Car feels faster than it is and interesting loss of power in higher RPM, Went and did a dyno run to see what my car produces. Options

[Michael N]

Today I had there afternoon off and went to a local shop to get a dyno run on my car to see what it actually produces rather than me guessing on what it produced. The local shop was running a special of 3 pulls for $85.00. The shop actually did 4 pulls and we awesome with me and my car. They are used to seeing high HP muscle cars etc but didn't pick on my car too much for being so low in HP. They did the pulls in 4th gear. The shop uses a dynapack dyno that bolts to the hubs which I like as there is no need for tied down points. Overall I am happy with the results as the engine is now 40 years old without a rebuild yet. It is a 2.4 liter 911S engine with MFI and produced 141.2 at the wheels.

What would cause the power to drop consistently between 6000 and 6500 Rpm? It drops and come back on again.

[charliew]

Put a af sniffer in the tail pipe and don't ask for best guesses. 99% it's af problems probably caused by metering controls that have gotten old. It could be only vibration of some connectors that just need replugging to get recleaned on their contact surfaces. When power falls off and comes back it's usually a worn throttle position or cam sensor on later stuff or fuel supply. If it gets comlicated also check the 12 v power supply that it stays up at higher rpms. My shadetree experience says manifold size, valve size etc doesn't cause dips in power. That is caused by sensor feedback or metering glitches. Fuel pressure, timing and so on.

I would do one pull in 3rd to see if a shorter interval doesn't show the dip. If it doesn't then suspect fuel supply or still maybe vibration.

On the brighter side at least it's a consistent problem and will make it much easier to fix.