4 Rotor Water Injection, Trigger water injection VIA Relay from ECU Haltech Output?
 

Hey guys,

Looking to run straight water only, at around 500cc on 4 rotor, pre-throttle body. The only reason is for extra protection. Engine will never see over 12-15psi on pump gas.

Rather than going with an elaborate kit I was hoping the following would work,

-500cc Nozzle
-200psi AEM pump
-Snowperformance Nozzle holder/check valve

and then activating the pump via an automotive 40amp relay, trigger the relay via output from the ecu. Have the output activate the relay via ground signal when ECU reads Map sensor at 8psi??

Will this be an issue for a basic relay, turning it on / off so many time on / off throttle?

relay can go to the bottom of your list of concerns, as long as you have a feed back for boost to drop if the relay fails. imo. feedback is what its' all about. on everything.

Cool!

Well, I'm not really concerned about failure as I will tune the car before adding the water. The water will merely be used to add additional protection in the event that an injector clogs, wastegate line, bad fuel, etc. Plane water so that AFR is unaffected.

However, have considered using an oil pressure sender to detect water pressure and utilize as fail safe

You want to use a solid state relay so you can control the pump with a PWM table output on your ecu. This way your pump is not just on or off, it's low at 8psi (or whatever you set it to come on at, I wouldn't bother unto 10psi) and 100% at your max psi.

A regular relay can only handle on or off, and therefor can't use a table output function of your ecu. This is why the stock fan system has multiple relays, they are only getting on/off signals instead of variably controlling fan speed.

Or... Just use a snow performance controller, and don't bother using your ecu to control it. Basically the same thing, but you'd use a regular relay to power the controller, and it takes care of the pump speed by itself.

The trick way to do it is to run the pump wide open under load. They have an internal bypass, so they'll build line pressure and hold it. Then trigger a solenoid at the injection point to meter flow. The ECU can then be mapped to control the amount of flow v. load/rpm. No SSR needed. This is how the old FJO system was controlled and it worked well. AEM has an inexpensive flow control valve that can be used as a failsafe input. No flow, no joy.

Good ideas guys

I'd like to do some progressive control but really its just straight water and whatever is most simple is fine with me.

I ran the basic on/off w/ hobbs switch on the 13b and 20b for 5 years and it always did me well!

So let me get this straight Ludwig,

The pump will engage at WOT, and then use the ECU to control the solenoid on/off shutter speed, so basically the solenoid is the flow control? and at 8psi WOT vs 15psi WOT the solenoid will allow different amounts of flow

Correct.

Or just run E85 and don't worry about the water.

Could you post a link to the solenoid you usually use?

https://www.holley.com/products/fuel_systems/fuel_injection/water_meth_kits_and_components/parts/557-106

Holley bought FJO several years ago. There stuff if the the same as the old FJO parts.

id like to run e85, but 4 rotor and pp that's going to be like -3 mpg hahaha

So you do flex fuel. Gas for toolig around. Corn brew when you want to get serious.

is there an ecu you can make stage injector work by disabling the first stage when the 2nd comes on..
also the ecu would have to stage the injectors based on map rather than rpm.
you could have two tanks, two pump two feed lines, two returns, ..
87 in one take going to primary injectors...
e85 in the 2nd tank going to the "while in boost" injectors.

This would be the end all be all solution for wanting to go on trips with an e85 setup.. you could even just use c16 as your "in boost" fuel... thats probably were this is most cost effective.

There are quite a few high end cars with two types of fuels. I remember seeing a supra and some of the underground performance cars switch fuel on the fly. That's for over 1000 whp, not really needed on a 4 rotor with 800whp

but dis gone be 1200hp 4 rotor

Yes. Syvecs can do it natively, I know for sure. Think Pro EFI can as well. We're doing something similar on a Drag Week car right now with a Holley Dominator system. It's being setup with a flex fuel system and a methanol system. Two completely separate systems. Flip a switch and you change maps and fuel systems. I'm sure we could do a fuel switch with Haltech Elite or AEM Infinity as well. Just never saw the need. The complexity of a two complete fuel systems is usually the limiting factor. Enough people have trouble getting one system setup correctly, let alone two.

honestly it seems this engine may max out the CFM of the turbo, and product around 900rwhp by 12-15psi. So gasoline alone should do the trick.

Really just want to have a little bit of post-turbo, pre-throttle body mist, just to keep carbon out of the engine, and a little extra assurance at bringing down IAT in the summer etc. This way if there's a fuel hiccup, tuning error, etc there's a little safe-guard.

And whether the water is spraying or not, the car would have already been tuned without out.

Im think just a basic relay like the coolingmist kit, and a check-valve to prevent dripping, and just kick it w/ the ECU or boost switch at over 5psi. Just a small 500cc or so

Holley has a nice nozzle/solenoid combo. It's the old FJO stuff that they rebranded when they bought FJO. Solenoid is right at the nozzle, no need for a check valve. Could also PWM it, if you ever wanted to. Price is fairly high at $230, but it's a sweet piece of kit.

$

That is one sweet piece for sure!
I'm looking at maxing a sxe7670 on a stock port FC block. any reason why i shouldn't use /experiment with pre and post turbo water AND the E85. i'll be able to spend lots of my free time on a loading dyno at automotion and can get lots of data :P i don't see why i shouldn't

What nozzle size do you need just for air temperature lowering for knock protection? I'm looking to purchase the Rb Racing rsr kit

C lud, replied to your pm twice but my window 10 crashed both times.. I may just call you. Where are you located?

that is a sweet looking piece

With the solenoid and ECU PWM control, you can run a large nozzle and meter the flow with the solenoid. Within reason.

Yeah, don't think I ever got it. We're located in Floyds Knobs, IN which is just outside of Louisville, KY.

It's just not necessary for detonation resistance. So you end up with something that's overly complicated and introduce more potential failure points. The simplest method to achieve your goal is best. With E85 you'll be able to max out your combination and not worry about detonation.

Okay will do. By the way wasn't there a thread going around recently that was demonstrating severely damaged rotor housing surfaces with E85?