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Antiquated eddy type sensors, the only reason not to jb4 your RS imo. If optical sensors were possible, then the factory ecu could get more accurate and timely data.
 

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I've openly argued with Terry on N54. He comes off as very arrogant and looks down on anyone who try to ask for info not readily available or to push the platform....even when we point out bugs in their firmware.
 

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Newport, Oregon
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Antiquated eddy type sensors, the only reason not to jb4 your RS imo. If optical sensors were possible, then the factory ecu could get more accurate and timely data.
Really? Antiquated? They are the industry standard for turbocharger speed measurement and are extremely accurate. They aren't impacted by moisture, dirt, and oil like an optical sensor would be in this application. Besides, an optical speed sensor needs an LED light source inside the turbocharger case located so that the light is interrupted by the vanes as they turn in order for an optical sensor to pick up rotation. Too complicated and prone to fail compared to eddy current sensors.

If anything, one might say not to JB4 a low-output VR30 without turbo speed sensors.
 

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2018 Luxe AWD, Stock + JB4
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Discussion Starter · #45 ·
Is it possible you are both right (Avedis and Ddnspider)? Without the sensors there is nothing to limit the turbo spin rate if you over boost the car - BUT - If you push the turbos to their limit, the speed sensors might pull some boost from the car that the turbos could still safely deliver (but exceed the limits programmed by Infiniti). The limits are applied to the RS stock model, so they might be set to a safe limit that is below the overall capacity of the turbos. Does anyone know if the spin sensor limits are modified when a tune is applied? Obviously JB4 can't override it.
 

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Is it possible you are both right (Avedis and Ddnspider)? Without the sensors there is nothing to limit the turbo spin rate if you over boost the car - BUT - If you push the turbos to their limit, the speed sensors might pull some boost from the car that the turbos could still safely deliver (but exceed the limits programmed by Infiniti). The limits are applied to the RS stock model, so they might be set to a safe limit that is below the overall capacity of the turbos. Does anyone know if the spin sensor limits are modified when a tune is applied? Obviously JB4 can't override it.
Assuming all things equal, it takes X amount of boost to make Y power. That equals Z amount of compressor wheel speed. It doesnt matter if your have a premium/luxe/SS/RS/"skyline"/unicorn. If the car is tuned then having optical speed sensors means exactly crap because the tuner can override it. If the car isn't tuned, the only thing itll save you from is either A) hitting the boost you want to (assuming youre trying to hit a reasonable boos target), or B) trying to hit a stupid amount of boost. lol. The speed sensors remind me of:
 

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2018 Luxe AWD, Stock + JB4
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Discussion Starter · #47 ·
Damn, video must have been good to get restricted!
 

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Damn, video must have been good to get restricted!
That's your YouTube/browser setting your YouTube to default to restricted mode. You can change it from your settings.
 

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Discussion Starter · #49 ·
Damn IT police! I'll check it at home.
 

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Do you have EWG wires? If so it's likely the settings controlling those. Otherwise I've seen it happen on both RS and non RS cars where they just commanded too much boost too suddenly.
 

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Do you have EWG wires? If so it's likely the settings controlling those. Otherwise I've seen it happen on both RS and non RS cars where they just commanded too much boost too suddenly.
i do have EWG wires. im using the default settings from N54 and a FF of 65. i could lower the FF to try and slow how fast the boost builds?
 

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Is that normal to have what I think is AFR1 (looking at the mustard-colored trace) above 15:1 until 1,800 rpm? Especially with max pedal?

101546
 

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i do have EWG wires. im using the default settings from N54 and a FF of 65. i could lower the FF to try and slow how fast the boost builds?
I had something similar until I tweaked the EWG settings and then it cleaned up. I believe Terry's thread on N54 walked through what to do when it happens. Its basically an oscillation due to closed loop correction that is causing over/undershoot against target.
 

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I had something similar until I tweaked the EWG settings and then it cleaned up. I believe Terry's thread on N54 walked through what to do when it happens. Its basically an oscillation due to closed loop correction that is causing over/undershoot against target.
ah, i found what i think you are reference were they decreased the Duty bias for below 4K rpm. ill give it a try, it seems odd that this is a new issue im having.:unsure:
 

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Antiquated eddy type sensors, the only reason not to jb4 your RS imo. If optical sensors were possible, then the factory ecu could get more accurate and timely data.
You are ignorant. an optical sensor is inferior to an eddy current sensor in every conceivable way.

an eddy current sensor can only ever measure exactly whats happening because its a passive sensor and doesnt have to convert the signal it receives. an optical sensor is active and as such, theres always a minute delay. in addition, it has to convert and analog signal to a digital signal. plus, theres only so fine a resolution a sensor can get to before it cant measure correctly. not to mention that optical sensors are affected by literally anything and absolutely require cleaning. eddy current sensors last forever unless an internal coil magically fails or the sensor sees 500F+ temps. if it does, you have bigger problems.

the eddy current sensor has 3 wires; 5V+, ground, and 0-5V sine wave signal.

the 5V+ and ground provide power to make a magnetic field. the return wire is what returns the signal from each blade on the compressor wheel. all that happens then is the signal gets divided by the number of blade on the compressor wheel. the result is displayed seemingly in RPM as referenced in the service manual. other mfgs use Hz as the measurement.

optical sensors are kind of similar but use a laser or led to do the same thing. once it bounces light off the compressor wheel, that signal then gets converted to digital, then converted again to something measurable. theyre affected by lower max heat, water, soot, water, oil, gasoline, etc.

The speed sensors do nothing but handicap the VR.
untrue. at best, you would be more correct if you said the tune was too conservative. all the sensors do is relay information. knowing the max compressor speed vs actual compressor speed is quite important.

also, knowing compressor speed becomes extremely important at altitude or when trying to push limits because density changes significantly affect compressor speeds.
 

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untrue. at best, you would be more correct if you said the tune was too conservative. all the sensors do is relay information. knowing the max compressor speed vs actual compressor speed is quite important.

also, knowing compressor speed becomes extremely important at altitude or when trying to push limits because density changes significantly affect compressor speeds.
You are exactly proving my point about having it for a warm and fuzzy like a warranty sticker.
 
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