what is the avg total advance for a bolt on engine would you run on 100 or 150 rwhp on spray?

 

You need to give more information when asking a question like this because the "type" of engine you're tuning plays a huge part in the answer.
The avg total advance is gonna depend on alot of things... bore size, spark plug positioning, combustion chamber efficiency, the list keeps going. For an engine that runs best with say, 34* total, you're gonna want to retard 4* for a 150 hp shot of nitrous. The rule of thumb being 2* for every 75 hp. You'll also want a plug of at least one heat range cooler. Then tune to find what the engine likes best.

-Mindgame

 

This question should be posted in the Nitrous forum.
Moving, Thanks.