Jump to content
SAU Community

Hicas

sturb25

By sturb25,
in Four Door Family & Wagoneers

 Share

Recommended Posts

QWK32 Veteran

QWK32

Posted
Posted (edited)

it only kicks in around 80kph as Aaron has said. its basically an electronic actuator (motor) that controls a steering rack attached to the back of the rear subframe and is liked to the rear of the wheel hub with a toe arm. on the R32 & S13 models it was a hydraulic setup driven off the power steering pump. it turns the rear wheels only by approx 0.7 deg from center, so if your where going around a right hand bend you wheels would be something like this:

front wheels // //

rear wheels \\ \\

when you install a HICAS lock bar you remove the actuator/rack and put a solid bar in between the two toe arms to hold the rear wheel toe where you want it.

edit: beat me with a much better diagram MIKE lol

Edited by QWK32
Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4753292
Share on other sites
Appealing Proficient

Appealing

Posted
Posted

HICAS is a very complex system, that is way over what most people think it is.

It helps to make a car feel shorter & more nimble, and helps to damp Yaw effect.

A long wheelbase car is easier to control but slower to turn. Rear wheel steering helps to turn the vehicle.

It has been heavily critisized for making the rear end feel loose, vauge and unnatural.

Lots of HICAS systems get taken off cars, mostly because owners do not fully understand what it is about.

It is there to make the car drive faster.

As you enter the corner the rear of the car actually gets kicked out, which reduces understeer, if you stay hard on the accelerator, as the car reaches the apex, the steering, G-sensors and throttle position will let the car "know" that it is at the apex, the rear wheels will come into phase and the car will steer straight though the apex, to take the fastest line through the corner.

It's kinda like taking a drifters line without drifting.

Your car should have the same system as the R34, which is also a model following control system.

It is pre-programmed to follow cornering models. It is not just feedback based.

If you really want to find out more about, and get a new admiration for our favorite car (sorry not the Stagea) get the book Nissan GTR by Alex Gorodji. Some of the above is taken from the book.

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4753764
Share on other sites
Raysboostin Mentor

Raysboostin

Posted
Posted
simple diagram

how_hicas_works.gif

i really hope it doesnt work that way, thats very dangerous!! if the rear wheels are turning in the same direction as the front wheels, instead of the opposite, then u r in big trouble if the front doesnt turn in. in an understeer situation, that would have the rear wheels turning u straight off the road!!

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4753813
Share on other sites
zei20l Grand Master

zei20l

Posted
Posted
HICAS is a very complex system, that is way over what most people think it is.

It helps to make a car feel shorter & more nimble, and helps to damp Yaw effect.

A long wheelbase car is easier to control but slower to turn. Rear wheel steering helps to turn the vehicle.

It has been heavily critisized for making the rear end feel loose, vauge and unnatural.

Lots of HICAS systems get taken off cars, mostly because owners do not fully understand what it is about.

It is there to make the car drive faster.

As you enter the corner the rear of the car actually gets kicked out, which reduces understeer, if you stay hard on the accelerator, as the car reaches the apex, the steering, G-sensors and throttle position will let the car "know" that it is at the apex, the rear wheels will come into phase and the car will steer straight though the apex, to take the fastest line through the corner.

It's kinda like taking a drifters line without drifting.

Your car should have the same system as the R34, which is also a model following control system.

It is pre-programmed to follow cornering models. It is not just feedback based.

If you really want to find out more about, and get a new admiration for our favorite car (sorry not the Stagea) get the book Nissan GTR by Alex Gorodji. Some of the above is taken from the book.

i would have to agree, i had a loaner R33 sedan with hicas, and for a big heavy car, this thing handled quite well and could be easily thrown around. i have no idea why people complain about hicas so much. i think they hear that one person doesnt like it and calls it useless, then it MUST be. if it WAS useless, car manufacturers wouldnt be equipping cars with it.......

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4754142
Share on other sites
QWK32 Veteran

QWK32

Posted
Posted

I think the biggest complaints about HICAS come from anyone who has a dedicated track/drift car, or frequents a track for racing or drifting. And because every second person thinks of themselves as a race car driver or drifter they remove it based on what the real race driver and drifters have said.

Personally I liked the HICAS on my old 32 but can vouch for the fact that once the tail end is out there, it's too easy to over correct because the HICAS system is also assisting the turn.

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4754451
Share on other sites
BensDR30 Experienced

BensDR30

Posted
Posted

You have to love the original HICAS implementation in the R31's - it had a couple of rams and flexed the entire K-frame on it's bushes!

4WS seems to have dropped off the radar these days, possibly due to it's mechanical complexity vs. what you can to with ESP and it's broader safety benefits.

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4754683
Share on other sites
lachlanw Veteran

lachlanw

Posted
Posted
i really hope it doesnt work that way, thats very dangerous!! if the rear wheels are turning in the same direction as the front wheels, instead of the opposite, then u r in big trouble if the front doesnt turn in. in an understeer situation, that would have the rear wheels turning u straight off the road!!

open your eyes before your mouth please

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4755401
Share on other sites
lachlanw Veteran

lachlanw

Posted
Posted

i really enjoy hicas . and really notice when it comes on . eg same piece of road at different speeds . also mint for turning on hicas test and your car sits there and every 2 seconds the rear wheels move full lock (1 degree ish) one way and then other way then back to normal as fast as they can . and every one says wtf is your car doing ? "its break dancing "

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4755416
Share on other sites
QWK32 Veteran

QWK32

Posted
Posted
Has anyone ever had HICAS work in a straight line? That sort of issue, giving the car a 'flick'? Possibly due to the wheel not being on straight...?

only when the speedo cable snapped when i was on my way home from work, hicas started playing up along with the usual heavy steering. i was crab walking up a straight road, very strange feeling.

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4755455
Share on other sites
GT-R32 Grand Master

GT-R32

Posted
Posted
only when the speedo cable snapped when i was on my way home from work, hicas started playing up along with the usual heavy steering. i was crab walking up a straight road, very strange feeling.

That's exactly what I had but without the heavy steering. :) Definite crab walk. Happens at higher speeds like 80km/h and you need to steer into it and if slow down quick a flick out of it. I recently had work done on the suspension but the steering wheel is not that straight after the alignment and wondered if that had anything to do with it...? Speedo cable is all good.

Link to comment
https://www.sau.com.au/forums/topic/282242-hicas/#findComment-4755483
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      After market rear camber arm adjustment

      By GTSBoy · Posted

      Wheel alignment immediately. Not "when I get around to it". And further to what Duncan said - you cannot just put camber arms on and shorten them. You will introduce bump steer far in excess of what the car had with stock arms. You need adjustable tension arms and they need to be shortened also. The simplest approach is to shorten them the same % as the stock ones. This will not be correct or optimal, but it will be better than any other guess. The correct way to set the lengths of both arms is to use a properly built/set up bump steer gauge and trial and error the adjustments until you hit the camber you need and want and have minimum bump steer in the range of motion that the wheel is expected to travel. And what Duncan said about toe is also very true. And you cannot change the camber arm without also affecting toe. So when you have adjustable arms on the back of a Skyline, the car either needs to go to a talented wheel aligner (not your local tyre shop dropout), or you need to be able to do this stuff yourself at home. Guess which approach I have taken? I have built my own gear for camber, toe and bump steer measurement and I do all this on the flattest bit of concrete I have, with some shims under the tyres on one side to level the car.
    • Jarsky
      R33 Fuel Pump & Brakes after alarm swap

      By Jarsky · Posted

      Thought I would get some advice from others on this situation.    Relevant info: R33 GTS25t Link G4x ECU Walbro 255LPH w/ OEM FP Relay (No relay mod) Scenario: I accidentally messed up my old AVS S5 (rev.1) at the start of the year and the cars been immobilised. Also the siren BBU has completely failed; so I decided to upgrade it.  I got a newer AVS S5 (rev.2?) installed on Friday. The guy removed the old one and its immobilisers. Tried to start it; the car cranks but doesnt start.  The new one was installed and all the alarm functions seem to be working as they should; still wouldn't start Went to bed; got up on Friday morning and decided to have a look into the no start problem. Found the car completely dead.  Charged the battery; plugged it back in and found the brake lights were stuck on.  Unplugging the brake pedal switch the lights turn off. Plug it back in and theyre stuck on again. I tested the switch (continuity test and resistance); all looks good (0-1kohm).  On talking to AVS; found its because of the rubber stopper on the brake pedal; sure enough the middle of it is missing so have ordered a new one. One of those wear items; which was confusing what was going on However when I try unplugging the STOP Light fuses (under the dash and under the hood) the brake light still stays on. Should those fuses not cut the brake light circuit?  I then checked the ECU; FP Speed Error.  Testing the pump again; I can hear the relay clicking every time I switch it to ON. I unplugged the pump and put the multimeter across the plug. No continuity; im seeing 0.6V (ECU signal?) and when it switches the relay I think its like 20mA or 200mA). Not seeing 12.4V / 7-9A. As far as I know; the Fuel Pump was wired through one of the immobiliser relays on the old alarm.  He pulled some thick gauged harness out with the old alarm wiring; which looks to me like it was to bridge connections into the immobilisers? Before it got immobilised it was running just fine.  Im at a loss to why the FP is getting no voltage; I thought maybe the FP was faulty (even though I havent even done 50km on the new pump) but no voltage at the harness plug.  Questions: Could it be he didnt reconnect the fuel pump when testing it after the old alarm removal (before installing the new alarm)?  Is this a case of bridging to the brake lights instead of the fuel pump circuit? It's a bit beyond me as I dont do a lot with electrical; so have tried my best to diagnose what I think seems to make sense.  Seeking advice if theres for sure an issue with the alarm install to get him back here; or if I do infact, need an auto electrician to diagnose it. 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      Then, shorten them by 1cm, drop the car back down and have a visual look (or even better, use a spirit level across the wheel to see if you have less camber than before. You still want something like 1.5 for road use. Alternatively, if you have adjustable rear ride height (I assume you do if you have extreme camber wear), raise the suspension back to standard height until you can get it all aligned properly. Finally, keep in mind that wear on the inside of the tyre can be for incorrect toe, not just camber
    • V35Newbie
      After market rear camber arm adjustment

      By V35Newbie · Posted

      I know I have to get a wheel alignment but until then I just need to bring the rear tyres in a bit they're wearing to the belt on the inside and brand new on the outside edge. I did shorten the arms a bit but got it wrong now after a few klms the Slip and VDC lights come on. I'd just like to get it to a point where I can drive for another week or two before getting an alignment. I've had to pay a lot of other stuff recently so doing it myself is my only option 
    • Duncan
      After market rear camber arm adjustment

      By Duncan · Posted

      You just need a wheel alignment after, so just set them to the same as current and drive to the shop. As there are 2 upper links it may also be worth adding adjustable upper front links at the same time; these reduce bump steer when you move the camber (note that setting those correctly takes a lot longer as you have to recheck the camber at each length of the toe arm, through a range of movement, so you could just ignore that unless the handling becomes unpredictable)
×
×
  • Create New...