MSD has a boost retard box that retards the timing in reference to boost.

The only downside of this is less duration of power per power pulse.

can i run 10-15 psi using this??

 

I have a pair of brand new boxes that have been mounted in my car for 3 years. Never needed them running 25psi with 9:7:1 compression rotors. This is more of a safety just in case type of thing. I'll sell you mine if your interested. They are just sitting in my race car.

 

Wouldn't you need 3 units or a 3 channel unit?

2 retard the 2 leading plugs that fire seperately and 1 retards the 2 trailing plugs that fire together wasted spark.

As far as power output and reliability there is some cross over point between higher compression and more retard Vs lower compression and less retard. I don't think there is any definitive info on where this lies for the rotary.

I guess it is about finding out what the maximum peak combustion pressure is you are shooting for and tuning around that then finding which set-up makes more power at that same peak pressure. They make very high pressure sensors for this type of tuning (can be used as knock sensors as well!).

edit- on the rotary the combustion chamber early in combustion cycle takes place in the rotor depression and the compression ratio depends on this as well. I am sure the shape/depth of this has some effect on power output as well as it has changed from symetrical to directional over the years. The combusting charge has to travel through this rotor depression as it is ignited before TDC.

Does the depth of the rotor depression (compression ratio) make a difference at high Hp?