compressed natural gas
- Thread starter k9lestat
- Start date
M35A2
Tinkerer
I've been looking into propane for a carbureted vehicle (older Jeep). MPG will be less as not as many BTUs per gallon. However, cost per mile should be much lower. Apparently a gas-only or dual-fuel setup is relatively easy on a carburated vehicle. Things are more complex with EFI. Suggest gotpropane.com for info, or perhaps some of our South American friends can chime in, as propane or CNG setups are commonplace there.
Over here in New Zealand we used to have a lot of CNG and LPG powered cars, the government even helped with the conversion cost for a while...
Ive had a couple of LPG 4X4s, but now that there are cheap diesel 4X4s everywhere you see very few LPG cars with the exception of large older V8 powered things and the odd truck.
CNG is almost dead as there are almost no fuel stations left that have it!
LPG has some disadvantages, you use about a third more volume to go the same distance as you would with petrol, so it has to be about half the price of petrol for any savings.
You also have to fit the tank somewhere, and its a big heavy tank...
LPG does work quite well for a 4X4 though, it dosent matter what angle you are on, and you usually get easier starting.
Ive had a couple of LPG 4X4s, but now that there are cheap diesel 4X4s everywhere you see very few LPG cars with the exception of large older V8 powered things and the odd truck.
CNG is almost dead as there are almost no fuel stations left that have it!
LPG has some disadvantages, you use about a third more volume to go the same distance as you would with petrol, so it has to be about half the price of petrol for any savings.
You also have to fit the tank somewhere, and its a big heavy tank...
LPG does work quite well for a 4X4 though, it dosent matter what angle you are on, and you usually get easier starting.
I've had 2 converted bifuel vehicles, both newer 1/2 ton trucks, one for business, one personal.
Overall, I loved it. IMO, the only major downside is fuel availability. CNG can be very hard to come by in certain areas of the country. Sticking with bifuel solves that, but it always feels wrong to be running on gasoline in a vehicle you've spend thousands converting to run on CNG.
On an older vehicle like yours, the installation is greatly simplified. Once you get into sequential port injection CNG systems, the tuning gets complicated and I found both my vehicles visiting my CNG tuner pretty often until all the little issues were sorted out. Often times the vehicle was working perfectly, but would throw a Check Engine light due to operating out of emissions specs (ECU would assume it was running too lean).
Tank size versus range can be a difficult decision. I had a 24.5 gallon equivalent CNG tank in my personal truck and that was just too big. I gave up more cargo space than I would have liked. In most full-size trucks, a 21 gallon tank is the way to go as it's width allows it to sit down lower in the truck bed, even allowing for a tonneau cover.
In a Suburban, you're either going to give up most of your cargo room to CNG tanks to get any significant range or you're going to mount 10 gallons of CNG in place of your spare, which cut's ground clearance and gives you an annoyingly short range. I highly recommend the first option, 18-21 gallons of fuel allows you a normal range, you'll quickly tire of filling up every 1-2 days with a 10 gallon tank.
Overall, I loved it. IMO, the only major downside is fuel availability. CNG can be very hard to come by in certain areas of the country. Sticking with bifuel solves that, but it always feels wrong to be running on gasoline in a vehicle you've spend thousands converting to run on CNG.
On an older vehicle like yours, the installation is greatly simplified. Once you get into sequential port injection CNG systems, the tuning gets complicated and I found both my vehicles visiting my CNG tuner pretty often until all the little issues were sorted out. Often times the vehicle was working perfectly, but would throw a Check Engine light due to operating out of emissions specs (ECU would assume it was running too lean).
Tank size versus range can be a difficult decision. I had a 24.5 gallon equivalent CNG tank in my personal truck and that was just too big. I gave up more cargo space than I would have liked. In most full-size trucks, a 21 gallon tank is the way to go as it's width allows it to sit down lower in the truck bed, even allowing for a tonneau cover.
In a Suburban, you're either going to give up most of your cargo room to CNG tanks to get any significant range or you're going to mount 10 gallons of CNG in place of your spare, which cut's ground clearance and gives you an annoyingly short range. I highly recommend the first option, 18-21 gallons of fuel allows you a normal range, you'll quickly tire of filling up every 1-2 days with a 10 gallon tank.
what kind of range does 18-21 gallon tank give you on the truck you have?
The MPG stays fairly close, you might lose 1mpg at most. My lifted Hemi Dodge got 13mpg before and after the CNG conversion. My stock Silverado 1500 4x4 got 16mpg in town and 19 on the highway on CNG, 16mpg and 20mpg on the highway on gasoline.
You do have to figure that only 80% of the CNG tank volume is usable due to the pressure differential required to drive the regulator. So in my Silverado, the 21 gallon tank gave about 16-17 usable GGE (Gallon of Gasoline Equivalent) of CNG, which translated to a range of about 300 highway miles. Around town, I'd usually fill up somewhere around 225 miles.
chasespeed
Explorer
One of the companies I worked for, had bi-fuel, and just LP powered service trucks, as well as diesel trucks.
I am all for it after seeing oil come out, at 6k miles, and still being carmel colored.
The newer SRW trucks(6.0gas engines), were getting a new type of system, that didnt give the ECM fits, and from what I was told, was EPA/CARB okay.
I would stick with propane power, over nat gas though. easier to find a fill station, bulk plant, etc. but, unless you're getting your LP at or near rack price, its almost not worth the cost to convert.
Chase
I am all for it after seeing oil come out, at 6k miles, and still being carmel colored.
The newer SRW trucks(6.0gas engines), were getting a new type of system, that didnt give the ECM fits, and from what I was told, was EPA/CARB okay.
I would stick with propane power, over nat gas though. easier to find a fill station, bulk plant, etc. but, unless you're getting your LP at or near rack price, its almost not worth the cost to convert.
Chase
LandCruiserPhil
Expedition Leader
Clean Energy is building 70 CNG stations this year and 80 in 2013 coast to coast.
HillbillyfromAL
Explorer
Just out of curiosity have you thought about a diesel swap? A 6.2 or 6.5 would definitely increase your mileage, and you could use bio fuel ie French fry grease.
keezer37
Explorer
Clean Energy at Pilot Fly J stations
Shell is expected to be working with Travel Centers of America soon.
So far, Exxon's not playing.
I believe the speed of the buildout is due to wanting to see demand for their investment and of course who's gonna buy the vehicles without the convenience of the stations. Typical slow start. Once the two sides reach the comfort zone, things should build out faster. Actually adding nat gas to existing stations is not difficult nor expensive. Westport has some info, cost calculator, and useful links to CNG stations.
1stDeuce
Explorer
A station just went in right by my place of employment. I was thinking that it would be a cost save to convert the Jeep to use CNG... I can find what seem to be good kits for $800 or so, and a 5-6 gge tank with several years left on it for another $400. CNG at the local station is $2.50/gge, while gasoline is about 3.70 a gallon right now. Given my 40 mile round trip daily commute, and my jeep getting ab out 17mpg, It would take me about 16k miles to pay for $1200 worth of conversion... That's about two years of work and back, given that I drive my truck some of the time too. And I'd have to fill the tank about every two days, since I can't fit (Or afford) a big tank in the Jeep.
Which means that I'm not terribly motivated at the moment, since I don't have a lot of cash burning holes in my pocket. If I lived in Cheyenne, CNG would be more viable, as it's barely over $1 a gallon!! I'll keep waiting, and make the switch at some point hopefully.
Chris
Which means that I'm not terribly motivated at the moment, since I don't have a lot of cash burning holes in my pocket. If I lived in Cheyenne, CNG would be more viable, as it's barely over $1 a gallon!! I'll keep waiting, and make the switch at some point hopefully.
Chris
LandCruiserPhil
Expedition Leader
The money saving is with long haul rigs. Semi trailers account for 25% of the US oil demand. Frieghliner recently did a coast to coast test and saved $1000 in fuel cost. But to make it happen sadly we need the support from top goverment. Change may be coming.:wavey: