ga33a

Hi All,

At the risk of sounding a little (or a lot) stupid, I need some help answering a question that's been bugging me for ages.

Picture this ... Richard Burns is flying towards a 90 right. He's cogging down through the box scrubbing off some speed. What can you hear? Each time he changes down (or up) you get a "chatter from the wastegate". Why does it do this? And why does the standard car not do it?

Cheers

Ga33a

fast bloke

The noise is suppressed on a standard car by restrictive air filters and zorsts

Mike Tuckwood

This one crops up now and again.

The predominant sounds in the scenario you explain are either (or a combination of) Turbine back pressure (no dump valve) or anti-lag.

If you want a more in depth explanation, I'll dig one out from work and post it up (unless John Felstead saves me the job).


Mike.

ga33a

That would be excellent.

Steve Fort

My car makes this noise now, since fitting a FMIC. I dont think that the BOV can dump all of the charged air in one go.

It does sound nice, but is there a risk of this damaging my turbo?

Sith

I think from other post's I read u may damage the turbo as the pressure is being forced back passed the bearing. If the turbo is designed for it and has a 360 degree thrust bearing it may be ok.

Not sure of this, just digging back from memory.

P.

richards

Ga33a,

Anti-lag makes the noise you're referring to - Anti-lag came on a certain model of special edition EVO6 RS that Ralliart used to sell - RSX? The £40K one anyway.

But it IS anti-lag - there's absolutely no way in this world that this 'noise' is supressed by restrictive air filters and zorsts!

Rich.

Anyway, John (Felstead) is the expert on this subject - I remember he has answered this before - use the search!!!

andy oakes

Well i wont anti lag and i wont it NOW!!!!!!

logiclee

This thread may give you some clues.

WRC sound thread

Lee

fast bloke

Dicks - you are obviously an expert in decoding questions. Ga33 could be talking about a number of sounds. The most likely two are overrun and antil-lag. I've been drinking for hours now, so I'm sure you will post explanations on how both work, and how the noises can be differentiated by an amateur like me

RichardPON

This question comes up all the time on the RS bb.

I think the sound you're referring to is turbo chatter. It's more often mistakenly called wastegate chatter. If I remember, the noise is made as the you back off the throttle, the pressurised air rushing back into the turbo, and being chopped up by the turbo blades.

The dump valve, in its Max Power entirety, is supposed to vent this air away from the turbo to prolong the life of the turbo and prevent turbo stall, since if the boost pressure is too high, then turbo blades have been known to shatter.

Anti-lag is the popping and banging noise you hear, as excess fuel is injected to keep the turbo spinning. I witnessed it on a cossie this evening! Very loud, and totally illegal for the road!

I'm sure I will be corrected if wrong, but that's it to the best of my knowledge!