gorally

I have recently hear some high frequency (almost like a squeaky break) noise coming from the engine( or the front ) of my 8. It only happen when I step on the throttle and it last may be 1 second. I can hear it clearly around 4-5000 rpm. I can't hear it when it over that rpm most likely because of the noise of the engine and wind. My 8 has 1300KM and little over 1 month.

Has anyone had this experience? Is this normal?

mysql101

completely normal. It's because the engine is opening up ports and air ducts to allow more fuel and air to the engine.

It actually happens at several rpm speeds.

mysql101

Here is a desc of what's happening:


Above 3250 rpm, and when engine load is great enough, the Secondary Shutter Valve opens to permit airflow through secondary intake passages. The engine is now using two intake pipes and two intake ports per rotor. This reduces restriction and increases airflow and torque. The Secondary Shutter Valve is controlled by a vacuum control solenoid. Although the High Power engine is shown, the Secondary Shutter Valve works the same way in the Standard Power engine.



Above 5500 rpm, the Variable Fresh Air Duct opens to add another intake air path. When open, the VFAD doubles the amount of air available to the engine and reduces restriction. The VFAD is controlled by a vacuum actuator. It is not open at all times because noise is also increased.
The VFAD system is only on the High Power engine. The Standard Power engine has a short inlet duct with a large diameter.



Above 6250 rpm, the Auxiliary Port Valve opens the third or auxiliary intake port for additional airflow. All six ports are now used to increase horsepower and torque. The Auxiliary Port Valve is controlled by an electric motor through gears, a rack and linkage. The valve cycles each time the ignition is turned off to clear carbon. The Auxiliary Port Valve is used on the High Power engine only.




The High Power RENESIS Rotary Engine takes advantage of pressure waves in the incoming air to boost charging. This increases torque and power at higher engine speeds. At engine speeds above 7250 rpm, the Variable Dynamic Effect Intake Valve opens to shorten the effective length of the intake tubes. Intake pressure pulses reflecting back and forth in the intake manifold tubes force more intake charge through the ports and into the chamber. The VDI Valve is on both High Power and Standard Power engines, and is controlled by vacuum.

gorally

Excellent explanation Jason.. Thanks.

mysql101

It was a good question.

While I knew about the above stuff, I had asked the same question you did - what is the metalic "whine" was at around 4-5k rpms? It sounds like something is wrong with the motor, but it's normal.

guy321

SOmething someowhere says that a squeaky noise sounding like a loose fanbelt could be detonation.

Mr M

When you depress the throttle quickly from idle with no load, and hear a little 'chirpping' sound, that is the rotary unique combustion sound (NOT detonation). It does sound a little like detonation - is that the sound you are referring to?

Or this guy could just have a loose alternator belt?

guy321

Well there's a tsb that specifically states that detonation sounds like a loose/squeaky belt.. and it does happen when you depress the pedal at mid - high rpm. I've experienced it before once when trying 87 octane , and it does not happen anymore.

Doctor Bob

Jason-very informative post! However I somehow remember reading somewhere that the high power engine makes less peak torque than low power engine even though makes more horsepower? Anyone know?

Thanks for great post,

Bob

mysql101

I don't know the exact numbers, but the low power version has lower gearing, which give it more torque. This applies for the AT version in the united states. I don't know what is done for the 5 speed manual in other countries.