On a rally car the turbo don't go in reverse. They have antilag which keeps the turbo spinning at full speed. Thats why they last 10 miles. They glow white as they're on full spin for so long.

Anti lag is done by seriously retarding the timing and injector a load of fuel so that it burns inside the turbo...

yea i was going to say that rally cars turbo's don't go in reversen that would completely defeat the object of anti lag

yeh als alters the ecu settings to fire fuel down the hot manafold on the exhaust stroke ( hot fuel hitting hot manafold ,igniting , spiining turbo faster on decelleration, ready for acceleration , fast skittle sound > turbo simple

dear o dear im drubnk!?

:trout stella?

wish i could remember!

the chattering sound is the metal flap on the turbo right.....when the air is coming out. im sure thats right.


thats what we were told when a mates cossie was set up.


he he....every ones knows different :trout :furious :D

No its the air stalling the compressor blades. As basically the compressed charge reverses back out of the turbo.

It causes stress on the shaft as a result. I personally wouldnt bother with a dump valve under 20psi. There arent many on the market which do a good job anyway, most are designed to be loud.

But the the dump valve also helps to prevent stress on the shaft i always thought:confused:

Yeah but its not an issue unless you are running high boost like 20psi plus.

this debate was had some time ago but i cant remember the company that tested it.
they took 2 cars, same setup, one with dv, one without.
and over a set period of time tested the turbos for wear etc.
both wore equally.

as martin says, was around 18-20psi plus that it became an issue due to the higher pressure.
but then this would then depend on the unit you are using as most uprated units can take more abuse than a factory standard unit anyway.

my old red one used to chatter well.
all i did was fit a k+n filter and upped the boost a bit.