VersaTune User Forum

Before I spend more than a couple hundred dollars on the AEM AFR failsafe gauge, can we set up VT to cut throttle and/or wgdc if afr goes lean at WOT? I run methanol and would love to have a backup plan if the methanol quits for whatever reason at wot.

No, the tune logic will not react to lean AFRs as far as I know, it doesn't have any fuel cut upper or lower AFR limit.
However, you can run a wire from your AEM failsafe to a device such as the Stratified guardian Angel. The problem is however that the AEM failsafe is an epic little stinky shit that you will find that it failed right when you will see 13.5 AFRs as 6000rpm and load 2.

If you want something tune based though I think you can let the tune logic consider the LTFTs even when load is high (anyway in the factory tune this limit I think is load 2.5), and if the ECu will try to compensate for a failed or failing methanol system running above, say, 102-105% will either start closing the throttle or even cut fuel if the situation persists. but that is going to be relatively slow and already in the danger zone when the system starts reacting (will have fuel but not the expected octane if the meth spray is not there).

Maybe moving to cooling mist is a better idea when you want true/working failsafe for meth.

I have the coolingmist system. Their failsafe is garbage. It does have a fault trigger if it senses out of the ordinary pump voltage (too high or too low) and I can trigger the GA with that. Also going to wire up the opposite and have the GA trip a relay for my methanol solenoid when it triggers so they``ll kind of watch each other`s back.

The cooling mist failsafe is actually the best you can get. It is sensing the pump duty cycle to figure out if you run out of meth and also you can put a level sensor on the meth tank.

But it doesn`t, really. It signals the pump to run the commanded duty cycle but it gets zero feedback FROM the pump, other than a completely open or shorted circuit (as long as the pump voltage is where it`s supposed to be the controller is happy). Handy, for sure, but it does not in any way measure or recognize pump output and if something goes south between the engine and the pump you`re still screwed. For instance, if for some reason you blow a meth fitting and you`re spraying methanol all over the ground the controller will never know it`s not getting to the engine (ask me how I know. I`ll be converting all of my lines to braided stainless and AN fittings when I get the car back). Another example would be if the solenoid quit. Line pressure would go up but voltage would be the same and the engine is getting no methanol. ZZB.

And I would never in a lifetime advise anyone to run a meth system without a level monitor of some sort. I`ve got a nice bright LED right on the dash that blinks when the tank gets to 33% and comes on full bright at 25%.

Do you only have the failsafe or also the CMGS?

The CMGS progressive controller.

This would require custom code to fuel cut+close throttle if APP > x% and lambda > safety threshold.
I will add it to the list of custom code enhancements.

Steve @ VersaTune wrote:This would require custom code to fuel cut+close throttle if APP > x% and lambda > safety threshold.
I will add it to the list of custom code enhancements.

it would be a remarkable addition. Game changer level.

This would be amazing if we had this feature. You could pretty much do away with needing external fail-safes.