Anyone actually FELT it work. Must admit I haven''t but I don't boot the car unless I am going straight as I'm terrified of crashing. I reckon you need to take the car onto a track to really learn the limits of grip and control as learning them on a public road could be disastrous.

Strange you mention this, had weird sensation today,went bit quick into and around roundabout,thought backend will go but no,started to go slightly then just seemed to whip back in line with front wheels,hard to explain realy how it seems to react to tight cornering etc,but having not had a car with this type of system before it does seem to react very differently to normal fixed rear axles.TonyC.

A few words.......

 

Traction Control..........

 

Get it!!!!

 

 

Matty.

 

------------------

I think its the case that with hicas 4 wheel steer that, if you are going slow the wheels turn against eachother to achieve a tighter turning circle and if you are going fast the turn with eachother thus straightening the corner out more, dont quote me on this i may be wrong!! See shit diagram

 

SLOW FAST

 

/ / / /

 

 

\ \ / /

 

 

 

[This message has been edited by b19rks (edited 02-07-2002).]

The HICAS system works alot differently to the Honda type systems like described above...

 

As the steering is turned, the rear wheels initially point the opposite way for a split second, then swap so they are both pointing the same way. This gives a balance more like a front wheel drive car - presumably so any muppet can drive one

 

HTH

 

CheerZ,

 

Andy

This information appeared on the forum some time ago, courtesy of Crazy-Eddy:

Like they say, "does what is says on the tin" what is described above is exactly how it felt at speed on roundabout/corners as i said previous. TonyC .

I was driving in the fast lane in rush hour on the M4 a few months back. Suddenly noticed the cars in front were slowing fast! I hit the brakes and they were not gonna stop me in time. Just as i resigned myself to a shunt i swerved at speed into the middle lane and proceeded to pass the cars now queued back in the fast lane.

Looking back on that manouver i'm astounded how well it all went. No tail swinging or tyre screeching. It probably looked reel cool. I put it down to the HICAS. I was toying with ditching the Hicas but not now. It saved me then.

 

The funniest thing tho was looking in the rear view mirror to see the face of a mini-van driver behind me who was standing on his brakes, panic smeared all over his face trying to control the tail of his van as it swung wildly from side to side. he dissappeared into the fast lane for a bit then came back to the middle lane. i don't think he hit anything. man i shoudn't laugh but it was funny!!!

I remember Henri le Hir did a lot of reaserch and testing on this. You will probably find the link if you search on TT net.

Paul

coogs,

i done exactly the same going down the M1 the other month! top thing on ya car is the hicas...cool

 

As the actual angle of variance is never more than ONE DEGREE how noticable is it??

Unless your bushes are in tip top nick it isn't going to be 'doing what it says on the tin'.

 

Personally I think it just gives a 'vague' feel to the back end at high speeds. If it was REALLY any good (as opposed to a mere gimmick)it would be on a lot more high performance vehicles.

Originally posted by kinace:

As the actual angle of variance is never more than ONE DEGREE how noticable is it??

Unless your bushes are in tip top nick it isn't going to be 'doing what it says on the tin'.

 

Personally I think it just gives a 'vague' feel to the back end at high speeds. If it was REALLY any good (as opposed to a mere gimmick)it would be on a lot more high performance vehicles.

 

how noticeable is one degree on your front wheels ? enough to know you need your tracking sorting out, thats for sure....

 

it is noticeable, but you need to know when it is going to be noticeable....

 

at about ~40mph or so you will get the opposite phase shift first, and once you know what speed it happens on your car, you can do some sharp turn ins and notice it

 

at high speed, you notice it most on fast lane changes, as mentioned above...

 

on a motorway, in a straight line, at 70, if i do a very quick 30-45 degree turn and return to center of the wheel, i notice that the car moves sort of diagonally sideways across the lane

 

if you did that in a non hicas car, you would get serious lurch to the left, and maybe induce a spin!!! beware

 

you can get exactly the same effect on the honda 4ws system, which is only "in phase" at that speed too, out of phase is low speed only

 

 

other performance cars with hicas ?

skylines have it.....

 

other than that ?

honda have their own, which does the same thing at high speed, and is in use on the NSX and prelude

mitsubishi have 4ws on the GTO and Galant

 

toyota(celica), mazda(MX6), subaru(svx) have a 4ws system

 

its a lot more common than you realise

HICAS, I believe, is only on the GTSt skyline. The GTR have ATESSA (the 4wd system) and would have been too difficult to get HICAS on. Probably. hehe not that you really needed to know that, or I dont even nkow if im correct.

Ill get me coat.

In the "300zx Enthusiast's Companion" it says (sorry no scanner yet):

 

The 300ZX Turbo has one extra technical feature of which the engineers are especially proud: Super HICAS. Other Japanese manufacturers offer four-wheel steering and in the case of Honda and Mazda it is two-phase, assisting low-speed manoeuvres as well as enhancing high-speed stability. Super HICAS is also two phase but of more subtle character. It is not arranged to make it easier to squeeze into parking spaces. The rear-wheel steering, which never exceeds plus or minus one degree, is purely designed to improve the car's response in medium and high speed swerves.

 

The rear-wheel steering system, which is integrated with the multi-link suspension and the front wheel steering, is electro hydraulic. It operates like this: electronic sensors detect the car's speed, steering angle and steering wheel movement, and if they exceed predetermined values, the computer directs a hydraulic actuator at the rear axle to steer the rear wheels via the rearmost lower suspension links. In normal driving, the movement is rarely more than 0.4 degree.

 

But, unlike other 4WS systems which, at speed, steer the rear wheels in the same sense as the front ones, Super HICAS first introduces a twitch of counter-steer before settling with all 4 wheels pointing in the same direction. The degree or suddenness of this touch of opposite lock is reduced as the speed rises.

 

Super HICAS automatically produces a precise form of the rally driver's technique of flicking the steering to the outside of a corner before turning into it. The result for the 300ZX is very sharp "turn-in", with better stability through the classic lane change nanoeuvre which reproduces emergency evasive action at speed. An ordinary car tends to swing its tail in such circumstances, but 4WS allows the front and rear tyres to develop their swing angles simultaneously to the benefit of handling.

 

If it is so good and they are so pleased with it, why doesn't Nissan fit Super HICAS to the N/A 300ZX as well. The answer is about economics, but NTC's testers say that the real benefits of the rear-steer become apparent at over 120 mph and they are happy with the handling of the regular car without it. The 300ZX Turbo, with its considerably higher speed potential, needed Super HICAS if it was to achieve the ambitious handling and stability standards they had set themselves."

 

Phew.

 

In Series 2 and later, I believe it was purely electrical without hydraulics?

 

Sounds like Coogs and jaylox already found the benefit! - Gio

HICAS, I believe, is only on the GTSt skyline

 

The HICAS system was available on a range of Nissans during 1989-present, including the 1989 S13's etc.

 

The Super HICAS system was fitted to the R32 GTR, R33 GTR and R34 GTR.

I belive the R32 GTR Super HICAS system is very similar to the Z32 300ZX system.

The R33 GTR had Yaw rate feedback added to the Super HICAS system.

The R34 GTR also had a further Revised SUPER HICAS system.

(I have wondered if the R33/34 GTR Super HICAS system could be fitted to a Z32! Yaw rate control would be good!)

 

In Series 2 and later, I believe it was purely electrical without hydraulics?

Yup.

 

------------------

 

Trev

1990 300ZX TT 2+2(import)

http://www.300zx.co.uk/rides/trey/

Originally posted by Trey:

The HICAS system was available on a range of Nissans during 1989-present, including the 1989 S13's etc.

 

The Super HICAS system was fitted to the R32 GTR, R33 GTR and R34 GTR.

I belive the R32 GTR Super HICAS system is very similar to the Z32 300ZX system.

The R33 GTR had Yaw rate feedback added to the Super HICAS system.

The R34 GTR also had a further Revised SUPER HICAS system.

(I have wondered if the R33/34 GTR Super HICAS system could be fitted to a Z32! Yaw rate control would be good!)

 

In Series 2 and later, I believe it was purely electrical without hydraulics?

Yup.

 

 

fair enough! just i never see any spec sheets with hicas (be it super or otherwise), listed!

regards