Anyone tell me what HICAS all about?

Heres the info I posted in Powerlords thread on the general board:

 

 

Here is text from a post Henri Le Hir made on tt.net back in December 2000 following his investigation into the HICAS system:

 

 

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I know that my little knowledge applies to the EURO Hicas, in my 2+2 TTz.

I KNOW that the Hicas in the 2+0 Z is "slightly" different, but givent that I drove both (US and EURO), I don't think the difference is that important.

Some US drivers had their hands on my steering wheel, and, they too couldn't find a real difference.

 

In the following, I'm discussing about Street Legal / Driven Z….not about people building a dedicated track racer….

 

Then….I replied to the question : Why do so many people seem to not want Hicas? please xplain? (n/m)

 

This question was asked in a discussion starting with…

 

I am really sick of that HISAC thing !! I wana drive a car without having to guess what is it gona do when I turn the steering wheel ! I have to say it was OK when the car was newer (except when turning back the wheel to exit a ramp or a turn, it always feel weird) but now it always feel weird !

I wana be able to eliminate it without having to buy that Stillen thing ! will it stop working if I pull out the fuse or will still have some rear end play !?

 

The reason WHY ?…..I found this pretty funny….but I digress

 

I have a bad rear left tie rod...

 

followed by….

 

But I still think that the car would better be off w/out the HICAS ... I know 94 and up you can disable them by pulling the fuse .. no hydraulic... I don't about mine .... also the HICAS does not activate under sever driving ..

 

Personally, I still think that the car would run 100 times better with a GOOD rear tie rod…..but maybe I'm wrong, and too stupid to understand the logic :-)

 

I never drove Z w/out HICAS before and I am sure I will enjoy a 100

times more than a stupid system turning the wheels for me !!

 

 

Do it, and report what you found...personally, I cannot tell before I tried !

 

Disturbing

 

Given that I'm myself a former rally racer, I understand some points loud and clear (especially Joe's).

Initially I found the HICAS to be a pain, a trouble, a worry.

This was especially true when I "pushed" my Z to the limit, and because that damm thing would do things by itself….but rater than "only" cursing it, I started to think about it, and analysing it's behaviour (how do you think I know HOW to disable it ???)

 

Unfortunately, there's no simple way to get your hand on the HICAS code, and dis-assemble it (like it's possible t do with the ECU)…..so…it had to be test & trial…in order to do that, I used video (in.board & external, good old stopwatch, accelerometers (G.Tec and G-Analyst)

 

The analyse phase took several months (up to one year), and included driving on the road & track, from crawling to 280 mph, under all kind of weather, from dry to snow and black ice, with perf , M&S and snow tires, driving my Z all year long..

 

I took pictures in the process (that keeps popping year after year…..and I got harassement - hate mail about them….seems that for some low level punks, I should get killed because I pay no respect to ma car…..and BTW 16 year old kid, it's my car, my money, and my life…..get one…you're added to my killfile, just be sure to NEVER need my help……but I digress), and with a remote switch allowing me to start/stop the hicas while driving.

I even tested the HICAS making a slalom event on snow, and driving at 4:00 at 120+ mph on an highway freshly covered by 5in of snow.

 

I soon discovered the following things.

On a given curve, I would pull MORE lateral G WITH the HICAS ON than OFF (so much for being the good driver I thought I was), then I discovered that I was mostly disturbed by the Hicas operation when entering a sharp turn, pretty fast, doing what I've been practising for years……conter-steering / steering…..the fact is….the HICAS will do exactly that, and MY racing technique would intrefere…..so I decided NOT to do the conunter-steering / steering, and let the hicas do it….of course, I made tests as well with the Hicas disabled.

 

Basically, I felt akward to go full speed in a turn à la Grandmother mode (i.e. turn the steering wheel, and go)….but…..this was the best way….actually, the HICAS will give any driver the ability to turn like a pro.

 

But…that's what it takes to learn a new car/tool/device, especially for people who never experienced it before (some replies were from NA owners, at least according to their profile)

 

Useless

 

I always grind my teeths when I see a post like "hicas is useless", "hicas does nothing", etc etc etc…..or when I see posts repeating incorrect information gathered god-know-where….one typical example being "Hicas does not work when speed is below 60 mph"

 

Sure….how do they know that…..repeating incorrect information (I know what's written in the Nissan tech manual….but in there…it's also written that the Det sensor is connected via TWO wires !!!).

 

During my analysing phase, I took the time to put a small LED diode on the actuation circuit of the HICAS. It was VERY interesting….as the led would blink at VERY low speed…and with minute steering angles….so much for the hicas being active only at high speed…in fact, it's almost always on…..and doing something….

 

Interestingly, I'm not the only one who found that….go in the search, and look for "HICAS" and "LED".

 

So, what next do we have with the HICAS eliminator…..well…..lose a couple kilos….great….but if weight is so important….why remove the hicas, and add rear amplifiers, speakers, 18' allow wheels, etc etc….and I'm pretty sure that there's a lot more potential in putting the driver on diet than removing the hicas :-)

 

Drag Racing.

 

First of all, I do NOT do drag racing….and I'm not interested in it, but I can still understand the physics of it…..

 

I've been told that HICAS is not good for drag racing….ok….I'm still waiting to get some REAL data about it (like time with / without)

 

I can understand if someone trying to build a dedicated drag Z wants to get rid of ANYTHING, including all weight…..but in a street driven Z…what's the goal ?

 

I know something for granted, the hicas WILL react to minute amount of steering.

 

In MY case…I see NO time difference when I accelerate WITH and WITHOUT the HICAS……but I do keep my steering wheel straight

 

I was in the past faced with people that were blaming the HICAS, while in fact were SHAKING the steering wheel (i.e couldn't hold it true while accelerating), or had such a bad BALANCE problem on the front wheels that the steering wheel was wobbling….can this trigger the HICAS….sure…is this a HICAS problem…I don't think so.

 

Finally, the US Z has a weight problem…..weight distribution is not as good ad the Euro one…especially for drag racing. And I'm pretty sure that it would be a good idea to put MORE weight on the rear axle to improve acceleration…ideally, getting some weight from the front and re-locate it to the rear…..it would even be possible to load the trunk with kitty litter…and see what this does….

But…removing some weight from the rear….it's counter-productive.

 

Last….is the HICAS dangerous….well….it's a device that will give and unexperienced driver that ability to go faster in the turns…..up to the point that the laws of physics will kick in.

At this time, well….either you know how to recover…..or you crash…..is that dangerous….sure….but what was dangerous was to drive above someone skill.

 

Finally….I'm quite surprised how many are taking a tongue in ckeek comment as a personal offence….so, to clarify things…

 

Honestly, how many people here dare to drive their Z on snow, ice…..take it to a track, take it to the limit…..given the number of posts I see on the forum about "warning, I lost control of my car under the RAIN"…..I'm sure that some do….but some don't….

 

If you know that…

 

You know you're not the best driver on earth

You're dedicated to improve your driving

You've already been doing some driving perf school / competition

You don't race in the streets

You already wore a helmet while driving your Z

You're not afraid to slide your car

If you push your car to the limit, and lose control, you understand that YOU did something wrong.

You're not afraid of driving your Z when it's raining.

 

Well….my comment was not aimed at you..

 

On the other hand…

You know you ARE the best driver on earth

You don't want to improve your driving, you're already the BEST

F**K the driving instructors, you are the B.E.S.T., no need for perf school

You DO race in the streets…you want to kill that Camaro, 3000GT, Honda (and may kill someone in the process)

You do NOT need a helmet, you never crash

You're afraid to slide your car….cause your expertise does NOT include emergency maneuvers

It's NEVER your fault when you lose control, but something / someone else

You're in panic mode when it's raining…

 

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You can see the post here : http://www.twinturbo.net/cgi-bin/ttnet_viewmsg.pl?forum=main&msg_id=630544

 

Later,

Trev

 

 

The following link may also help, and was imaged up for us by Crazy Eddie. http://www.btinternet.com/~dave_edwards/Site/hicas.htm