MK I 225bhp possible boost issues - advice needed!

[BrendanM]

Hi all,

I picked up a 52 plate 225bhp TT with 77k miles on the clock a fortnight ago. A couple of gremlins have since come to light.

I've had the coolant temperature sensor and thermostat replaced to resolve a cooling problem. And next up is a possible boosting issue. When accelerating hard a loud whooshing sound can be heard. It happens in all gears and becomes apparent from 2500 rpm onwards through to whenever I lift off or change gear. To me it sounds like escaping air. It makes the car sound fantastic but I'm certain this can't be a stock sound in a healthy 20V turbo engine. I should add that it's not noticeable to the ear below around 2500 rpm. I'm new to this engine and have just come from a diesel so my next question is what rpm does the turbo spool up at on the 20V turbo? If it's before 2500rpm I'm wondering why I'm not hearing the whooshing noise before then.

Also, on 2 occasions when changing from third to fourth under heavy acceleration I heard a popping sound like a loud fire cracker. Again I'm assuming this was the sound of pressurised air escaping.

Can anyone shed any light? Will a diagnostic help identify where my troubles lie?

Cheers in advance for any help.

 

[pcmac]

Hi,

It could be an intake/manifold/turbo pipe leak and worth checking ASAP, especially as it's in all gears. Without knowing exact fault you don't wanna run the risk of causing any knock on issues. Diagnostics are handy, it will certainly (should) identify where loss of power is taking place but not necessarily show exact fault, needs a good grease monkey in there



Mac