Jump to content
SAU Community

Constant *thud* Noise Over 80Km/h

Rekin
 Share

Recommended Posts

Rekin Grand Master

Rekin

Posted
Posted

Hello all,

During a trackday training day i went backwards over a ripple strip and heard a massive bang underneath the car. Assumed I smashed the dump pipe on the ripple strip. Turned back around and kept on driving as normal. Everything seemed to be fine till the end of the day.

When driving back i noticed a constant thud noise coming from the car when Im over 80km/h.

It sounds like a flat spot or buckled rim; *thud* *thud* *thud*. From 80kmh+ the sound is quite noticeable.

Clutch in; Sound still there

Clutch in, neutral, clutch out, rolling at speeds above 80km/h sound still present.

This would mean its related to suspension, diff, tyres, rims, tailshaft?

Wheels have been balanced and aligned. Rims have been checked for any buckling and seem fine.

The kicker is that the thud sound comes and goes! If i drive up to the city, the thud noise is quite loud. However, after a couple of hours and driving back the sound is completely gone! Its hard to replicate it to any mechanic as it seems to come and go and Im not sure why :/

Any help would be greatly appreciated.

Might chuck on a set of stockies for a week and see if i can still hear/feel it. That would eliminate tyres/rims as being the problem.

Thanks all...

Link to comment
https://www.sau.com.au/forums/topic/358494-constant-thud-noise-over-80kmh/
Share on other sites
MBS206 Grand Master

MBS206

Posted
Posted

Sounds definitely like a flat spotted tyre.

Drove a VN to Canberra from Sydney with 4 flat spotted tyres, exactly the same thing but it came at 100KM/H, and would come and go.

Could also be felt through steering and floor. They were some massive flat spots though... LOL

Rekin Grand Master

Rekin

Posted
  • Author
Posted

Sounds definitely like a flat spotted tyre.

Drove a VN to Canberra from Sydney with 4 flat spotted tyres, exactly the same thing but it came at 100KM/H, and would come and go.

Could also be felt through steering and floor. They were some massive flat spots though... LOL

both rear tyres have been replaced and sound still there. Unless i flat spotted the fronts, however dont get any steering wheel shake/wobble... Will swap to stockies and see what happens!

cheers

NickR33 Grand Master

NickR33

Posted
Posted

both rear tyres have been replaced and sound still there. Unless i flat spotted the fronts, however dont get any steering wheel shake/wobble... Will swap to stockies and see what happens!

cheers

my bet is bent rim... I went straight on at turn 1 sandown over the ripple strip... thought I had knocked a wheel weight off or flat spotted a tyre... turned out to be a slightly bent rim as the tyre place couldn't balance it... it only needs to be a few mm out and will thud like that at certain speeds

Birds Grand Master

Birds

Posted
Posted

Swap wheels first, if that doesn't work, get it up on hoist (if you can) and drive it at 80km/h+

If it makes the sound then you know it's drivetrain related. Could be the diff or a loose driveshaft.

GTRsean Grand Master

GTRsean

Posted
Posted

Sounds definitely like a flat spotted tyre.

Drove a VN to Canberra from Sydney with 4 flat spotted tyres, exactly the same thing but it came at 100KM/H, and would come and go.

Could also be felt through steering and floor. They were some massive flat spots though... LOL

Hmm, maybe from texi?????????!!! Not as smooth as she used to be :domokun:

Rekin Grand Master

Rekin

Posted
  • Author
Posted

Could the castrate inside the cat converter have been dislodged from it's body?

interesting, although you can feel the thud through the body of the car and its always at a constant rate. Will suss it out.

my bet is bent rim... I went straight on at turn 1 sandown over the ripple strip... thought I had knocked a wheel weight off or flat spotted a tyre... turned out to be a slightly bent rim as the tyre place couldn't balance it... it only needs to be a few mm out and will thud like that at certain speeds

haha yeah i went off backwards on turn 1 at Sandown over the ripple strip :domokun:

Swap wheels first, if that doesn't work, get it up on hoist (if you can) and drive it at 80km/h+

If it makes the sound then you know it's drivetrain related. Could be the diff or a loose driveshaft.

Will swap wheels over and then drive it on a hoist :P

Cheers

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

    • Marek
      Hi everyone.

      By Marek · Posted

      Haha, i kow right? Could have bought so many cars for the same amount of money (or less) but driving Unicorn gives you at least +1mln to style 😅. Like wise man said "life's to short to drink cheap wine and drive boring cars" 😉
    • ARB26
      S1 Autech 260RS Wiring Diagrams

      By ARB26 · Posted

      Newbie here, proud owner of an Autech 260RS. I'm on the hunt for wiring diagrams specific to the 260RS, particularly S1. I've ran my eyes through R33, R34 Diagrams, there are some similarities, however continue to find incorrect wire colours and pins on connectors in the 33,34 diagrams.   I was hoping someone could point me in the right direction? I'd be happy to pay for the originals in Japanese. I can translate them, at least they would be accurate.   Any help please would be greatly appreciated, never heard an RB26DETT before let alone driven one, and I've got a spaghetti monster of goodness to sort out.   Cheers Benny  
    • DanMac34
      R34 Speedo not working after manual swap

      By DanMac34 · Posted

      Hey all  im wondering if you can help me please I have put a rb20 box in my r34 gtt as my auto packed up and a friend had a spare box I know it’s not ideal but it will get me up and running for now. we have done the conversation and everything is working great but my Speedo we got a s13 speed sensor but my Speedo reads double now and I bought a speed converter but still not having any luck.  so I thought I’ll reach out and pick your brains  any help would be appreciated please as I wanna drive my car again 
    • joshuaho96
      Speed Sensor replacement

      By joshuaho96 · Posted

      Drain it. I got official Matic D but you can get whatever is listed as Matic D compatible.
    • QB6SAGR
      Tein Circuit Master- rebuild worth it?

      By QB6SAGR · Posted

      Thanks guys,  Yeah I should at least have them dynoed, at least then I know what I've got as a starting point.  The springs on these are hard as rocks. I vaguely remember Russman saying he was going to sell the shocks to me with the rocks fitted, as he was keeping the softer springs for his new setup.  I didn't click at the time but of course that was to let me know the shock/spring wouldn't be matched.  I also remember pricing up new springs around 2014-15, but, house, money etc. it never happened. So that was another reason to have them rebuilt. I have rebuilt the forks on many motorcycles so I think I could handle the seals on these easily enough, but getting the valving right would be a rabbit hole I cbf exploring.  Duncan, interesting to hear RP was tuning these back then. I might give them a call.  In the mean time I have been busy fitting sway bars. The Whiteline rear sway bar I purchased 15 years ago finally got fitted, along with the Whiteline front bar that showed up last week. Just waiting on new links for the front sway bar to finish that off.  And my spare set of advan AVS VS5's should be back from the powder coaters in a Pearl White finish sometime this week, with a set of Hankook RS4's lined up for fitting.  And then I just have all the suspension bushes to do. A comprehensive kit is on the way... Lots to do before the Ararat hill climb. Cheers guys 🍻   
×
×
  • Create New...