RE: Nissan GT-R More Rumours
Thursday 21st August 2008
PistonHeads has written plenty on the new fast Nissan, and it seems that these days you can't open any of the car magazines without seeing a GT-R looking back at you. But CARandDriver.com decided to put the GT-R to the test, but not against its rivals, this time it was competing against itself.
When they tried the first GT-R, provided by Nissan, they recorded 0-60 in 3.5 seconds and the quarter- mile in 11.5. So pretty much on the money then, but what happened when they tried another two cars? Surprisingly, these cars recorded significantly slower times, so had the evaluation car been tweaked in some way? Something wasn't right.
Nissan GT-R More Rumours
Just how fast is the new Nissan?
Nissan claim the GT-R delivers 480 bhp and can cover the 0-60 sprint in 3.5 seconds, the quarter- mile taking a shade longer at 11.8 seconds. Impressive stuff for a car weighing 1,740kg.
Magazines were claiming independent 0-60 times of between 3.2 and 3.4 seconds, so CAR and Driver decided to get 5 GT-Rs together and see what they recorded on the track and on the dyno.
Another car was tested, this one recorded times similar to those claimed by Nissan so it was time to strap it to the dyno. This car, the fourth tested, produced 415 bhp at the wheels, so allowing for a drivetrain loss - estimated at 20% for a four wheel drive car - that equates to 519 bhp, or almost 40 more than claimed by Nissan.
As the results were inconclusive, a fifth car was rolled onto the dyno, this one produced identical figures to those claimed by Nissan, but delivered 420bhp at the wheels, so over 520 bhp.
We don't know what to make of it all. Is it another attempt to rubbish the GT-R, or a genuine problem showing that not all GT-Rs are the same? Make up your own mind by seeing the full report, and by reading the response from Nissan here
Discussion
fluffyducky said:
Seems a waist of time to me. It has been regularly stated that the engine is hand made, and therefore will produce varying amounts of power... so they proved what we all know... woop de doo. Silly billy's.
Yeah but a 40hp variance. No infact if it's 40 more could it also be 40 less too. So a possible 80bhp variance.And I suspect it's hand assembled not hand made. Variance should not really be more than ~1 or 2% at most (4.8-9.6bhp). Either that or Nissan need much tighter quality control.
That depends on the exact meaning of 'hand built', personally I think it's just been injected into the marketing for the masses to catch onto and probably involves a bloke putting a couple of bolts in...
I think the engines are probably just underrated as the minimum power you should expect even at altitude.
I think the engines are probably just underrated as the minimum power you should expect even at altitude.
PhillipM said:
That depends on the exact meaning of 'hand built', personally I think it's just been injected into the marketing for the masses to catch onto and probably involves a bloke putting a couple of bolts in...
I think the engines are probably just underrated as the minimum power you should expect even at altitude.
I think that thats probably the main point here, much like the veyron it is designed to produce 480bhp in the worst case conditions. Air pressure and temperature will make a big difference on a high power turbo'd engine.I think the engines are probably just underrated as the minimum power you should expect even at altitude.
Plus, who honestly really cares whether it has 520bhp when it says 480bhp....surely its a good thing!
The trouble with such dyno tests points to 3 area's:
1. The units of measure. Variance between metric and imperial and the differing standards (SAE and DIN) mean you can have quite a variane just by using a calculator to attain the different standards and units.
2. Dyno types. There many different types and makes of dyno/rolling road. Most work different, some are inertia and some eddy current load bearing, all this means the same car can make very different numbers on different rolling roads - none of which are directly comparable to flywheel derived numbers on an engine dyno being used and setup to different standards.
3. Drivetrain loss. In the artical it says estimated at 20%. What they really mean is guessed. As they, in reality have no idea. It could be 15% or it could be 25%. That alone gives an error margin of 65bhp! 495-560bhp range.
And that assumes the number dervied from the wheels is comparable to the units, measurement technique and standards used by Nissan. There could quite easily be another 20-40bhp error.
It really wouldn't surpise me that Nissan have done a little bit of fettling and maybe not been 100% truthful on the HP output. Espcialyl given previous track records for Nissan and other Japanese car makers.
But sadly all this kind of test can prove is consitency or lack of it from one car to another. It does not prove anything in terms of absolutes.
I guess it would have been very handy if they could dyno'd the Nissan supplied car along side privately owned ones to see if there was a variance.
Another approach - The SAE (Society of Automotive Engineers) offer a certified rating system. I think it's stricter than normal and may envolve and SAE observer or something. Anyhow the engine would be tested to full SAE Net Standards with the result being certified by the SAE.
I believe the C6 z06 actually made a slightly higher HP reading than GM originally claimed under the certified scheme, while the Mazda RX8 actually didn't make the claimed figures.
If Nissan would sign up to such a thing, it would help dispell some of the fog surrounding the production cars at least.
1. The units of measure. Variance between metric and imperial and the differing standards (SAE and DIN) mean you can have quite a variane just by using a calculator to attain the different standards and units.
2. Dyno types. There many different types and makes of dyno/rolling road. Most work different, some are inertia and some eddy current load bearing, all this means the same car can make very different numbers on different rolling roads - none of which are directly comparable to flywheel derived numbers on an engine dyno being used and setup to different standards.
3. Drivetrain loss. In the artical it says estimated at 20%. What they really mean is guessed. As they, in reality have no idea. It could be 15% or it could be 25%. That alone gives an error margin of 65bhp! 495-560bhp range.
And that assumes the number dervied from the wheels is comparable to the units, measurement technique and standards used by Nissan. There could quite easily be another 20-40bhp error.
It really wouldn't surpise me that Nissan have done a little bit of fettling and maybe not been 100% truthful on the HP output. Espcialyl given previous track records for Nissan and other Japanese car makers.
But sadly all this kind of test can prove is consitency or lack of it from one car to another. It does not prove anything in terms of absolutes.
I guess it would have been very handy if they could dyno'd the Nissan supplied car along side privately owned ones to see if there was a variance.
Another approach - The SAE (Society of Automotive Engineers) offer a certified rating system. I think it's stricter than normal and may envolve and SAE observer or something. Anyhow the engine would be tested to full SAE Net Standards with the result being certified by the SAE.
I believe the C6 z06 actually made a slightly higher HP reading than GM originally claimed under the certified scheme, while the Mazda RX8 actually didn't make the claimed figures.
If Nissan would sign up to such a thing, it would help dispell some of the fog surrounding the production cars at least.
Yep, just power variances.
To pretend that the tolerance differences in the build 'because it's hand made' make 40bhp difference here and there, means some cars are clearly built terribly compared to others
Quote a low figure, most will get more most of the time, but magazines will always quote the low ones. Ergo, the car performs better than it 'appears' it should, so people think it's somehow better than it is.
I'm sure Nissan did this with the R34. Quote 276bhp, but it's making more like 330-340bhp.
Dave
To pretend that the tolerance differences in the build 'because it's hand made' make 40bhp difference here and there, means some cars are clearly built terribly compared to others
Quote a low figure, most will get more most of the time, but magazines will always quote the low ones. Ergo, the car performs better than it 'appears' it should, so people think it's somehow better than it is.
I'm sure Nissan did this with the R34. Quote 276bhp, but it's making more like 330-340bhp.
Dave
A little off-topic, but I've noticed there are some GT-R's in the classified, one in particular claiming to be a physical car in the UK. What's the deal with servicing, insurance etc if I was (theoretically) to buy that car? I assume that the Nissan Performance centres would refuse to service it, as not officially launched until 2009?
Just interested in how much of a ball-ache it might be.
Just interested in how much of a ball-ache it might be.
Not sure if your all aware but the law when homologating performance allows a 5% tollerance. hence if Nissan claim 470BHP then in actual fact the engine may only produce 446.5BHP. You can bet all the performance certification was done on the highest spec hand fettled engine to ensure it makes as much as possible, even though they have to do COP testing (conformaty of production) to ensure the engines performance does not deviate away too greatly that is an internal audit and never shown to the legislative bodies unless called for.
basically this will only make 470 BHP on the biggest of downhill dynos.
basically this will only make 470 BHP on the biggest of downhill dynos.
I wonder if it's the running in, press cars get thrashed from the word go so they usually loosen up more quickly (and wear out sooner), while other owners might mollycoddle their cars so they will still be pretty tight and restrictive of power. It would be interesting to know how the owner of the 520bhp car ran his in.
So they stick it on a rolling road and say its 520 HP based at best on a rough guestimate of the actual transmission losses. Patent nonesense!
My car can vary by 50-60 hp depending on which dyno I take it to so frankly this story is just an irrelevance.
Car & drivers figures are usually b
ks anyway. Typical Yanks.
My car can vary by 50-60 hp depending on which dyno I take it to so frankly this story is just an irrelevance.
Car & drivers figures are usually b
ks anyway. Typical Yanks.Gassing Station | Japanese Chat | Top of Page | What's New | My Stuff