Whilst driving my car around today I noticed a rattle has developed when the boost maxes out. At the moment the car boosts at 15 PSI, there is no rattle present until 10 PSI. It sounds like what i can only describe as a small metal ball being spun around unside the turbo.

Any ideas people ?

PS.

The car is a 1994 impreza wrx sti.

 

I had the same, it turned out to be the turbo heat shield on the up pipe to the turbo that was loose. I have to take the up pipe off to remove the shield so it is going to rattle a few more weeks before i can get enough money together.

 

Knowing what it is, is half the problem!
Let's hope it's not det!

JohnD

 

How can u tell if its det ?

I bloody hope not, I only dropped this engine in about 3 weeks ago !

 

I had a look at this today, i filled the car up with v-power then added some octane booster and its still making the same noise. I did notice the oil was a little low so i topped this up too.

I just cant work out what is causing this, the car starts and runs like a dream, no knocking, not tapping, no smoking atall. I also checked the heatshield, its on there solid so thats not causing the noise either.

 

Drove the car to work this morning (didn't boost) and noticed my oil temp got higher than it usually does. Usually is sits around 85 degrees but today, even on a cold morning it went up to around 95/100 degrees.

When i started the car up i also noticed a burst of bluey/grey smoke from the exhaust. It only lasted for about 10 seconds and then cleared up.

Would this be related to my problem ?

 

Will it absolutely positively not do it just free revving the engine?
If it does, then I'd be inclined to think it was a heat shield, however you saying it only does it on boost would make me think things are going Pete Tong..
Stay off boost until you can get it checked properly.

The second thing to worry me is why you put an engine in it three weeks ago... did the last one blow up by any chance?
Did you find the cause?
If not, one would have to suspect you are about to do the same to the new engine as the fault is still present!

 

If I rev the car whilst is standing still, there are no noises present at all. It only happens when the boost goes over 10psi. The last engine went because the previous owner run it with blown head gaskets and I wasn't overly confident with it afterwards.

 

Gaskets may well have gone due to the excess boost and or det..

 

Is there any way to distinguish if it is det ?

I would be well and truly gutted if it was !

 

Someone suggested retarding the ignition, any guides on how to do this safely ?

 

Unless it is chipped you cannot.
If it is, get the chip removed.
But to be honest, you are better of fixing the fault rather than trying to work round it.
It may not be det at all but better to err on the side of caution until you find the root cause.

Take it somewhere where they know what they are doing and let them decide what the fault is. It's almost impossible to diagnose without actually listening to it.

 

Could you make that a bit clearer as it doesn't make a lot of sense.
15psi is higher than 10psi

 

Sorry Fuzz, im abit stressed out and not making much sense at the moment.

Basically the max boost is 15PSI but the rattle noise isn't present until it goes past 10PSI. Therefore whilst the turbo is boosting right up until 10PSI it sounds fine.

As for the noise, it i had to describe it. It sounds like a fan spinning but catching something on the way around.

 

Well that doesn't sound like det, that's more like the metal ball you spoke about in your OP.
Could be something as simple as a cracked up pipe.
Let a professional have a listen to it and put your mind at rest.

 

Possible turbo shaft bearing? As the boost rises, there's more axial thrust on the bearing.

JohnD

 

my car was doin that and it was the front heat shield on the headers
hope this helps