HFS-4 Q&A, application for your engine...

[aus jd 2703]

Annoyingly no. I'm at the limits of my ecu's mapping and I can't use a fuel cut defender. I guess I'll wait till I get a standalone to take advantage of WI.

[Richard L]

In this case, water injection will only have minimal effect on your application.

[Jockeygolfs]

I have an 11' STI. If I do the dual injection (one before the intercooler and the other after the intercooler), do I need to use two of the same sized jets? I currently have DW 850 injectors. Based on the chart it appears I would need the (2?) 1mm jet and the .7mm restrictor. I will be between 21 and 25 PSI.

[Richard L]

Based on your total fuel flow of 3400cc/min. you only need to run one 1mm jet if you run below M50:W50. Above M50:W50. you need to install a smaller jet berfore the intercooler, perhaps a 0.6 to 0.7mm. Still using a 0.7mm restrictor.

[Jockeygolfs]

Great. I will be running 50/50, probably less than 50 meth. If I'm only running one jet do you think it is best to be after the intercooler or after the intercooler? I think after is the typical installation.

Thanks again,

[Scooter09]

Originally Posted by spoilboy1

Can you post some pics.

I couldn't figure out a good way to mount the tank, so I used locking cable to "strap" it down.






I made my own gage bracket. I'm thinking of moving the gage in a bit, thoughts?

[trek800099]

Hi, I'm in the planning stages of installing the HFS-4 kit in an 06 US STI. I have a few questions I hope Richard can help with.

I'm running stock injectors and I figure I will only need a single injector of 1.0mm and a restrictor of. 0.7mm? Current boost is 21.5. Or am I way off?

Next can I use the HFS-3 wiring diagram located here http://www.aquamist.co.uk/vbulletin/...ead.php?t=1711 for my car?

In regards to the 12volt requirements I see they need to be switched on with the ignition, but do they need to stay live at 12volts during cranking? I recently installed a wideband O2 sensor that required this and I'm wondering if this system needs this type of power too or can it switch off for the few seconds during cranking then back on once the car is running?

I've noticed on some of the wiring diagrams the power supply for the pump relay says "battery" and others say "switched" can you clarify.

I thank you very much for your time and help.

[Richard L]

1. You have a total fuel flow of 2200cc/min. if you are running a M50:W50 mix (recommeneded), you should be flowong around 330-440cc/min. That will be a 0.9mm jet.

2. Yes you can indeed use the same diagram as the HFS-3. I am getting around to update the H4/Subaru drawings.

3. The reason for suppyling 12V to the red wire of the grey harness at the "pre-crank" or the "run" key position is to prevent accidentally injecting water/meth into the engine at the "accessory" key position. It does not have to stay alive during cranking. Fiollow the wirng of the H3 diagram.

Ae regarding the 12V supply to the pump (12 Awg) any switched 12V or bettery will do. Thre 12V supply to the molex connector should ideally be switched. This is it prevent the controller being "live" at all time in case you drop something metallic onto the circuit board of the controller during installation or initial testing.

Richard

[Richard L]

Originally Posted by Scooter09

[IMG]

Can you disassemble the plug and rotate it 180 degrees so water can not flow into the plug.

I really like the way your secured the tank.

[Scooter09]

Originally Posted by Richard L

Can you disassemble the plug and rotate it 180 degrees so water can not flow into the plug.

I'm not sure what you mean? This is the way it came to me from Jeff, all I did was turn over the bracket that secures it under the cowl.