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Old 12-30-2008, 06:54 PM #2791  
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For a girl's car, they sure don't seem to want to drive it. My wife and two daughters (who both drive) have no interest in driving my Cayman. I guess that's not a bad thing.
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Last edited by USCCayman; 12-30-2008 at 07:19 PM.
Old 12-30-2008, 07:00 PM #2792  
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http://www.autoblog.com/2008/12/30/m...-r-horsepower/

Quote:
Originally Posted by Autoblog
Last summer, Motor Trend estimated that the Nissan GT-R made at least 507-horsepower at the crank, which is quite a bit more than the manufacturer's official 480-horse rating. Now, MT decided to put to rest the firestorm it created by strapping yet another GT-R to a new type of dynamometer that's reportedly capable of calculating exact drivetrain losses, something that had previously been nothing more than an estimation. Three runs were conducted, and Godzilla delivered figures that were consistently within just a few percentage points of each other. So, what's the scoop?

According to MT, the average of those three separate dyno runs reveals that Nissan's supercar is delivering 485-horsepower @ 6050 rpm and 470 lb-ft @ 3800 rpm. That's nearly spot on for horsepower, but a good deal more torque at the crank than its official 430 lb-ft. -- we're not complaining. These tests also prove that there are indeed significant losses due to the GT-R's twin-clutch, all-wheel drive configuration, though that's also what helps launch the supercar from a dead-stop so quickly. Thanks for the tip, Franz!

So apparently, Motor Trend did another dyno test on a GTR and they're claiming that the power rating is accurate. Now if they can only get their hands on the GTR than ran 7:29 in The Ring.
Old 12-30-2008, 07:55 PM #2793  
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The GT-R, at 3900lbs, is just too heavy to go 50 minutes at a competitive pace at it's power levels. Heck, even much lighter race cars on slicks have to manage their tires for a sprint like that. The brakes could easily become an issue too.

The 1st Gen. CTS-V at 3800lbs could compete, but it isn't as fast, hence less tire/brake wear. Either way, the transitions will hurt it too.

Oh, Nissan "defined" a Supercar: 8.8lbs per hp or less, 186mph speed obtainable on public roads, sub 8min 'Ring time. I guess that makes the CTS-V 6M a super car too!
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Last edited by Deuuuce; 12-30-2008 at 07:57 PM.
Old 12-30-2008, 11:23 PM #2794  
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http://www.motorauthority.com/dyno-t...r-ratings.html

According to this article from MotorAuthority, the dyno test that was done by using a Hyper Power Dynamometer's DYNOmite, calculates a powertrain loss between 5% to 17%.

Quote:
Originally Posted by MotorAuthority
Testing cars for power ratings is a tough and tricky business - accounting for different conditions, locations, equipment and techniques can make it tough to generalize results. And to make matters worse, there is often a lot of guesswork employed to get between real, delivered wheel horsepower and output at the crankshaft, or vice-versa. A recent test of Nissan's GT-R has answered some of the ongoing questions of how it performs so well, however, and taken a good bit of the fiction out of the process.

Rumors and reports from around the web have been claiming Nissan's stated figures for the GT-R's twin-turbo V6 are understated ever since it began its remarkable climb up the many performance charts. All-wheel drive and tons of rubber just couldn't make up for the massive power deficit, they claimed. But it turns out Nissan's claimed 473hp (353kW) figure isn't far from the truth at all, according to MotorTrend. The torque numbers are about 40lb-ft (54Nm), or roughly 9%, larger than Nissan's 434lb-ft (588Nm) rating, and could help explain a little of the car's low-end acceleration abilities.

The key to this latest round of testing is the use of Hyper Power Dynamometer's DYNOmite, which allows testing not just of engine output, but of powertrain drag. After a dyno pull, instead of ceasing to record data, the machine records the slow-down period, and measures the drag due to the car's powertrain, including engine, transmission and wheels.

The end result? As physics would suggest, the parasitic losses of the drivetrain increase with speed, varying from 23hp (17kW) at 50mph to 84hp (62kW) at 100mph. That works out to a real-world inefficiency ranging between 5-17%, depending on speed - quite good for an AWD car.

One thing to keep in mind, however, is that this is just one particular example of the car - power figures can and will vary from vehicle to vehicle. It will simply take time and repetition to see if these results are more or less representative of the general population of Nissan GT-Rs than previous tests. The method, however, is a definite improvement.
Old 12-31-2008, 07:24 AM #2795  
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Sure data is always good when there is a 12% variance.
Old 12-31-2008, 08:41 AM #2796  
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Add in the standard deviation factor for a sample basis of...

ONE !!!
Old 12-31-2008, 12:04 PM #2797  
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This thread gets very technical at times. I actually feel like I have learned a great deal about the mechanics and techniques involved in racing cars by participating in this thread. I feel like I have gone through the classroom insturction and am now ready to get out on the track with an instructor. We give each other a little heck now and then, but in all I think we are having fun.
Old 12-31-2008, 12:13 PM #2798  
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Quote:
Originally Posted by USCCayman View Post
This thread gets very technical at times. I actually feel like I have learned a great deal about the mechanics and techniques involved in racing cars by participating in this thread. I feel like I have gone through the classroom insturction and am now ready to get out on the track with an instructor. We give each other a little heck now and then, but in all I think we are having fun.
If you would like to try a Driver's Education Event, Chin would be a good place to start.
They are at Sebring about every other month or so.

Chin is a little more expensive than some of the other clubs...

but you will get A LOT MORE TRACK TIME and likely get a better instructor.

Many of us Z06'ers instuct for them, and Chin also has instructors who drive Porsche's.

Their web site is: www.chinmotorsports.com

Also check the internet web for information on preparing for D E and what you can expect at the track.

BMW also puts on a good event especially Peachtree BMW at Road Atlanta.

If you want aditional info... send me a PM.

Cya @ the track,

Trumper

Last edited by trumperZ06; 12-31-2008 at 12:18 PM.
Old 12-31-2008, 03:51 PM #2799  
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GT-R stability control vs. AWD control

The AWD control makes the difference?

While I agree a skilled driver should be faster with stability control turned off, what I contend is that the GT-Rs AWD remains variable during 10/10ths driving. Please correct me if I'm wrong.

The electronically controlled clutch pack is controlled via a computer getting input from multiple sensors (wheel speed, steering position, throttle and yaw-rate sensors). This is NOT stability control.

I believe the Evo X has this and if I'm not mistaken, the benefit was demonstrated on Top Gear test of Prodrive's AWD experimental car.

This allows for faster lap times and is actually a driver's aid. One reason AWD isn't allowed in many race series.

My apologies if this has been covered but I think it's a prime example of having an inherent driver's aid vs. a recovery system like Stability Control.
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Old 12-31-2008, 07:20 PM #2800  
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Quote:
Originally Posted by Deuuuce View Post
The AWD control makes the difference?

While I agree a skilled driver should be faster with stability control turned off, what I contend is that the GT-Rs AWD remains variable during 10/10ths driving. Please correct me if I'm wrong.

The electronically controlled clutch pack is controlled via a computer getting input from multiple sensors (wheel speed, steering position, throttle and yaw-rate sensors). This is NOT stability control.

I believe the Evo X has this and if I'm not mistaken, the benefit was demonstrated on Top Gear test of Prodrive's AWD experimental car.

This allows for faster lap times and is actually a driver's aid. One reason AWD isn't allowed in many race series.

My apologies if this has been covered but I think it's a prime example of having an inherent driver's aid vs. a recovery system like Stability Control.
You are making my point (I think). All these systems are BOTH a driver's aid AND a safety system. In theory, they can make even a pro driver faster if calibrated correctly.

In the case of AWD, I actually think the TT's center diff is fancier--- I think it is fully electronic. The GT-R documentation makes it sound less fancy, but I'm not sure.

Point is that some here think AWD is in the category of a bad system. Anything that makes me go around the track faster AND safer is a good thing.
Old 01-01-2009, 08:29 AM #2801  
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Chrisn - the points about if calibrated correctly would make a pro driver faster is correct. If calibrated for less and less input from the computer

Driver's aid is for the 95% of the people out there and its not for the 5% who can drive from 8/10 to 10/10th of their cars. Racers push their cars to the edge and they don't want the electronic devices to kick in at moments they are wanting that push. They like less intrusive systems as the GT2, BMW M Modes(CSL), Ferrari Race, etc.

I would still like to know why Nissan drives the Ring with VDC disabled?
Old 01-01-2009, 11:20 AM #2802  
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Quote:
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I would still like to know why Nissan drives the Ring with VDC disabled?
I'll bet there are 3-4 spots where the car gets light and gives too much wheel spin at WOT. I'll bet the net diff is <5 seconds around track. Understand that when REALLY racing that is a lifetime, but most people (even decent drivers) would leave on in case they screw up. Even pro drivers lose it from time to time-- that's why it is called 10/10ths.If you have proper safety gear and you are not paying for the car-- who cares I guess.

My point about being FASTER was a bit silly/theorhetical-- but if you allowed very detailed tuning, it would have to make you faster. It's just another variable that you can optimize.

Agree that in real world, they make pro drivers slower in street cars. But, for the good systems, not by much.

BTW, I think MDM ("//M-Mode") is MORE intrusive than VDC or PSM in sprt mode-- at least on an M5. Perhaps in CSL they dial it way back. I wish all cars had what that souped up Lotus has (the 240R?)--- a dial with an analog setting of how much slip angle you want before intervention.

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Old 01-01-2009, 11:26 AM #2803  
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Quote:
Originally Posted by chrisn View Post
You are making my point (I think). All these systems are BOTH a driver's aid AND a safety system. In theory, they can make even a pro driver faster if calibrated correctly.

In the case of AWD, I actually think the TT's center diff is fancier--- I think it is fully electronic. The GT-R documentation makes it sound less fancy, but I'm not sure.

Point is that some here think AWD is in the category of a bad system. Anything that makes me go around the track faster AND safer is a good thing.
The problem that you arent considering is that an AWD car can never be as light as a comparable RWD car. Not only that you add drag, and power understeer challenges to dial out, and yes the GT-R plows to contrary to the fanboys that were here proclaiming otherwise when it was released.

Add to that the fact that as you add more traction to the wheels (I.E. slicks), it over-rules AWD's advantage. The only place AWD will have an advantage is in adverse conditions and on factory cars without traction. The mistakes racing series made was giving the AWD cars an advantage by being able to add components (AWD) without the weight penalties that accompanied them, then once they finally did, they were racing in europe where the conditions change almost by the day and the AWD cars won on consistency in adverse conditions.

But you wont find any race drivers that prefer TC, and stability control, or even AWD (except steve millen).
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The GT-R is harder to drift than a 997 TT or 997 GT3, therefore if you are trying to drift, the GT-R will consequently get a faster lap. Normal apexing and driving not included.

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Old 01-01-2009, 12:16 PM #2804  
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Quote:
Originally Posted by trumperZ06 View Post
If you would like to try a Driver's Education Event, Chin would be a good place to start.
They are at Sebring about every other month or so.

Chin is a little more expensive than some of the other clubs...

but you will get A LOT MORE TRACK TIME and likely get a better instructor.

Many of us Z06'ers instuct for them, and Chin also has instructors who drive Porsche's.

Their web site is: www.chinmotorsports.com

Also check the internet web for information on preparing for D E and what you can expect at the track.

BMW also puts on a good event especially Peachtree BMW at Road Atlanta.

If you want aditional info... send me a PM.

Cya @ the track,

Trumper
Thanks Trumper! I actually do plan to enroll in a DE event at some point. Thanks for the offer to PM. I do need some more info, so I will check in with you soon. Many thanks.
Tony
Old 01-01-2009, 01:12 PM #2805  
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I was looking through some "CAR" magazines I had purchased. In the August 2006 issue on page 99 there is an article about the Porsche 959 by Gavin Green, one of the writers for that magazine. He was referring to an article he had written about that car 19 years ago, which would be 22 years ago now. He indicated that in it's time, the 959 was a technical tour de force, pioneering variably split computer-controlled 4x4 and computer controlled damping stiffness. It was the fastest car of it's day, doing 0-60 in 3.7 seconds and topping out at 197 mph. He then added that the Porsche purists had a problem with the car because it wasn't as much fun to drive as a 911. The 911 purists complained that all that new-fangled electro-trickery took away the animal, and did not challenge the good drivers and intimidate the poor ones as the 911 was famous for. The author said that the 959 did not wag it's tail, oversteer outrageously, or require constant steering correction to extract big speeds. He said the 959 was a "point and squirt" supercar that was marvellously efficient and enormously fast, but it was also a touch "soulless" and more "engineering showcase than drivers delight". He said the 959 was the car that begat all the electronically controlled engineering-rich supercars of today, but the 911 purists did not like the car because it forgot to involve the bloke behind the wheel. This article was written a good two years before all the arguments we are having about the 911 vs. the GTR, but I think it explains why Porsche did not develop a car with all the computer control that characterizes the GTR.
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