Throttle plates and compressor surge

[Wild Thing]

i get it on my 2.4, well at least i get a TSHHHHH noise if i cane it then lift off. maybe ill record it one day.

I think the TSHHHHHHHHHH noise is you $hiting yourself while trying to brake from high speed before you hit the roundabout lol

[Tallyman]

Got to admit I really cannot hear my turbo either spin up or down at all. I know it's working, because I can blow off the chavs in their corsa's away from the lights for at least the first 200-300 yds before they catch up and overtake. I used to hear it on my Volvo 940 2.3L petrol (and feel it as well) but unless I really kick down on the Surf's throttle (and watch the fuel guage drop rapidly in response) I can't hear anything, even when revving it on the drive. Must be all that diesel clatter masking it.

[dirtydog]

no mine is stock apart from the boost has been wound up a bit. 2.4's have very loud turbos (well mine is loud!) but 3.0 are quieter, i think its because the turbo is low down on a 3.0 and right under your ears on a 2.4.
im getting good between speedhumps now!

[Wild Thing]

no mine is stock apart from the boost has been wound up a bit. 2.4's have very loud turbos (well mine is loud!) but 3.0 are quieter, i think its because the turbo is low down on a 3.0 and right under your ears on a 2.4.
im getting good between speedhumps now!

My 3.0L turbo whistles louder than my 2.4 did

[dirtydog]

can we have a "whistle off" to decide then please?

[TonyN]

My 3.0L turbo whistles louder than my 2.4 did

I had one like that to work on, had a big grommet missing under the dash! New one quitened it right down.

Generally the 2.4 has a much more noticeable turbo noise, for the above mentioned reasons.

[Bikenuts]

You don’t get turbine stall on a Surf as it actually has two throttle butterflies, a large one controlled by your foot and a smaller one controlled by the ECU via a vacuum switching solenoid – to a diaphragm actuator – the one that isn’t the EGR diaphragm. This small throttle is held open for a few seconds when you back off the throttle suddenly to limit engine braking, disable it and wire it closed and you will find you can lock the wheels by backing off suddenly accompanied by pigeon impressions from the turbo.

[monsterer]

You don’t get turbine stall on a Surf as it actually has two throttle butterflies, a large one controlled by your foot and a smaller one controlled by the ECU via a vacuum switching solenoid – to a diaphragm actuator – the one that isn’t the EGR diaphragm. This small throttle is held open for a few seconds when you back off the throttle suddenly to limit engine braking, disable it and wire it closed and you will find you can lock the wheels by backing off suddenly accompanied by pigeon impressions from the turbo.

Ahhh! Thankyou! Very refreshing to find an answer in the end - that makes perfect sense and vindicates my observations...