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---- 806-065 ----- HFS4-v3.1 system for DI engines The most advanced PWM system to date. **(4-5 weeks)**

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5.10 KGS
Estimated Shipping Time:
*** 3-5 weeks *** (many apologies)
Calculated at checkout
* led colour:
Std. Jet sizes or select any 3:

(Maximum Size: . Type: )
Universal or Car model specific:
Estimated HP?:

(Maximum Size: . Type: )
Model of car if not selectable above:

(Maximum Size: . Type: )

Product Description


** Please note the HFS4 supports all DI engines under the "universal" option

Update: we are offering a 3000cc/min pump option for 1000hp+ engines. It is not recommended for engines below 950hp. When this option is selected, we will include the 1600cc FAV and large flow sensor tube.  

In keeping with the excellent integration with the Di engines, the latest HFS4-v3.1 is packed
with even more capabilities. 

An additional AUX input (0-5V) allows the system to alter flow based on air, exhaust temperature or air fuel ratio. If one of signals exceeds a pre-set level, failsafe will be triggered to protect your engine. The standard turbine flow sensor based failsafe remains.

A “Fast Acting Valve” (FAV) controls the delivery rate based on a PWM signal from the 

HF4 controller. The FAV enables superior linearity and atomization across the entire injec-
tion range. A constant line pressure (160 psi) is provided by an Aquatec pump working
in the “by-pass” mode. This method is very similar to the conventional fuel injection sys-
tems, allowing wide dynamic range and lighten responses to engine load.

The combination of quality components, superior method of delivery and a precision Di
signal decoding algorithm, the HFS4-v3 remains to be the most advanced and capable
water/methanol injection system in the world to date.

Lastly, we have oulined a capability and price comparison chart here against some popular brands (subject to currency fluctuations). 


User manual: version3 (serial no. 121500 on)

User manual: version3.1 (serial no. 121750 on)

User manual: version3.12 (serial no. 122228 on)


 Choosing water/methanol flow for your application:

  • 100% water:  10-15% water/fuel ratio or 0-5-1cc per BHP 
  • M50/W50: 15-20% MW/fuel ratio or  1-1.5cc per BHP
  • 100% methanol: 20-25% methanol/fuel ratio or 1.5-2cc per BHP 

Selecting the correct jet or jets for the required flow: 

  • Calculate the "true" pressure by subtract the 160psi pump pressure by the "boost" pressure
  • Select the jet or jets from "true" pressure from the chart below (compensated).
  • Always pick the next size up or allow 10-15% more to allow more headroom.  

Notes on Direct Port application:

  • Divide the final flow amongst the DP jets
  • Allow one extra jet for IAT cooling, normally twice the size of the DP jet.  (re-calculate DP jet)
  • Ideally the DP jet should have an external or internal check valve to minimise vacuum induced after-spray. 
  • Insert an "high pressure inline filter" before the FAV to minmise the risk of clogging. 
  • Order extra jet adaptors (806-357N) - Std. kit comes with two.
  • Recommend using the aquamist Hex Manifold. (comes standard with all compression fittings)
  • Optional PTFE (4mm) is optional but ideal for combating the heat in the engine compartment. Essential for track or rally events   
  • Keep hose run to the DP jets as short as possible. Not necessarily need to be "equal" length.    
  • Contact aquamist for your unique application before ordering.  




Other Details

Full kit without water tank.
Std. jets:
0.8, 0.9, 1.0mm (if not specified with order)
richard@aquamist.co.uk (purchased from here only)

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