R33 GTR - Ticking sound under load

[judasentinel]

Hi all,

I have a faint but audible ticking sound coming from the turbo side that only comes on under load. It goes away under cruising or deceleration or under acceleration. I am wondering what it is. Since it comes on only under acceleration load, and goes away as soon as I let off the load/gas pedal, I feel it is the turbos....any clues as to what it could be? To tell you in words, it sounds like tick tick tick, but very rapid. And it seems to be coming from the passenger side...so perhaps not the knocking sound?

I have the old school APexi AVC Type R installed. Some say it is the sound of the boost solenoid but I am not sure why.

Please help as I dont want it to be a symptom of something dangerous/damaging.

Thank you.

Munib

[R33-East]

Sounds like the boost solenoid. I have the Apexi controller as well and my solenoid is right on the drivers side strut tower, the ticking is very noticeable in that location.

[judasentinel]

does the solenoid actually make a ticking sound? I think mine is in the engine bay, but not sure where. Does it look like a smal silver cylinder? Has Apexi written on it, so I think thats what it is. Why and how does it make that sound? I hope it is not my turbos making it, with the wheels/fins touching/grinding intermittently. I have good boost, all the way to 1 bar.

[Skym]

Best way is to check on a dyno to put your mind at rest.

Boost control solenoids do make sounds, but usually can hear it happening at idle. Same with turbo compressor wheels that are out of balance.

It could be one or more of the lifters might need reshimming (part of routine maintenance with RB26, solid lifters is to check the lifter clearances. The GTS hydraulic lifters self adjust / maintenance free, so no clearance check is necessary). Or there is a leak in the cam cover gasket and are hearing the ticking sound of the lifters (this is common due to age, rubber shims under mounting screws for the cam covers are failing). This usually happens near the rear of the head, sometimes front of the head. Obvious sign is oil leaking onto the block, oilpump, etc.

Or if sounds like nails in a tin can type of sound, it could be audible knock. This could be due to lack of fuel or CAS is not set correctly. It usually happens when under load.

[R33-East]

does the solenoid actually make a ticking sound? I think mine is in the engine bay, but not sure where. Does it look like a smal silver cylinder? Has Apexi written on it, so I think thats what it is. Why and how does it make that sound? I hope it is not my turbos making it, with the wheels/fins touching/grinding intermittently. I have good boost, all the way to 1 bar.

Yes that is the solenoid. Not sure why it makes that sound, I was worried too when I first heard it. If the sound is a very rapid ticking and its coming from the direction of the solenoid, its probably that.

[nimblestix]

It will make a clicking sound based on the pulse width freq, think of it as a switch opening and closing really fast to control the amount of boost being fed to the wastegate actuators. The speed it opens and closes is called the frequency, that dictates how much boost is applied to the actuators and how much is bled off.