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Technical Turbo / waste-gate noise on Twinair

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Technical Turbo / waste-gate noise on Twinair

The Twins

The Twins

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I have noticed recently that I can hear a 'ch ch ch'... turbo, waste-gate noise as I lift off the throttle to change gear. It's not very loud or unpleasant but it is a change as I never detected this sound previously.
Is it indicative of wear or something not functioning correctly.
I've heard this sound on some other Turbo cars with bigger tuned engines but never before on my TA.
Any thoughts as to what has changed?
Thanks.
 
Last edited:
The Twins said:
IAny thoughts as to what has changed?
Click to expand...

Perhaps your hearing is improving. Mine always did it but you have to be giving it a boot full with no traffic around and the windows down to really hear it. Could also be Luigi's excitement over all the remap talk.
 
UFI said:
Perhaps your hearing is improving. Mine always did it but you have to be giving it a boot full with no traffic around and the windows down to really hear it. Could also be Luigi's excitement over all the remap talk.
Click to expand...

Lol. I can hear it with windows up!
 
I just drove a twinair, but it was cold and belonged to someone at work so couldn't hear the recirc valve, i feel robbed :p
 
306maxi said:
I just drove a twinair, but it was cold and belonged to someone at work so couldn't hear the recirc valve, i feel robbed :p
Click to expand...

I've only just started hearing mine. I'm sure it didn't do it until recently. Is recirc valve same as dump valve?
 
More or less, except it doesn't 'dump' into the atmosphere (making a lot of noise), it 'recirculates' into the intake (making minimal noise).
 
Put a K&N panel filter on it and you'll hear more of a 'chirp'.

The waste gate rattles like mad - I put a small spacer washer on the clevis pin of mine to stop the clevis moving around so much which quietened it down somewhat. The exhaust is too muffled (close coupled cat) to actually hear any turbine noise though the exhaust, you're hearing the impeller chop on the inlet side.
 
It could be at low boost it's clocking turbine mine does it in reverse pshhhhh flutter
 
bgunn said:
Put a K&N panel filter on it and you'll hear more of a 'chirp'.

The waste gate rattles like mad - I put a small spacer washer on the clevis pin of mine to stop the clevis moving around so much which quietened it down somewhat. The exhaust is too muffled (close coupled cat) to actually hear any turbine noise though the exhaust, you're hearing the impeller chop on the inlet side.
Click to expand...

Yes it's got a K&N. Had it from the beginning. Was reading about Forge waste gate actuators (recirc valve ?) they reckon they hold more boost and less drop off in power at higher revs. ??? Maybe they mean if its fitted to an EVO FQ etc...
 
The Twins said:
Yes it's got a K&N. Had it from the beginning. Was reading about Forge waste gate actuators (recirc valve ?) they reckon they hold more boost and less drop off in power at higher revs. ??? Maybe they mean if its fitted to an EVO FQ etc...
Click to expand...

Waste gates and recirc valves are two different things bud.
Recirc valves take the excess boost and 'dumps' it back into the intake instead of backwards through the intake which can stall the turbo.
Wastegates open at higher revs and lets excess boost out through the exhaust. It stops the turbo from spinning faster than its maximum limit for the car (all have different limits)
The forge uprated actuator has a stiffer spring so that the wastegate doesnt open as early and the car can hold full boost for longer however if the spring is too stiff it can overboost for too long and cause damage.
 
Sweex said:
Waste gates and recirc valves are two different things bud.
Recirc valves take the excess boost and 'dumps' it back into the intake instead of backwards through the intake which can stall the turbo.
Wastegates open at higher revs and lets excess boost out through the exhaust. It stops the turbo from spinning faster than its maximum limit for the car (all have different limits)
The forge uprated actuator has a stiffer spring so that the wastegate doesnt open as early and the car can hold full boost for longer however if the spring is too stiff it can overboost for too long and cause damage.
Click to expand...

Thanks for explanation Sweex!
 
Sweex said:
Waste gates and recirc valves are two different things bud.
Recirc valves take the excess boost and 'dumps' it back into the intake instead of backwards through the intake which can stall the turbo.
Wastegates open at higher revs and lets excess boost out through the exhaust. It stops the turbo from spinning faster than its maximum limit for the car (all have different limits)
The forge uprated actuator has a stiffer spring so that the wastegate doesnt open as early and the car can hold full boost for longer however if the spring is too stiff it can overboost for too long and cause damage.
Click to expand...

Took the words out of my mouth.

You won't get much more out of the turbo fitted to the 85hp TA engine, as it's operating very high up on the compressor map in order to give a nice low boost threshold. If you start trying to generate more boost by holding the wastegate shut for longer, you'll find the charge temperature increases very quickly as the turbo is operating outside of its efficiency envelope.
 
bgunn said:
Took the words out of my mouth.

You won't get much more out of the turbo fitted to the 85hp TA engine, as it's operating very high up on the compressor map in order to give a nice low boost threshold. If you start trying to generate more boost by holding the wastegate shut for longer, you'll find the charge temperature increases very quickly as the turbo is operating outside of its efficiency envelope.
Click to expand...

Thank bgunn. I'm not suggesting doing anything with the turbo (other than changes as part of remap - at some point) I'm just interested to learn from you guys : )
 
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