GTR 0-60 in 3.3 sec!
12-20-2007, 05:02 AM
#61
Registered User
Originally Posted by ITR #203,Dec 19 2007, 11:21 AM
With that said, I'm still not sure if I believe a trap of 121+. AWD drivetrain loss sucks. This thing has to be packing some major power if its true (please note that the dyno in the other thread is a dynopack which although more accurate/consistent in some respects will read higher due to the lack of the rotational mass and the lack of power loss during the transfer from the tires to the rollers).
12-20-2007, 05:09 AM
#62
Registered User
[edit] How it works
ATTESA-ETS is featured in the north-south layout vehicles, and was first used in August 1989 in the R32 Nissan Skyline GT-R and Nissan Skyline GTS4. It utilizes what is mostly a conventional RWD gearbox. Although the Skyline GT-R is exclusively AWD, ATTESA-ETS is also used in Nissan models that are also available as RWD such as the A31 Nissan Cefiro which was the second Nissan to feature the system exactly a year later in August 1990. Drive to the rear wheels is constant via a tailshaft and rear differential, however drive to the front wheels is more complex by utilizing a transfer case at the rear of the gearbox. The drive for the front wheels comes from a transfer case bolted on the end of an almost traditional RWD transmission although the (bell housing is slightly different to allow the driveshaft for the front wheels to pass it, the main body is exactly the same as the RWD transmission, the tail-shaft is different to couple to the transfer case). A short driveshaft for the front wheels exits the transfer case on the right side. Inside the transfer case a chain drives a multi-plate wet clutch pack, torque is apportioned using a clutch pack center differential, similar to the type employed in the Steyr-Daimler-Puch system in the Porsche 959. On the rear differential is a high pressure electric oil pump, this pump pressurises Normal ATF oil (0-288psi) into the transfercase to engage the clutchpack. The higher the oil pressure the transfer case is supplied with, the more the clutch pack engages, this is how the torque to the front wheels is varied. The transfer case has its own dedicated ATF (nissan special ATF) oil to lubricate the chain/clutch pack. The front driveshaft runs along the right side of the transmission, into a differential located on the right of the engine's oilpan. The front right axle is shorter than the left, as the differential is closer to the right wheel. The front left axle runs through the engine's sump to the left wheel.
The ATTESA-ETS layout is more advanced than the ATTESA system, and uses a 16bit microprocessor that monitors the cars movements at 100 times per second to sense traction loss by measuring the speed of each wheel via the ABS sensors. A three axis G-Sensor mounted underneath the center console feed lateral and longitudinal inputs into an ECU, this ECU controls both the ATTESA-ETS 4WD system and the ABS system. The ECU can then direct up to and including 50% of the power to the front wheels. When slip is detected on one of the rear wheels (rear wheels turn 5% or more than the front wheels), the system directs torque to the front wheels which run a viscous LSD. Rather than locking the AWD in all the time or having a system that is "all or nothing", the ATTESA-ETS system can apportion different ratios of torque to the front wheels as it sees fit. This provides the driver with an AWD vehicle that performs like a rear wheel drive vehicle in perfect conditions and can recover control when conditions aren't as perfect. The advantage to a more traditional ATTESA (Viscous LSD) system is response in hundredths of a second.
[edit] ATTESA-ETS Pro
In 1995, with the introduction of the R33 Skyline GT-R, Nissan introduced a new version of their ATTESA system. It was named ATTESA-ETS Pro, as an upgrade from the earlier ATTESA ETS. It was standard equipment in the R33 Skyline GT-R Vspec model, however it was offered as an option on the standard R33 Skyline GT-R, and called the "Active LSD option". It was also standard equipment on all R34 Skyline GT-R models.
ATTESA-E-TS Pro differs from the standard ATTESA-E-TS in a few ways. Where ATTESA-E-TS controls the front to rear torque-split, the Pro is also capable of left-and-right torque split to the rear wheels. This is done via an active rear limited-slip differential. Additionally, the ATTESA-E-TS Pro was marketed as controlling the four-wheel independent ABS braking system. This is not part of the AWD system, but the ECU makes use of the same sensors to determine wheel slip and traction.
On ATTESA-E-TS Pro equipped vehicles, the front differential remains a standard limited slip differential, not being linked to the ATTESA-E-TS Pro system.
[edit] ATTESA-ETS (GT-R version)
The 2009 Nissan GT-R uses a version of ATTESA-E-TS designed to work with that cars rear transaxle layout. The system is unique in that it utilizes two driveshafts under the vehicles centerline with a second driveshaft runnng slightly to the right of the main driveshaft and engine sending power to the front wheels. It is so far, the only rear transaxle based AWD system for a front engined car in production.
Unlike the previous ATTESA systems which relied heavily on mechanical feedback, the system in the GT-R uses electronic sensors and hydraulically actuated clutches. Has a yaw-rate feedback control system to effectively manage slip angle. Front rear torque split can go from 2:98 during a standing start to a maximum of 50:50[1]
[edit] Models
ATTESA-ETS is featured in the north-south layout vehicles, and was first used in August 1989 in the R32 Nissan Skyline GT-R and Nissan Skyline GTS4. It utilizes what is mostly a conventional RWD gearbox. Although the Skyline GT-R is exclusively AWD, ATTESA-ETS is also used in Nissan models that are also available as RWD such as the A31 Nissan Cefiro which was the second Nissan to feature the system exactly a year later in August 1990. Drive to the rear wheels is constant via a tailshaft and rear differential, however drive to the front wheels is more complex by utilizing a transfer case at the rear of the gearbox. The drive for the front wheels comes from a transfer case bolted on the end of an almost traditional RWD transmission although the (bell housing is slightly different to allow the driveshaft for the front wheels to pass it, the main body is exactly the same as the RWD transmission, the tail-shaft is different to couple to the transfer case). A short driveshaft for the front wheels exits the transfer case on the right side. Inside the transfer case a chain drives a multi-plate wet clutch pack, torque is apportioned using a clutch pack center differential, similar to the type employed in the Steyr-Daimler-Puch system in the Porsche 959. On the rear differential is a high pressure electric oil pump, this pump pressurises Normal ATF oil (0-288psi) into the transfercase to engage the clutchpack. The higher the oil pressure the transfer case is supplied with, the more the clutch pack engages, this is how the torque to the front wheels is varied. The transfer case has its own dedicated ATF (nissan special ATF) oil to lubricate the chain/clutch pack. The front driveshaft runs along the right side of the transmission, into a differential located on the right of the engine's oilpan. The front right axle is shorter than the left, as the differential is closer to the right wheel. The front left axle runs through the engine's sump to the left wheel.
The ATTESA-ETS layout is more advanced than the ATTESA system, and uses a 16bit microprocessor that monitors the cars movements at 100 times per second to sense traction loss by measuring the speed of each wheel via the ABS sensors. A three axis G-Sensor mounted underneath the center console feed lateral and longitudinal inputs into an ECU, this ECU controls both the ATTESA-ETS 4WD system and the ABS system. The ECU can then direct up to and including 50% of the power to the front wheels. When slip is detected on one of the rear wheels (rear wheels turn 5% or more than the front wheels), the system directs torque to the front wheels which run a viscous LSD. Rather than locking the AWD in all the time or having a system that is "all or nothing", the ATTESA-ETS system can apportion different ratios of torque to the front wheels as it sees fit. This provides the driver with an AWD vehicle that performs like a rear wheel drive vehicle in perfect conditions and can recover control when conditions aren't as perfect. The advantage to a more traditional ATTESA (Viscous LSD) system is response in hundredths of a second.
[edit] ATTESA-ETS Pro
In 1995, with the introduction of the R33 Skyline GT-R, Nissan introduced a new version of their ATTESA system. It was named ATTESA-ETS Pro, as an upgrade from the earlier ATTESA ETS. It was standard equipment in the R33 Skyline GT-R Vspec model, however it was offered as an option on the standard R33 Skyline GT-R, and called the "Active LSD option". It was also standard equipment on all R34 Skyline GT-R models.
ATTESA-E-TS Pro differs from the standard ATTESA-E-TS in a few ways. Where ATTESA-E-TS controls the front to rear torque-split, the Pro is also capable of left-and-right torque split to the rear wheels. This is done via an active rear limited-slip differential. Additionally, the ATTESA-E-TS Pro was marketed as controlling the four-wheel independent ABS braking system. This is not part of the AWD system, but the ECU makes use of the same sensors to determine wheel slip and traction.
On ATTESA-E-TS Pro equipped vehicles, the front differential remains a standard limited slip differential, not being linked to the ATTESA-E-TS Pro system.
[edit] ATTESA-ETS (GT-R version)
The 2009 Nissan GT-R uses a version of ATTESA-E-TS designed to work with that cars rear transaxle layout. The system is unique in that it utilizes two driveshafts under the vehicles centerline with a second driveshaft runnng slightly to the right of the main driveshaft and engine sending power to the front wheels. It is so far, the only rear transaxle based AWD system for a front engined car in production.
Unlike the previous ATTESA systems which relied heavily on mechanical feedback, the system in the GT-R uses electronic sensors and hydraulically actuated clutches. Has a yaw-rate feedback control system to effectively manage slip angle. Front rear torque split can go from 2:98 during a standing start to a maximum of 50:50[1]
[edit] Models
12-20-2007, 10:23 AM
#64
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Originally Posted by Chris S,Dec 19 2007, 08:35 PM
Why would I do that? I suspect the same. I lust over the GT-R and the Z06, but I suspect buying one would invite trouble. My old 480hp Supra Turbo was a blast to drive, but it really was overkill for the streets...if I wasn't driving too fast, it wasn't as much fun as a slower car.That's why I like my CS - it's plenty fast to have fun on the street or track, but also perfectly enjoyable driving the speed limit.
Relax, for once we agree on something!
Damn, both the GT-R and ZR-1 are such nice cars! The Vette looks stunning!
12-20-2007, 10:30 AM
#65
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Originally Posted by duboseq,Dec 20 2007, 09:09 AM
[edit] ATTESA-ETS (GT-R version)
The 2009 Nissan GT-R uses a version of ATTESA-E-TS designed to work with that cars rear transaxle layout. The system is unique in that it utilizes two driveshafts under the vehicles centerline with a second driveshaft runnng slightly to the right of the main driveshaft and engine sending power to the front wheels. It is so far, the only rear transaxle based AWD system for a front engined car in production.
Unlike the previous ATTESA systems which relied heavily on mechanical feedback, the system in the GT-R uses electronic sensors and hydraulically actuated clutches. Has a yaw-rate feedback control system to effectively manage slip angle. Front rear torque split can go from 2:98 during a standing start to a maximum of 50:50[1]
The 2009 Nissan GT-R uses a version of ATTESA-E-TS designed to work with that cars rear transaxle layout. The system is unique in that it utilizes two driveshafts under the vehicles centerline with a second driveshaft runnng slightly to the right of the main driveshaft and engine sending power to the front wheels. It is so far, the only rear transaxle based AWD system for a front engined car in production.
Unlike the previous ATTESA systems which relied heavily on mechanical feedback, the system in the GT-R uses electronic sensors and hydraulically actuated clutches. Has a yaw-rate feedback control system to effectively manage slip angle. Front rear torque split can go from 2:98 during a standing start to a maximum of 50:50[1]
also very cool with the yaw sensors managing slip angle... assuming they tuned this for particular tires, does this mean the car will electronically maintain the optimal slip angle for the particular tires during a hard corner by continuasly altering torque side-to-side? if it does, thats bad-ass ... but how can it account if you swap to different tires with different optimal slip-angle's?
with all that though... i think its still an underrated car... but that feeds the mystique factor... the Z06 crown is undeniably been put in play...
12-20-2007, 11:12 AM
#66
Registered User
Originally Posted by Iceman1,Dec 20 2007, 02:30 PM
also very cool with the yaw sensors managing slip angle... assuming they tuned this for particular tires, does this mean the car will electronically maintain the optimal slip angle for the particular tires during a hard corner by continuasly altering torque side-to-side? if it does, thats bad-ass ... but how can it account if you swap to different tires with different optimal slip-angle's?
with all that though... i think its still an underrated car... but that feeds the mystique factor... the Z06 crown is undeniably been put in play...
with all that though... i think its still an underrated car... but that feeds the mystique factor... the Z06 crown is undeniably been put in play...
But torque is altered from side to side the way it was explained to me,"the ATTESA-E-TS Pro was marketed as controlling the four-wheel independent ABS braking system. This is not part of the AWD system, but the ECU makes use of the same sensors to determine wheel slip and traction."
This ECU is capable of making fast calculations from multiple input sources (I think 100 x's per second) and the system as a whole is regarded as one of the best AWD systems on the market today.
12-20-2007, 12:09 PM
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Originally Posted by Iceman1,Dec 20 2007, 11:30 AM
interesting... i didnt realize it was a rear-mounted trans-axle configuration... this means on a straight line launch, the GTR's drivetrain loss is similar to a RWD Porsche's 12% loss till the rear-tires lose traction...
12-20-2007, 05:59 PM
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Actually with the rear mounted transaxle and the front engine the GTR will have more drivetrain losses than the Porsche. The 911 engines are bolted to the transaxle, no driveshaft. With the AWD 911 the engine is still bolted to the transaxle and a driveshaft sends power to the front wheels. Having multiple driveshafts allow for more opportunities of loss.
