Turbo speed gauge - which turbo is being measured?

[David Montgomery]

Silly question, just because I’m curios. Which turbo does the gauge measure? Is it left or right or an average of both? I can’t imagine they both spin at exactly the same speed. Maybe the speed difference is so minimal that measuring just one is good enough. I know it’s a pointless question, but it would be interesting to know anyway.

 

[CasualSpec]

only one sensor. the turbo speed sensor is on the passenger side turbo.

 

[robin]

Can I assume that one turbo is right bank and the other left?. Some twin turbos work with the second one kicking in as needed?.
thanks

 

[CasualSpec]

yes, sorry. mechanics here in the states call the right side, while sitting in the car, the passenger side. the right side. driver side for left side.

both turbos work at the same time.

 

[Koryak]

The VR30DDTT 400Hp engine has a speed sensor for each turbo according to https://www.infinitiq50.org/threads/vr30ddtt-engine-reference-page.124743/
I'm guessing the analog gauge shows a highly damped average of both for driver readability. Most of street driving is done with low turbo revs but this changes very quickly with throttle

 

[CasualSpec]

call me wrong. yes, there are two sensors. one on each turbo. i went through the service manual and found it.
my guess, the gauge shows an average speed for both.

 

[Koryak]

I'm guessing the 400 Hp engine used in the Z has 2 sensors because the turbo RPM at full boost is getting a little edgy for the compressors. I see slightly more PSI with faster spin up using octane boost but don't like using the chemistry for daily driving. It might be possible to read both sensors independently with a live data scan tool.