The Canto 6.9 1667 would not come up to RPM had to lean it down and took the plug on two tries.
Put my redone 2167/3 on and it lit right up.
It takes lots of load to make it work.
Way more than usual.
Will try it more here when I get time. Only got 4 runs in till the rain came.
It will change how you prop the boat big time.
For heat racing this will change every thing!!!!!!!!!!!!
Time for a new boat it is way over powered now for heat racing.
You pull the trigger and it walks side ways with all the power.
Do it Martin you will not regret it!
It is hard to wrap you mind around a 15 to 1 + CR on high nitro.
There is a point I am told that the RPM will go down then you back up a little.
There is no exact answer to how much is to much.
This is virgin territory.
shorter pipes and higher timing will be on the plate with this as the CR will take care of the bottom end.
This will be a great tuning tool.
Keep the MSV under 60 M/sec and the plug will live and make the squash as tight as you can with out hitting the piston at top RPMs,
45 to 50% squash area.
Start at 14 to 15 CR to see results.
DO NOT use brass! I tried this a few years ago with brass and it was a disaster.
That is why I shelved it till now.
toroidal head 3.jpg courtesy of Jim Allen.