Reason 370GT Coupe's FWS are all disabled

[Vee37]

Most of the coupes I have seen in AUS are P or SP models, which include 4WS; including mine. Its on the plate. However, its disabled. Is i it disabled because

1. To meet AUS Compliance

2. It was too expensive and/or complicated/difficult to keep working in Japan, by the original owner

OR some other reason

Is there anyone here who has the 4WS enabled/working? Mine is a 2008 coupe.

[steV36]

How do you find out if it’s disabled? Can you feel it when you’re driving?

[nickcorr]

My R33 GTS-T, M35 ARX and V36 Type SP all had their 4WS connected as far as I was aware. No error messages etc.

[GTSBoy]

Nissan's HICAS, and all other 4WS steer systems until the very most recent ones (last 10 years, Porsche, etc), are all...... crap. utter crap. A good idea that didn't work properly.

Hence, we piss them off. The cars are more predictable without a 3-brain-cell computer sawing away at the back wheels while you're trying to balance the car on the limit of longitudinal and lateral traction.

[joshuaho96]

On 7/28/2022 at 9:44 PM, GTSBoy said:

Nissan's HICAS, and all other 4WS steer systems until the very most recent ones (last 10 years, Porsche, etc), are all...... crap. utter crap. A good idea that didn't work properly.

Hence, we piss them off. The cars are more predictable without a 3-brain-cell computer sawing away at the back wheels while you're trying to balance the car on the limit of longitudinal and lateral traction.

The 4WS in the V37 is also extra annoying in that in normal operation it disconnects the steering wheel from the steering column, supposedly because this allows for better steering response. Porsche supposedly planned a 4WS system in the 993 but killed it at the last minute because they couldn't get it to work as intended. About 15 years later they finally did figure it out and that was what we got in the 991.

[Vee37]

On 7/29/2022 at 12:41 PM, steV36 said:

How do you find out if it’s disabled? Can you feel it when you’re driving?

I have checked by looking at the rear wheels while driving slowly in a tight curve. I have seen YouTube vids for other cars, where the rear wheels will steer even if you are stationary, probably ready for when you start moving; at slow speed pointing the opposite to the front.

On 7/29/2022 at 2:44 PM, GTSBoy said:

Nissan's HICAS, and all other 4WS steer systems until the very most recent ones (last 10 years, Porsche, etc), are all...... crap. utter crap. A good idea that didn't work properly.

Hence, we piss them off. The cars are more predictable without a 3-brain-cell computer sawing away at the back wheels while you're trying to balance the car on the limit of longitudinal and lateral traction.

I do NOT drive my car aggressively. I drive mostly around the city, and could see a benefit when driving through the very tight curves in the narrow ramps in the parking lots I often use. And, if it isnt ridiculously expensive, I could try it for myself, and then turn it off again if it is crap, for my driving. Also, if its to meet AUS compliance, that removes any practical option to give it a try.

Edited July 29, 2022 by Vee37

[niZmO_Man]

My HICAS goes one step further and actively tries to kill me while driving. That's why it's unplugged haha (yes I should remove it entirely).

[soviet_merlin]

From what I have read HICAS only kicks in at speed, i.e. 80km/h upwards. So not much help in parking lots unless you go full Tokyo Drift.

I found this topic helpful. Haven't really seen it described well anywhere else.

 

[GTSBoy]

On 7/29/2022 at 9:38 PM, Vee37 said:

I drive mostly around the city, and could see a benefit when driving through the very tight curves in the narrow ramps in the parking lots I often use.

That's not what HICAS is for. It isn't intended to make tighter turning radius in low speed corners. That was what the other shitty Japanese 4WS steering systems on the Mazda MX-6 and Honda Prelude were for, because in the 80s FWD chassis designers hadn't worked out how to give medium-large FWD cars a decent turning circle. In fact, the turning circle on pretty much all FWD cars sucked balls up until the mid 90s. These types of systems counter steered the rear wheels to improve the turning circle.

HICAS DOES NOT COUNTER STEER.

HICAS was intended by Nissan to improve the turn in response of "sporty" cars that were actually just pleb grade chassis with a GT/coupe body on top. There's little difference between an R chassis, an A chassis, an S chassis, or most of the other Nissan RWD offerings of the time. Even the V chassis is only an evolution of the same mass produced old shit. So, the chassis is not necessarily that "sporting". But the cars that had HICAS ladelled onto them were marketed as sporty, so they had to try to make them as sporty as possible without making them too harsh and jittery. If you were to improve the turn in without resorting to 4WS, you would simply improve the geometry a little, increase ARB stiffness, damper tuning and so on, but all of these things make the car ride more harshly and can be scary to normal plebian drivers, particularly in the wet.

So, what HICAS does is induce a moment of in-phase steering as you turn into a corner. It does this because tyres only start to create a turning force against the road when there is a slip angle between the direction the tyre is pointing and the direction that it is actually travelling along the road. At the front, this is achieved by turning the wheel. You turn the front wheels to point a different direction to the direction that the car is travelling, then the slip angle exists, and then the tyre starts generating a turning force. That then starts to rotate the car, and it is only after the car starts to rotate around its axis that the rear tyres start to have a slip angle and start generating a turning force. The rear tyres are totally slaved to the rest of the car. There is a delay. HICAS instead causes the rear tyres to have a slip angle immediately and start generating a turning force immediately, causing the rear of the car to start to rotate in the desired direction much earlier in the process. This is experienced as improved turn in - the rear end feels more "alive" and "sporty" and any other such terms you like to apply.

The trouble is that the computer only knows a few things. It only has a steering angle input from the steering wheel sensor and a speed sensor, and bugger all else. No lateral G sensor, nothing else. So it has no bloody idea exactly how you're driving the car. And the computer is a bloody simple and stupid device with a simple program that says if X then Y - pretty much. And that program is only good up to about 7/10ths driving. After that, when you're pushing the car hard through a turn, the last thing you want is the 4WS computer interpreting your repeated steering inputs (as you fight understeer, etc) as new corner entries and to keep changing the angle of the rear wheels. HICAS is simply the best way to fling your car off the corner in reverse when you're really going for it. It sucks. It just sucks.

[joshuaho96]

On 7/29/2022 at 4:36 PM, GTSBoy said:

That's not what HICAS is for. It isn't intended to make tighter turning radius in low speed corners. That was what the other shitty Japanese 4WS steering systems on the Mazda MX-6 and Honda Prelude were for, because in the 80s FWD chassis designers hadn't worked out how to give medium-large FWD cars a decent turning circle. In fact, the turning circle on pretty much all FWD cars sucked balls up until the mid 90s. These types of systems counter steered the rear wheels to improve the turning circle.

HICAS DOES NOT COUNTER STEER.

HICAS was intended by Nissan to improve the turn in response of "sporty" cars that were actually just pleb grade chassis with a GT/coupe body on top. There's little difference between an R chassis, an A chassis, an S chassis, or most of the other Nissan RWD offerings of the time. Even the V chassis is only an evolution of the same mass produced old shit. So, the chassis is not necessarily that "sporting". But the cars that had HICAS ladelled onto them were marketed as sporty, so they had to try to make them as sporty as possible without making them too harsh and jittery. If you were to improve the turn in without resorting to 4WS, you would simply improve the geometry a little, increase ARB stiffness, damper tuning and so on, but all of these things make the car ride more harshly and can be scary to normal plebian drivers, particularly in the wet.

So, what HICAS does is induce a moment of in-phase steering as you turn into a corner. It does this because tyres only start to create a turning force against the road when there is a slip angle between the direction the tyre is pointing and the direction that it is actually travelling along the road. At the front, this is achieved by turning the wheel. You turn the front wheels to point a different direction to the direction that the car is travelling, then the slip angle exists, and then the tyre starts generating a turning force. That then starts to rotate the car, and it is only after the car starts to rotate around its axis that the rear tyres start to have a slip angle and start generating a turning force. The rear tyres are totally slaved to the rest of the car. There is a delay. HICAS instead causes the rear tyres to have a slip angle immediately and start generating a turning force immediately, causing the rear of the car to start to rotate in the desired direction much earlier in the process. This is experienced as improved turn in - the rear end feels more "alive" and "sporty" and any other such terms you like to apply.

The trouble is that the computer only knows a few things. It only has a steering angle input from the steering wheel sensor and a speed sensor, and bugger all else. No lateral G sensor, nothing else. So it has no bloody idea exactly how you're driving the car. And the computer is a bloody simple and stupid device with a simple program that says if X then Y - pretty much. And that program is only good up to about 7/10ths driving. After that, when you're pushing the car hard through a turn, the last thing you want is the 4WS computer interpreting your repeated steering inputs (as you fight understeer, etc) as new corner entries and to keep changing the angle of the rear wheels. HICAS is simply the best way to fling your car off the corner in reverse when you're really going for it. It sucks. It just sucks.

In fairness, the R33 GTR and R34 GTR added a yaw sensor at least to make the HICAS have some kind of closed loop control. It still doesn't make it a great system, but less egregiously trying to send you off the road like I've heard from multiple R32 owners. If the yaw sensor fails from age you can get interesting behavior as well, there's no redundancies in the system.

[sonicii]

On 7/29/2022 at 4:27 PM, joshuaho96 said:

The 4WS in the V37 is also extra annoying

4WS in the V37??  Not in any of the AuDM models that I have seen.  If you mean DAS, it isn't 4WS.

[joshuaho96]

On 7/29/2022 at 11:26 PM, sonicii said:

4WS in the V37??  Not in any of the AuDM models that I have seen.  If you mean DAS, it isn't 4WS.

If the system is called 4WAS by Nissan it does. I guess it's fair to say what's actually happening is that it's silently adding the 4WS steering angle change to your steering input through a gearbox and so it's technically still coupling the steering wheel to the wheels directly. You can see it in this system diagram:

[sonicii]

Are you sure those documents are for a V37 and not a V36 with 4WS?

There is certainly no rear steering components on My Q50S premium with DAS.  the DAS system completely disconnects the physical connection between the steering wheel and the rack with just an angle sensor and feedback motor in the column,  it does have an electronic clutch that can reconnect a physical connection there is a system failure, but with zero power assistance.

[GTSBoy]

On 7/31/2022 at 11:39 AM, sonicii said:

the DAS system completely disconnects the physical connection between the steering wheel and the rack with just an angle sensor and feedback motor in the column,  it does have an electronic clutch that can reconnect a physical connection there is a system failure

And yet....you still bought the car?

[joshuaho96]

On 7/30/2022 at 7:09 PM, sonicii said:

Are you sure those documents are for a V37 and not a V36 with 4WS?

There is certainly no rear steering components on My Q50S premium with DAS.  the DAS system completely disconnects the physical connection between the steering wheel and the rack with just an angle sensor and feedback motor in the column,  it does have an electronic clutch that can reconnect a physical connection there is a system failure, but with zero power assistance.

I'm pretty sure you're right, it's for the V35 and V36. In the V37 I guess it went away.

[sonicii]

On 7/31/2022 at 3:36 PM, GTSBoy said:

And yet....you still bought the car?

yeah, it gets a bad wrap, and if you want to track the car, it probably wouldn't be ideal.  But for daily road use, I prefer it to the steering on my V35 now.

[mooij]

It certainly gets a bad wrap, and I was pretty concerned about it when I first purchased. 

I messaged some Japanese/US/NZ drifters who also use the platform and they basically said its not a big deal.

Some leave it, some disconnect it and others remove it all together by replacing the subframe with a non 4was option.

 

I've done mulitple time attack/drift days so far with it with no real issues.

 

Having said that I have aquired a z34 rear subframe to remove it when I eventually get around to it.