Odd air-like whistling/ whirring noise after intercooler upgrade

[rockit]

I just put in a 600x300 intercooler and started the car and noticed a change in noise from the engine at idle.

Its a whistling whirring noise, it sounds like its coming from the inlet manifold or somewhere around the rear or the engine but its hard to isolate exactly where its coming from.

its mainly noticeable at idle, it doesn't seem to get any louder at higher revs. It just seems to get drowned out by general engine sounds at about 1-2k rpm.

I did notice a similar noise before I upgraded the IC, but it was only audible when I was positioned in certain spots towards the back of the engine. Since doing the upgrade its become a bit louder and audible from any angle around the engine.

I took off all the intake pipes and cleaned everything thoroughly before putting it all back together. while I was working on It I had each pipe taped up at both ends until I was joining it to the next pipe. So there really shouldn't have been any grit that could have been sucked into the engine or anything like that.


heres a vid of it, probably not much use, but thought its better than nothing.

its the air-like whistling noise that you can hear the entire time under the other noises, doesn't really seem to change pitch or volume that much except as location/angle over the engine changes

anyone have anything similar happen and know what it is? did I screw up the intercooler upgrade somehow? is it something I should be really worried about?

 

[fieldy107]

Sounds like a vac leak. Check all piping and vac lines. If they are all fine then it could be a seal, injectors, throttle body etc...

 

[VOLK]

Boost leak/smoke test will show up any vac leaks pretty rapidly. You can make your own or purchase off the shelf, which I did, from turboboostleaktesters.com.

 

[rockit]

thanks, ill look at all the hoses, but they all did seem on there pretty well when I checked before starting it after swapping the IC.

is there anything under the intake plenum that could leak or make that sound??

just going by ear it really sounds like its coming from inside or under the plenum itself.

 

[NuffNuff]

Mine did this. The hot side pipe of the Intercooler had a clamp on tight. But it was not flat. Took it off and back on and no more siren noise.

 

[rockit]

might also be worth mentioning that its not having any issues at all running, no hunting etc, seems to be running fine except for the noise.

 

[VOLK]

Injector seals in lower manifold harden and end up inducing vac leaks.

 

[trotty]

Could it be the alternator? Bearing maybe on its way out? What's ur fuel consumption like?

 

[rockit]

It's around 12/100km give or take a bit..

I'm starting to suspect it's actually th injector seals as volk said.. Couldn't find any boost/vac leaks from any of the hoses I could trace.

Also poked around more and it definitely.sounds like it's coming from.under the intake plenum.

 

[dwarfmarine]

i had a very similar sound too..

magically disappeared when i replaced the TB seals

 

[rockit]

thanks all, Ill probably replace the injector seals and the TB seals. It seems likely its one of those as I cant find a issue in any of the hoses and thats the area where the noise is coming from. Is there anything else that's worth doing while I have the manifold off?

 

[uzz320]

I have a boost leak detector that you are welcome to come round and use - it will find any leaks in about 5 mins.

 

[fieldy107]

Is there anything else that's worth doing while I have the manifold off?

spark plugs and leads.

 

[VOLK]

Having the manifold off is a regular occurrence, it'll happen many more times so don't feel the need to get everything done. However, if you're gonna have the plugs and leads out as per fieldy's suggestion, perhaps do rocker cover and spark plug gaskets if they haven't been replaced. If they haven't, there's a significant chance you'll discover an oily spark plug or several.

 

[rockit]

does the manifold gasket need replacing each time the manifold is taken off?

 

[uzz320]

No - but if it has been on for a long time it may delaminate itself when you take it off. Mine has been off a handfull of times since I replaced it (it delaminated the first time I removed it) and has been fine.

 

[rockit]

so I made up a little boost tester, just a 60mm pvc pipe end cap and a tyre stem valve, then went investigating.

it seemed that the system didn't hold any pressure whatsoever (although I doubt the little emergency tyre inflating compressor I was using was moving much air) the needle on the gauge didn't even move and there was a definite air leak hissing noise coming from the engine bay, much more obvious that is was simply an air leaking without the engine running!

after a bit of poking about I found that if I pulled the red tipped hose off the elbow before the throttle body and plugged the nipple with my thumb the system would pressurise up until the point where It started leaking from under my thumb without any evidence of a leak elsewhere.

after this discovery it was a easy job finding the leak!

It appears that there's a brass T piece fitted with some sort of poor mans boost controller (at least that's what I assume it is).. one branch goes up to the red tipped tube on the elbow, another branch heading down to the wastegate actuator tube mounted to the engine (at least I assume that's the tube its going to!) and the final tube has a short hose on it and a "festo 10351 GRE-1/8" fitting on the end. a quick google search found that the fitting is simply an adjustable pneumatic system exhaust valve. pictures below:

one of the hoses on the T-piece was only pushed on 1 barb along the T-piece and secured with a zip tie, so only a slight movement caused it to leak.. guess when I was re-fitting the intecooler piping I accidentally bumped it and caused the leak.

so I (hopefully) solved the leaking noise issue, but am now faced with another issue! what to do about the "boost controller" if that's what it is!



has anyone seen a "boost controller" like this? or know how it would work?

is it safe to use this? wont it basically cause a small boost leak??

should also note that the factory boost control solenoid has been completely bypassed, the original tube that went to the elbow has been blocked off.

 

[VOLK]

Dodgy. Think I'd rather run gate boost than that. Ultimate solution is ECU controlled 3 port solenoid.

 

[uzz320]

My friends r33 has the exact same festo thing being used as a boost controller - actually works really well. But I would prefer a 3 port controlled by the ecu.

 

[TME_Steve]

it'll work ok, just primitive