Timing

[Norman Lane]

At what timing should I see at 3500 RPM, I think right now I am running 18 to 20 degree's, and my fuel ratio is 15 to 1. My headers are cherry red. Also a one tuner suggest that at 3500 RPM that I run 35 to 40 degree's of timing and go 14 to 1 on the fuel ratio, and when the car is wide open run between 25 and 28 degree's. And 3 other suggest that I running 13 to 1 and 25 to 28 degree's of timing at 3500 RPM, Thanks for any input.I have a P1SC1 procharger, Kenney Bell Boost a Pump,AlkY Meth Kit, installed a cam, and 58 lbs injectors.

[ian@thetuningschool]

Normaly for a supercharged car with alky i run around 19 -23 degrees but it depends on the car and 11.5 AFR for WOT. The part throttle range i keep stock timing unless it is detonating and afr should be around 14.7 while cruising and part throttle. If headers are cherry red then you are running way to lean.

Ian

[Mez]

Originally Posted by Norman Lane

At what timing should I see at 3500 RPM, I think right now I am running 18 to 20 degree's, and my fuel ratio is 15 to 1. My headers are cherry red. Also a one tuner suggest that at 3500 RPM that I run 35 to 40 degree's of timing and go 14 to 1 on the fuel ratio, and when the car is wide open run between 25 and 28 degree's. And 3 other suggest that I running 13 to 1 and 25 to 28 degree's of timing at 3500 RPM, Thanks for any input.I have a P1SC1 procharger, Kenney Bell Boost a Pump,AlkY Meth Kit, installed a cam, and 58 lbs injectors.

You have a lot of mods and I would only let someone tune your engine that has a lot of experience and proven success with your mods. Don't fool around or your engine will become a big paperweight.

There is a large table which determines ignition advance based on RPM and g/cyl air mass which is another way of saying load. So at 1500 rpm under light load, say cruising on flat ground at 60 mph, 35 degrees may be OK +- a few degrees. But at 3500 rpm with any boost, you will not be OK with 35 degrees of advance.

25-28 degrees of advance is the range for non-boosted engines. So if you run 25 degrees advance at WOT with any boost, that probably is way too much and you will definitely see lots of knock and timing being pulled out.

Your AFR is targeted by the PCM to be at 14.69 during light throttle (cruise) to maximize fuel economy. But once you start opening up the throttle, seeing boost, the PCM should be programed to go richer...somewhere between 10-12 depending on many things including RPM, load, boost level, timing, engine coolant temp, inlet air temp, etc.... Your headers glowing red should tell you to STOP RIGHT NOW and find the problem and fix it.