t25 screaming when motor gets up to temp? what's up

[Mangid]

Ok so I've got the SR redtop with the t25. When I first start the motor up and it's cold, there's no noise from the turbo except for the faint whine it normally makes, and it boosts/runs/sounds perfect. Then when the car heats up, the turbo makes a loud screaming noise under boost (At least I think it's the turbo, it only happens under boost). There is no smoke from the turbo, no exhaust leaks, no shaft play, no loss of power or boost/vacuum leaks, and no oil in the pipes... so really the only indicator is the noise. What could be the problem? Do you think the oil is thinning out as the car heats up or something? I use 5w30.

Thanks guys
Modified by Mangid at 2:27 PM 3/30/2009

[aznrib]

What does it sound like, any video of it? Kinda off topic but does your turbo start to spool at about 5.9 in/hg?

[Mangid]

I'll try to get video... and yeah I think it spools before 0 vaccuum, because the blowoff valve opens below 0. It's an hks ssqv

What does that mean?

[V8slayr]

My T28 did the same thing. But it only did it on really hot days. It's like a very loud whistling sound. I never figured out what it was either but i'd like to know.

[Mangid]

I really cant think of anything... when I took the intake off of the turbo I expected it to be all messed up with oil leaking and a ton of shaft play, and it's perfectly fine. The noise is unsettling though... it's that bad. I'll try to get some video of the noise up tomorrow. It might be the exhaust wheel scraping the inside of the housing, because it sure isn't the cold side wheel.

[aznrib]

if it doens't sound like metal scrapping then you're ok. If in fact it is the exhaust wheel then it would happen all the time. You'll be able to hear it even if its cold.

[Sil80315]

if it doens't sound like metal scrapping then you're ok. If in fact it is the exhaust wheel then it would happen all the time. You'll be able to hear it even if its cold.

that depends on what the turbo is doing..Ive had a t25 make the same sound and if it sounds like you are supercharged and not turbo charged when your under boost then your turbo is on its way out. I drove for awhile with it like that till one day it just popped and i made no boost and had to creep it back to the shop.

if i were you I would check for shaft play and look at the compressor wheel and start looking for another turbo

[PyR0NiAk]

that depends on what the turbo is doing..Ive had a t25 make the same sound and if it sounds like you are supercharged and not turbo charged when your under boost then your turbo is on its way out. I drove for awhile with it like that till one day it just popped and i made no boost and had to creep it back to the shop.

if i were you I would check for shaft play and look at the compressor wheel and start looking for another turbo

he already said there is no shaft play...

Ok so I've got the SR redtop with the t25. When I first start the motor up and it's cold, there's no noise from the turbo except for the faint whine it normally makes, and it boosts/runs/sounds perfect. Then when the car heats up, the turbo makes a loud screaming noise under boost (At least I think it's the turbo, it only happens under boost). There is no smoke from the turbo, no exhaust leaks, no shaft play, no loss of power or boost/vacuum leaks, and no oil in the pipes... so really the only indicator is the noise. What could be the problem? Do you think the oil is thinning out as the car heats up or something? I use 5w30.

Thanks guys

Modified by Mangid at 2:27 PM 3/30/2009

[Mangid]

that depends on what the turbo is doing..Ive had a t25 make the same sound and if it sounds like you are supercharged and not turbo charged when your under boost then your turbo is on its way out. I drove for awhile with it like that till one day it just popped and i made no boost and had to creep it back to the shop.

if i were you I would check for shaft play and look at the compressor wheel and start looking for another turbo

When the turbo spools, it's really really loud. My friend driving next to me said he could hear it, and it sounds like a ridiculously huge turbo or supercharger. I'm trying to find a replacement turbo just in case, but it's hard to find a good condition OEM garrett t25 or t28. (Not looking to spend $1000 on a GT series). If anyone knows where to find one I would appreciate it.

[Sil80315]

he already said there is no shaft play...

neither did mine till it ripped itself apart.. shaft play isn't always the case of a blown turbo..ive seen turbos with no shaft play at all but have blown seals.

its always a good idea to have a back up turbo..you can find t25s for around 100 in good condition

[Mangid]

Yeah I'm trying to get a replacement before this one grenades itself. Any idea where I could find one stateside, or what other vehicles' turbos would work?

[s13_chris]

Umm my brother had the same issue. Turbo flange gasket was completely torn apart. Its a b**** to do but you have to take off exhaust manifold, IC lines, coolant and oil lines, pull the turbo and replace all hardware and gasket. Then do everything backwards haha. I don't know if there is a write up on it but I am about to do the same thing.

Atleast this is what it sounds like to me, mine grinds metal because one of the bolts to the downpipe is broken.

[Mangid]

I already did that gasket 2 months ago and replaced it with a steel gasket and copper lock nuts with red loctite. I'll check to see if it blew out again but i doubt it.

I remember the sound that the turbo made when the gasket was blown, and this doesn't sound the same.

[Mangid]

It sounds like the wastegate is messed up. It sounds like a screamer pipe, but a lot higher pitched. As soon as the blowoff valve opens up, the noise stops.

What do you think... boost leak?

Modified by Mangid at 4:16 PM 4/3/2009
Modified by Mangid at 4:46 PM 4/3/2009

[Mangid]

Video:

http://www.youtube.com/watch?v=d8Syn0kDBDA

The grind on the first 1-2 shift is because that synchro is shot

[srpowered240sx]

i'll put money on the turbo leak. my twin brothers sounded twice as bad, and had just about no gasket left, and i just fixed my little brothers that had 4 of the five studs on the back of the exhaust housing off the turbo broke off. the gasket was fubared to say the least. its very common for people to overlook it upon install, or take fixing it upon themselves and ive fixed too many that people have swore up and down they just fixed it. just pull the turbo with manifold off, its a fairly straightforward process of pulling the intake, ic piping, turbo oil and coolant lines, disconnect exhaust and pull off the mani.

if thats not it, and i believe it is; then you may have an issue with the wastegate not opening fully when the actuator lets it go. my buddys crx had the issue, and we had to grind out some of the exhaust side of the turbo to let more exhaust escape between the outlet of the wastegate and exhaust wheel. it worked well too and it ran made the sound stop and the overboosting stop.

good luck.

[s13-t]

dude no joke, my $s*** sounded EXACTLY the same. it was a huge exhaust leak where the manifold meets the turbo and another small one where the elbow met the down pipe. try and re torque all those spots.

[Mangid]

Yeah the nuts backed out on the turbo to manifold flange AGAIN, all are loose and one is missing. I'm getting sick of fixing this, I bought new lock tabs this time and I guess I'm gonna have to use a combination of lock tabs, lock nuts, lock washers, and lock tite to make these damn nuts stay tight