Folks, I have the SR Motorsport underdrive pulley kit on my RX-8. This morning on my way into work I went into the hidden screen section of the Nav System and displayed the Vehicle Stats...or something like that. The one output I was focusing on was the ACC....which is the measure of the Voltage in the car's system. I am unsure what ACC is an acronym for exactly.

With the underdrive pulley kit my ACC read a constant 13.8V at 3000 RPMs or any other RPM for that matter. If I turned my headlights on the voltage would drop slightly to ~12.8V for less then a second before going back to 13.8V The highest I saw the voltage was a 14V reading when I turned the lights off again...only for a brief second.

So can you folks with a standard pulley set tell me what your ACC is reporting? I am curious to see what type of effect this pulley kit is truely having on the cars electrical system. Thank you

 

The voltage will not be affected by an underdrive kit because it is the current that varies with rpm. When you saw the drop to 12.8v you were actually seeing a by-product of A/C (current) change and the regulator allowed enough current through the car's charging system to bring the operating voltage back to the proper 13.8-14v. Try this; when you next start your car turn on your map light(s). Let the car idle and in about 15-20 seconds you will notice the voltage regulator doing it's job. There will be a slight flicker in the lights and the rpm's will change slightly. What happens with an underdrive kit is that the current output of the alternator drops at a given rpm versus the stock kit. However, at higher rpm's(typically 2K and above) the enigine's speed is enough to overcome any differences between the two pulley sets.

ACC, most likely, means the accessory circuit voltage.

Your mention of the hidden screen portion of the nav system makes me now wonder if I should have ordered that, too.

Charles