VW TDI on CNG

'strokeThis_'07 said:
Very nice man. Too bad Questar doesn't have any stations here; before I moved there were two stations. They sit 150 miles away now and I'm on propane at home:doh:

I'm guessing the switch goes from straight diesel to CNG? Is it a diesel/CNG mix?
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It's a mix, there needs to be a spark still so the diesel is used as the spark plug..
I'm running about an 75/25% mix cng/diesel.



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C111 said:
Too bad thats not actual fuel economy.
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Actual is closer to 95mpg average. At 65mph I'm not using much diesel at all.

CNG mileage is usually about 38-45mpg, then take the 200+ from the diesel and the average drops to the previously mentioned 90's.

In either case my conversion was done for the power, and that it's a blast.


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Can you break down the entire system for me? Like what the entire system does and how it works with the diesel motor to function. Also can you drive on just diesel or just CNG?

I'm looking to take on a 160 mile commute for work and this would really help.
 
zukgod1 said:
Actual is closer to 95mpg average.
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Incorrect, your "MPG" measurement is false because it doesn't take into factor the supplemental fuel.

If you look at the total cost, supplemental fuels don't save any money.
 
C111 said:
Incorrect, your "MPG" measurement is false because it doesn't take into factor the supplemental fuel.

If you look at the total cost, supplemental fuels don't save any money.
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.He saving money because he burning CNG which is cheaper then Diesel. But one factor you have to look into is the pay off time it takes to actually takes to start saving money.

I use to run WVO in my Ford back when I was driving in every day. I built my own kit and could get the WVO for free. In the end it cost me about 15-20 cents a gallon by the time you figure filtering and stuff. Not to bad but it still took me 2 years to pay off and I built the kit my self had less then 1500 into it.

In this case the OP said he was spending $45 in diesel a week before which is 180 month.

Now he spending 45 a month on diesel and 2 dollars a day on CNG so a total gas bill of 105 month. (2*30days=$60+$45 in diesel=105)

180-105=75 a month in saving
3500/75=46 month to pay for it self or 3.888 years
That kind of a long time in my book since I cant leave a vehicle alone for for more than a year with out change something on it.

But like the OP has said he did it more for the power then the MPG.

Either way I support anyone that is not relaying on the pump as often

Mike
 
I guess I wasnt consirdeing the home fill stations as I have CNG close to me. Either way its a long time.

I'm also willing to bet that you could do your own kit for far less then 3500 which would bring the pay off time down.

One thing I dont like is the room they take up in the vehicle. I would need something different for that or take the spare tire out.

Mike
 
C111 said:
Problem with that is the kit needs to be DOT and EPA certified.
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Once again your posting incorrect information.


The kits do not need to be DOT/ EPA certified.

Compliant is the word your searching for maybe? Yes that's it compliant.
 
iker42 said:
Can you break down the entire system for me? Like what the entire system does and how it works with the diesel motor to function. Also can you drive on just diesel or just CNG?

I'm looking to take on a 160 mile commute for work and this would really help.
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Gladly.

This system isn't much different than a Propane system really.

It's fogged in pre turbo, the system uses the factory sensors ie; crank TPS and coolant temp sometimes.

It's really simple as far as function goes.

As the CNG is injected there is more power created thus you push the go peddle down less/cutting back the diesel being used, your are still at the same speed but your foot is hardly on the throttle. The OE ECM doesnt know about the CNG it just knows your letting off the throttle so it cuts back the diesel

As mentioned our system uses the tps and crank sensors to know what is going on and gives us a couple options as far as the amount cng injected.
For instance it can be set to start injecting at say 1500rpm and at 2.5v on the TPS opening the stepper motor 250 steps (out of 500) then it can be cut back at 2500 rpm.

The CNG ECM gives us 2 settings we can use, these 2 settings can be set at any RPM and any voltage on the TPS.
Set it so it doesn't com on till your on the free way and at 2000 rpm and .8 TPS.
Then change it so it comes on at 1000 rpms and 1.5 volts.

In my car I have it set to turn on at 1200 rpm and .5 on the TPS the valve opens to 180 steps.

Then the second setting I have is at above 2100 rpm and TPS at .5 volts (using cruise control) the stepper motor opens to 215 steps.

I do tons of freeway driving so i have it set for freeway driving.


We just finished a 2004 F-350 6.0ltr and the customer doesn't use his cruise ever so we set it so for freeway driving it opens up at 2000 rpm and 1.5 TPS to 500 steps, around town it's set to open at 1200 rpm, .8 tps and 180 steps.


The CNG cant burn without a spark so it needs the diesel to act as the spark plug but that's all it needs the diesel for.

If you are driving down the road and run out of CNG it just naturally runs on diesel (push the peddle down more) so aside from power you dont know the difference.



Is there something specific you have a question about?
 
turbom700 said:
I guess I wasnt consirdeing the home fill stations as I have CNG close to me. Either way its a long time.

I'm also willing to bet that you could do your own kit for far less then 3500 which would bring the pay off time down.

One thing I dont like is the room they take up in the vehicle. I would need something different for that or take the spare tire out.

Mike
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You are correct Mike, one could put one of these systems together for really cheep.
Like $1000.00 ish maybe..

There are some specific things that need to be know when running the 3600 PSI lines but it's nothing that cant be answered.
Picking up used CNG tanks is easy that's what I did. New tanks are cost prohibitive as far as I'm concerned.

And space is another concern as well.

Most people that are installing these in trucks will get one of those really shallow tool box's and mount the tank under it not really loosing and space.

Then on occasion we will mount tanks where the spare tire is mounted like you mentioned which works out really well.
 
Not really any specific questions. Just trying to get the just of the system. I had read before of a system(I think was incorprated with bullydog) that used new injectors and a computer that controlled the injection. I really like the system your describing. I can get CNG and tanks for free, as well as do the install, so I may be contacting you in the next year for a system. Is the system universal? Or is there differences for say an Audi tdi vs a vw tdi?

Thanks
Mike
 
Where is a good place to look for this stuff at? Like valves,tubing,used tanks stuff like that.

Also I'm not very knowlageable with this stuff but does it need to be heated like propane to turn it into a vabor? Or can the minute you start driving on a cold engine will it start injection?

Thanks
Mike
 
iker42 said:
Not really any specific questions. Just trying to get the just of the system. I had read before of a system(I think was incorprated with bullydog) that used new injectors and a computer that controlled the injection. I really like the system your describing. I can get CNG and tanks for free, as well as do the install, so I may be contacting you in the next year for a system. Is the system universal? Or is there differences for say an Audi tdi vs a vw tdi?

Thanks
Mike
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The system is the same for any car Mike, so no worries as far as that is concerned.

You program the parameters according to the engine it's installed on.
 
turbom700 said:
Where is a good place to look for this stuff at? Like valves,tubing,used tanks stuff like that.

Also I'm not very knowlageable with this stuff but does it need to be heated like propane to turn it into a vabor? Or can the minute you start driving on a cold engine will it start injection?

Thanks
Mike
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The regulator has coolant lines going to it/ from it so it doesn't freeze.

It will run as soon as the engine starts.. :)

The kits we sell have all the valves/ tubing in the box.. :rockwoot:

Do a craigslist search to CNG tanks and there was a post previously in the thread on page one I think where another member has some tanks for sale.
 
Excellent do you have a webiste that I can look around?

I'll get in touch with BBX for the tanks.
 
I'm not here to sell these kits but I can and will help you will the technical side of the install so it's done correctly and safely.
Dont want anyone running out and getting hurt. :rules:
 
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