Hi James,
Pull the air cleaner out of a four-cylinder diesel and start it up, the noise from the intake is very loud (turbo engine a quieter than non turbo), the Toyota I fitted in a van was non-turbo.
I have a Nissan bus 3.3 litre turbo (4 Cyl, 120hp) factory vehicle the air intake noise at idle is quite high more so when standing beside the bus.
Why do Nissan LD28 engines have air silencers James?


Peter H

1994 BigHorn Lotus (Trooper)
3.2 DOHC