T25 Sr20det: bad sounding noise from turbo in full boost?? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

goodlucksilvia · 08-09-2020, 07:26 PM

I have a stock redtop 1992 sr20det. I just refreshed all of my turbo gaskets, so far everythings been driving smooth and pulls as it should.
It had the manifold to turbo gasket leaking before and sounded like a tractor, but thats all gone. No power loss now. Only other thing id note is that there was a leak because i hadnt tightened the coolant return line on the turbo enough but that was fixed.
I also repaired part of the egr that connects into the intake box but i dont think that should make a big difference because before then it ran fine.

However there's a new noise now. It wasnt happening at first at all, and it comes and goes now but happens a good 90% of the time I'm getting onto full boost while accelerating quickly. It doesnt come on until FULL boost, up until then everythings all good.

Its loud enough you can hear it over the sound of the engine& exhaust.
It sounds like a shout of a higher pitched rattling or scraping noise.
It is not a turbo death whine noise.

The only other thing i can think of is wastegate. I didnt thoroughly check it myself when i had the turbo apart, but I do at least remember the penny and arm not appearing to be loose in any way. So far, i know there was no shaft play from my memory as well, it felt and looked solid.

Tomorrow I'm going to check the shaft out for play again, and see from the outside if the wastegate arm has play....

Other than that, I wanted to ask around on here if you guys have any ideas of what it could be. I've owned this SR for a year. I've never owned a turbo car before, these are all new things to me but I know that sound isnt right.

Any pointers or speculations would be greatly appreciated. I cant seem to find anything online about this.

S14rebuild · 08-10-2020, 04:50 AM

Scraping noise? Sounds like ur veins/fins are touching in the housings.

Pull the turbo and inspect it

Matesh · 08-16-2020, 01:43 AM

could be a manifold/dump crack like at a weld

one time i dropped a bolt inside my dump pipe behind the turbo and it was bouncing around on my cat made a hell of a rattle only at certain times

Sent from my iPhone using Tapatalk

goodlucksilvia · 08-16-2020, 04:09 AM

Update, I checked everything out to be fine.
I was able to get a friend to help me listen for the noise and we found the problem immediately.
Before, it would have been hard to figure out where the noise was coming from since nothing seemed broken on the turbo.
An odd piece of my exhaust from the down pipe was broken/loose. It's still a stock exhaust, so there's heat shielding around the area. I last recalled it to be secured.
It' just so weird because you could only hear it coincidentally at rpms that the turbo starts working.... but the case was just that certain rpm range rattling the loose piece. Shit was so loud too.

Yikes... Thanks for anyone who replied to my idiot ass, lol

08-09-2020, 07:26 PM	#1
goodlucksilvia Join Date: Jul 2019 Location: USA Posts: 8 Trader Rating: (1) Feedback Score: 1 reviews	T25 Sr20det: bad sounding noise from turbo in full boost?? I have a stock redtop 1992 sr20det. I just refreshed all of my turbo gaskets, so far everythings been driving smooth and pulls as it should. It had the manifold to turbo gasket leaking before and sounded like a tractor, but thats all gone. No power loss now. Only other thing id note is that there was a leak because i hadnt tightened the coolant return line on the turbo enough but that was fixed. I also repaired part of the egr that connects into the intake box but i dont think that should make a big difference because before then it ran fine. However there's a new noise now. It wasnt happening at first at all, and it comes and goes now but happens a good 90% of the time I'm getting onto full boost while accelerating quickly. It doesnt come on until FULL boost, up until then everythings all good. Its loud enough you can hear it over the sound of the engine& exhaust. It sounds like a shout of a higher pitched rattling or scraping noise. It is not a turbo death whine noise. The only other thing i can think of is wastegate. I didnt thoroughly check it myself when i had the turbo apart, but I do at least remember the penny and arm not appearing to be loose in any way. So far, i know there was no shaft play from my memory as well, it felt and looked solid. Tomorrow I'm going to check the shaft out for play again, and see from the outside if the wastegate arm has play.... Other than that, I wanted to ask around on here if you guys have any ideas of what it could be. I've owned this SR for a year. I've never owned a turbo car before, these are all new things to me but I know that sound isnt right. Any pointers or speculations would be greatly appreciated. I cant seem to find anything online about this.

08-10-2020, 04:50 AM	#2
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,495 Trader Rating: (8) Feedback Score: 8 reviews	Scraping noise? Sounds like ur veins/fins are touching in the housings. Pull the turbo and inspect it

08-16-2020, 01:43 AM	#3
Matesh Join Date: May 2020 Location: Australia Age: 37 Posts: 6 Trader Rating: (0) Feedback Score: 0 reviews	could be a manifold/dump crack like at a weld one time i dropped a bolt inside my dump pipe behind the turbo and it was bouncing around on my cat made a hell of a rattle only at certain times Sent from my iPhone using Tapatalk

08-16-2020, 04:09 AM	#4
goodlucksilvia Join Date: Jul 2019 Location: USA Posts: 8 Trader Rating: (1) Feedback Score: 1 reviews	Update, I checked everything out to be fine. I was able to get a friend to help me listen for the noise and we found the problem immediately. Before, it would have been hard to figure out where the noise was coming from since nothing seemed broken on the turbo. An odd piece of my exhaust from the down pipe was broken/loose. It's still a stock exhaust, so there's heat shielding around the area. I last recalled it to be secured. It' just so weird because you could only hear it coincidentally at rpms that the turbo starts working.... but the case was just that certain rpm range rattling the loose piece. Shit was so loud too. Yikes... Thanks for anyone who replied to my idiot ass, lol