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How to Install a CNG System on a 2011 FJ

27K views 51 replies 22 participants last post by  Voodootank  
#1 · (Edited)
Note: If you decide to attempt to do this modification yourself, and you make a mess of it, or it has deleterious effects, I cannot be held responsible. PROCEED AT YOUR OWN RISK!

Now on to the installation.

This guy 銀チタンstarted this thread http://www.fjcruiserforums.com/forums/engine-performance/143058-cng-conversion-alternative.html#post2101736, and it got me interested in the subject. I began researching cng fuel systems to keep up with the thread, and I had expected that the whole concept was based on hype, or had an Aquilles heel that wasn't immediately apparent. Instead my research revealed that the concept actually has merit, and can make economic sense, assuming that you have a way to regularly refuel your vehicle.

Here is what I discovered.

* CNG (compressed natural gas) is low carbon/low soot and does not blacken oil. This means a longer service interval, and less engine wear.

* CNG is naturally cleaner burning, resulting in low ash, and lowered nitrous compound emissions.

* Natural gas is produced domestically.

* The supply of natural gas, in the U.S. is growing daily.

* Natural gas is inexpensive compared to gasoline.

On this last point let's take a look at the economics of installing a cng system. These are my projected savings.

I use 15 gallons of gasoline each week, and I currently pay $3.67 for each gallon.

15 gals/wk x $3.67 = $55/wk

$55 x 52 wk/yr = $2,860/yr, cost of gasoline.

I can buy CNG for $1.85 gge (gasoline gallon equivalent) however it is 10% less efficient than gasoline, so I need to add ten percent to the number of gallons that I use each week to account for this loss.

15 gals/wk x 1.10 (add 10%) = 16.5 gge, CNG needed per week.

16.5 gge/wk x $1.85/gge = $31/wk

$31 x 52 wks/yr = $1,612/yr, cost of CNG.


Cost of Gasoline per year = $2,860

Cost of CNG per year = $1612

Diffence $1,248 (savings/yr)


Given these economic realities I determined that installing a cng fuel system on my FJ could make economic sense.

Let's use the numbers generated above to establish a target budget.

I intend to keep my FJ for five years and I would like the cng system to have payed for itself in half that time, or 2 1/2 years.

Rate of payback = $1,248 (savings/yr) x 2 1/2 years = $3,120

$3,120 is the target budget for installing the cng system, and I believe that this is possible if I do most, if not all of the work myself.

Let's consider the practical issues associated with automotive cng fuel systems.

There are three main issues related to installing, and operating on compressed natural gas (CNG).

First; is finding a CNG system that will work on the FJ.

CNG systems are not commonly installed on imported vehicles so finding one that is compatible with the SFI (sequential fuel injection) system used on the FJ does require some research.

Second; The cylinders used to store the compressed natural gas, are either heavy, and moderately expensive or lighter in weight, and incredibly expensive. Also each cylinder has an expiration date, and cannot be re-certified.:huh:

The availability of used cylinders for sale in the aftermarket is limited, and buying used tanks is risky, but the risk can be mitigated by buying from a reputable dealer, and/or having the tank inspected before purchasing.

Third; is the availability of refueling points.

Refueling points are critical to being able to take full advantage of the savings afforded by operating on CNG. In my particular instance there is a public cng station about six miles away.

Find refueling stations here - Alternative Fueling Station Locator

I should mention that there are also home refueling stations available that can compress the natural gas that is delivered to your home.

Now I will begin the installation of my CNG system.

To begin this installation I had to decide what configuration of storage cylinder(s) I would need. I decided for practical reasons to mount the cylinders on the exterior of the vehicle.

The frame of the FJ is a fully boxed, fully wrapped design, and because the spare tire mounts to the rear door, there is an open area under the rear of the vehicle that is well protected on the sides, and rear by the frame. This became the logical place to mount the cylinders.


I located a set of used cylinders in the proper configuration and order them from a reputable dealer in Utah. While waiting for the cylinders to arrive I installed a block heater. This will give me the ability to preheat the engine. The reducer requires a flow of warm coolant in order to operate properly and preheating the engine on chilly mornings will allow me to begin operating on CNG sooner, saving gasoline, reducing cold engine wear, and providing cabin heat sooner - http://www.fjcruiserforums.com/forums/engine-performance/143817-how-install-circulating-block-heater-2010-2012-fj-cruiser.html

The cylinders arrived by truck. There are two cylinders in this pack, and each holds 3.5 gge, for a total of seven gge @ 3,600 psi.

EDIT: The tanks are actually much more limited in capacity. They actually hold only 2 gge each for a total of 4 gge @ 3,600 psi.

These are type II cylinders and have five years remaining before the expiration date. These cylinders were a good compromise between weight, price, and useful service life. The cylinder pack weighs 150 lbs empty (200 lbs full), and I paid $550 for it, plus an additional $130 for shipping.

So far I have spent $680 of the $3,120 budgeted for this project ($3,120 - $680 = $2,440 budget remaining).

Here are pics of the cylinders, and the 14 ga. steel shield that came with it.


^^^DOT certification (@ left) is important if you intend to install the cylinders in a vehicle.



The project this weekend is to fabricate brackets that will serve to mount the cylinder pack to the frame of the FJ.

I went to my local scrap metal dealer yesterday and bought a few pieces of steel. I payed 25 cents a pound, and the total was $10 ($2,440 - $10 = $2,430 budget remaining).

Today I cut, fit, and ground the pieces needed for the center support bracket.

I had the pieces welded together and paid the welder $40. I also spent $10 on grade 8, bolts, nuts, and washers ($2,430 - $50 = $2,390 budget remaining).



"The regulations for tank brackets are here: NFPA52 6.3.4 “the fuel container rack shall be able to withstand the force… in 6 directions up to…. 6 times the weight of the container when full"

Source: http://www.younkincng.com/ "Jim's CNG Install Manual"

The cylinders I am installing weigh 200 lbs when full, and six times that number equals 1,200 lbs. I designed the brackets to support a minimum of 1,200 lbs.





^^^
7/16" grade 8 bolt and washer.
 
#2 · (Edited)
The cng cylinders need to be protected from heat. To mitigate the heat issue created by the exhaust pipe I wrapped the exhaust pipe with header tape. The cost of the header tape was $52 ($2,390 - $52 = $2,338 budget remaining).





Cylinders are installed! well only long enough to check the fit and fabricate the pieces for the lateral support brackets. I am happy with the fit and the lateral support brackets seemed to design themselves once the cylinder pack was installed into position. I'll have the pieces for the lateral support brackets welded up in the next day or so. Til then the cylinder pack had to be removed.






^^^ This elbow in the exhaust pipe is where the pipe passes closest to the cylinders and there is a 1 3/4" gap. The steel debris shield, fitted with thermal matting, will be installed in the gap between the pipe and the cylinders. This will add another layer of protection between the exhaust pipe and the cylinders.

Cylinders are installed, permanently this time. The lateral support brackets turned up good and everything fitted together well enough. Here is a pic of the driver's side lateral support bracket. The passenger side is a mirror to the driver's side support.

I payed the welder $30 to weld the lateral supports together and spent an additional $28 on primer, black enamel, and various grade 5 & 8 fasteners = ($2,338 - $58 = $2,280 budget remaining).



^^^ Debris shield installed.

Placing the tanks, and their added weight in the rear of the FJ has reduced body roll and improved the handling. The FJ now corners flatter and seems more resistant to upset in general. It does sit lower in the rear so I will need to upgrade to a heavier spring to lift the rear up to stock position and put some bounce back into the rear suspension.

I am also considering installing airbag helpers in the stock springs. This would allow me to adjust the lift and "spring" rate.

Update: After about six months the rear settled about two or three inches and rear axle was hitting the bump stops more often than I might have liked, so I installed Airbags in the rear springs. They work well and adjusting the height of the rear is now as simple as adjusting the pressure in the bags. To allow me to correct for the inherent driver's side lean, I opted to install the airbags with separate airlines and Schrader valves. I run the drivers side bag five to ten pounds higher than the passenger side, lifting the drivers side rear corner.
 
#3 · (Edited)

^^^ From this angle you can see that the debris shield does not hang any lower than any other part of the vehicle. Rear departure angle is also unaffected.

I ordered the Sequential Injection CNG fuel system. Ten day lead time and costs $1,129 ($2,280 - $1,129 = $1,151 budget remaining). I could have payed about half as much for a Mixer system but it would have interacted with the stock fuel management system in a way that is undesirable from both an engine emissions and performance stand point. Instead I opted to pay the difference and purchase a system that will not interfere with the stock fuel management system.

The installation of the CNG fuel delivery system will require removal of the intake manifold in order to drill, and tap the aluminum runners in preparation to installing the CNG injectors. I ordered a set of intake manifold gaskets from the dealer last week. The cost was $22 ($1,151 - $22 = $1,129 budget remaining).

Kit arrived, good quality.

I found a mechanic to consult with through an add I posted to Craigslist. The mechanic works for a company that maintains a large fleet of CNG powered vehicles. I took the kit over to his Garage and had him look the kit over. He liked the quality of the components and stated that it should work well in the FJ. I also had him check my installation of the cylinders and he gave the install the okay as well.

I will consult with the mechanic again when the system is ready for first fill. We will go over the entire system before fueling/pressurizing the system for the first time to ensure that everything is installed correctly and that all of the connections are sound.




 
#4 · (Edited)
Here are the components mounted into a modular aluminum frame.

Before installing tubing.




After installing tubing.




The module mounted in the engine bay.





Cost of building the modular frame was $77 in materials. ($1,129 - $77 = $1,052 budget remaining)
 
#5 · (Edited)
Installed cng injectors to the intake manifold.

NOTE:The angle of these injection nozzles relative to the flow of air through the manifold is wrong.

The nozzles are crossing the flow of air that is passing through the manifold and this can cause a type of vapor lock that leads to poor performance. To understand what is happening in this instance consider what happens to the air inside a bottle when you blow across the top of it. The air vibrates but not much air actually moves in or out of the bottle. The fix for this mistake follows below.

NOTE:The hoses are a bit too long. The hoses all need to be the same length so after determining how short the longest hose needed to be, I shortened all of the other hoses to that same length.





To address the improper nozzle angle, I pulled the injection nozzles out of the manifold and plugged the holes. I then drilled the new holes so that the injectors are angled to be in line with the flow of air through the manifold. This will tend to help evacuate all of the gas from the hose quickly and improve performance.

There was just enough room in the corner of each port to squeeze in an injector nozzle. I placed a bit of epoxy at the base of each nozzle to lock it in place.



Completed plumbing.




Installed an aftermarket locking fuel door.

I ordered the same model of aftermarket locking fuel door that I previously used to replace the OEM gasoline fuel door. Using the same model increased the likelihood that the key ways would be the same, and they were. This allowed me to have the lock sets matched and now one key can be used to open either fuel door.





For safety I wrapped the sharp edges of the metal with black plastic door edging.


The cost of the fuel door was $93 with shipping. ($1,052 - $93 = $959 budget remaining)
 
#6 · (Edited)
April 26, 2012 - I installed the ECU in the cabin to keep it dry and locate it near several connection points . I used a little space from the back of the glove box to provide for the ECU.




The wiring is 90% with only the connections to the OBDII, ECU, and Tachometer left to connect. This is where I discovered a difference between the 2009 models and 2010 models.

All data does not have the 2010+ models in their system so I had to spring for the 2011 wiring diagram from toyotaparts.com. It carries a hefty price tag at $171, but I need it and I can always resell it later. ($959 - $171 = $788 budget remaining)

The wiring diagram book arrived and the wiring is now complete. I am dealing with issues at the moment and hope to have them worked out soon.

Three months have passed and I have worked through each part of the system and verified each operation. I have determined that the problem lies in the ECU. This is the brain of the system and if it is malfunctioning the system will not work. The vendor has declined to honor any warranty and I refuse to purchase a replacement ECU from a vendor who will not honor a warranty.

In the interest of moving this project towards a successful completion I have decided to replace the defective ECU with a competitors ECU. I can re-use most of the original parts with the exception of the defective ECU, wiring harness, CNG injectors, and temp/pressure sensors.

I am purchasing the replacement parts from a reputable dealer in Europe and the cost is 600 euros ($796) including shipping. ($788 - $796 = -$8 budget remaining).

The replacement parts arrived from Finland and I swapped out the ECU and CNG injector solenoids. After configuring the software the engine switched over to running on CNG and then sailed through calibration. The engine runs just as well on CNG as it does on gasoline but with a substantial reduction in emissions and cost/mile (CNG is currently selling for $1.70/GGE).

My FJ is now dual fuel with extended range (335 mi. petrol & 70mi. CNG = 405 mi. total range)

Here is Old and Busted - V V V


and here is the New and functional ECU - V V V


To reduce the possibility of an electrical fault, I soldered each connection and then covered it with shrink tubing.




The new CNG injector solenoids (cyl. 1 - 3 - 5) - V V V (I used 3.5mm nozzles in the injectors.)





The new system is made by RAM regulator products; The system is OBDII compliant and when working properly it should not generate codes. I cannot claim originality on installing this system into an FJ, that honor goes to Matti in this thread - http://www.fjcruiserforums.com/forums/engine-performance/143058-cng-conversion-alternative-5.html#post2146651

Thanks for blazing the way Matti.

The supplier I purchased the new parts from is here - Google-kääntäjä

Contact Jani for more info - CNG House Oy <jani.luoma@cnghouse.fi>; Jani's English is very good and they have a well stocked warehouse.
 
#7 · (Edited)
Be sure to sticker your vehicle so that others will be properly warned that an unusual hazard exists.

I designed my decals at zazzle and customized the size of one decal so that it will fit on the fuel door. I also added wording that describes how to shut off the supply of gas coming from the cylinders.







MILEAGE AND PERFORMANCE RESULTS:

With a few miles logged I have some results to report.

* My overall fuel savings is averaging 40%:clap:

* CNG has an octane rating of 130 and the performance is very good. The engine sounds smoother running on CNG, not as throaty, and acceleration is strong. According to the ScanGage the engine can make 237hp on CNG. The engine could make more hp but, the reducer is limited to a capacity of 180 kw, or 240 hp.

(see spreadsheet below)

Note: The reason some amount of petrol is still being used is because the engine runs better on petrol while heating up. After the engine warms up it automatically switches to CNG. To reduce the amount of petrol I use to heat the engine, I installed an electric engine block heater. This is a circulating type heater and I use it on cold Winter mornings.
 

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#8 · (Edited)
Here is an interesting development regarding a technological breakthrough in gas storage. This has the capacity to triple the amount of compressed natural gas that can be stored in a conventional storage cylinder, at conventional pressure.


Watch the video and then consider this; These scientists are proposing that this feat is accomplished by putting magic beans (Metal Organic Frameworks, or MOF's) into a storage cylinder that would otherwise have only gas in it, and that by doing so up to three times more gas can be put into the same cylinder, at the same pressure.

If the addition of their magic beans were causing the gas to condense into a liquid this would not be hard to believe, however the gas remains in a gaseous state.

This is some weird science and our intuitive notions about displacement do not seem to apply here. We naturally conclude from our own experience that when we place something in a closed space, the amount of space available within that closed space is reduced by the amount of space occupied by the thing that we put in there. This notion however does not seem to apply in this instance. So what is going on?

For more on the brain teasing aspects of this technology check out this article;

MOF smashes gas storage ceiling | Chemistry World

The article seems to imply that magic beans are nothing more than an orderly arrangement of many seats and that each seat is just the right size and shape to accommodate a single molecule of gas.

When a gas molecule enters the tank and takes a "seat" inside a magic bean, it ceases flying about randomly, and instead becomes part of an orderly arrangement. As the orderly seating process continues more room is provided for more gas molecules. If the entire tank is filled with magic beans then order is also achieved throughout the entire tank. This orderly arrangement process is the key to this scientific breakthrough and allows for greater storage capacity without the need to condense the gas into a liquid.

Understanding this then, we can see that our intuitive notions about displacement still hold true because each magic bean is simply a porous sponge for gas. The magic beans actually occupy very little space and yet they provide vast internal areas where individual gas molecules can be stored in ordered arrangement.

This is cool science and this discovery may have solved one of the most vexing problems related to using CNG as a motor vehicle fuel, namely that the CNG storage cylinders are heavy and suffer from limited capacity. By adding magic beans (MOF's) to storage cylinders, the storage capacity could theoretically be tripled; This breakthrough has the potential to make CNG much more practical as a fuel for all types of mobile platforms (e.g. cars, trucks, boats...).

UPDATE (01/05/2014): MOF's can now be ordered here: MOF Technologies - Metal Organic Frameworks

Another hurdle might have been cleared with the introduction of MOF's at reasonable cost. Up til now the problem has been the difficulty, and attendant expense involved in manufacturing MOF's on an industrial scale. The company linked to above seems to have cracked the problem and they currently offer four different types of MOF's for a variety of applications. Of note here is that one of the types offered is ideal for methane storage (Natural Gas is 90% methane).

It won't be long before someone installs MOF's into vehicle storage cylinders, tripling or even quadrupling the CNG range without the need to alter the size of the cylinders.

This is cool science that has actually made it to the market place.
 
#9 ·
This is going to be awesome. I can already tell!!
 
#12 ·
Definitely looking forward to seeing how this turns out.

:cheers:
 
#20 ·
This is freaking awesome! My neighbor has three CNG vehicles and I am jealous ever time he fills his cars at home. Keep us posted! :rocker:
 
#27 ·
The above given installation method along with picture is been very useful, as CNG is been very useful for each and every vehicle now days and such type installation method is been very helpful for the preparation of the installation of the CNG in the vehicle.
 
#32 ·
Thanks everyone. I am glad this is helping.

This forum has been a great resource for me and this is my way of giving a little back.

Regarding my kit, I am waiting to see how it all shakes out before I recommend anything. So far it has gone well.

Thanks for your patience while I work through the issues that are bound to crop up in a project like this. I am still plugging along as time allows. :cheers:
 
#33 ·
Build Thread is Awesome and am glad that you are making headway. I have looked into a lot of Italian and other overseas kits but haven't found one stateside I like.

I am more interested in the ECU and Injectors. Since you have been working with your system, I have a question or two you might be able to help me out with.

1. If you were to use an ultrasonic transducer to vaporize gasoline would the CNG Injectors, ECU and possibly other components of your system be able to manage the proper AF ratio as CNG is injected as a Vapor.

2. If you don't think this is possible do you see another method of controlling the AF Ratio?

I know it is a little odd but the principal of the medium (vapor) being injected into the manifold is the same.
 
#35 · (Edited)
1&2. The CNG ECU in my system is OBDII compatible and when operating on CNG it simply looks at the same information used by the vehicles ECU to manage the gasoline system, and then uses that information to manage the ratio of CNG to match what the system would see if it actually were running on gasoline. OBDII compliant systems operate this way and are less likely to cause problems with OEM systems. Non-compliant systems use emulators to create OEM signals artificially. I recommend an OBDII compliant system for this and other reasons.

Are you going to be able to to switch back to run on gas if you need to? IE, flip a switch and change fuel sources?
Yes.