Propane Injection

fraso · April 17, 2008

With fuel prices going continuing to increase, many people seem to be overlooking the “old” alternative fuels like propane and CNG. For modern EFI engines, propane injection conversions can make a lot more sense than hybrids or E85. The payback on a conversion obviously depends on the amount the vehicle is driven as well as the difference in price between gasoline and the alternative fuel.

Modern propane injection systems get propane economies of around 90% of the vehicle’s gasoline economy. Although the installed cost of a propane injection conversion can run upwards of $4500, the fuel savings can still make for a very quick payback on pickup trucks used in fleet service. In Ontario, gasoline is now selling for over $1.15/litre ($4.35/gallon) while propane is still selling for around $0.60/litre ($2.27/gallon) or less. In the Toronto area, propane is usually cheapest around the airport. On-site refuelling is even cheaper and propane can cost as low as $0.40/litre ($1.51/gallon).

While it might be tempting to save some money on the conversion by bolting-on a fumigation system, it is much more costly in the long run. Besides having lower fuel economy (75-80% of gasoline economy) than an injection conversion, this type of conversion runs the risk of intake manifold backfires. Besides, injection systems switch back and forth between fuels completely automatically and transparently and don’t give any OBD fault codes.

While EPA-approved kits are only permitted for commercially installed systems in the USA, owner-installed kits are not prohibited. Often, the installing mechanic and vehicle owner will work together to do this type of conversion because the work would then be considered a repair rather than a conversion. The reason injection conversions are more expensive than the old bolt-on Impco fumigation conversions is that there is a lot more work involved. However, the underhood equipment is comparable in cost to a fumigation kit. The 8.1L SVIS installation manual shows the work involved in a conversion. A conversion on a truck would be very similar to the propane conversion done on a 2003 Impala.

Draenor · April 17, 2008

Take your sales crap to the Blundra forums.

fraso · April 17, 2008

I happen to be most familiar with Technocarb systems. However, there are several cng/propane system manufacturers or distributors in North America:

http://www.baftechnologies.com/

http://www.baytechcorp.com/

http://www.cleanfuelusa.com/lpi/lpi_system.php

http://www.ecofuel.com/

http://www.hybridfuelsystems.com/

http://www.jasperengines.com/

http://www.parnellusa.com/

http://www.prins-lpg.com/en/general/north_...rket/index.html

sam5828 · April 17, 2008

[email protected] · December 17, 2008

I've seen gasoline powered gm trucks converted to dual fuel propane. There's a small shop in Mississauga Ontario that's been doing it the right way for years. On the bigger gm engines they use two control boxes and the injection system is run by the same computer as in the truck. It's still an expensive modification, but trucks use a lot of fuel. It doesn't work on a deisel. Even with gas prices dropping, propane is always twenty cents less than gasoline. Gotta help the bottom line.

DofD · December 17, 2008

Hi there and welcome to GM Trucks!

I had a propane conversion on my '90 Silverado Sport Side. While propane is cheaper, the mileage and performance really sucked.

txab · December 17, 2008

Hi there and welcome to GM Trucks!

I had a propane conversion on my '90 Silverado Sport Side. While propane is cheaper, the mileage and performance really sucked.

+1 on the mileage and performance sucking

ZZ327 · December 18, 2008

Id rather go with my homemade hydrogen injection setup

[email protected] · December 18, 2008

Hi there and welcome to GM Trucks!

I had a propane conversion on my '90 Silverado Sport Side. While propane is cheaper, the mileage and performance really sucked.

That's too bad. Those systems usually cost around $3500 including tanks. I've driven a 2007 Silverado with a Sequin propane conversion and performance was up around 15%. Any of those systems should be fuel injection, dual fuel.

Did your's require starting on gasoline then switching to propane once the coolant is hot?

Many had the old fumigation style system, famous for a backfire when you shut off the engine. (popping sound).

DofD · December 18, 2008

It was a conversion just to propane, no gas, on a 5.7L TBI engine. When I did it in 1990, it cost about $1900 including the tank. The tank held about 70 litres and I would only get about 250km before needing to refuel. I also lost about 15% in performance. I didn't run into the backfiring problem until the diaphragm needed replacing.

[email protected] · December 18, 2008

It was a conversion just to propane, no gas, on a 5.7L TBI engine. When I did it in 1990, it cost about $1900 including the tank. The tank held about 70 litres and I would only get about 250km before needing to refuel. I also lost about 15% in performance. I didn't run into the backfiring problem until the diaphragm needed replacing.

Yep, that sounds about right. There's still guys looking to put those old systems on used. Fumigation type is kind of a joke now. Most propane repair shops will fix them for you, but nobody's installing anything but the fuel injected ones in my area.

I see where some new gm tow trucks are being converted to dual propane now. But I don't like to see the tanks mounted on top. There should be a way to keep them under the vehicle.

svensk · December 19, 2008

schwan's did one thing right when they purchased Bi-Phase. Those propane powered 8.1L topkicks had some scoot.

[email protected] · December 28, 2008

schwan's did one thing right when they purchased Bi-Phase. Those propane powered 8.1L topkicks had some scoot.

Could have saved themselves a lot of money. All that technology is available from suppliers as parts, from around the world. Most of it is being upgraded monthly. The best injectors are quiet, no noise. I don't have any experience with Bi-Phase product, but are they quiet? How long do the injectors last?

mattgob86 · January 10, 2009

Schwan's also uses their propane to keep their freezers cold.

dietz4ibanez · January 10, 2009

With fuel prices going continuing to increase, many people seem to be overlooking the “old” alternative fuels like propane and CNG. For modern EFI engines, propane injection conversions can make a lot more sense than hybrids or E85. The payback on a conversion obviously depends on the amount the vehicle is driven as well as the difference in price between gasoline and the alternative fuel.

Modern propane injection systems get propane economies of around 90% of the vehicle’s gasoline economy. Although the installed cost of a propane injection conversion can run upwards of $4500, the fuel savings can still make for a very quick payback on pickup trucks used in fleet service. In Ontario, gasoline is now selling for over $1.15/litre ($4.35/gallon) while propane is still selling for around $0.60/litre ($2.27/gallon) or less. In the Toronto area, propane is usually cheapest around the airport. On-site refuelling is even cheaper and propane can cost as low as $0.40/litre ($1.51/gallon).

While it might be tempting to save some money on the conversion by bolting-on a fumigation system, it is much more costly in the long run. Besides having lower fuel economy (75-80% of gasoline economy) than an injection conversion, this type of conversion runs the risk of intake manifold backfires. Besides, injection systems switch back and forth between fuels completely automatically and transparently and don’t give any OBD fault codes.

While EPA-approved kits are only permitted for commercially installed systems in the USA, owner-installed kits are not prohibited. Often, the installing mechanic and vehicle owner will work together to do this type of conversion because the work would then be considered a repair rather than a conversion. The reason injection conversions are more expensive than the old bolt-on Impco fumigation conversions is that there is a lot more work involved. However, the underhood equipment is comparable in cost to a fumigation kit. The 8.1L SVIS installation manual shows the work involved in a conversion. A conversion on a truck would be very similar to the propane conversion done on a 2003 Impala.