Prins LPG conversion kits VSI-2.0 and VSI-3 DI
Prins LPG conversion kits from HybridSupply come in two system lines: VSI-2.0 LPG for port injection (MPI) petrol engines with 3 to 8 cylinders, and VSI-2.0 DI / VSI-3 DI for petrol direct injection engines, with one kit per vehicle make. As a wholesaler, HybridSupply supplies installers, garages and LPG specialist dealers with these kits, plus Prins spare parts, the PDT mini diagnostic interface and R115 documentation.
More sub categories:
Prins VSI-2.0 and VSI-DI: systems and scope of supply
Prins Autogassystemen is based in Eindhoven (Netherlands) and is part of Westport Fuel Systems. According to the manufacturer, VSI stands for Vapour Sequential Injection: the LPG is injected in vapour form, one cylinder after another. The category contains three product groups:
- Prins VSI-2.0 LPG: kits for 3, 4, 5, 6 and 8 cylinders. Each kit includes the ECU, eVP 500 reducer, main and injector wiring harnesses, injector rail, Keihin filter with pressure sensor, switch, hoses, pipe, small parts and warranty card; a MAP sensor is optional.
- Prins VSI-2.0 DI / VSI-3 DI: front kits for petrol direct injection engines, listed as one item per vehicle make from Alfa Romeo to Volvo. Each product page lists the covered vehicles by model, engine size, output, model years, engine code and emission standard. The current kit version is always supplied, at present VSI-2.0 DI or VSI-3 DI.
- VSI-2.0 electrical kit for 8 cylinders: ECU, main wiring harness, KN8 injector harness and switch for repairing existing VSI-1 systems. According to the product data, the ECU can also be used on smaller engines.
Tank, multivalve and filling point are not part of the Prins kits. You can add them from LPG tanks, Multivalves 67R-01 and LPG filling points. How Prins compares with other manufacturers is covered in the article Which LPG conversion kit manufacturers are there?
Choosing the kit: system line and injector size
The system line depends on how the petrol engine injects fuel: VSI-2.0 LPG is designed for port injection (MPI), while VSI-2.0 DI and VSI-3 DI are intended for petrol direct injection (DI). Whether a direct injection engine is covered can be checked by engine code in the vehicle table of the relevant make.
For the VSI-2.0 LPG kits, injector size depends on the number of cylinders and engine output. The table shows the range given in the product data; the limits of the intermediate sizes are listed on each product page:
| Cylinders | Injector sizes | Smallest size | Largest size |
|---|---|---|---|
| 3 | 32, 43, 52, 63 cc | 32 cc: below 39 kW | 63 cc: below 75 kW |
| 4 | 32, 43, 52, 63, 73, 82 cc; 52 to 82 cc also as BOXER version | 32 cc: up to 50 kW | 82 cc: up to 160 kW |
| 5 | 52, 63, 73, 82, 100 cc | 52 cc: up to 100 kW | 100 cc: above 200 kW |
| 6 | 43, 52, 63, 73, 82, 100 cc | 43 cc: below 90 kW | 100 cc: above 240 kW |
| 8 | 63, 73, 82, 100 cc | 63 cc: below 200 kW | 100 cc: above 320 kW |
Technology and components of Prins VSI systems
- eVP 500: The Prins eVP 500 LPG reducer (vaporiser) works without a diaphragm, has an integrated shut-off valve and an outlet pressure set by software; no MAP connection is required. According to the product data, it is rated for up to 370 kW and approved under E4 67R-01 0358. Repair kits for Prins VSI reducers are listed under LPG repair kits.
- Injector rail and filter: According to Prins, the injector rail was developed together with Keihin. Filter sets for Prins VSI and the eVP reducer are in the gas filters category.
- ECU: According to Prins, the AFC ECU controls the changeover strategy, fuel quantity, safety functions and diagnostics; the AFC 2 handles up to 8 cylinders. Replacement ECUs for VSI-2.0 and VSI-DI are under ECUs.
- Emulators for VSI-DI: Prins VSI DI emulators of the GEN2 generation are available in several types for 4 and 6 cylinders under injector emulators.
- Regulations: According to Prins, the VSI-2.0 system complies with UN ECE Regulations R67-01 for LPG components and R115 for retrofit systems and is suitable for Euro 5 and Euro 6 vehicles.
For installers: approvals, diagnostics and spare parts
For vehicles registered in Germany, HybridSupply provides the individual emission confirmation (EAB) or the R115 documents for the VSI-2.0 LPG kits; you apply for them after ordering, quoting the shop order number. For Prins systems not ordered together with a kit, the PRINS individual exhaust emission confirmation / R115 is available. Which documents belong to an R115 conversion is summarised on the page R115 useful information.
For diagnostics and calibration, the PDT mini diagnostic tool kit connects the ECU to a PC: a USB interface with a 380 cm cable for Windows 10 or later, detected automatically from Prins diagnostic software V2.0.1.0. It is not compatible with the older PDT.
All Prins items, from the eVP 500 to KN8 and KN9 wiring harnesses, switches, brackets and the VSI-2.0 service book, are shown in the Prins manufacturer list. The additives Prins ValveCare and InjectorCare are under ValveCare & InjectorCare; the InjectorCare instructions are available in German, English, Spanish, French and Dutch under Downloads. Private drivers looking for a Prins conversion can use the contact form: HybridSupply puts them in touch with a dealer and an installation partner.
Frequently asked questions about Prins LPG systems
What is a Prins LPG system and how does it work?
A Prins LPG system is a retrofit kit from the Dutch manufacturer Prins that lets a petrol engine also run on LPG (autogas). The VSI system vaporises the liquid LPG in the eVP 500 reducer and injects it in vapour form, cylinder by cylinder, through its own injector rail; the AFC ECU calculates the gas quantity and switches between petrol and LPG. VSI-2.0 LPG is used on port injection engines, VSI-2.0 DI and VSI-3 DI on direct injection engines.
Which Prins kit is suitable for direct injection engines?
Petrol direct injection engines need the Prins kits VSI-2.0 DI or VSI-3 DI; VSI-2.0 LPG is designed for port injection engines. According to Prins, the VSI-3 DI uses less than 5% petrol in LPG mode. Whether an engine is covered is shown in the vehicle table of the Prins DI kits, listing engine code, model years and emission standard.
Are Prins systems also available for CNG?
Yes. According to Prins, the VSI system also exists as a CNG version, in which a CNG pressure regulator replaces the eVP 500 reducer and a CNG tank replaces the LPG tank. This category contains the LPG kits; for existing Prins CNG systems, the Prins CNG reducer is available as a spare part.
Which approvals do Prins conversion kits have?
According to Prins, the VSI-2.0 components meet UN ECE Regulation R67-01 and the system meets R115 for LPG retrofit systems; the eVP 500 reducer carries approval E4 67R-01 0358. For registration in Germany, HybridSupply supplies the EAB or R115 documents via the category Emission confirmations / R115. In other countries, the national rules for registering an LPG conversion apply.
Which software is used to set up and read Prins systems?
Prins systems are calibrated and read with the Prins diagnostic software. According to Prins, one tool covers all Prins systems and offers an actuator test and freeze frame data for the first two fault codes. The PDT mini USB interface connects the ECU to the PC; it is listed under Software & interfaces.
How much standby current does a Prins LPG system draw?
According to Prins, the AFC 2 ECU of the VSI-2.0 system draws less than 1 mA in sleep mode. The manufacturer’s brochure gives no figure for older ECUs such as VSI-1.
Where can garages buy Prins kits and spare parts?
HybridSupply in Lübeck (Germany) is a wholesaler of autogas components and supplies Prins VSI-2.0 and VSI-DI kits, Prins spare parts, the PDT mini interface and R115 documentation, alongside AEB, BRC, KME, Landi Renzo, Lovato and STAG in the LPG & CNG kits range. Installers, garages and dealers order through a business account, which shows net prices after login.