Jump to content
SAU Community

Swaying On Highway

Jay11
 Share

Recommended Posts

Jay11 Community Regular

Jay11

Posted
Posted

Hey guys,

Need some help!

My 34 GTT has started swaying on the highway when I hit minor bumps.

The best way to describe it is that it feels like the back wants to go a different way than the front.

Also it feels like it kind of corrects itself a bit, not sure whether that's got something to do with the HICAS?

All I know is it scares the hell out of me driving on the highway now, it's kind of like driving on ice (not the drug).

Any help would be great!

Cheers,

Jaylon

Link to comment
https://www.sau.com.au/forums/topic/358371-swaying-on-highway/
Share on other sites
jrm Veteran

jrm

Posted
Posted

If your HICAS steering sensor is mis-aligned, this can cause 'crabbing' at speeds 80kph - worse, at approximately 110kph HICAS will turn off which will stop that crabbing and the rear end would kick out (experienced this myself).

I would suggest you get a suspension specialist to check your rear suspension first - see if there's any movement in bushes, etc - and particularly in the HICAS rear steering rack - this can and does happen, as it's a wearing part. If the HICAS steering rack is worn & has movement, it will basically like your rear wheels are loose and that can make the car particularly unsettled even at 60kph going over bumps (I've experienced this too).

Anyway, give that a shot first and see if you can rule things out - but there's plenty of things you can do once you've ruled that out.

  • 3 weeks later...
Jay11 Community Regular

Jay11

Posted
  • Author
Posted

Got the HICAS lock bar installed and the car is worse than before, now happening bad at 80k's when going over a bumpy surface, can even do it at 60k's.

When my car was parked in my driveway I tried to push the rear from side to side but it had no give, it was solid as a rock.

Not sure if it's going to be a rear shock or maybe bushes?

It got aligned on Monday, thought they would pick something like that up when they were aligning it?

Trying to sell the car so gotta get it fixed ASAP.

Anyone have any advice?

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

What is the castor figure? Sounds like it started after they changed the bushes. You need max castor for straight line stability at speed 6deg or 7 deg. (usually only acheivable with adjustable arms although you can usually get a bit of adjustment with eccentric bushes). But from what you say it could be something coming adrift. Suspension shop should have checked all bolts for tightness and used a bar to check ball joints etc. A suspension shop should have a rig to test shocks or you can do it yourself. Walk around the car and push each corner down hard and let go. It should come up and stop. If it goes up and down even once the shock is shot. What is your warrant of fitness test like over there? In NZ the inspection usually picks up faulty ssupension items and a new wof will be good if you are selling.

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

    • MBS206
      R32 Gtst - Track Car

      By MBS206 · Posted

      Biggest thing is you're okay!   It sounds like between the accident, and the drive home, it was a pretty torturous trip again! On the bright side, you took the opportunity to enjoy the event more from the perspective of a spectator, than as an entrant!   Sad to see so much damage to the car. It really has taken a HUGE hit in the front end. If/when you choose to repair, hopefully the rails are straight (At least from shock tower backwards). Hopefully the extra cage coming through there has save most of the chassis rails, and HOPEFULLY saved the motor too. Best of luck when you eventually get motivated to start pulling it down to check it all out
    • MBS206
      Slight brake pedal stutter after new pads

      By MBS206 · Posted

      Sounds more like what Brad said, that it's mainly transfer. What pad bed in procedure did you use, and did you replace/machine the rotors, or just swap pads?
    • PranK
      Slight brake pedal stutter after new pads

      By PranK · Posted

      The stutter is almost entirely in the pedal. I don't feel the brakes release and reapply as you would with ABS engaging but the pedal feels that way, without the brakes releasing. It only lasts for less than a second and the pedal is fine again. It's hard to explain, sorry.  I'll get under this weekend and just double check everything is tight. Fluid is at max where I left it.
    • MBS206
      Slight brake pedal stutter after new pads

      By MBS206 · Posted

      What bedding in procedure did you use?   When you say stutter, what exactly do you mean? Like it feels like someone letting go of the brakes momentarily and regrabbing them again to get you to stop? Re-reading your post, and that is what it kind of makes me think you're explaining, like theres a little bit of a jolt, likely just as you're reaching a stop. I've only had this issue once. And if its caused by what caused mine, you will want to get the car up on stands again and check it over. Mine was a case of a caliper mounting bolt coming out and letting the caliper rotate on the other remaining bolt and gave play in a wheel as it came to a stop. But not every stop either!
    • bcozican
      R32 Gtst - Track Car

      By bcozican · Posted

      Yeop... binned it   This will be a summary will not many pics atm and cbf  Fixed the samsonas - it was totally munched Put a new precision 7675 T4 on with proper split pulse mani Got to Sydney to get to car - drove to canberra to get racecar - drive back to sydney that night Next day all day at Plasmaman putting on new clamps cleaning some things up and adding another large engine oil cooler sitting at the rear above diffuser to keep things cooler Next day - Tuesday - on Dyno - killer wikid awesome pumped out really good numbers - more mid range and on lower boost levels Wednesday - first prac - all day again getting the suspension right - had to borrow front suspension again - out do a lap come in - out do a lap - in - what i had just couldnt handle the load at the more consistent higher speeds - got a lap in at the end of the day that was pretty reasonable  Put it this way that lap wouldve had me in 4th in Pro am for the whole event - with only 700 hp and used tyres Thurs first official prac day - lap out warm up - then entered a hotlap with above setting and 80% effort took corners 1,2,3 and into 4 car felt awesome -  rear came around out of nowhere bang into the wall near front on at whatever 140 kmph Done, over, gone Just one of those how did that happen apparently as all indications show nothing out of the ordinary Got to spend the rest of the time at the event like I hadnt done before - was actually Ok mainly as I had my family and my boy is 9 and got treated like a rockstar Long trip home, lost a trailer wheel in nowhere land, X5 airbag suspension gave up half way across nullabour and rode on bumps stops (its now completely fine) had to do a 19 hr drive day on day 3 as accommodation got screwed up so just had to keep driving till found a town with some Now to reassess - hopefully the motor and other things are OK but yet to be seen too. There is no easy fix there is no i'll just order that part and get it sent - we'll have a talk to people see what can happen and what the go is but at minimum its rebuild from scratch struts forward and alot of time effort and $ should and if I return and if but maybe/ when  I have the cage tied into the front strut towers - if I didnt have that things couldnt been worse you can say its just a front end but if you know what goes into these cars... you'll know what that actually means in reality   Car was very fast. Disappointing we just didnt get to show it Effort doesnt win you races though     Apparently this is motorsport !  
×
×
  • Create New...