Staging Triple Fuel Hat

My car has a triple pump hat in it with a return system. Everything works great, but the 3 pumps are wired with their own relays and run all the time.

Since this is overkill and can lead to fuel heating, I’m planning to stage 2 of the pumps.

The method I’ve seen (other than expensive controllers) is to use a Hobbs pressure switch thats normally open and closes at 2-4 psi.

My concern with that is if the switch was to fail it would remain open under boost, lean out and you know how that ends.

So I’m thinking instead of using a normally open pressure switch that closes under boost, I’ll use a normally closed vacuum switch that opens under 2 in/hg of vacuum. This way if the switch was to fail, the result is the 3 pumps run all the time which won’t cause the issue of a failed pressure switch.

The other option I’m considering is to use the snow performance meth controller to kick the 2 additional pumps on based on the MAF or MAP voltage. My car came with a stage 2 meth kit which is no longer used as I’m straight E85 now.

Anyone used a setup like either of these and have input?


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Run 2 full time, not 1.

The meth kit is interesting, but would it have enough voltage to drive a relay?

jony51999 said:

...My concern with that is if the switch was to fail it would remain open under boost, lean out and you know how that ends...

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Would the failure mode for the meth controller be the same as for the Hobbs pressure switch?

I’m not real familiar with the meth controller yet so I’m not positive on how I would set it up. I do know that it has an adjustable on/off based on 0-5v, which I could signal from either the MAF or MAP.

I’m also thinking of using a Hobbs pressure switch to cut the ignition/injectors off as an additional safety measure to prevent a leak condition. If I figure out a good way to do that, the Hobbs reliability/potential failure causing a lean condition would be eliminated.




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What gauge is it that can be used as an interrupt in case something goes wrong? I remember in the video of it they had it tied into the ECU power so when the gauge saw a lean condition it shut down the car for a second. Definitely an attention getter.