Snow Performance Stage 3 DI Install Notes

[Bull Run]

I just upgraded from AEM V2 to Snow Stage 3 DI. AEM V2 worked fine but I've run out of things to upgrade (unless they open an E54 station nearby, which is highly unlikely, or end up installing a built motor) and wanted to try Stage 3 DI for its display and to see if referencing FRP (Fuel Rail Pressure) in addition to boost improves injection accuracy.

I reused most of the plumbing and wiring from the AEM V2 and ProMeth multi-port install, so I'll just highlight the differences as I don't think I saw any WMI installation guide posted on this forum for systems that utilized FRP sensor. This should also help folks with installations of other systems that also reference FRP, such as Aquamist.

The first thing to do is to bench test the system as you don't want to find out that it's DOA after the installation. I first tested the pump by hooking it directly to the battery. Then I hooked the pump up to the controller, set the controller to trigger at 1 PSI, and blew into the boost reference tubing to ensure that it read the pressure and triggered the pump.

Clear boost pressure reference tubing fits tightly into the existing vacuum line used by AEM V2 controller. I put a small clamp on it to ensure that it doesn't pop off during boost. The wiring looks like a rat's nest right now as I'm holding off on trimming and soldering the connections until I'm good with the current mounting location. Meanwhile, I just rolled them up with twist ties and trucked them out of the way.

The final step was to tap into the wire carrying the FRP data. One possible location is at the FRP sensor, which's locate near the throttle body at the end of the fuel rail. Middle gray wire is the one to tap. There isn't much of slack in the wiring so it'll be difficult to do any splices without taking the intake manifold off, but it's much easier to locate the wire here than at the ECU harness side.

I chose to tap by the ECU harness as I tapped into other wires in the past at that location without issues. Pin 37 is the one to use. Note that the factory repair manual refers to a blue wire but the actual wire is gray, just like at the sensor (at least for my 2015). Grayed out circles on the harness diagram are pins without wires, so it's easy to see which one's #37 in the middle row.

I used a temporary connection/splice for in case I made any mistakes. The plan is to go back and solder the connection/splice once the long-term test shows no issues.

I fired up the car once everything was hooked back up. Fortunately, I didn't see any CELs and the controller displayed FRP percentage.

A short test drive showed that everything seems to be working fine. Other than setting the boost to start at 3 PSI and max at 22 PSI, I left the other settings at default for now.

Few more FRP sensor facts:

From the factory repair manual, this allowed me to understand why WMI systems for DI reference FRP instead of fuel injector pulse width:

FUEL RAIL PRESSURE (FRP) SENSOR

The FRP sensor is a diaphragm strain gauge device. The FRP sensor measures the pressure difference between the fuel rail and atmospheric pressure. The FRP sensor nominal output varies between 0.5 and 4.5 volts, with 0.5 volts corresponding to 0 MPa (0 psi) gauge and 4.5 volts corresponding to 26 MPa (3771 psi) gauge. The sensor can read vacuum and may lower the output voltage to slightly below 0.5 volts. This condition is normal and is usually the case after several hours of cold soak before the vehicle dome light is turned ON. The FP assembly is energized at the same time the dome light is commanded ON. A disabled or malfunctioning dome light does not affect the FP assembly control.

The FRP sensor is located on the fuel rail and provides a feedback signal to indicate the fuel rail pressure to the PCM. The PCM uses the FRP signal to command the correct injector timing and pulse width for correct fuel delivery at all speed and load conditions. The FRP sensor, along with the fuel volume regulator (part of the fuel injection pump), form a closed loop fuel pressure control system. An electrically faulted FRP sensor results in the deactivation of the fuel injection pump. Fuel pressure to injectors is then provided only by the FP assembly. When the fuel injection pump is de-energized and the injectors are active, the fuel rail pressure is approximately 70 kPa (10 psi) lower than FP assembly pressure due to the pressure drop across the fuel injection pump. Thus, if the FP assembly pressure is 448 kPa (65 psi), then the fuel rail pressure would be approximately 379 kPa (55 psi) if the injectors are active.

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[Bull Run]

Mounted the controller on top of the dash to monitor boost, FRP, and injection percentage while driving. Ran the wires through the hole where the adaptive cruise control/shift lights normally go if equipped. The plan is trim the plastic cover so rest of the cover can snap back in place.

Another ongoing experiment is to utilize the windshield washer fluid bottle. The only time that I sprayed the washer fluid was when I was testing it out and since winter washer fluid already has 30% methanol, I don't think that using 50% mixture won't be a problem if I do need to spray. Ordered a spare bottle and tried on it in case I mess it up.

Drilled a hole on the bottom and cut threads using a 3/8" NTP tap. Installed 3/8" NTP to 1/4" tubing quick connector that came with the Snow kit along with E-6000 methanol resistant sealant.

Drilled a 13/16" hole on the side and installed the low fluid level sensor that also came with the kit. The circuit is open when there's fluid in the bottle, and closed when the fluid level drops to the sensor level.

Filled the bottle with water after the sealant cured and didn't see any leaks through the connector or sensor even when shaking the bottle. Hooked up a multimeter to the level sensor and confirmed that the circuit closed after draining enough water. I believe this bottle is ready for installation!

I also ordered a 4-pin relay and a fuse box to avoid attaching all devices that require switched 12V to a single wire. The plan is to connect the fuse box to the battery through the relay that's triggered by a switched 12V wire. Below is a wiring diagram that I drew up for the end state after the SafeInjection (Snow's failsafe) and flow/boost gauges installation.

For the failsafe action, my plan is to have it trigger the relay that opens the circuit between the ECU and TCWRVS. This will limit the boost to the WGA spring rate.

 

[RubyRed15]

I like your location for the unit, but that cable looks awful (but what can you do?). Would it not fit on top of the steering column, or is that just too low for your preference?
What's the quantity of the washer tank? That's a really good idea. Where are you mounting the pump?
Snow took the SafeInjection off the market, for some reason, several months ago... new old stock?

 

[Bull Run]

I like your location for the unit, but that cable looks awful (but what can you do?). Would it not fit on top of the steering column, or is that just too low for your preference?
What's the quantity of the washer tank? That's a really good idea. Where are you mounting the pump?
Snow took the SafeInjection off the market, for some reason, several months ago... new old stock?

I decided to go for "function over form" for this as I had an injection LED on top of the steering column with the AEM kit and found that it's hard to keep my eyes down there to take a look when I'm accelerating hard enough to trigger the WMI.

I still see SafeInjection for sale on eBay and am waiting for a flash sale to order, but I may have to order sooner rather than later if they discontinued it. AEM has flow based failsafe kit as well, so I can always go that route if I don't end up with the Snow one.

I played around with the wiring diagram and I think I found a way to also have the low fluid sensor trigger the failsafe solenoid and consolidate warning LEDs into one.

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For those who are intimidated by the diagram above, what's with all the bells and whistles (minus the power nozzle setup). If you're going with just the controller, the simple diagram blow's all you need.

I'm going to swap the bottle this weekend in addition to installing the fuse box and failsafe relay. Once done, I'll fill up the original washer bottle with water and pour it into the AEM 1 gallon bottle to compare and let you know. I haven't decided on the pump location yet, I'll take the bumper cover off to see where I have room.

 

[RubyRed15]

Understood about mounting too low. Very interested in your progress!

 

[Bull Run]

[QUOTE="RubyRed15, post: 2441069, member: 12228"}]What's the quantity of the washer tank?[/QUOTE]

Tested it today by filling the old washer thank with water and pouring it into the 1-gallon AEM tank. It filled it about 3/4 high, so I'd say 3 quarts, just like the bottle that came with the Snow kit.

 

[Bull Run]

Finally found some time for the installation and re-wiring of the kit.

The first thing I noticed after the bumper cover removal was that the ducting for JTL brake cooling kit ran right below the washer tank. This was a no-go since I already tapped the bottom of the new tank for the fluid outlet.

Fortunately, there is plenty of space behind the tank (enough space that someone with metal fabrication skills can create a pump mount and mount it there), so I ran the cooling duct through there to get air from the lower grill. It looked like the underbody cover is strong enough to support the weight of the pump, so I mounted on it underneath the tank.

Cut a hole in the plastic block-off by the intercooler and zip-tied the duct there. It's hardly noticeable once the bumper cover is installed.

The failsafe relay is mounted access the turbo using an existing screw, which also serves as its grounding point. The current from the ECU to the Turbo Wastegate Regulating Valve Solenoid (TCWRVS) runs through it. This circuit is closed when the relay is not energized. Once energized, the circuit opens and TCWRVS become disabled, which limits the turbo to the WGA spring rate. For example, if you're running a WGA with 10 PSI spring, max boost you'll see will be about 10 PSI. You can test this by simply unplugging the TCWRVS pigtail and going for a test drive.

Splices for the TCWRVS and FRP sensor wires were made by the ECU harness. Rewrapped the wiring bundle with some friction tape to keep the factory look.

Behind the wheel well cover by the driver's side firewall is the junction point for all the wires and hoses in and out of the engine bay and the cabin. I cut an electrical distribution box into halves to make it function as two, one for the failsafe circuit and the other for the pump circuit. Distribution box makes future expansions easier by avoiding multiple taps for a given wire.

The failsafe side has three wires; low fluid warning source (+) wire, and (+) wire for the failsafe relay and the warning light. If Safeinjection is added, its warning source (+) wire will be added here.

The pump side currently only has two wires, pump (+) wire from the controller and pump (+) wire going to the pump. Future accessories triggers from the pump activation goes here, such as the trigger wires for the Failsafe and anti-gravity feed solenoids.

The expanded view of the junction area, with the distribution box cover on.

I installed a 4-pin relay as shown in the wiring diagram (forgot to take its installed picture), which goes to a fuse box where the old AEM controller used to be mounted. It also works as the distribution box for the ground (see the black wires on the top).

It only has two active circuits now, one for the controller and the other for the low fluid level failsafe. Boost and flow gauges will be added here once installed.

Fuse box with its cover installed.

I turned the car on before filling the tank to test the low fluid level failsafe. Verified that it worked by seeing the warning light mounted above the steering column light up and the check engine light flashing.

Code P0246 will be record when the failsafe activates.

Turned the engine off, cleared the code, filled up the tank, and fired up the engine once I verified that there were no leaks. The warning light stayed off and no new codes were logged.

While I didn't install any gauges this time, I went ahead and tapped the (+) wire for the parking light and ran it to the cabin before reinstalling the bumper cover. This will provide a 12v source for the nighttime mode.

 

[Bull Run]

The WMI kit's been running great so far. My next test will be to let the fluid run down by usage to ensure that fluid level failsafe works as designed in "real life" situations.

I like that relocated brake cooling duct's not noticeable even in daylight unless you get up and close. I plan to relocate the driver's side duct and finish it up with a GT lower grill with the sides opened up.

 

[MakStang]

@Bull Run thank you for this great thread. I bought the Snow Performance Stage 2.5 Boost Cooler wmi kit from Adam and I have a couple of questions related to its installation.

• You used the washer fluid container, but I will use the tank that came with the kit. Any suggestions on the ideal location for installing it? In my mind the best location for the tank and the pump is in the trunk, but the instructions suggest that ideally they should be located in the engine bay. Any suggestions would be very much appreciated.
• Is the underbody cover strong enough to support the weight of the pump? This may be the ideal location for the pump, but the pump is heavy and I wonder if the underbody cover will hold.
• Which nozzle did you use? Adam initially told me to use nozzle #6, but the kit came only with nozzles #2 and #5 and Adam told me that nozzle #5 is fine.
• What % methanol are you using? I know that 50% is what almost everyone uses, but Adam told me to use 70%. I will discuss this further with him of course, but I need to know the consensus.
• Do you mind posting a photo of how you mounted the nozzle on the cold side charge pipe? I would like to get an idea on how to secure/where to locate all those tubes in the engine bay.

I may have some additional questions as I go through the installation. I hope you don’t mind me asking them in this thread.

 

[Bull Run]

@Bull Run thank you for this great thread. I bought the Snow Performance Stage 2.5 Boost Cooler wmi kit from Adam and I have a couple of questions related to its installation.

• You used the washer fluid container, but I will use the tank that came with the kit. Any suggestions on the ideal location for installing it? In my mind the best location for the tank and the pump is in the trunk, but the instructions suggest that ideally they should be located in the engine bay. Any suggestions would be very much appreciated.
• Is the underbody cover strong enough to support the weight of the pump? This may be the ideal location for the pump, but the pump is heavy and I wonder if the underbody cover will hold.
• Which nozzle did you use? Adam initially told me to use nozzle #6, but the kit came only with nozzles #2 and #5 and Adam told me that nozzle #5 is fine.
• What % methanol are you using? I know that 50% is what almost everyone uses, but Adam told me to use 70%. I will discuss this further with him of course, but I need to know the consensus.
• Do you mind posting a photo of how you mounted the nozzle on the cold side charge pipe? I would like to get an idea on how to secure/where to locate all those tubes in the engine bay.

I may have some additional questions as I go through the installation. I hope you don’t mind me asking them in this thread.

• I used to have it mounted in the trunk with the TUNE+ mount when I was running the AEM kit and it worked fine. Looks like there is enough room in front of the engine to mount a bottle there but I haven't seen it done in person.
• I had the pump in the spare tire area when the bottle was mounted in the trunk. I haven't had any issues with the pump on the underbody cover so far but I haven't been driving much recently as I mostly work from home now. I found another picture that shows a more secure location.
• I reused the Pro-Meth multi-port setup so I didn't use the Snow nozzles. When I had the AEM, single 550cc nozzle was more than plenty for the stock block setup on 91 oct that dynoed at around 360 WHP on a Mustang dyno (those tend to read lower than Dynojet).
• I'm using 70% now. methanol's lighter than water so that should get you closer to 50% by weight
• Before the Pro-Meth setup, I had the single nozzle on a bung that came with the AEM charge pipe. If you don't want to swap out your charge pipes, you can get a throttle body spacer with mounts for the nozzles.

 

[MakStang]

Thanks for the detailed info. Where exactly is that location where the pump is mounted in the second photo? I am a bit lost...

 

[Hellman109]

Looks to be on the crash bar and the picture is at an odd angle, the bar in the middle looks like the sway bar?

 

[MakStang]

I tried fitting the tank in the position shown in the first picture, but it’s too tight and it fits too closely to the timing cover and belts. It seems to me that the only alternative is to fit both the tank and the pump in the trunk. My concern is that I will have to pull all those wires and lines all the way to the engine bay and I don’t see how I can do this, lol! I mean, I will have a professional do it but still...

 

[ronemca]

With help from my friend the metal fabbing wizard, I have a bracket that holds the bottle AND the pump bolted about 14" beneath the drivers side headlight with existing holes (no drilling was needed) It fits perfectly...the bottle-to-pump hose is about 4" long...and the pump-to-nozzle hose is about 22" long. It could have been shorter, but I wanted a nice gentle bend between pump & nozzle. (The nozzle is inserted into a Mishimoto cold side pipe about 8" in front of the TB) When it's time to refill the bottle, I just reach down and unscrew the cap and insert a funnel with a one-foot plastic hose on it. Easy-peazy.

 

[MakStang]

@ronemca do you have any photos of this setup? I was thinking to do the exact same thing but I didn’t know how to hold the tank and the pump in place. I would like also to take a look at this bracket, I may ask some metal fab wizzard do the same for me!

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