Rattling noise every time my engine nears 5800 rpm's
 

My 2004 rx-8 6-speed rattles everytime I near 5800 rpms, be it in 1st gear, 2nd gear, 3rd gear.... Any ideas? I brought it to the dealership and they said this is normal. I don' t think this is normal?

try this, hold it at various rpm 3500, 4500 5800 for 10 seconds or more......listen for that rattle or knock. If you hear a knock or rattle, I would ask your dealer to do an oil analysis. (ususally takes a coupke of days for the sample) This sounds very close to what happened to my car when a bearing went in the engine.


or it could be nothing.

I get mine at 3250 RPM in any gear.

It's a high-frequency metallic rattle (gear harmonic resonance?)

Of course the service department says they can't hear anything.

an idea,

http://www.finishlineperformance.com...er_recall.html

beers

also a tsb on heat sheild.

At engine speeds below 3250 rpm, air flows through the primary intake ports only. This keeps the intake air velocity high.
At the lower end of the primary intake tubes near the ports, high velocity air discharges from the Port Air Bleeds. This is the Jet Air Fuel Mixing system. The air discharge is caused by the pressure differential between the upper end of the primary air intake and the port air bleeds. This high velocity airflow blows fuel off port surfaces and increases turbulence. Atomization is improved and the mixture distribution is optimized. Atomized fuel is directed toward the ports and away from surfaces for the Anti-Wet Port effect. This Jet Air Fuel Mixing system is present in both Standard Power and High Power engines.

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.

What you are hearing is most likely normal.

Dammit, Jason! Stop being so vague, and give us some specifics! :)

Seriously though, this has been discussed to death by many people, including myself. I believe we have un-officially decided..................Normal.