Newb questions.

[Richard L]

The reasons for the boost incorporation:

Many turners still use boost only to control flow due to their previous tuning with boost based only system. Unfortunately all modern direct injection engines no longer use boost as a load signal. Actual air flow into the engine is the combination of the throttle angle and boost.

In your case, use the boost for compensating the manifold pressure acting against the spray pressure.

For SC engine the boost is actually useful and it is tied up with RPM. But I still recommend using Fuel Idc as flow control, it is more precise. It take account of the air temperature raise after the SC.

The HFS2 is no longer available, future uncertain.

The HFS3 is more suited for your application. You can configure to floe based on 70% IDC and 30% boost.

[FI_Rubicon]

Originally Posted by Richard L

The HFS3 is more suited for your application. You can configure to floe based on 70% IDC and 30% boost.

Thanks for the response and support.

If I understood correctly, the system is setup by default at 50/50 (IDC/boost) and I would just need to twiddle one of the trim pots to get it to 70/30. DO I have this right?

Pardon me but would the HFS-4 be more suited to my application? Or did I misunderstand the HFS-3? I thought that the HFS-3 would read in IDC *or* boost but not both, whereas the HFS-4 reads in both signals.

Incorporating a 3-way valve based failsafe seems easy, now that I think I understand it. It seems clear how to plumb the vacuum/boost lines. I still need to figure out how to tie it in electrically. Looks like I can use a relay and the HFS controller will provide a ground trigger source to engage the failsafe.

The jeep sees some harsh environments so it would be good to get any tips on setting up maximum filtration for maximum reliability when out in the forest etc.

[Richard L]

The HFS3 can read all the identical signals such as boost and IDC as the HFS4 except you can vary the ratio infinitely. Not everyone wants to pay extra for the HFS4. In your case, you have the best.

Not sure what you meant by maximum filtration.

[FI_Rubicon]

Originally Posted by Richard L

The HFS3 can read all the identical signals such as boost and IDC as the HFS4 except you can vary the ratio infinitely. Not everyone wants to pay extra for the HFS4. In your case, you have the best.

Not sure what you meant by maximum filtration.

Ah, okay. I think I will need to twiddle that knob. So it sounds like I am an HFS-4 candidate.

With respect to maximum filtration.... Since this is a jeep that sees a lot of harsh off road environments, I want to make sure that I setup the system such that I minimize the risk of getting a clogged jet or something while out on the trail.

[Richard L]

The HFS4 has two inline filters, one in-tank and one before the flow sensor.

If you place your tank in the trunk at recommended, how likely the are dusty particles get into the tank?

[FI_Rubicon]

Well, it's a jeep wrangler so there is no trunk per se. With the hard top or soft top on, the cargo area is like an SUV. With the top off, the tank will be exposed more like it would be in the bed of a truck.

Which brings me to another question - how loud or quiet is the pump and is it tolerable in the rear cargo area of an SUV (read: no covered cargo area)?

If the included filters and instructions are adequate here then nothing to worry about, I suppose.

[Richard L]

As long as you keep the cap on and give it a wipe before opening, it should be OK.

[FI_Rubicon]

Okay, thanks. Maybe I will just make a small tarp like cover for it when I am out on the trail to keep the layer of dust off.

[FI_Rubicon]

Hi Richard,

Just a public thanks for all of the help here on the forum, through PMs and in email I ordered a new HFS-4 last night. Looking forward to it.