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Discussion Starter · #1 ·
Hi all,

Had my car mapped yesterday after a complete cambelt service and turbo upgrade just two months ago.

Drove the car with new belt for about 2 weeks prior to mapping it yesterday and there was absolutely no noticeable "whinning/whirring/supercharger" noise.

The car was obviously pushed pretty hard on the dyno making 578 at 1.4bar, and when i got the car back yesterday, I could hear a whinning/whirring noise up to about 3000rpm. Above that I cannot hear it well, but that might be due to the exhaust/engine noise drowning it out.

I have checked the tension in all the smaller belts and even adjusted them slightly but the noise is still present. I am assuming its coming from the timing belt...I used a DAYCO belt.

What I want to know is..is there any chance the belt would suddenly start to make a noise after the dyno session? Maybe stretched? If it's stretched, then that would indicate it's loose so that means it shouldnt make a noise.

I am so confused...please help...
Thanks :wavey:
 

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Discussion Starter · #3 ·
Have read all those threads :) but in none have I across issues where belts started off fine for the first few hundred miles and then started to make a noise. Usually it was from the beginning and then people loosened them up.....hence why I am a little lost and concerned...
 

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Its not the belts, its the tension pulleys.

Tension pulleys will rust from the inside.

As good practice, on new builds tension pulleys should always be changed for new.
If car is sitting for longs periods, tension pulleys deteriorate.

This was the advice from RB motorsport.
 

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Discussion Starter · #5 ·
The tensioner pulley is two months old...that's when I did the cambelt service...replaced the idler and tensioner pulleys as well as water pump and all other belts.
 

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I personally think your getting paranoid especially as you have double checked everything, time to just enjoy the car.
 

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Discussion Starter · #8 ·
sam, I am enjoying the car....but i am worried a bit more now that the sound only appeared after the 2 days with the mapper. prior to this I did about 400 miles with the new belt and tensioners and heard nothing.

I might have to remove the cam cover and check the belt tension again...doh! don't like hearing funny noises all of a sudden..
 

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I'd drop the power steer belt first to eliminate pump noise.
I presume the tuners altered cam wheel settings so they might have over tensioned the aux. belt when re-assembling.
If the noise remains it will be the idler's bearings. Over tensioned cam belt makes the idler bearings (not tensioner) work too hard.
 

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The A/C tensioner pulley can whine like a goodun too.
 
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