Fuel cut rev limiter w/ HFS6

[5mall5nail5]

Hi Richard/All -

My ECU now supports a staged rev limited with fuel and spark cut. With just spark cut my engine wants to continue to build boost when the limiter sets in because of the fuel entering the hot manifold and igniting.

I am wanting to run a fuel and spark cut limiter but am nervous because of the methanol injection. I am running 50:50 water:methanol direct port with check valves from Aquamist. I have the (6) .5 or .6mm jets one per cylinder (I think .6mm).

If I cut fuel but keep spark, or cut fuel and spark, do I have to worry about the water/methanol mixture being enough volume per runner/cylinder to ignite/pre-ignite? Again, this is .6mm direct port on a 2.8L 6 cylinder engine running 50:50 water methanol.

Thanks!

[Richard L]

Do you have a choice of cutting fuel only? It is more suitable for the HFS6. If you cutting fuel and spark together, there is always an unknown factor until you tried it out.

[5mall5nail5]

Richard I can cut fuel, spark, or fuel and spark. I am/was hesitant though on cutting fuel at all because I worry that should the mixture somehow ignite with residual meth taper I could have issues. For instance, if I cut injectors, nothing comes out (some residual on the intake runners, but nothing out of the injector valves). However, if I cut fuel only w/ the HFS6 active there is still some volume behind the HSV that, though the HSV will stop pulsing, there should/will be some outflow from the system. I am putting my check valves right at the nozzles, but still.

[Richard L]

Look like you need to cut fuel and spark. At lease you know the residual meth will not be ignited.