Hi, I've just had my MYO2 WRX modified (green filter, decat up pipe, sports cat down pipe, decat centre, wr sport rear box & ecutec remap) by one of the recognised (& highly recommended) scooby specialists.

Although I'm delighted with the increased power & hugely improved overall drivability, I'm less impressed with the horrid buzzing/rasping noise (sounds like a cheap & nasty half muted car horn) that occurs when I accelerate hard in 2nd, 3rd, & 4th gears (not tried 5th) between 4500-6500 rpm - it only stops when I lift off the throttle.

To start with this only happened very occasionally, but it has steadily increased (in less that 700 miles) to the point it does it nearly every time I accelerate hard.............

I've spoken to the 'specialists' concerned & have been told "it's nothing to worry about". But as this is such an annoying noise I'm sorry to say I feel I'm being fobbed off.

Before I start getting heavy, I'd be grateful for any ideas anyone might have about what could be causing the problem.

 

From your description, could be gas escaping and causing something to vibrate. My first bet would be to check for blowing gaskets around the up/down-pipe region, or holes/leaks around the intercooler hoses etc.

 

Thanks for the speedy reply.

I should have said before besides the other items listed, I fitted new samco induction hoses before remap & have checked for leaks on these & the bypass valve since, so pretty sure they're not leaking.

 

sounds like an exhaust leak.. the buzzing is the gasket vibrating.. check downpipe to turbo bolts/nuts are tight and also tap the heat shields and check them for damage / tightness as it might be them vibrating.

 

this may sound really stupid but could it be the needle on your boost gauge? my defi boost gauge buzzes like a b astard

 

I think an exhaust leak is a possibility as I'm sure I can hear something blowing from the area of down pipe when the engine is cold. However this seems to go away as soon as it starts to warm up.

I can see I'll have to get my spanners out when the weather improves a bit - not that fond of lying in a pool of ice cold water if I can help it........brrrrrrrrrrrr

 

Doesn't sound stupid at all, but sadly it can't be the boost gauge as I don't have one (yet) - couldn't afford one after having all the other stuff done........... But thanks for the thought anyway.

 

the downpipe will expand as it heats and so the blowing would be less obvious..

you can get to the downpipe nuts and bolts from the top of the car..

 

Cheers JGM, I'll have a look tomorrow.

Might be my turn for a daft idea, but could it be the wastegate leaking/dumping boost pressure?

 

Thanks for the advice JGM

Having taken the car back to the "specialist" concerned earlier today, I can now confirm you were pretty close.........

It was the gasket at the base of the decat up-pipe that was blowing/resonating.......

It seems the flange on the bottom of the up-pipe wasn't 100% flat/true, so the joint wasn't bolting up evenly.

Thanks again.......

 

Thanks for the advice Hades, you was right as well......

Please see above

Thanks again.......

 

glad it is sorted!

 

Me too, good news. Also glad to be right again!

 

Big smiles all round..................

Especially as I've got an unadulterated scooby soundtrack to go with the wonderful (& highly useable) power increase.

Just begs the question what were these renowned Subaru "specialists" doing fitting duff parts - hardly the best example of attention to detail, or quality service for that matter!!!!!!!!