Jump to content
SAU Community

Recommended Posts

Stagea RB25DET stock as a rock.

Harsh induction noise at around 5,000RPM sound is similar to a fan belt slipping or loud air leak, have all the belts as tight as you would want them. Sound seems to be coming from turbo area, only at high RPM with a stab of throttle in Neutral. Happens on the road too when kicked down (auto box).

Have unplugged the BOV to see if that was where the sound was coming from but no luck, only just coming on to boost but it is definitely down that path somewhere. The car is freshly imported so has come to me with this problem so I can't shed any light on how it may have developed.

I am not going to flog it to see what happens, just wondered if any turbo experts out there could throw a suggestion in the ring? My Dad is a mechanic but has very little experience with turbos (I have less!), we are not sure where to look and want to avoid major pull downs for something that may be simple.

Any recommendations for a Turbo workshop in the Geelong area would be great too? Would love to have someone that knows their stuff have a look and listen...

Cheers

Luke

would this be like a screaming sound?

I wouldn't say screaming... loud like a belt slip but not "holy crap, what's that?" loud... It doesn't sound right but not catastrophic at the same time...

Luke

Hmmm... Have a look at the exhaust from underneath the car... Are there any pipes running off the waste gate/turbo that are cut off and vented atmospherically??? If so, you have a screamer pipe :ban: thatā€™s the only conclusion i can think of if its an "induction" noise heard at around 5000RPM as that is when the waste gate is fully open... The screamer pipe is a separation of the waste gate housing from the turbo as to vent the boost pressure atmospherically, its meant to help increase top end power however is illegal in Australia... sounds awesome on large turbos... Let us know how you go..

Regards,

Sarkis

Also check your exhaust manifold, dump pipe and front pipe for cracks. I had a similar problem on my s15, once the turbo started really boosting it made a noise similar to what you describe. If your car ever scrapes or bumps over anything (speedbumps, ect) this can certainly happen, even tiny cracks can cause this.

Cheers

Nick

Edited by stolen_s15
Also check your exhaust manifold, dump pipe and front pipe for cracks. I had a similar problem on my s15, once the turbo started really boosting it made a noise similar to what you describe. If your car ever scrapes or bumps over anything (speedbumps, ect) this can certainly happen, even tiny cracks can cause this.

Cheers

Nick

Will be investigating pipes and possibly manifold and turbo to exhaust gaskets, don't want it to be a turbo bearing!!! I have only driven it 40km and it's not even on the road yet... :ban:

It's doesn't scrape on anything, pretty stock height but the car is new to me, no existing damage underneath so I think I am pretty safe there.

Great advice guys, keep it coming.

Luke

To add to this, another question: In neutral, slowly bring the revs up to 3k, should I see boost?

I see vacuum, but do get some boost when bringing revs up quickly with a reasonable, not to aggressive stab of the loud pedal...

Luke

are you getting any error codes from the consult port (assuming you still have a stock ecu)??

Stock ECU, stock everything as far as I know, have not gone down that path yet.

you will only get boost in neutral if u really punch it. there is no load to bring the boost on.

Really? That's very good to know, so if I "stall it up" I should see boost? Will try that tomorrow.

Cheers

Luke

thats one advantage of turbo's over superchargers. in a manual turbo if you miss a gear and rev it out there is little boost, where-as in a supercharger if you miss a gear the engine still cops full boost. thats why holden never made the supercharged v6's in manual.

Matey - has the sweet-as Stag got a pod filter (no airbox)? They make 'induction' noise, sort of.....

damn that sucks that you've got a worry so early in Stagea ownership. it'll come good tho, no doubt about it :ban:

Matey - has the sweet-as Stag got a pod filter (no airbox)? They make 'induction' noise, sort of.....

damn that sucks that you've got a worry so early in Stagea ownership. it'll come good tho, no doubt about it :P

All stock air box etc.

Yeah I know dramas, will get it sorted, don't have a choice!

Luke

Hmmm... Have a look at the exhaust from underneath the car... Are there any pipes running off the waste gate/turbo that are cut off and vented atmospherically??? If so, you have a screamer pipe :( thatā€™s the only conclusion i can think of if its an "induction" noise heard at around 5000RPM as that is when the waste gate is fully open... The screamer pipe is a separation of the waste gate housing from the turbo as to vent the boost pressure atmospherically, its meant to help increase top end power however is illegal in Australia... sounds awesome on large turbos... Let us know how you go..

Regards,

Sarkis

Well considering he says it does it in neutral... and a screamer/wastegate wont open in neutral

its fair to say that its got nothing to do with a "screamer" pipe

mate the best place for work on turbo's is Dalton's down on wood st. chris is real helpful and he would screw you around. also geelong tuneups which is on wood st to are supposed to be pretty cluey. (i think one of the guys there racers in some porsche league).

either way there are both off fyans street.

good luck

mate the best place for work on turbo's is Dalton's down on wood st. chris is real helpful and he would screw you around. also geelong tuneups which is on wood st to are supposed to be pretty cluey. (i think one of the guys there racers in some porsche league).

either way there are both off fyans street.

good luck

ICER33

Thanks for the info, I will look them up, would be nice to have a trained ear have a listen before I get too carried away...

Cheers

Luke

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


  • Similar Content

  • Latest Posts

    • I like it when the counter chick leads you out the back into the racks and says "have a grub around in here and see if you can find what you need. I'll be back in a few minutes. Just left me in front of a massive motorised shelving system and 2-3 million fasteners, so I could find a peculiar SS shoulder bolt with cap head. Gotta love country towns.
    • I used thisĀ https://osgiken.com.au/product/os-giken-os-250r-lsd-gear-oil-80w250-1-litre/ Ā  shut my nismo 1.5 pro up by heapsā€¦. Not silent though. Gives the car character and personality. It ainā€™t a carolla. If you want silent, put a quaife in it.
    • It's about the same time for me from Bunnings, or the Fasteners. My big push away from takeaway food, and gluten in general keeps me away from the Bunnings Snags too! Weather up here, I've been out for two walks today in the beautiful sunshine. Had a few little drizzles, and some wind, that honestly, a tin of beans and I could compete on how harsh she blows Thankfully, being this bit inland, we're not getting anything much really. Will probably pick up a bit more when/if Cyclone Alfie decides to come ashore. A few areas in the GC though, and south into NSW are really getting smashed though! Right now, I'm just annoyed Alfie hasn't hit, as I'm not allowed to crack into the BBQ foods like the bacon and eggs until the Cyclone hits "In case we lose power"...
    • I love fastener joints, the price difference between them and joints like Bunnings or Super Cheap is amazing, and they either have exactly what you want, or they can get it to quick They have even given me some for free when I only needed a couple of specific size In saying this, I have paid premium for fasteners from Bunnings if they have the sizes I need, but only for convenience really, as my local is only 10 minutes away, the Sushi joint near them is also a considerationĀ  How's the weather Matt? Stay safe mate
    • Wideband is worth setting up if only for tuning purposes. I would not mess with the ignition system unless there's a misfire. HKS crank trigger is popular out here for the relatively easily sourced Denso crank sensor, not a bad idea to install as well regardless of power level on a standalone. Boost leak test is worth thinking about. Oil pressure sensor tied to a fuel cut isn't a bad idea either. Getting the tune figured out is a good idea. Without putting eyes on it and getting under it there's no way for us to tell you exactly what it needs but most likely you're down to the last 10% that will make a big, big difference in how happy you are with the car.
Ɨ
Ɨ
  • Create New...