Our Products

We created our own unique fuel additive dosers - they work and are well proven

We have developed automatic additive dosing systems that have a range of options which cover most of the known needs to directly dose fuel tanks on completion of fuelling for small tanks, or in stages during fuelling for large tanks, or directly into fuel flows during fuelling.

Automatic Additive Dosing System 

Towai Technologies' Automatic Additive Dosers (AAD) provide an automatic and self contained system which:

  • Can receive fuel data from a wide range of sensors including fuel tank level sensors, CAN networks, electronic flow meters or Keypad Display Units.
  • Accurately dispenses the correct volume of additive into fuel tank(s) or fuel flow over a range of operating and climatic temperature conditions.
  • Supports the full range of known fuel additives with different dosing ratios and a wide range of viscosities.
  • Has three different additive tank capacity options - 5 litres, 20 litres, and 55 litres, and can be connected to an external additive tank to increase additive capacity.
  • Is self-contained within its mountings, and has power supply options of either 12 volts or 24 volts dc.
  • Covers the full range of automatic additive dosing requirements.
  • Supports connections to a vehicle onboard computer and to a wireless modem.  

Approximate installed sizes are:

  • AAD 5L       Length: 300mm  Depth: 260mm  Height:  260mm - includes mounting cradle.
  • AAD 20L    Length: 450mm  Depth: 440mm  Height: 440mm - includes mounting cradle.
  • AAD 55L    Length: 470mm  Depth: 430mm  Height: 470mm - mounts directly with no mounting cradle required.

Click Here for our AAD Product Range Brochure

Our Range of Options  

The brand names for our expanded range of Dosers, which can be supplied with either moulded Polyethylene, Stainless Steel or Aluminium additive tanks, are:

  • FTAD – Fuel Tank Additive Dosers for vehicles, vessels & machines – 20L additive tank for additive dosing ratios < 2,500:1 & 5L additive tank for additive dosing ratios > 2,500:1 – so filling should only be needed during servicing
  • BTAD - Bulk Tank Additive Dosers – for installations currently up to 125,000 litres with dosing in stages during fuelling to ensure even mixing - based on our AAD 20L additive tank
  • FFAD - Fuel Flow Additive Dosers - for fuel tankers or depots with dosing directly into the fuel flow during fuel deliveries – based on our AAD 20L additive tank
  • FBAD 55L – Fuel Flow & Bulk Tank Additive Dosers – 55L additive tank rather than a customer supplied additive tank
  • RTAD - Remote Tank Additive Dosers - SS enclosure for connecting to a separate customer supplied additive tank
  • KPAD - Keypad Display Unit Additive Dosers - for when no fuel level sensor is fitted - 20L or 5L additive tank

Note:  An additional customer supplied additive tank can be directly connected to the BTAD or the FFAD to increase the total additive capacity.

Industry Compliance

EMC  (Electromagnetic Compatibility) Compliance

Our Electronic Control Board has passed FCC Part 15, Subpart B (class A), ICES-003 (class A), CISPR 22 (class A) and CISPR 25 (class A) EMC compliance testing.

WOSL Approval

Wiri Oil Services Ltd (WOSL), which is collective of the four major New Zealand oil companies, has approved Towai’s Fuel Additive Dosers, including wiring and pipework, for installation on fuel delivery tankers.

Website Downloads Page

Our Doser software and associated documentation can be downloaded from the password protected Downloads page.

If permission to access this page has not already been obtained, then request it by emailing peter.mcgregor@hftnz.co.nz

If approved, Towai will advise you of your password for access to the Downloads page by return email.


Pricing varies dependent upon the options chosen which include:

  • Moulded polyethylene or fabricated stainless steel or aluminium additive tanks.
  • Cellular modem to enable remote communications with the Doser.
  • Remote switches and operating LEDs for Fuel Tankers.  
  • Number of solenoid valves for fuel tanks - from 1 to 4.
  • Automatic with no driver input, or if no suitable fuel level sensor is fitted then a Keypad Display Unit with minimal driver input.
  • Size of Applicator tank - 5, 20 or 55 litres.
  • Heater fitted - which maintains a minimum set additive temperature for cold climates.
  • Vehicle/machine, vessel, bulk tank or fuel flow options. 

Please contact us for pricing for your application via the Contact page.


Automatic Additive Doser units are warranted against defects in material and workmanship under normal use and service for a period of 12 months from the date of delivery to you, provided that they have been stored, installed and used in accordance with normal industry practices and conditions.

Click Here for our Full Warranty Conditions