Originally Posted by EBMods

XRC test are good. Turbo plugs absolutely can increase peak power and broaden that peak curve. It can be measured with the right equipment.

If everything was the same, Head Volume, Squish Width, Squish Angle, Head Clearance, etc... so that your Static Compression Ratios are identical. Without a doubt the turbo plug has the potential to out perform the standard plug. Not considering transition between head and plug, but just how the plug seals alone offers that extra effective cylinder pressure to make more power.

Turbo plugs seal at the base of the plug or top of the combustion chamber. Standard plugs seal on the top of the head button, outside of the combustion chamber. So when in a dynamic state, the effective compression is lost with any leakage around the threads. What this does is increases the head volume reducing the effective compression ratio, and reducing your BMEP. ( Average Cylinder Pressure)

Sometimes running standard plug engines I will drop the head .002" to help.

Hope this helps.

Ed