Some of the rules around here are a bit squishy, as the mods try to retain some flexibility and allow a free exchange while still being safe. The automotive rule is not squishy at all. But I'm no mod, so maybe they see this case differently. Maybe a race car is not an "auto".

I think I understand that you're trying to avoid a loss of flow of the water/methanol since it is providing cooling and slows detonation, similar to an octane boost.

Were you thinking of protecting each cylinder individually? I'm trying to understand the flow rate. I think it's much lower than most industrial flow detectors will be made for. I was thinking detecting a loss of pressure would be easier, but that would not protect against a situation where it plugs, and you still have pressure but no flow.

my plan is just to monitor the the line after the pump so i will be able to pick up a failed in the pump or a loss in performance from the pump but come to think about it you may be right even through the line is under pressure the cant be a very high flow rate. thus far this is the only sensor ive found that can handle methanol http://za.rs-online.com/web/p/flow-...47B377D247C5E5C647B31307D2426706F3D313426736E. but perhaps a pressure switch might be better suited to my application

 

Modern cars use knock sensors to detect detonation. I wonder if it wouldn't make sense to just use that here. No detonation = no problem?

 

the knock sensor on my car only works is when there is detonation the object of this is to prevent it from happening and the aggressive tune im running it will detonate if its not getting the added cooling and octane from the water meth and it doesn't matter if the knock sensor picks it up it will be to late. this would just be an added safety feature