Aquamist HFS-4 Water / Meth Injection System

Aquamist HFS-4 Water / Meth Injection System
Aquamist HFS-4 Water / Meth Injection System

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Our Price: $842.76

Availability: Usually Ships in 1 to 2 Weeks
Part#: 806-084

Gauge Color*:

First Jet*:

Second Jet*:

Third Jet*:

The Aquamist HFS-4 brings never before seen features to the water alcohol injection market. The HFS-4 is the most capable water/alcohol injection system in the world and features:
  • Auto sensing inputs for conventional and Direct Injection applications
  • User adjustable proportioning of IDC to Boost inputs for tuning the injection curve
  • New flow-sensor hardware and mapping features for the best failsafe and user interface
  • Added functionality for interfacing with many standalone EMS and piggy-back systems

Built on the foundation of the rock-solid HFS-3, the Aquamist HFS-4 system adds new features to make it the most advanced system Aquamist has ever produced. The most exciting feature of the HFS-4 is the user adjustable trimming of boost and IDC inputs. This gives the user infinite adjustability of the injection curve.

h4 controller Aquamist HFS 4 Injection System

In conjunction with the boost (Map Sensor) input that can be mixed with the IDC signal, the boost input can be scaled with a link on the back of the controller. The options are 2bar, 3bar, and Absolute.

The Aquamist HFS-4 also has 3 fixed flow maps with expanded range for one through multiple jets. This expanded range ensures the HFS-4 can handle any flow rate the pump and valve combination can throw at it.

The HFS-4 continues the tradition of PWM valve injection which is unmatched in the industry. The PWM injection provides superior control of the injection amount allowing precise mapping of the injection curve with load. The effect on the vehicles AFR are consistent in any gear and load situation providing for optimum driveablity and performance.

The Aquamist HFS-4 also features the best flow sensor in the world for the application, made in-house at Aquamist, capable of flowing ANY water or alcohol mixture or concentration. This unit has been produced and continually developed for over a decade and thousands of units.

Integration with standalone EMS or Piggy-back systems has never been easier. With the variable input, the system can be driven with either a PWM or 0-5V signal. The unit also has 0-5v and raw pulse outputs from the flow sensor for feedback to the control system.


The system comes with three jets sizes .8mm, .9mm and 1.0mm as standard. You can pick any three sizes from the drop down menu. .3mm jets maybe substituted for an additional charge.

Choosing Not Required for the second jet option also deletes the tee and jet adapter along with the second jet. You will only be able to install 1 jet in your setup if you delete the second jet from the options.

Choosing Not Required for the third jet option only deletes the third jet.

Calculating Jetting:

Calculating jet sizing for Aquamist systems is quite easy:

1) First, you will need three pieces of information. Fuel injector size, number of cylinders(hopefully this one comes easy) and peak boost pressure.

2) Take the number of cylinders and multiply by the injector size. For example, let’s use a 4 cylinder with 800cc injectors. This car would have a total of 3200cc of injectors.

There is a general rule of thumb for injection. Three guidelines are below:
For 100% water target 10% – 15% of fuel flow
For 50/50 mix target 15% – 20% of fuel flow
For 100% methanol target 20% – -25% of fuel flow

For this example we will use a 50/50 mix. So find the range of jetting you need by the following:
3) Multiply your total fuel injector number from step 2 by 15% and 20%.
3200cc x 15% = 480cc
3200cc x 20% = 640cc

4) Subtract your peak boost pressure from the system running pressure on the chart and find the appropriate jetting range.

For the example being discussed we want to target 20% which would be 640cc. We also know our peak boost is 30psi. The new Aquatec pumps run at 165psi, the older Shurflo pumps at 125psi. We have a brand new HFS-4 installed in our test car so we use the 165psi starting point.

4) We start at the 165psi line, and subtract our 30psi boost pressure. This means we need to look at a phantom line of 135psi. So we have our 640cc target, we look down the columns and estimate that between the 130 and 140 columns 640cc is going to fall around…….wait, it’s off the chart. We need to use two jets. So, we split the 640cc in half and see that 320cc falls between the 130 and 140 columns right right between the .7mm and .8mm jet range. In this instance we will pick two .8mm jet as we can always trim the flow down with the gain functions.

Now, the hardest part is finding a spot for two injectors in the intake system.

IMPORTANT NOTE It is best to test your jetting into a container and measure the flow. Since every build and configuration is different this will be your best measure of the system performance.

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