[quote=“vmo”]The NIssan GT-R R35 uses a particular transaxle system:
The engine is in the front part, and the gearbox in the rear part (the classic transaxle system), but the GT-R is 4WD.
And the solution of NIssan is put two transmission axis: one from engine to the gearbox, and other from gearbox to the front differential. This system is called ATTESA E-TS AWD system (I think). Pure efectivity:
I don’t see how this system is even close to effective, there are so many places for drivetrain loss to occur. They should have stuck to how the r34 and previous models were but updated it that way the car would have created more whp and could have been more then electronic toy.
It’s no more complicated than a traditional 4WD drivetrain, the center differential is just integrated into the rear transaxle and spins a somewhat longer propshaft than usual.
that’s exactly where it fails, on a early model gtr you had 7 locations for drivetrain loss, on this r35 system you have a minimum of 9 as I cannot see the rest of the front driveshaft. Anytime you add a joint in the shaft the energy has to be re transferred, while this doesn’t seem like a big issue, but it is as this is where you lose whp as well as through the trans as well. so if you look at this system it is just silly.
Well, the car is very fast on the track, even compared to simpler and lighter designs, so they must have done something right.
And it must not be that bad in terms of power losses.
Main difference compared to a typical AWD design is that instead of having the transmission mounted directly to the engine, with the front diff integrated into the assembly and a prop shaft sending the power to the rear diff, you have a propshaft sending the power to the transmission, with the rear diff integrated into the gearbox assembly and a propshaft sending the power to the front diff.
So you pretty much just take you usual setup, put the front part at the back and add a propshaft between the engine and transmission.
just to clarify I never said it doesn’t preform well, I just think they massively over complicated what could have been a better functioning system that could have made the car not only more affordable, but also funnier to drive.
Not only does this system on the GTR add unnecessary weight on top of the added drive train loss, but this system is actually very poorly designed and many GTRs have already had to have new transmissions installed because of how weak they are. Simply put even under stock HP numbers these transmissions are not up to the task. There is a reason why Nissan will not warranty the transmission if traction control has been disabled and launch control engaged, it puts massive strain on the AWD system.
As someone who has owned many AWD cars and Fwd counterparts, I can tell you first hand you lose a ton in drivetrain loss and anywhere that an extra joint is, like say a steady bearing in a 2 piece driveshaft, it becomes a serious weak point after you begin modding. This is why you see aftermarket 1 piece shafts, its to reduce the loss and help make the drivetrain stronger and more reliable.
Also I love the GTR I am not hating on it at all, it does work very well and has held many records its just my personal opinion that there was a better and cheaper way to obtain the same results or better.
One of the changes is they removing the chain driven transfer case from the back of the r34’s transmission and integrated into the rear transaxle, this actually reduced the parasitic loss, which was balanced by the addition of the front gearbox which allows the front wheels to have the same active LSD setup as the rear wheels through the use of a hydraulic clutch.
The weight of the primary shaft(from engine to gearbox) is reduced, compared to the R34.
Because the shaft only has the direct torque from the engine to wrestle with.
Thats 612 nm, the shaft on the R34 has 975nm to cope with. (392 nm * 3.827 ratio on 1:st gear - 35% to front wheels)
And the weight distribution is far superior, so whatever tiny extra energy losses it has, f**k that. A car is a bunch of compromises anyway.
Nissan’s problem isn’t one of drivetrain efficiency, it’s one of packaging. If they wanted to build the front and center differentials into the gearbox like the Lancer Evolution or WRX STi, they’d have to do one of the following:
Build the car much, much wider to fit those large engines transversely (in the case of VR38DETT, how to route turbochargers) between double wishbone front suspension. Weight and aero is compromised.
Mount the entire engine longitudinally and well in front of the front axles. Handling is severely compromised.
Besides, the R35’s weak transmission has nothing to do with the fact that it uses a rear transaxle. Excellent ideas with questionable engineering seems to be a common trait of post-Renault Nissan cars.
Nissan’s problem isn’t one of drivetrain efficiency, it’s one of packaging. If they wanted to build the front and center differentials into the gearbox like the Lancer Evolution or WRX STi, they’d have to do one of the following:
Build the car much, much wider to fit those large engines transversely (in the case of VR38DETT, how to route turbochargers) between double wishbone front suspension. Weight and aero is compromised.
Mount the entire engine longitudinally and well in front of the front axles. Handling is severely compromised.
Besides, the R35’s weak transmission has nothing to do with the fact that it uses a rear transaxle. Excellent ideas with questionable engineering seems to be a common trait of post-Renault Nissan cars.[/quote]
The GT-R it was designed 100% by NIssan, without the help of Renault (at difference of the rest of Nissan Models).
And the nissan doesn’t need much fuel to had 550 or 600hp (12l/100km real fuel consumption is well), but for me, the fuel consumption in a sport car doesn’t import much.
