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Compressed natural gas, viable option?


Guest TeamNissan

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Guest TeamNissan

I have read some other members begin to delve into cng as a option before but I really wanted to start a thread to pool info, opinions and links about the subject.

 

120 octane? half the cost of petrol? fill at home? barely lower millage then petrol? insanely clean? There are a million facts I'm not 100% on but 90% of what I read and hear I love.

 

My question on feasibility would be how tunable is the system at all? Could a after market ecu be made to work? How about keeping the entire petrol set up and just adding the cng making a duel fuel z. Duel msns? 2 dif maps since cng octane is so much higher?

 

How do cng cars drive? I hope not like propane

Any tax incentives on converting to duel fuel? I know there is for buying new.

 

I have seen some diagrams and the system looks so simple... a tank a single tb injector type distribution system a regulator... Is it that easy?

 

Well I'm already ranting, just excited over the prospect. I hope we can get this snow balling asap so I can get learnin* lol.

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Guest TeamNissan

Ya there are alot of city vehicles around the tristate are running on them as well, like dodge v8 rams and ford f150s go dirt cheap. I wonder how cng will respond to boost though.....

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I will get some of the links that I have gathered ith CNG/LPG vehicle conversions and post them up here.

 

This has been a pipe dream project of mine since I was 13 years old; I have looked into both an economy-minded, simple TBI type setup as well as the possibility of using it in a high performance application. I haven't done anywhere NEAR enough research to know enough to SAY anything about the idea, yet.. but I am in love with it and want to see this thread blossom.

 

I will respond once I have time to go through my histories and bookmarks and private messages, and list the links.

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I have know people who drove carb'd dual fuel pick up trucks as their daily driver. The system had a manual dashboard switch to select between a standard gas carb OR the the CNG.

 

I am not sure where you get the "half the cost of petrol" from. I would have to see some numbers before I believe that one.

 

And the fuel at home things are still pretty experimental and pretty damn expensive. I think I read somewhere the Honda system was in the neighborhood of $6000.

 

Aftermarket ECU's could work, but you need a different stoic metric ratio with CNG than the 14.7:1 needed with gas. Do a google search on flex fuel vehicles to get the proper mixture.

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CNG, thorough the home-filling option costs around 40 cents a gallon for the equivalent energy (about 28cfm of CNG for the same BTU input of a gallon of gasoline). Commercial CNG is available from anywhere from 80 cents a GGE (Gas Gallon Equivalent) to around a 20% discount over local Petrol Prices---the cost of the CNG is dirt, really, anything over compression costs is pure profit for the vendors. Some make more than others.

 

As for "I hope it doesn't drive like propane"---you mean a converted Gasoline to Propane Conversion. Dedicated Propane and / or CNG vehicles SMOKE Petrol engines. My F250SD Pickup had as much torque with CNG as my old F350SD 7.3L Powerstroke Turbo did! Climbed Palomar Grade on I15 easily---the petrol truck had to drop out of Overdrive to keep up with traffic. When you have a 13:1 cr motor, you got torque!

 

As for flexible fuels, it gets touchy, In CA if you have ANY fuel in the vehicle other than the CNG or Propane, you are not eligible for the HOV lane stickers. Add to that the compromise in performance you will have to get to even have a car that will run on Gasoline and CNG---retard the timing, drop the compression ratio, or both!

 

Dedicated and Purpose Built is the way to do it! As a commuter car daily driver you can't beat it. Of the tens of thousands of miles I put on the CNG Vehicles I used while working for Clean Energy Fuels (see their website) I never was stranded, and once you get a guide to where you can fuel---it really becomes nice to be able to zip around in the Carpool Lane and smile when the CHP pulls you over. Ever have a cop APOLOGIZE for pulling you over? I had it happen regularly, and it was a big PERK to driving a CNG vehicle! LOL

 

There is a company AFV (Alternative Fuel Vehicles) on Gothard Street in Huntington Beach CA that specializes in conversions. If you build the engine properly (13:1 CR at least) the conversion process will give you a vehicle with better performance than a Petrol Vehicle, comparable MPG, with the only tradeoff being range. You will be limited depending on what size tanks yo ucan fit in whatever chassi you have. My F250 was around 275 miles to empty, and E350 Van about 350. Compared to my Diesel F350 at almost 575 miles to empty, and my Current F250SD Petrol with the 5.4 SOHC engine at close to 400, it's more of an 'around town' kind of proposition.

 

Smaller cars with smaller engines will go similar distances. I believe the Honda Civics were around 275 on a fillup. Crown Vics as I recall, though only went 150 miles, unless you filled the trunk with the extended fill tanks, then you were good for 250 or 300 miles to empty.

 

It just takes som modicum of route planning.

 

Hell, you can buy a complete Modular Ford SOHC CNG Engine Assemly complete with 13:1 Forged Slugs right from the Ford Parts Catalog!

 

Talk about a Hybrid Z waiting to be made!!!

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Guest TeamNissan

Thank you tony, I have been waiting all this time for you to chime in since your actually the one who got me into the idea.

 

When I said I hope is doesnt run like a propane engine I didnt mean performance at all which I should have made more clear. I mainly meant the sound and smell. Every propane vehicle I ave had experience with sounds really bad and smells even worse lol. Idk if that just my experience or the way it goes. Esp forklift when they zoom off and your standing around them they stink to high heaven.

 

I have also noticed how reg available these factory and state converted cars are. Thats why I ask about how tunable stealing a stock say ford v8 and swapping all the stuff over would be. Or would it be better to go with injectors and a stand alone just for it?

 

I also realize that there would be SERIOUS compromises in having a engine that could run both but I'm not interested in having both fuels run well. Would be really nice to have reg gas aval in case you cant find a cng fill. Even if its built all out for cng but could still run pooly on gas.

 

I would def be interested in a turbo application, have any info or opinions on that? thnx

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I am sorry I am dozing about posting any links up here, I'm gonna have to go through and find what I have read again the hard way because I appear to have failed to bookmark any of it.

 

Most of what I have found has been merely information convincing me that it cannot be incredibly difficult to do; as I believe I said above, the LPG vehicle has been a dream of mine since I was 13 or 14.. so roughly half my life at this point. Honestly, I had never considered a PERFORMANCE engine running propane until very recently, when I learned the anti-detonation qualities of the stuff.. TeamNissan, please forward me anything your research turns up; I would LOVE to find a book somewhere, or ANYTHING that would help educate me furhter in this field. Unfortunately, most web links I was able to find were predominantly trying to sell me packages for specific vehicles, most of which weren't automobiles... :rolleyesg

 

I am mind-bogglingly interested in the concept of a turbocharged LPG or CNG (LPG would be preferable to me, for fueling convenience purposes only) L-powered Z... it is going to be such a long time before i get to the engine on my car that I have ALL the time in the world to research the project, but all of my attempts to find more info thus far have hit dead ends.

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lpg is very popular in australia,has very good high performance turbo potential however a couple of obstacles to overcome if you are going to make the most of it

you need to run twin mixers to supply enough gas for over 350hp,this means twin tanks or illegally running a second outlet from one tank or enlarging the single line

you need to run either dedicated gas carbs(GRP over here) or gas injection(injectors not big enough for more than 60hp per injector) if it is going to be high performance tuneable

ideally you need to run a stand alone ignition computer

lpg over here is 100 octane(used to be 110 until greedy multinationals figured out they could mix it with cheap butane and make the same money off the public)

currently our govt is giving 100% rebate for converting to LPG,it costs about 60c per litre as oppose to $1.40 for decent petrol.....so lots of incentive to make the move

have a look on this forum for guys running RB30 turbo lpg in 3000lb cars doing 10 second 1/4 mile times

http://www.calaisturbo.com.au

only down side in a Z is tank placement,60L donut tank in the spare wheelwell is the tidiest but not a lot of range,other than this it's get out the oxy torch to make more room in the back where the fuel tank was

keep us posted

paul

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LPG (Propane) is the fuel of choice and legislation at the Speed Zone in Hacienda Heights. These are small Propane Powered Dragsters...V8 Powered, over the valve cover headers and mufflers. They have a standard sportsman tree for launch, and in about 100 feet do zero to 60 in around 3 seconds.

 

Propane Powered....

 

Now as to the smell...my CNG Catalyzed vehicle smelled like steam. That's it. Steam. You have to understand that adulterants and refining byproducts in Gasoline make for a lot of the smell...sulfur mostly. That gives you the rotten egg smell.

 

Forklifts are (if they are older) usually carburetted, and not fuel injected like newer ones. The newer fuel injected LPG forklifts are so safe OSHA lets you use them indoors. If you are smelling something, it's something along for the ride, or simply a carburetted truck running way rich (which they tend to do!)

 

The old days of carburetted systems are thankfully gone. The advantage Propane has over CNG is that you can get MASSIVE range---comparable to gasoline. As stated the standard LPG tanks are all over in Japan. A 60L Donut tank would be MORE than enough to get comparable range as a petrol version.

 

CNG range will probably be half that...5 or 6 GGE is my guess with the smaller 3600psi tanks mounted below a flattened floorboard (no spare tire).

 

Think about it: a 10:1 CR Turbocharged Engine...

 

Think about it.....

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http://www.propanecarbs.com/impco/125carburetor.html

http://www.eere.energy.gov/afdc/progs/res_guide.cgi?LPGRG

http://www.lngplants.com/carbturbo.htm

And this one is interesting since it lists current Nissan Products for Conversion:

http://www.vags.net.au/LPG-product-range.htm

http://www.eere.energy.gov/afdc/pdfs/conversion.pdf

http://www.primaryinfo.com/cngkits.htm

http://www.impco.co.jp/index_e.htm

http://www.impco-beru.nl/pdf/Leaflet%20CNG-1.pdf

 

And if you look at #7 on this list, you will find the company where I formerly worked, actually I did work at #8 as well... They are now in Cerritos apparently.

http://www.google.com/Top/Science/Technology/Energy/Transportation/Natural_Gas_Vehicles/

 

"Google Is Your Friend"---you just need to know what to look for!!! LOL

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http://www.propanecarbs.com/impco/125carburetor.html

http://www.eere.energy.gov/afdc/progs/res_guide.cgi?LPGRG

http://www.lngplants.com/carbturbo.htm

And this one is interesting since it lists current Nissan Products for Conversion:

http://www.vags.net.au/LPG-product-range.htm

http://www.eere.energy.gov/afdc/pdfs/conversion.pdf

http://www.primaryinfo.com/cngkits.htm

http://www.impco.co.jp/index_e.htm

http://www.impco-beru.nl/pdf/Leaflet%20CNG-1.pdf

 

And if you look at #7 on this list, you will find the company where I formerly worked, actually I did work at #8 as well... They are now in Cerritos apparently.

http://www.google.com/Top/Science/Technology/Energy/Transportation/Natural_Gas_Vehicles/

 

"Google Is Your Friend"---you just need to know what to look for!!! LOL

 

I have tried every string I could think of, I was grasping at straws and you threw me a few. Thanks, man :2thumbs:

 

I cant STOP thinking about a 10:1 turbo engine! I want to build my car a step at a time, and my first thoughts are, build engine, 88mm pistons, shaved p-90, flat tops, 10:1 compression.. megaquirt, and EFI.. and then, LPG turbo conversion. possibly TT, but THAT depends on what i do for an intake manifold... but thats all blah blah.

 

If only I had the money to DO and not just THINK.. :rolleyesg

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Keep in mind, CNG conversions are subsidized in many states and through the Federal Government.

 

You might be looking at Tax Credits for some of the costs associated with converting your vehicle!

 

I would make the Greenies scream 'foul' but hey, that's what we're here for, right? :lol:

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how about running a dedicated lpg engine (13+ compression) and using a small fueltank with racegas. Then you would have the benifits of the cheap lpg, and you would still be able to use the racegas as a decent backup system.

 

Last month I am helped a friend of mine to convert his 280zx to megasquirt (it is up and running fine). After this summer he is going to convert it to lpg vapour injection. He has a 70 liter ringtank in the spare tire location. I am very interested to see how the car will run on megasquirt and lpg. I am thinking of converting my lpg converter system in my datsun c31 laurel to injection too. It's always nice if someone else pays your tuition fee. :).

 

note: LPG stand for liquified petroleum gas. It is not straight propane. It is a mixture of propane and butane. The mixture is adjusted for winter/summer temperatures. (maybe this information is europe specific but I don't think so).

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how about running a dedicated lpg engine (13+ compression) and using a small fueltank with racegas. Then you would have the benifits of the cheap lpg, and you would still be able to use the racegas as a decent backup system.

 

Last month I am helped a friend of mine to convert his 280zx to megasquirt (it is up and running fine). After this summer he is going to convert it to lpg vapour injection. He has a 70 liter ringtank in the spare tire location. I am very interested to see how the car will run on megasquirt and lpg. I am thinking of converting my lpg converter system in my datsun c31 laurel to injection too. It's always nice if someone else pays your tuition fee. :).

 

note: LPG stand for liquified petroleum gas. It is not straight propane. It is a mixture of propane and butane. The mixture is adjusted for winter/summer temperatures. (maybe this information is europe specific but I don't think so).

 

 

first paragraph, good idea for a gasoline "backup" but race fuel is roughly as difficult, or more difficult, to find than LPG, at least here.

 

Second paragraph, by vapour injection you mean, a multi point injection system very similar to the standard gasoline FI type, correct? If so, then that is exactly what I am wanting to do, great to hear I will not be totally blazing my own trail.

 

Third paragraph, I believe that the amount of butane mixed with the propane varies by locale; my understanding is that its relatively "dirty" so to speak in Australia, but living in south Florida (tropical weather year round) I am not too concerned about a "wintertime" mixture; I don't anticipate any road trips in this vehicle outside of tropical regions, so personally I am not concerned about that. However, it is an excellent point to consider when deciding just how high to take your compression ratio.

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Second paragraph, by vapour injection you mean, a multi point injection system very similar to the standard gasoline FI type, correct? If so, then that is exactly what I am wanting to do, great to hear I will not be totally blazing my own trail.

not really. there is also a liquid fuel injection system around made by vialle. Lots of alfa romeo's where fitted with this system. This system is basicaly like a multi point fuel injection system. high pressure pump @450psi (in the tank), fuel regulator and injectors. A vapour injection system inject vapour and not liquid lpg. This system has no pump but instead uses the pressure in the tank to get the lpg to the engine. There are a couple of different systems out there.

 

check this site for a couple of different vapour injection stategies (look under product)

 

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

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The IMPCO systems and the Ford CNG/Propane-LPG systems all are vapor injection. They have fuel rail pressures in the range of 100 psi. Standard Bosch Style injectors used to flow on the average of around 1100CC/min fluid equivalent. Basically that's the difference, the flow because of gasseous versus liquid fuel. This is how GM makes the switchover, they flip a switch and you are running on gasoline but at way reduced spark timing and your idle quality generally degrades (imagine the idle quality for a 1000cc/min petrol injector!)

 

The pros/cons come to fuel availability in your area, and BTU content of the gas. CNG has 1K BTU per CF, Propane something like 800 (if I recall correctly, feel free to correct me).

 

So for a given cubic foot of volume, you will need around 28 CF of CNG to equal the content of one gallon of gasoline, and about 20% more propane/lpg.

 

Where LPG/Propane shines is the fact that you can easily liquefy it, and store it in liquid form onboard...allowing a MUCH longer driving range than with gasseous fueled high pressure storage systems (CNG is stored onboard in cylinders at between 2400 and 3600psig---temperature compensated).

 

You could get LNG (Liquid Natural Gas) but it's cryogenic temperatures, hundreds of degrees below zero, like LN2 or LOX. Not consumer friendly---but you will be amazed how many city busses and garbage trucks run LNG simply because they can go comparable distances as a Diesel Powered Counterpart.

 

Really, Propane is really nice as a fuel, but if you live where it's cold, you need alternative fuel to start and get the vaporizer/tank heater going. At -30 or -40 the pressure in the tank may be too low for EFI to work properly. In extreme cases (remember I did the carb conversions in the 70's and 80's) the 3-5psi for carburettors could not even be obtained during winter, so they HAD to have a gasoline fuel option just to get it started and running! Same for my Alcohol Setup...wouldn't run when cold...bummer!

 

One of the nice things is that CNG and Propane UNLIKE Biodiesel and recycled Vegtable Oil is currently EXEMPT from most taxes, so there's little chance of engine up owing someone back taxes for an illegal conversion (read about the green tree hugger in Berkley who just got nailed by the Feds for running vegetable oil in his Mercedes? $2500 Fine for not paying ROAD TAXES on a diesel fuel! And they reported him to the State, who nailed him as well! Running on vegetable oil is best done WITHOUT a "Ask me how I run my car on 100% recycled Vegetable Oil" Bumper Sticker---which is what got him nailed in the first place! Guy was paying 35% more for Vegetable oil from the store thinking he was doing a good thing for the planet, and the government nailed him on Tax Evasion... just like Capone! BWAHAHAHAHAHA!)

 

I, er....Digress...

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  • 1 year later...

So....anybody done this on a Z yet? I've looked around the internet about conversions and there are a bunch of sites that are overly concerned about "illegal conversions." Surely there must be somebody around here who could care less about red tape and can show us their awesome CNG-Z?

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