Do buses experience turbo surges?

[Kenster102.5]

When on some buses like the Orion VII or NG, I forgot which bus it was on, but when the driver lets of the gas I thought I heard it turbo surging/fluttering, where there is still compressed air in the charge pipe.

The turbo, however, has no power to spin, b/c theres no load on the motor ( ~0-5% TPS) so theres no exhaust.

This causes there to be more pressure on the turbocharger to backspin than spin in a forward direction.

When a turbo will "surge" making a kinda 'wub wub wub wub' sound (I've heard this) and go between spinning forward and backwards with the unequal pressures.

So do any buses have turbo surge, or is it just the transmission "farting"?

On a diesel Passat it would sound like this

Thanks

Ken

[Bus_Medic]

When on some buses like the Orion VII or NG, I forgot which bus it was on, but when the driver lets of the gas I thought I heard it turbo surging/fluttering, where there is still compressed air in the charge pipe.

The turbo, however, has no power to spin, b/c theres no load on the motor ( ~0-5% TPS) so theres no exhaust.

This causes there to be more pressure on the turbocharger to backspin than spin in a forward direction.

When a turbo will "surge" making a kinda 'wub wub wub wub' sound (I've heard this) and go between spinning forward and backwards with the unequal pressures.

So do any buses have turbo surge, or is it just the transmission "farting"?

On a diesel Passat it would sound like this

Thanks

Ken

not turbo surge.

on the series 50egr (the one with the most pronounced noise)what you're hearing is the electric solenoids adjusting the variable geometry impeller blades(vanes).

[Mystic]

not turbo surge.

on the series 50egr (the one with the most pronounced noise)what you're hearing is the electric solenoids adjusting the variable geometry impeller blades(vanes).

We have one Orion V in our fleet of 6 that makes loud backfire type noises whenever the driver lightens up on the gas pedal. It's sounds like it's chugging along sometimes, but then these random pow sounds and black smoke shoots out of the exhaust. I would assume the turbo has some problems with it, since the other buses make similar chugging sounds when coasting, but not that pronounced. Also we had two Orion V's that we called "whistlers" and you could hear them clear across town coming.

[306 Carlton]

not turbo surge.

on the series 50egr (the one with the most pronounced noise)what you're hearing is the electric solenoids adjusting the variable geometry impeller blades(vanes).

You hear this all the time on our D60LFs.

They also tend to do the pop thing with the black smoke or as I like to call it the 'fart'

[TRANSIT_FREAK]

SEPTA's Neoplan AN460's go through it all the time. especially in the summer months.

our AN460s have series 50 engines

Listen at 2:08 (the turbo turns on) and listen to the take off after 2:09