HSF-2 for STi running Link G4 standalone
 

I have a 2007 Subaru STi with a fully built 2.34L motor, Borg-Warner EFR 7670 turbo, and FMIC all controlled by a Link G4 Extreme ECU. I live in California where we only get crappy 91 octane and I never really had the desire or the fuel system capacity to run E85 so I've contemplated meth injection.

I'm looking at the HSF-2 system specifically as I don't need the flow gauge but I still would like the failsafe feature. I was thinking of adding the turbine flow sensor to my order and performing the low and high flow failsafe logic in the ECU itself.

I already have dual fuel, ignition and boost maps in the ECU and I can trigger the second map to activate when I get the injection signal from the HSF-2/3 controller and when flow is between the low and high flow limits I set in the ECU.

I'm pretty sure I can make all that work as long as the HSF-2/3 controller has the necessary outputs. I'm all out of analog outputs but my ECU can accept digital speed inputs(frequency) that I can use for flow indication. Does the HSF-2/3 controller have an output for that?

I can also output a PWM signal that mimics IDC, can that be used as a trigger to start injection? If not what are my options for injection start and what kind of signal is required?

I'm running 1100cc injectors and plan on running around close to 28-30 psi of boost when all said and done so I need around 880cc of injection. I was going to go with two nozzles, a 1.2 and a .8 size to give me the required flow but I had a question about nozzle placement. I was thinking of putting the .8 nozzle pre intercooler and the 1.2 nozzle post intercooler. The post intercooler is still about 2.5 feet from the throttle body. What's your opinion on that nozzle placement? Is there any benefit to putting a nozzle pre intercooler or would it be best to have both nozzles on the cold side piping? Thanks for all the help.

Kelly

Re: HSF-2 for STi running Link G4 standalone
 

How about a more direct question... Can the HSF-3 controller give me a frequency output that represents meth flow?

I see the available 0-5V flow output but I have no more analog inputs. I do have frequency inputs though.

Re: HSF-2 for STi running Link G4 standalone
 

I believe we talked already via email. The white wire of the green harness is the raw pulse output from the flowsensor.

Re: HSF-2 for STi running Link G4 standalone
 

Thanks for the response. Do you have any input on the nozzle placement? Is it even worth it to have a nozzle pre-intercooler?

Re: HSF-2 for STi running Link G4 standalone
 

Depends on how much you are spraying and what you are trying to do. Some folks do put a small jet pre-sc.

Re: HSF-2 for STi running Link G4 standalone
 

Why not keep it simple ?

4 nozzles, one in each runner controlled via FAV and your Link ecu. The ecu or a simple pressure trigger could energise the pump then you could control actual water/meth flow completely via the ecu.

Re: HSF-2 for STi running Link G4 standalone
 

You'd have no failsafe, other than the o2.

Re: HSF-2 for STi running Link G4 standalone
 

For me I think its easier from a hook-up and wiring aspect to let the HSF3 controller handle the initiation of flow and to monitor for tank low level and for me to make my flow failsafe in the ECU. Four wires between the HSF3 controller and the ECU make it a pretty easy hookup. It would be a lot more wiring to do a completely ECU driven meth injection system.

I may go direct port at some point but I'm looking for maximum IAT reduction now and could always add those 4 ports later.