Cracked EM?

[Dr H]

More developments with my strange 'whooshing' noise!

Just had a long detailled conversation with AET Turbos about the strange 'whooshing' noise my turbo makes on full boost. They rebuilt it 12 months and 7500 miles ago.

As the car holds boost they reckon it is VERY unlikey that it is the turbo unless the higher boost has cooked the bearing - which I find very unlikey after only 7,500 miles.

Their (or should I say Grant's) other suggestion is that the EM is cracked . He thinks that a very small crack would cause this noise but the car would still hold boost as there is so much air comming through the system on full boost.

Would someone like to confirm (or preferably not) this as a possibility

Cheers

[Pisobiker]

Leigh, as far as I know standard S2 EM is keen to cracking on cylinder 1 and 5 runners, which, once removed the heat shield should be relatively easy to spot on cylinder 1 too.
I actually think if you had such a loud wooshing sound coming from EM, crack would be so big you should also hear a much louder exhaust noise coming from under the hood not only when on boost but also pretty clearly at idle or while lightly accelerating manually at the TB, making it easy to spot as well. You should even feel pressure escaping from the EM while going near it with your fingers.

I think the wooshing noise to be more likely an intake leak problem. For example, I have experimented myself a small cut in the TB hose (metal pipe to TB) will cause a leak not worsteninig performances and boost behaviour too much, while being heard very neatly from inside the car when running.


Marco

[Dr H]

Cheers Marco

I'll check for any cracks if I can see them. The guy I spoke to at AET runs a 600+hp I5 engine ina Mark 1 Golf chassis so seems to know our engine inside out. He says he has experienced cracks too small to notice at idle but that leak at high boost. You can really hear the noise if the window is open!

I have replaced all the hoses with Samcos and Paul N has pressure tested it and given it a clean bill of health on that side of things.

Maybe I need to get it on some rollers to get it to run on boost whilst being able to listen under the bonnet? I'll aslo check the intake path for any holes.

Thanks

Leigh

[GandalfS6]

Dr H - the only problem with rollers are that once they switch on their fans you struggle to hear anything!

[audiman]

Leigh, I would tend to agree with Grant. I too have been having detailled chats to him about turbo options. This bloke knows his stuff. I just bought the same turbo that the golf had on it 18 months ago

You may find that the manifold has warped too, as they are prone to doing that aswell. You will see black sooty marks around the edges on cyls 1 and 5 where the manifold meets the head. BTDT with my s2 manifold and also my RS2 one

[Dr H]

Cheers Tom

Got to admit Grant does sound like he knows his stuff. I'll take a look at the manifold tomorrow and see what I can come up with.

What actually causes the warping and cracking. As you know my car has low miles and has only had a homefry - no other mods on the engine

Grant did tell me he has and unwarped, uncracked manifold at home. I may be giving him a call depending on what I find.

[Dr H]

Dr H - the only problem with rollers are that once they switch on their fans you struggle to hear anything!

Yeah I did wonder about that, I've had it on the rollers before and it is pretty noisy!

[audiman]

Heat, they get a little warm and they are just crap quality

[Greenm3]

@ Dr H
Today i got a really loud whooshing sound from what sounds more like the left hand side of the bonnet, and didnt lose that much noticable power was just not quite boosting correctly.....i found it to be a boost leack where i had tightened a jubilee so tight it had crimped the hose producing a really small boost leak after the IC.
It was difficult to spot becuase normally you just look and tighten, but you couldnt see it because it was on the underneath.
Suggest checking hoses again......

[Dr H]

@ Dr H
Today i got a really loud whooshing sound from what sounds more like the left hand side of the bonnet, and didnt lose that much noticable power was just not quite boosting correctly.....i found it to be a boost leack where i had tightened a jubilee so tight it had crimped the hose producing a really small boost leak after the IC.
It was difficult to spot becuase normally you just look and tighten, but you couldnt see it because it was on the underneath.
Suggest checking hoses again......

Cheers but hoses ae totally fine - checked then thoroughly with Paul N. My guess is either craked EM or a leak on the inlet side (air box etc), will check it all this weekend.

[Doug_RS2]

A leak on the airbox won't cause a problem(apart from letting crap in) as it is beforoe the MAF.

[Dr H]

Could make a noise though?

[Doug_RS2]

Could do - I suppose - best tihng to fix that noise is to get a huge exhaust with no silencers and you will never hear the annoying noise again

[audiman]

Hell yeah, thats what i would do.

[Dr H]

I'm working an an exhaust