST, IF YOU SAT IN PASSENGER SEAT, YOU’D PAP YOURSELF
7min 20sec to 7min 30sec

ALMOST CERTAINLY INVOLVES SLICK TYRES
Anything under 7min 20sec.

If you want to debate this and other aspects of the Nurburgring, join the ‘Ring group page in the community. In fact, they’ve been discussing this for a few days already.

And yeah, this probably should be merged.

One last note on power... according to one dyno, my car made nearly 170 bhp with just an exhaust. On another, it took me a full exhaust, an intake, an aftermarket ECU, cams and a port and polish to achieve this. Which is why I take any dyno from that particular dyno, the dynapack (which gave the GT-R 435 whp in Japan... the dyno people incorrectly read as saying 470 whp, when the screen shot obviously shows that the figure is torque corrected for 15% drivetrain loss... idiots) with a big grain of salt.

 

[GilesGuthrie]

Please continue discussion in this thread rather than raking over the same coals in two places at once.