The anatomy of a WMI failure

[Lex]

Currently tuning a customer with a Water-Methanol Injection (WMI) system and a big turbo. It's a 2010 MS3 with a GTX3071 and a D10 nozzle running a 50/50 mix.

In the middle of a 2-3-4 gear run his WMI system failed and it's interesting to have a look at the data before and during the failure. It also shows that it's not all sunshine and rainbows and a WMI failure can ruin your day. In this case the failure was the tank running low.

The graphs below show normal WMI operation during a 4th gear pull. Notice that the Boosted Air Temperatures (BAT) don't rise during the pull more than 10F.



Also note the injector duty cycle. The car has WOT fueling trims that are compensating for the extra fuel supplied by the WMI system. His duty cycle stays around 90%.



Now here the failure happens half way through the 4th gear pull in this 2-3-4 pull. First notice the big rise in BATs during the 4th gear section and the Knock Retard (KR) of 4*.



A second piece of data confirming WMI has stopped spraying is the injector duty cycle that is now over 100%. You can see the jump in duty cycle associated with the knock just as the system fails.



Moral of the story is that if you are pushing the car on WMI, a failsafe is a great idea. You can couple any of the existing failsafe devices from WMI kit manufacturers with the GA. We are also working on a failsafe system that can be setup to catch these scenarios with any WMI kit but unfortunately it is still under development.

[dale_gribble]

Wait, guardian angel works with existing WMI failsafes? Please elaborate.

EDIT: I am a retard. I definitely overlooked that. I was looking for this exact function yesterday. Badass...

The AEM has a 12V+ trigger, so I am pretty much on it.

[Lex]

Originally Posted by dale_gribble Wait, guardian angel works with existing WMI failsafes? Please elaborate. EDIT: I am a retard. I definitely overlooked that. I was looking for this exact function yesterday. Badass... The AEM has a 12V+ trigger, so I am pretty much on it.

Yes and if the failsafe has a trigger to ground, a very simple relay will trigger the GA. I have schematics for this if anyone has a failsafe with a trigger to ground.

[dale_gribble]

The AEM 30-3020 failsafe/gauge setup looks like a great pairing for this as a WMI failsafe (on top of GA boost control). It has a high side +12V trigger line and a low side trigger also.

This is exactly what I was looking for and it was under my nose this whole time.

[dev]

@mize13; Glad you bought the failsafe?

[Jonathanhair07]

@ms6mil; I been reading up on failsafe/Guage setups since I bought my meth kit. AEM makes a good one. Figured I would tag you in this. this would ease the fear if anything was to fail.

[Jpspeedthree]

Not sure how you head out to do some logs and you decide to do them without checking how much meth you have in the tank. Good info though and Failsafe is a good idea.


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[Lex]

There are a large number of reason for a system to fail. Whether its low fluid, a seized pump, wiring connection or a leaky fitting.

The important thing to take away is that - should there be a failure, can you catch it and do something about it? If you can't, how high is the risk?

If you're running a smallish D07 and lower nozzle and a 50/50 mix the methanol won't affect your fueling and timing increases due to meth will be small. So a failure is not as risky. For people relying on meth for fuel and significant timing increases on stock motors it is much more critical.

[KCi]

Great info Lex! GA will be my next shopping list. I have AEM kit as well.

[btstarcher]

@mazdafreak;