Most cars on the road today have sequential injection systems. The older cars had bank or batch-fired multi-port (MPFI) or throttle-body injection (TBI) systems. Although all injected cars can be easily converted with a propane injection system, TBI systems generally require a fumigation (mixer upstream of the TBI) system in the conversion. In some cases, TBI engines have been converted with LPG multi-port injection conversions.
Many conversions done in the 1980s and 1990s involved Impco carburetion equipment adapted to TBI and MPFI engines with Dual Curve controllers. Autotronic Controls Corporation has since closed their Dual Curve division and Dual Curve controllers are now obsolete as well as Technocarb's EFS600 fumigation conversions. Technocarb generally recommends their SVIS Injection Conversion Kit for most older EFI engines including TBI. Since the SVIS controller does not change ignition advance, some engines may potentially be optimized for propane with Timing Advance Processsors.
A concern many people have with propane conversions is the availability of propane. Because all EFI conversions are bi-fuel, the motorist never runs the risk of being stranded from running out of fuel. The only risk is that the propane station on the trip is more expensive than the motorist's favorite station at home. In Canada, propane motor fuel stations are extremely common, comparatively more so for cheap fuel than in the USA. Many propane stations in the USA are not set up for refueling cars so their prices are often more expensive than they should be. To find a refueling station in your area or for your trip, please visit the following directories:
- US DoE Alternative Fueling Stations
- Alternative Fuel Fill Stations and Prices (also lists Canadian stations)
- Propane Gas Association of Canada - Refueler Locations (Canadian stations)
- Superior Propane - Cardlock Locations (Canadian Stations)
For trips through locations you haven't been before, it's a good idea to always call ahead to check prices, hours, and availability.
Because of the unsuitability of using LPG fumigation equipment on EFI engines, the only practical alternative is an injection conversion. For those applications that don't have a model-specific kit available, many people have been left without a viable option for converting their personal vehicles. Technocarb has created economical universal bi-fuel vapor injection conversion kits to fill this void for 3&4-cylinder, 5&6-cylinder, & 8-cylinder engines. LPG V-10 Dodge and LPG V-10 Ford conversions are also available but are somewhat more expensive due to the smaller economies of scale to produce the V-10 controller. Installing these systems is a bit more work than bolting-on an Impco mixer and converter in place of a carburetor but injection conversions work much better and are more fuel-efficient. Besides being fully OBDII-compliant (no check engine lights) and having better fuel economy, the other advantage of injection conversion systems is that they eliminate any possibility of intake manifold failures from backfires.
Windows-based configuration software is included in the package so a laptop computer and an interface cable are required to configure the conversion. We recommend using Technocarb's SVIS conversion kit. The work involved with any injection conversion is very similar to the SVIS Chevrolet Impala conversion.
Check with the emission testing authority in your jurisdiction before performing any modification. Always have your system professionally inspected and approved before putting any fuel into the new propane system.
EFI Conversions - USA
European conversion system manufacturers cater to the smaller vehicles that most people typically drive. However, due to the emission control requirements imposed by the US EPA, very few European manufacturers have any EPA-certified systems available for commercial installation in the USA. The cost of obtaining EPA-certification is extremely high ($150,000+) and the 1-year certificate only applies to a particular vehicle (model, engine, year). CARB-certification costs even more. As a result, very few EPA or CARB certified conversions are available and the few that are available are only for fleet vehicles like the Ford Crown Victoria where the alternative fuel system manufacturer has any hope of recovering its investment.
Alternative fuel system conversion shops can be fined for installing a non-EPA certified system. In states requiring CARB emission control systems, the presence of a non-certified system on an engine can potentially even cause the vehicle to fail the visual test. It is possible for individual vehicle owners to modify their vehicles as they see fit and modifications can potentially pass an emission test if the vehicle owner does not tamper with the emission control equipment. The beauty of injection conversions is that all of the vehicle's emission control equipment remains in place and fully functional. When properly configured, injection conversions can also be fully OBDII-compliant.
EFI Conversions - Canada
In Canada, European injection systems meeting EN67 can potentially meet Canadian safety standards and the emission regulations generally only require the vehicle's tailpipe emissions to be as clean on the alternative fuel as it is on gasoline.
For older carbureted cars (pre-1987), Impco carburetors can usually be retrofitted quite easily. Dual-fuel systems are a bit harder to install because a propane mixer must be mounted upstream of the gasoline carburetor and hood clearance becomes an issue. With suitable adapters and mixers slowly becoming obsolete, these types of dual fuel conversions are best done on pickup trucks and vans with plenty of hood clearance. Raso Enterprises has dual fuel conversions available for these vehicles. The challenge with dual fuel conversions is optimizing ignition timing for each fuel. For fumigation conversions, we have the AEB526N (Wolf-N) for electronic ignitions and the AEB531 (Patinos) for breaker-point ignitions.
For older carbureted cars, installing a propane injection system using the MegaSquirt® EFI Controller is another possibility. For those people who are familiar with this controller, Raso Enterprises has developed a propane injection kit, which is ideal for hot rods and race cars. It can be used in both a mono-fuel and dual fuel modes. This item is available for 4-cylinder, 6-cylinder, and 8-cylinder cars. Dual fuel (with a gasoline carburetor or EFI system) is possible with MegaSquirt's Table Switching Control capability. Our MS Propane Injection kit for 8-cylinder engines contains the following parts:
Mono-fuel (or straight) conversions are easiest to do but have more difficultly passing emission tests because emission regulations generally require ALL emission controls to be in place and functional. As such, a mono-fuel conversion will then have trouble passing a visual inspection. This is the reason that these types of conversions are recommended for off-road use only. Adding a dual fuel propane injection system to a carbureted engine will not disable any existing emission controls and so will likely not fail any emission tests (check with your emission testing authority to be sure before ordering).
While there are a few importers of propane conversion equipment into North America, offshore equipment generally can not be legally installed in new on-road conversions unless the components meet the requirements of CSA B149.5 (in Canada) or NFPA 58 (in the USA). However, for people wanting to convert their personal off-road vehicles to propane operation, the following manufacturers are most likely to have suitable kits to convert their vehicles.
North American Manufacturers
Technocarb Equipment held 44 US EPA certifications for GM, Ford, and Chrysler vehicles (which totaled more than all of the existing certifications by other manufacturers added together) until the EPA cancelled all existing EPA Certifications under Option 3 Memorandum 1A for ALL manufacturers. Technocarb is in the process of recertifying their systems to meet the latest EPA regulations.