Jump to content
SAU Community

Turbo Beginning To Go On Rb20det?

mjfawke

By mjfawke,
in Engines & Forced Induction

 Share

Recommended Posts

mjfawke Collaborator

mjfawke

Posted
Posted

My engine has decided to start making a new noise - if I go from off-throttle to full throttle at reasonably high RPM (3k+) in 1'st/second gear, I get a squeal like a slipping fan belt for about half a second (and yes, I have checked the belt, and no - it's not wheelspin). No noise if it builds boost slowly. I can also get the noise by getting the revs up to 4K then going full throttle for an instant - but it's so damned noisy under the bonnet I can't work out where it's coming from (but it's not the fan belt). I'm thinking turbo thrust bearing... any dissenting opinions?

Link to comment
https://www.sau.com.au/forums/topic/199128-turbo-beginning-to-go-on-rb20det/
Share on other sites
crofte Collaborator

crofte

Posted
Posted

Pull off the air box lid and filter, give the bitch a tweak of the throttle and listen to the turbo. You should be able to determine any unsatisfactory noise. Failing that remove the pipework and check shaft, carefully.

Leadfoot Enthusiast

Leadfoot

Posted
Posted
My engine has decided to start making a new noise - if I go from off-throttle to full throttle at reasonably high RPM (3k+) in 1'st/second gear, I get a squeal like a slipping fan belt for about half a second (and yes, I have checked the belt, and no - it's not wheelspin). No noise if it builds boost slowly. I can also get the noise by getting the revs up to 4K then going full throttle for an instant - but it's so damned noisy under the bonnet I can't work out where it's coming from (but it's not the fan belt). I'm thinking turbo thrust bearing... any dissenting opinions?

Yep, sounds like turbo bearings.

Had same thing. At first the squeal only came in under boost.

By the time I got home it was constant.

The best way I could describe it would be the "woooooooo" sound made by a crowd at the fireworks.

Even with turbo removed there was no real discernable play in the shaft. All turbine blades were attached. Turbo looked fine.

Rotating the shaft by hand the bearings felt a bit rough however even that was difficult to tell.

In the end, turbo replaced, no more noise.

mjfawke Collaborator

mjfawke

Posted
  • Author
Posted

Thanks everyone, but as the noise only occurs for about half a second, I don't think it's a leaking gasket or pipework. I also run a pod with 3" induction piping, so no issues hearing noises - but with the bonnet open free revving, all I can hear is serious suction noises from the inlet. A sticking BOV might be the answer if it is slow when closing.... I'll have a look at that next.

Fry_33 Proficient

Fry_33

Posted
Posted
Thanks everyone, but as the noise only occurs for about half a second, I don't think it's a leaking gasket or pipework. I also run a pod with 3" induction piping, so no issues hearing noises - but with the bonnet open free revving, all I can hear is serious suction noises from the inlet. A sticking BOV might be the answer if it is slow when closing.... I'll have a look at that next.

You will not hear the noise with the car parked and the hood up. The car will not be producing boost as it will not be under load. As stated the simplest answer is the best place to look first, mainly because it is the cheapest thing to do. There only needs to be a tiny leak, you won't hear it off boost but when on boost the pressures are high enough to make the difference.

mjfawke Collaborator

mjfawke

Posted
  • Author
Posted

... and as I said before, I can hear the noise when free-revving, I just can't work out where it's coming from.

And it's not the BOV. As an extra bit of info (left window open, driving alongside retaining wall so I can hear better) , the noise occurs for about 2 seconds in 1'st gear, and about half a second in 2'nd gear.

I think at this point, I'm just going to wait for the noise to change before looking further. It doesn't seem to be getting any worse, and it only happens when I abuse the car anyway.

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

    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • funkymonkey
      Jacks that fit under GTR lips that can reach the subframe?

      By funkymonkey · Posted

      I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      You are all good then, I didn't realise the port was in a part you can (have!) remove. Just pull the broken part out, clean it and the threads should be fine. Yes, the whole point about remote mounting is it takes almost all of the vibration out via the flexible hose. You just need a convenient chassis point and a cable tie or 3.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      ..this is the current state of that port. I appreciate the info help (and the link to the Earls thing @Duncan). Though going by that it seems like 1/4 then BSP'ing it and using a bush may work. I don't know where I'd be remote mounting the pressure sender... to... exactly. I assume the idea here is that any vibration is taken up by the semiflexible/flexible hose itself instead of it leveraging against the block directly. I want to believe a stronger, steel bush/adapter would work, but I don't know if that is engineeringly sound or just wishful thinking given the stupendous implications of a leak/failure in this spot. What are the real world risks of dissimilar metals here? It's a 6061 Aluminum block, and I'm talking brass or steel or SS adapters/things.
×
×
  • Create New...