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Leaking air sound at 2K RPM

1K views 7 replies 4 participants last post by  needalift 
#1 ·
G'day Guys and Gals.

Recently I notice an "escaping air sound" when I exceed 2K RPM. Only happens for a short burst and no noticeable loss of power.

Scenario goes: Slow down for a round about etc. and put the boot in and once I hit 2K a "escaping air sound" comes from the engine bay. Only for about 2 secs or until I take the foot off.

I suspect the Turbo area but can't figure where to start looking.

additonally, I have noticed a marked increas in smoke while driving.

Any clues?
 
#2 ·
Sounds like a boost leak mate. Check all your hoses and hose clamps which lead from your turbo through your intercooler and into the manifold. You may notice a dirty area where the compressed air has been spraying oil vapour out. The lack of boost being fed into the engine will be causing the smoke as the air fuel ratio will be becoming rich at these revs... Hope this helps... Let us know how you go...
 
#3 ·
As needalift says, but thoroughly check where the end tanks are clamped onto the intercooler core, this is a favourite area too leak, usually accompanied by the black stain. You may need to lift the intercooler off to check the bottom as well.

Off course if you have a catch can fitted then this will make it harder to see.
 
#5 ·
Is it under load (driving) or only when reving (stationary)? Boost is only made under load.

What motor do you have? Some (maybe most) motors have a boost bleed off valve that will bleed are once it's relief pressure is reached (to protect the turbo from over boosting).

Have you recently increased boost? When I had my TD42T done, they increased boost to 12.5PSI which is just below the 13PSI relief valve pressure. When I gave it a bootful, the boost would spike to just over 13PSI which opened the relief valve and bled boost off resulting in a bad noise and loss of power. Solution - install boost guage and remove the relief valve (blocked the hole with a 1" screw in bung).

Just some things to think of.

Cheers.
David
 
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