Hey just looking for a little help on this - first off i'm running a new B20b / B18C hybrid using stock B20b pistons (yeah JDM but I still believe they're the same old low comp. pistons). My calculated compression ratio is almost exactly 9:1 (planning for boost soon) and I'm curious what my ignition timing should be. On my GSR I was running 16-18 degrees base ignition advance, but I'm wondering if the lower compression on the same head suggests I should run more or less advance.

On a possibly related issue, I'm also having trouble with a very low / rough idle. Starts nicely, but after the car is warmed up it will stumble and occasionally stall at stop lights unless I feather the throttle a bit. Do I just need to adjust the idle screw to raise it up a bit and smooth things out?

Thanks!

 

with that low of compression, you can prolly run on upwards of 20 degrees. just make sure do do a couple full load runs to see if its detonating. and for idle check the idle screw as you stated.