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Water/meth fail safe

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Hello Andre i have a question here about the best way to setup a safty limmit in Link g4+ ecu for a water/meth pressure safty limmit.when pressure drop under load.i do have setup a pressure sensor install to measure the water/meth pressure when active.water/meth not active by Link ecu it have its own controler.

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I can give you an example but you will need to give more info about how you want this this to work and how the car is used. For instance, will you ever want to drive the car with meth injection turned off?

Hello Adam thanks for your replay the car will be driven at that boost level on meth injection only .its a Mit evo 9 with Link plug in ecu that works gr8 .i want to setup this fail safe for the customer as in the past a meth Teflon broke off and customer drove the car a wile under boost with out meth injection knock control have done his job at this stage ,would like to get some examples to setup the yand x axis to suit .its a daily driven car so meth injection will be active all the time under boost and start at 10psi that i can remember.

My first thought would be to set the gp Limit table up with MAP on one axis and Meth pressure on the other. You can then lower the RPM limit at any point above your switch on boost (10 psi) when you have insufficient water injection pressure. You'll need to use a delay here as it may take a few tenths of a second for the system to build full pressure depending on the system. This is better than nothing however the better option is to use a WMI system with its own safe guards that can then send a signal to the ECU. We tested the AEM system which is great as it has safe guards for water level in the tank as well as directly measuring the water flow. This allows you to set up limits for both high and low water flow.

Hello Andre ok i can setup the y and x axis as you recommend the other part is how do i set a delay in the link software.

I will be using boost driven pre-turbo atomiser so don't have to worry about pump fail but will be using an optical level sensor in the tank to digital input to lower target boost with low water. A switch in line with that same logic would allow you to drive the car without cutouts operating once a fault was established as ber Andre's suggestion.

The rev limit suggested will be savage but that will let the user know something is up could then lower boost target with another input, assuming you aren't running gate pressure with the AI.

@Bellotech - Under the GP Limit setup there is an activation delay. This will delay the limit activation for whatever time you define once the conditions for the limit are met. I'd suggest a delay of perhaps 0.1-0.2 seconds and see how that matches the response of the WMI pressure. Ideally you want the least delay possible without it falsely triggering.

@ Slides using boost pressure to pressurise the WMI system certainly has the potential to be more reliable than a pump, there are still potential areas for failure such as the line to the nozzle developing a leak or the nozzle becoming blocked so you do have a little more to consider than just the water level.

You're right that bringing in a cut is quite harsh but without the option to monitor water flow and water level the options are a little limited.

Hey Andre,

I'm looking at building a WMI setup with failsafes for my 2JZ as I don't want to go E85 as the car gets driven once every 4-6 weeks.

I have looked at your AEM video with water flow sensor as well as the HD controller and it's got me thinking of building a better failsafe system using off the shelf components instead of coding an arduino system.

I'm running a Motec M800 with the 3.5 software and there's a nitrous map config.

My Idea was to run the Nitrous maps to compensate for the WMI over the base maps.

There's 3 stages, 3 Digi inputs, with 3x 3D and 2D fuel and ign maps.

Stage 1 = everything OK - reduce fuel and add ignition timing - keep boost at the petrol tuned level

Stage 2 = everything OK - reduce fuel and add ignition timing, perhaps add more boost pressure via a secondary comp map that's activated.

Stage 3 = Error - Warning Light - run base fuel and timing map, run lower boost. - no changes to safe petrol map.

Is the above possible on the M800 series ECUs in the way I have described or would I need to upgrade to a another ECU that has WMI compensation maps.

I race the car at the track and on the touge / long hill climbs - there's not enough time to look at any gauges on tight corners on a street course for example - it's flat stick, white knuckled action in the corners and when there's a straight - a quick glance is all I can afford.

thanks guys for the reply .will make some changes in my current setup .

@racetune - I can't see a problem with what you're suggesting off hand although I haven't used that specific solution. The nice thing with the M800 V3 firmware is that it's incredibly flexible so there's not too much you can't do with it if you get a little creative. You'd just need to ensure the digital inputs are doing what you need to give the M800 the correct information.