Fitted FMIC - Whats the 'Chatter'
 

Hi all

fitted a fmic and when driving i noticed a loud chatter sound when i change gear - used to be a pppssssshhh (HKS Ind. kit is fitted and you could hear the air go back into the intake)

ant ideas what it is? and is it bad for it?

cheers

tim

wastegate chatter buy the sounds but dont quote me

matthew

Most of us that have changed to a big FMIC have suffered this problem.
The catter sound is the turbo stalling, caused by pressurised air being forced back through the turbine blades.
This can eventually cause the blades to break so is worth getting sorted ASAP.
There is approx 3 times the air in the system when a FMIC is fitted ( bigger intercooler, longer pipes etc ) and the DV cant cope with dumping all this air.
I solved mine by fitting a bigger bore signal pipe, Thats the small diameter pipe from the inlet manifold to the DV. Was 4mm bore , now 8mm bore.
If this does not work you will have to reduce the spring pressure in the DV. Some DVs have a adjuster on and some you can take apart and fit a weaker spring.
This should then sort it.

Andy

thanks for the replies

where abouts is this pipe i should enlarge?
and i only have the standard dumpvalve if that makes a difference