Decreasing Flow as I reach redline.

[m.s4]

I'm running the HFS-3 in IDC with 2 x .8 mm jets.

It seems (per Bar indicators on the gauge) that it actually decreases flow as I build my RPMs.

It is my belief that it is suppose to increase with IDC?

[Richard L]

Can you ensure the red led only just come on with the "gain" trimmer at red line and no further.

The reason for this is to do with steady flow of a non-pulsing FAV. pulsed flow tend ro read higher by a turbine flow sensor. If you like more flow, add more jets. The system can handle up to 3x 1mm jets, about 1500cc/min.

[rs4steve]

i have the same problem as the revs get close to red line the flow drops off on the gauge ,the red gain light comes on pretty much as i hit the red line , did you ever get to the bottom of this ?

ps what car was the system fitted to out of interest.

[Richard L]

I can siggest a possible reason for this.

As the inline valve IDC is approaching 100% Duty Cycle, the pulsing effect on the delivery line begins to drop until there are no more pulse when the inline valve reaches a static state.

The turbine flow sensor will read lower as the valve is approaching static or 100% open. you will hear the valve gets quieter and less whipping on the line between the jet and valve. I suggest reduce the gain before the <95% red led lights up. I assure you you will not get less flow.

As soon as I have a moment, I will do some test to verify this.

[bananas]

For what it's worth, I had this same issue when at high boost (25-30psi). I've narrowed my problem down to an air pocket or bubble. Fully repriming the pump seems to have solved the problem. If I let my meth level get too low, the problem reoccurs.

I also had this symptom when the fittings prior to the pump were not fully tightened; during a test I could see air bubbles entering the nylon hose at the loose fitting.

Now the flow meter seems to show approximately the same number of bars when I'm between 60%IDC and 90%IDC.

[Richard L]

If the flow meter show the same amount of flow at top, try backing off the IDC gain a bit. It is not a good idea to have the red led light up.

Another possibility, if you dial in a x1.5% gain anfd your fuel injector run quite high DC%. The HFS-3 will max out much earlier. Cehck the volatge on test pin18. Those are your fiinal W-IDC signal before the FAV. 0-5V = 0-100%.