I checked out my timing tonight with a timing light, but I think the car was idling below 700 RPM. Will it skew my reading that much? The pointer was right on the 18 degree mark, but again the car was idling slow like around 550 RPM.

 

why is your car idleing so low.

did you jumper the ECU while changing the timing?

platinum.

 

Yes, I jumpered the service jumper for the ECU. Not sure why it idles so low.

My biggest question is how much will a few hundred RPM affect my ignition timing measurements? Is it significant enough to re-do all my testing? Or can I feel confident that it's close enough to 18 degrees?

 

dont know man. i have been a 100 or so off and it has been fine, so i would say your ok, but i have never been that low.

cant you adjust your idle screw untill it's at the right rpm then adjust the timing if needed.

platinum.

 

So let's say it's 19 degrees. Does that mean I'm losing power? How far can you advance ignition timing before you start to lose power?

 

Does anyone know how much timing advance is too much on a normally aspirated B16?
Is it 19, 20, 21 degrees??

Thanks

 

There are too many factors to make it a hard and fast rule. Octane/quality of gas, elevation, condition of the engine, compression... Assuming you're using 91 octane, the motor is in good condition, and everything else is average, you can advance your timing to the high side of spec. More than that and you're likely to lose power and ping the motor. You might want to get adjustable cam gears, a vtec controller, and an adjustable fpr, then take it to the dyno and get it all tuned.

 

With the changes in the weather around here, I got it idling 750-800rpm. I adjusted the timing to 17 deg advance, and the A/F gauge indicates the car runs stoich (it used to run rich)

This would leave me to believe I'm getting a more complete burn. I'll be turning up the fuel pressure a bit today to try and get it running slightly rich.