Hicas, What Does It Actually Do

[bren]

Ive doen a search and can find lots about ditching the Hicas but cant seem to find an explanation of what it does and when.

Do the wheels turn the same way as the front or the opposite way?

Does the Hicas system try to work as some sort of stability control or does it just improve turn in?

Ive removed the Hicas today with a locking bar but Id like to know exactly what the system was designed to do

[djr81]

The short answers is to type HICAS into the search engine & all will be revealed.

But to answer your questions:

Do the wheels turn the same way as the front or the opposite way?

Both

Does the Hicas system try to work as some sort of stability control or does it just improve turn in?

It doesn't work like an electronic stability control system if that is what you are thinking. It is supposed to make the car steer better.

Ive removed the Hicas today with a locking bar but Id like to know exactly what the system was designed to do

Why did you remove something when you don't know what it does?

[kjb_r33]

I beleive you have to be doing more than 80 kph, and pulling more than 0.4 of a G for it to work. I think they turn the oppoosite way to the front wheels to bring the arse around and they only turn 1 degree

[hrd-hr30]

SAE Technical Paper 891978, 1989, pp.14951504 'Development of “Super Hicas”, a New Rear Wheel Steering System with Phasereversal Control',

Author

Eguchi, T., Sakita, Y. Kawagoe, K., Kaneko, S., Mori, K. and Matsumot, T., Nissan Motor Co., Ltd

says that HICAS uses steering angle and road speed to determine what to do at what time. it has a maximum of 1 degree movement, and operates between about 20 and 120kph. Basic summary is that at lower speeds and higher steering angles it counter-phase steers initially then changes to on-phase steering. at higher speeds within that operating range it steers in the same phase as the front wheels. remember it only steers up to a maximum of 1 degree!

I keep it connected on my GTR which is mainly used for motorsport, although everyone else will tellyou it causes all sorts of eratic behaviours and make the car unstable under brakes and during turn-in, as well as making it hard to hold a line through a corner. I have not experienced any of those problems.

[Munkyb0y]

Mine hasnt shown any issues either. R33 GTST.

bren, why did u remove it if it was working fine?

[JCMarshall_Law]

Removing the HICAS was one of the best mods I made on mine for track work, makes the car a whole lot more predictable and therefore easier to drive at the limit.

[GTRgeoff]

That was the Super HICAS on 32's Harry and it's common knowledge the GTR32 behaves in a much more rear dominant way to 33's and 34's. When we get to 33 the HICAS is electric and operates over 80kmh and in the same direction as the steering input to induce understeer by holding the rear in. This is great for normal driving by normal drivers.

We then take the car to the track or get it loose during some spirited driving and the HICAS gives us understeer into a corner, so the driver turns in harder and eventually some oversteer may occur. The driver then corrects oversteer by turning on some opposite steering and the HICAS follows pulling more oversteer into the equation. We now enter tankslapper phenomena and this is exacerbated by the useless viscous LSD in 33's which are easily overpowered once hot. As the inexperienced driver tries to correct and stay on the gas to keep going the car becomes more unstable as the HICAS keeps dragging the rear about, eventually going around and all to often hitting a wall at the track.

Now a HICAS lock isn't for everyone. On my GTR33 I barely notice HICAS because it has AWD and a decent LSD, as does a GTR32, but on both R33 GTS25t's it was noticeable enough, especially on my track car that I got rid of it. The auto is a pretty stock car and I don't stick it to it on the streets so no point losing the HICAS.

[hrd-hr30]

That was the Super HICAS on 32's Harry and it's common knowledge the GTR32 behaves in a much more rear dominant way to 33's and 34's. When we get to 33 the HICAS is electric and operates over 80kmh and in the same direction as the steering input to induce understeer by holding the rear in. This is great for normal driving by normal drivers.

yeah, I only searched for info on the system as used in my 32 GTR.

alot of other 32 GTR drivers report the same kind of problems with HICAS making the car unstable.

[GTRgeoff]

Yeah, wasn't taking a shot. Just establishing the difference between the systems.

I'd suggest for inexperienced drivers the changes could be difficult to deal with. You have the track background and experience where maybe you just accept it and modify your driving style as I do. Once I'm up to installing the lock in the GTR33 I can start to explain the changes it makes. Not that I track it. Only do DECA and a few nice roads as well as it being the daily.

[Tommy629_R32]

hey i was just wondering if the r33 hicas system will r32? and if the arms are the same?

[bren]

The short answers is to type HICAS into the search engine & all will be revealed.

But to answer your questions:

Do the wheels turn the same way as the front or the opposite way?

Both

Does the Hicas system try to work as some sort of stability control or does it just improve turn in?

It doesn't work like an electronic stability control system if that is what you are thinking. It is supposed to make the car steer better.

Ive removed the Hicas today with a locking bar but Id like to know exactly what the system was designed to do

Why did you remove something when you don't know what it does?

As I said in the first line of my post, I did a search but couldnt find an explantion of exactly what the system did and when.

I know it is a form of rear wheel steering and I have been told on numerous occasions that remvoing it will improve the handling and predictablity of the car. Thats why Ive removed it. Just because I dont fully understand how the system works does not mean that I wont reap the benefits of removing it. Now Id like to improve my understanding of exactly what the system does and when.

GTRgeoff,

Excellent, thankyou The car does feel 'strange' when pushed hard. Im afraid I cant describe it any better than that. I dont notice it so much now that Im used to the car but Im hoping removing the Hicas will bring a more nimble and predictable element to the back end when pushing hard. Ive fitted a 2 way diff as, like you say, tjhe original unit is appauling. Im hoping the car will now be much more 'chuckable'.

Ill be back on track in the next week or two to do some testing as Ive just fitted some new 356mm front rotors, new oil cooler, am getting the alignment set and have raised the car 20mm all round to lower the roll centre and I need to see if it all works well before we go to SPA race track in Belgium on the 25th August followed by a few days hooning round the Nurburgring in Germany for the following week

Do you guys know of the Nurburgring?

[GTRgeoff]

Tommy, the arms are different, so no.

bren....I hate you. Spa and the 'ring. Done helping you mate!

You'll probably find it less chuckable with the 2-way as it will force a little understeer (a 1.5 would be better for circuit) so get some adjustable caster bushes or arms and pull about 7 deg of caster on the right and a little more on the left to counter the road camber during normal driving. this will counter the occasional "hardening" of the steering at low speed with the HICAS unplugged, unless you have a black box fitted to trick it. The extra caster also sharpens turn in dramatically and makes the car feel smaller and far more nimble.

Enjoy. You bastard!!

[bren]

Tommy, the arms are different, so no.

bren....I hate you. Spa and the 'ring. Done helping you mate!

You'll probably find it less chuckable with the 2-way as it will force a little understeer (a 1.5 would be better for circuit) so get some adjustable caster bushes or arms and pull about 7 deg of caster on the right and a little more on the left to counter the road camber during normal driving. this will counter the occasional "hardening" of the steering at low speed with the HICAS unplugged, unless you have a black box fitted to trick it. The extra caster also sharpens turn in dramatically and makes the car feel smaller and far more nimble.

Enjoy. You bastard!!

Lol

I dont mind the 2 way, its been on the car for a while and its quite easy to push the car into a bit of oversteer when it washes wide. Its just a little hard to control hence the Hicas removal I like the 2 ways ability to lock on corner entry when I want to have a play. Ive run a 1.5 way and 2 way on previous cars but the Kaaz on the Skyline is the most agressive Ive experienced so far.

The cars got adjustable castor and rear camber arms, Im just sourcing some front camber arms then Ill get the whole lot set up to suit fast road/track. Any suggestions as to what to set the rear camber and toe and front camber to?

How does the Hicas removal stiffen up the front steering?

[Modena]

I hicas

[R33S2]

The thing about hicas that annoys me is how it will pull you out of a poweslide, quite sudden and unpredictable, although I can almost guess when it comes on, I either have to back off or end up in opposite lock which if I have the room is OK as it will slide that way for another Hicas attack.

I do like the effect, for such a large car as mine, it makes for easy normal driving.

[GTRgeoff]

bren, R33's have variable rate power steering that gets harder over 80kmh. With the HICAS unit unplugged, unless you have the Tomei black box the steering can firm up at low speeds like 40-50kmh. Never really bothered me but some get really wrapped around the axles over any minor thing, I think their mothers breast fed them too long, but a bit of extra caster just makes it almost unnoticable.

[Kushil Abeysinghe]

As I said in the first line of my post, I did a search but couldnt find an explantion of exactly what the system did and when.

I know it is a form of rear wheel steering and I have been told on numerous occasions that remvoing it will improve the handling and predictablity of the car. Thats why Ive removed it. Just because I dont fully understand how the system works does not mean that I wont reap the benefits of removing it. Now Id like to improve my understanding of exactly what the system does and when.

GTRgeoff,

Excellent, thankyou The car does feel 'strange' when pushed hard. Im afraid I cant describe it any better than that. I dont notice it so much now that Im used to the car but Im hoping removing the Hicas will bring a more nimble and predictable element to the back end when pushing hard. Ive fitted a 2 way diff as, like you say, tjhe original unit is appauling. Im hoping the car will now be much more 'chuckable'.

Ill be back on track in the next week or two to do some testing as Ive just fitted some new 356mm front rotors, new oil cooler, am getting the alignment set and have raised the car 20mm all round to lower the roll centre and I need to see if it all works well before we go to SPA race track in Belgium on the 25th August followed by a few days hooning round the Nurburgring in Germany for the following week

Do you guys know of the Nurburgring?

Nurburgring.......you taking the liner to Nurburgring......wow...man stuff of dreams...good luck....have a lot of videos of Nurburgring driving...you just que up pay and go to the track......hehehe.....you should let it RIP in german autobans as well......

[bren]

Nurburgring.......you taking the liner to Nurburgring......wow...man stuff of dreams...good luck....have a lot of videos of Nurburgring driving...you just que up pay and go to the track......hehehe.....you should let it RIP in german autobans as well......

Weighty steering isnt a bad thing, I prefer it

Kushil Abeysinghe,

We dont see much of Germany, we just drop in through Belgium then a quick blast and we are at the Ring. No autobahns on the way

http://www.multimap.com/map/aproute.cgi?cl...e_pan〈=

We have been tot he Ring twice before, both times in an XJR Jag. Great car and a lot of fun but Im really looking forward to taking the Skyline, it whould be pretty mind blowing in comparison to the Jag

We have been having overheating issues with the Skyline despite fitting a Greddy rad and 19 row oil cooler so we are now halfway through fitting a 34 row cooler right in the mouth of the bumper. Ill be bolloxed if the cars going to overheat with this thing fitted! Ill get some pics when its in later today, it should look really cool. And of course work well

[jjjDavey]

whats it mean if the hicas light turns on all of a sudden?

[johnGTS-t]

i still have HICAS and my car is for Targa's and track. i dont know any different so it isnt bothereing me yet.

i feel quite at home in the car. best time at baskerville is 1.03.9 and the group ill be running in the fastest time is 1.02 something. the car is about 80% standard with a set of re55 race tyres. only other things done are

car r32 gts

lowerd springs (kings)

strut bar

caster arms

pod filter

reset computer

octane boost

7'' rims

only running about 1deg of camber all round so far.