More water / meth injection

tarmac terror
Posts: 30
Joined: Fri Apr 27, 2012 5:30 pm

More water / meth injection

Post by tarmac terror »

Been giving water / meth injection a closer look of late and am swaying towards an EMS-based system fromCoolingmist.
I have searched for info about these systems on here but the only relevant stuff I could find was from some time ago...

My question is this...with an S8, could I have the ECU directly controlling the pump via PWM? The Coolingmist blurb states:-
While many aftermarket ECUs have the ability to send a PWM signal ,they do not have the ability to run the 10-13 amps the pump will draw and systems did not have a failsafe input for the ECU
I'm sure the S8 can output an easy 10-13A on a spare injector output and can take an input for a float sensor for low water level. The last recommendation I found (albeit a while ago regarding an Aquamist system) said that it would be best to keep the supplied controller and leave the ECU out of the equation. I just feel that it would be a neater, more integrated solution to have the S8 manage the pump directly and giving it sight of low water/meth levels so it could apply measures should the fluid run out.

So, do you still recommend using the supplied controller or would you say that control via the S8 is better??

TT

pavlo
Zen Performance
Posts: 406
Joined: Mon Aug 04, 2008 9:18 am

Re: More water / meth injection

Post by pavlo »

The ECU cannot do that sort of current on an injector output, and it would be borderline with an ignition output. But you can easily use a full bridge motor controller to do 10-12 amps (I have done this for fuel pumps), and there are a couple of strategies that would be okay to use, the nitrous strategy would be idea, you could even use it to add ignition advance with the water on (if you're brave!).

The issue with using the ECU to directly drive anything is that it will be sinking the current itself, so you're ground wiring will be bearing the brunt. Coils can pull lots of current but they run at a comparatively low duty cycle most of the time so the average current is low. A cheap full bridge (half bridge could be used but they are mostly full bridge on ebay) from ebay will do the job and isolate the motor from the ECU.

If the motor was more like 8-10amps when actually current probed I would be more inclinded to use an ignition output directly, but make sure you add an anti flyback diode.

tarmac terror
Posts: 30
Joined: Fri Apr 27, 2012 5:30 pm

Re: More water / meth injection

Post by tarmac terror »

Yes, sorry I actually MEANT ignition output but had injectors on the brain :D

So, just so i'm clear...you are suggesting that i could run the pump directly from the ECU using a full bridge?

TT

pavlo
Zen Performance
Posts: 406
Joined: Mon Aug 04, 2008 9:18 am

Re: More water / meth injection

Post by pavlo »

I would suggest an EXTERNAL full bridge, triggered from an ignition output using TTL.

I have used something like thing in the past:

http://www.ebay.co.uk/itm/High-AMP-60A- ... 3cd43263b5

I wouldn't bother with a kit as such, just a pump and buy your nozzle(s) from aquamist or similar. You could always use a flow sensor to interlock the boost solenoid, or level sensor as a nitrous input and use that to turn the ignition modification off if the level was low. There are a number of ways it could be done relatively safely.

pavlo
Zen Performance
Posts: 406
Joined: Mon Aug 04, 2008 9:18 am

Re: More water / meth injection

Post by pavlo »

Or just run 8 injectors with the secondaries running methanol only from a separate dedicated fuel tank and pump and have them active on a specific calibration.

stevieturbo
Posts: 898
Joined: Sun Dec 07, 2008 2:04 pm

Re: More water / meth injection

Post by stevieturbo »

Aquamist offer a " Fast Acting Valve" and some nice nozzles with built in check valves that you can easily install in the intake, or wherever you like

Although if using the FAV controlled via the ecu, no real need for the check valves

So the ecu just turns the pump on initially, then water flow is ecu controlled via the valve, rather than relying on pump duty

AEM and Labonte offer a flow meter with 0-5v output which could maybe be used for tuning changes.

tarmac terror
Posts: 30
Joined: Fri Apr 27, 2012 5:30 pm

Re: More water / meth injection

Post by tarmac terror »

Apologies for dragging this up again......Looking to get this sorted out once and for all and get it installed prior to ECU purchase....

Am I right in saying that if I buy a pump, solenoid, nozzle(s), pipework, tank and external full bridge then I can connect an ECU output to the full bridge to control the pump duty and water/meth flow without the need for a dedicated controller?



Sorry for the need for spoonfeeding on this? I'm good with all the theory behind W/M and the physical installation. It's just the controlling of the pump thats giving me a (I'm sure, highly unnecessary) headache!



TT

stevieturbo
Posts: 898
Joined: Sun Dec 07, 2008 2:04 pm

Re: More water / meth injection

Post by stevieturbo »

I think your easiest way to do this given there is no proper water injection feature.

Have the pump turn on at a set rpm, load, whatever, in readiness for action.

Configure the solenoid or solenoids as a secondary injector

Then via the split table, you can easily base methanol flow directly relative to fuel flow...ie actual load.

Also trimming if need be via the primary/secondary injector size. Might need only 10%, 20% split etc etc

You have various fuel split maps via CAL etc so could easily turn the meth off/on on different maps as needed

If you have a solenoid for flow metering, then you do not need to control pump speed. Simple off/on would do.

If you do not have a solenoid for flow metering, then you would be using pump speed for this instead

tarmac terror
Posts: 30
Joined: Fri Apr 27, 2012 5:30 pm

Re: More water / meth injection

Post by tarmac terror »

Yes, silly me.....

Thanks for the detailed reply, most of which has gone over my head in relation to the 'how' bit of doing it in the ECU software :shock:

As for the flow control, you're absolutely correct!!! It'll be the solenoid controlling flow NOT the pump in the config I have in my head :)

I shall start getting the bits together and take it from there I think. I don't have the ECU yet....just prepping the car and wiring to make the install a bit easier for whoever does it :? :?


TT

RICE RACING
Posts: 215
Joined: Mon Feb 24, 2014 1:08 am

Re: More water / meth injection

Post by RICE RACING »

You are over complicating the matter, I have done WM50 injection for 20+ years and me a Richard Lamb are in agreement that the way I do it works and does it well, I can help you if you want it?? just send me an email or pm with your project.
http://www.riceracing.com.au
Real turbo road cars fast > reliable > durable
Water Injection Specialist

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