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Awd Vs Rwd

Midol

By Midol,
in Four Door Family & Wagoneers

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pixel8r Mentor

pixel8r

Posted
Posted

The ATTESA system used in the GTR and Stageas is mostly all the same - but with tweaks here and there to suit the vehicle and its intended use. I think mechanically it is more or less the same and the way it works is also more or less the same, but the AWD computer will be set up differently to suit the car.

And yes it is true the system will read many different inputs (100x per second) - throttle position, ABS sensors (to determine lost traction), and longitudinal and latitudinal g-force sensors, to determine the weight-shift of the car, sideways and front-back g-forces etc and basically the rule is: If ANY wheelspin (or POTENTIAL for wheelspin) is detected at any wheel, the system will direct torque away from that wheel. The torque split is completely variable - from up to ~95% rear to about 50% front 50% rear - or it can be anywhere in between - as the computer sees necessary.

Its one of the most advanced AWD systems in the world, and works extremely well. It is however not designed for heavy offroad use or situations where you are in AWD constantly (ie. all day). The 4x4 Nissans do still use a form of ATTESA but they also feature the usual 4WD diffs etc to support 4WD mode. On stageas and GTR's the system relies on clutch packs which will wear out if used all the time. Its more like a backup system to ensure maximum traction on the road - and it is more than capable of achieving this.

My favourite thing about ATTESA is that its RWD most of the time, so you get the fuel economy/drivetrain losses of a RWD car (in theory) when just cruising around, but the safety and traction of AWD when you need it. In my opinion its much better than full time AWD systems like mitsubishi and subaru, however those systems have their advantages as well (just that those advantages usually manifest themselves on a rally circuit, not on the road).

nickcorr Proficient

nickcorr

Posted
Posted

Actually this is a complete can of worms with some manufacturers claiming full time AWD when they don't have it...

Subaru actually have 4 different AWD systems, depending on engine and transmission options. I won't go into too much detail, but only manual Subarus actually have full time AWD. All the automatics have a clutch pack replacing the centre active diff, or viscus coupling, of the manual versions. That makes them part time AWD, same as our Nissans.

But hey, when have marketing guys ever worried about the truth...

The ATTESA system used in the GTR and Stageas is mostly all the same - but with tweaks here and there to suit the vehicle and its intended use. I think mechanically it is more or less the same and the way it works is also more or less the same, but the AWD computer will be set up differently to suit the car.

And yes it is true the system will read many different inputs (100x per second) - throttle position, ABS sensors (to determine lost traction), and longitudinal and latitudinal g-force sensors, to determine the weight-shift of the car, sideways and front-back g-forces etc and basically the rule is: If ANY wheelspin (or POTENTIAL for wheelspin) is detected at any wheel, the system will direct torque away from that wheel. The torque split is completely variable - from up to ~95% rear to about 50% front 50% rear - or it can be anywhere in between - as the computer sees necessary.

Its one of the most advanced AWD systems in the world, and works extremely well. It is however not designed for heavy offroad use or situations where you are in AWD constantly (ie. all day). The 4x4 Nissans do still use a form of ATTESA but they also feature the usual 4WD diffs etc to support 4WD mode. On stageas and GTR's the system relies on clutch packs which will wear out if used all the time. Its more like a backup system to ensure maximum traction on the road - and it is more than capable of achieving this.

My favourite thing about ATTESA is that its RWD most of the time, so you get the fuel economy/drivetrain losses of a RWD car (in theory) when just cruising around, but the safety and traction of AWD when you need it. In my opinion its much better than full time AWD systems like mitsubishi and subaru, however those systems have their advantages as well (just that those advantages usually manifest themselves on a rally circuit, not on the road).

Angus Smart Grand Master

Angus Smart

Posted
Posted

I hate that about carsales and most online car websites. when i was looking for a Legnum or stagea or anything really

most dickheads say the car is a manual when its a damn auto.. really annoying when your trying to find just a manual car..

Sydneykid Grand Master

Sydneykid

Posted
Posted
The ATTESA system used in the GTR and Stageas is mostly all the same - but with tweaks here and there to suit the vehicle and its intended use. I think mechanically it is more or less the same and the way it works is also more or less the same, but the AWD computer will be set up differently to suit the car.

And yes it is true the system will read many different inputs (100x per second) - throttle position, ABS sensors (to determine lost traction), and longitudinal and latitudinal g-force sensors, to determine the weight-shift of the car, sideways and front-back g-forces etc and basically the rule is: If ANY wheelspin (or POTENTIAL for wheelspin) is detected at any wheel, the system will direct torque away from that wheel. The torque split is completely variable - from up to ~95% rear to about 50% front 50% rear - or it can be anywhere in between - as the computer sees necessary.

Its one of the most advanced AWD systems in the world, and works extremely well. It is however not designed for heavy offroad use or situations where you are in AWD constantly (ie. all day). The 4x4 Nissans do still use a form of ATTESA but they also feature the usual 4WD diffs etc to support 4WD mode. On stageas and GTR's the system relies on clutch packs which will wear out if used all the time. Its more like a backup system to ensure maximum traction on the road - and it is more than capable of achieving this.

My favourite thing about ATTESA is that its RWD most of the time, so you get the fuel economy/drivetrain losses of a RWD car (in theory) when just cruising around, but the safety and traction of AWD when you need it. In my opinion its much better than full time AWD systems like mitsubishi and subaru, however those systems have their advantages as well (just that those advantages usually manifest themselves on a rally circuit, not on the road).

R32GTR N1's don't have ABS (or ABS sensors), but they still have ATTESA. Personally I have never seen any 4WD response from wheelspin, it's all about throttle position, plus longitudinal and lateral G forces. R32's will go zero front torque split, R33/34's always have some drive to the front. As long as you keep the oil temperature under control, the ATTESA will handle a full day in 4WD. The clutch pack is wet, so not prone to the wear that a dry clutch gets. There is an argument that says a 50/50 torque split will actually wear the clutch pack less than 5/95. The less slip there is the lower the friction wear and 50/50 has zero slip so zero wear. The only problem with 50/50 is the front diff is so much smaller than the rear one and it simply won't take the load. Yes, I have broken the front diff in the Stagea.

Personally I think a RWD biased 4WD would make a much better rally car than a FWD biased 4WD, for the very same reasons it makes an ATTESA equipped circuit race car the best of the 4WD systems.

Cheers

Gary

Daleo Grand Master

Daleo

Posted
Posted
AWD harder to get off the line...? What are you smoking mate? Clearly would be your tyres if ur rwd :) the awd is super easy to launch HARD

I think what he might mean is that the optimal AWD launch has a small amount of wheelspin, which can be difficult to achieve. I know with my m35, a zero wheelspin standing start (stalled against the torque converter) is not nearly as fast as one with even a small amount of wheelspin (also stalled against the converter)

Thanks to Andy and Jetwreck for the correct launch procedure! :thumbsup:

pixel8r Mentor

pixel8r

Posted
Posted
Actually this is a complete can of worms with some manufacturers claiming full time AWD when they don't have it...

Subaru actually have 4 different AWD systems, depending on engine and transmission options. I won't go into too much detail, but only manual Subarus actually have full time AWD. All the automatics have a clutch pack replacing the centre active diff, or viscus coupling, of the manual versions. That makes them part time AWD, same as our Nissans.

But hey, when have marketing guys ever worried about the truth...

hmm didn't know that - interesting. Either way the subaru system still would not be computer controlled to the degree our nissans are, allowing the torque split to vary anywhere from ~95% rear to 50-50 depending on circumstances. As I understand it (and I could be wrong), the wrx's and evo's have only a couple of preset torque split settings, that are mostly handled mechanically.

As for the AWD vs RWD thing, cars that are RWD only are a tad lighter - which in my opinion is the ONLY benefit to RWD. There are other benefits, slightly quicker, lower fuel consumption - but these are due to the weight difference also.

If you were to compare a RWD and AWD stagea with the same weight (ie. remove the front tailshaft on the AWD), the AWD is quicker down the 1/4 mile. Something to do with the AWD launch compared to RWD. Also the more power the car has, the more this swings even more in favour of AWD...

However the above was only done by someone on here with a s1 or s2. Not sure if the same holds true for the M35.

I agree getting an M35 off the line quickly is no easy task. Not sure if its just gearing or if the torque converter bogs down or what...

Daleo Grand Master

Daleo

Posted
Posted
yes the correct one demonstrated with my car several times lol poor car!

Haha, I thought I was doing well when I stalled mine up and let fly at about 2500rpm, then the guys told me to hold out until the rear wheels start to turn... Biiiig difference!

Note*, All undertaken on closed private roads, street drag racing is naughty... DON'T DO IT!

zei20l Grand Master

zei20l

Posted
Posted

yeah i didnt do it on the street either later that night. but it so happens i was 'parked' next to a taxi that was creeping up on me. i used this trick and shot out of the smoke.

im guessing its VERY bad for the atessa system as its slipping the clutches a lot.........

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