nissan sr20det dwell problem

[tasos triantafillidis]

the car  is a nissan sr20det gti-r fwd and i,m having problem with misfires.dwell is set at 3,6 ms,but when it reaches approximately 7000 rpm,it starts falling around 3 ms,and the car starts misfiring.does anyone have experience with a problem like this?any ideas?i have changed everything from ignition system,igniter,distributor,ht leads,coil,spark plugs but there was no difference.

thanks in advance,tasos.

[Simon]

You are running out of available dwell time at that RPM you only have 4.3ms between firing events.

You will likely have a 1ms spark duration which drops the available dwell to 3.3ms

This is a primary reason multi coil applications came about.