VW TDI Diesel Gets 120 MPG on one Gal of Diesel with CNG blend!!

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CNGVW

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VW TDI Diesel Gets 120 MPG on one Gal of Diesel with CNG blend!!
I will give the math up front. 2001 VW TDI 129 K using my new CNG blend test system.
Round trip 90 % Highway 75-80 MPH.
60 Miles round trip used .51 Gal of Diesel and 1.2 GAL (GGE) of CNG yes I have the slips.
That is a 60% blend of CNG it has very smooth power to boot.
The EGT never went over 990F on long uphill pulls.
Using this system should give you a 70% reduce in fuel cost per mile traveled
If I do the math right here on an average a TDI gets 45 MPG at $4 a GAL that is 11.2 cents costs per mile traveled.
Using a CNG blend system it cost 03.3 cents per mile traveled on Diesel. CNG cost per mile traveled is
.02 cents at $1.00 a GAL (GGE). If I did the math right someone please check it that is a cost of
05.2 cents per Mile traveled a savings of 58.2 %. I pay for home fueling now .40 cents a GAL that should push me in the 80% saving on fuel cost.
I have over 1000 miles on this test system no codes just works.
Bob Mann
 

Rickstah

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Impressive tech, Bob! I'm sure your efforts are covered somewhere, but is there a place where we can follow this, because I have questions about bulkiness, costs for equipment, how to fit into a Jetta, for example, thanks!
 

CNGVW

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Bob Mann Auto, 111 High St, Pembroke MA 02359
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Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
Hello it has been talked of here. But I have built the system round a simpler way I think.
I would like for someone to post the fax number for Fred’s site or email me I so I can talk of a price for this.
So the point was to show we can blend fuels and cut costs for miles traveled without giving up performances.
I use a CNG vacuum controlled regulator modified by me. We dump it in the air intake after the MAF and before the turbo inlet. I use an ECT from http://thesensorconnection.com and wire it in to turn on/off the CNG for safety. It runs about $200
The front end of the kit is very easy to install about 2 HR. Than a high pressure line ¼ inch or 6mm is run from the tank to the regulator.
I give up some trunk space for a CNG tank on a Jetta ½ the trunk on this TDI I use 2 small test tank that fit in the spare tire space 1.5 GAL filled.
For the front end kit I see it in the $500 range
Used tanks can be found from $100 to $1000.
Someone but it to me this way if you pay $4.00 a GAL for Diesel and get 40 MPG so for 60 miles it was $6.00 and for me with CNG blend it cost ( using $1.00 a GAL for CNG) it cost $3.20 to do the same 60 miles that is a reduction of in half of fuel costs. But when you put the home fueling station in the math I pay .40 cents a GAL of CNG at home. It is now better I need someone to check this math is it 50% or 100% reduction ??
Bob Mann
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Sterling, Massachusetts. USA
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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
.51 gallons of diesel: 33422.8 BTU
1.2 gallons of CNG: 198,750 BTU
total BTU: 232,172.8
or the energy in 1.8 gallons of diesel.
60 miles on the energy in 1.8 gallons of diesel is 33.3 mpg.

Good work!
 

BKmetz

Administrator, Member #10
Staff member
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Lug_Nut, I think you need to recheck your BTU values.

The BTU value of #2 diesel per galloon is not fixed. It changes to from one delivery to the next depending on the crude it was refined from. It's more like a range from 124,000BTUs (winter blend) to 139,000 BTUs.

I would say the heating value of .51 gallon of diesel would be around 65,000BTUs.

CH4/CNG is 1000BTUs per SCF (Standard Cubic Foot= 1ft cubed at zero degrees centigrade at sea level). 1 therm of CH4 = 100,000BTUs. So 100 SCF = 1 therm.

To me, the GGE is misleading because one needs to know the pressure and temperature when filling the tank. To know how much CNG was used there needs to be a flow meter that measures SCF or therms used.

To use the known numbers, an A4 TDI returns 45 MPG on average. The average heat value of #2 diesel, is say around ~130,000BTUs/gallon. The energy needed to travel 60 miles at interstate speeds would be around ~200,000BTUs.

So, 200,000BTUs used - 65,000BTUs diesel = 135,000BTUs CNG used. So in my best guestimate, 135,000BTUs of CNG was used, or 1.35 therms or 135 SCF.

There is no magic here. It is simply substituting one fuel for another as the amount of energy needed/used to move the car does not change.

Someone else will have to crunch the numbers to determine the cost of the installation kit, home filling station, electricity used to run the home filling station, and the CNG used.

:)
 
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RWHP

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Lug_Nut, I think you need to recheck your BTU values.

The BTU value of #2 diesel per galloon is not fixed. It changes to from one delivery to the next depending on the crude it was refined from. It's more like a range from 124,000BTUs (winter blend) to 139,000 BTUs.

I would say the heating value of .51 gallon of diesel would be around 65,000BTUs.

CH4/CNG is 1000BTUs per SCF (Standard Cubic Foot= 1ft cubed at zero degrees centigrade at sea level). 1 therm of CH4 = 100,000BTUs. So 100 SCF = 1 therm.

To me, the GGE is misleading because one needs to know the pressure and temperature when filling the tank. To know how much CNG was used there needs to be a flow meter that measures SCF or therms used.

To use the known numbers, an A4 TDI returns 45 MPG on average. The average heat value of #2 diesel, is say around ~130,000BTUs/gallon. The energy needed to travel 60 miles at interstate speeds would be around ~200,000BTUs.

So, 200,000BTUs used - 65,000BTUs diesel = 135,000BTUs CNG used. So in my best guestimate, 135,000BTUs of CNG was used, or 1.35 therms or 135 SCF.

There is no magic here. It is simply substituting one fuel for another as the amount of energy needed/used to move the car does not change.

Someone else will have to crunch the numbers to determine the cost of the installation kit, home filling station, electricity used to run the home filling station, and the CNG used.

:)
Why even say that....shouldn't you be supporting the alternative fuel being as you are the administrator of the alternative fuel board? I think its pretty amazing that you may only have to visit the pump for fuel once a month. I've looked into the conversion and every way I work it out, it pays for itself in a year..all of the above factors included. I might try it out over the next few months on my 2000.
 

CNGVW

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Bob Mann Auto, 111 High St, Pembroke MA 02359
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Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
CH4/CNG is 1000BTUs per SCF (Standard Cubic Foot= 1ft cubed at zero degrees centigrade at sea level). 1 therm of CH4 = 100,000BTUs. So 100 SCF = 1 therm. The true number for CNG is 114,118.8 BTUs =1.14 Therms here in the North East
Below is a good link for CNG infomation.
https://docs.google.com/document/d/1NbaKYme3bqOw0b6KMxXSjOLHLNeflalPy9gIAiTYFMQ/edit?pli=1#
Just to clear up how the test was run filled up the tank with Diesel till it dripped out the fill rim. Drove next door to a Public CNG filling station and filled tanks with CNG the dispenser read out in GAL.
Drove it on some stop and go roads and then highways at 75-80 MPH to location then used the same return route and same fuel stops to top off.
There is no magic here it just shows if you can control the blend fuel and it is cheap and works with the diesel seamlessly .You can drive your cost per mile for fuel down.
This is nothing new to diesel trucks just to TDIs here.
You are more than welcome to drive the car and test it just give me a call 781-588-3968.
Bob Mann
 

Abacus

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Bob: thanks for posting this, but...personally, I would like to see a longer test since 60 miles isn't long enough to reach a reasonable conclusion.

As with any scientific procedure, repeatability is key to withstanding scrutiny.

Not trying to douse any fires here since I am interested in the process, but if you have over 1,000 miles on this system, why are you only posting the results from a 60 mile stretch? Can you give us a longer run and post the results? Thanks.

60 Miles round trip used .51 Gal of Diesel and 1.2 GAL (GGE) of CNG yes I have the slips.
....
I have over 1000 miles on this test system no codes just works.
 

cevans

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There is no magic here. It is simply substituting one fuel for another as the amount of energy needed/used to move the car does not change.

Someone else will have to crunch the numbers to determine the cost of the installation kit, home filling station, electricity used to run the home filling station, and the CNG used.

:)
Exactly, the "fuel economy" is besides the point in this situation since CNG and diesel are different fuels, BTUs are also a bit besides the point as all BTUs aren't created equal when it comes to using them. For practical purposes it is cost per mile that is important.

If CNG can lower your cost per mile (by half), this concept works. Then you need to see where the break-even point is. Firstly of the "conversion" kit - and if necessary the home filling.
 
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CNGVW

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Bob Mann Auto, 111 High St, Pembroke MA 02359
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Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
Bob: thanks for posting this, but...personally, I would like to see a longer test since 60 miles isn't long enough to reach a reasonable conclusion.

As with any scientific procedure, repeatability is key to withstanding scrutiny.

Not trying to douse any fires here since I am interested in the process, but if you have over 1,000 miles on this system, why are you only posting the results from a 60 mile stretch? Can you give us a longer run and post the results? Thanks.

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I have been testing the system to make shore it was a turnkey setup and worked out some bugs. I have plans to redo the MPG test in a more controlled environment. I will be making it a loaner to those that wish to drive it.
Bob Mann
 

CNGVW

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Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
Hello on Bio-d I do not know.
Be careful on just jumping in to diesel/CNG. I have over 8 hard years on CNG conversion on turbo gasoline engines Bi-Fuel systems. I designed this kit for TDIs I spent a year on just planning it.
I worked on the car a bit today it started to slip the stock clutch when the CNG was engaged so www.IDPART.com sold a leftover old stock clutch to me.
Fixed an EX leak. Fixed a window and will clean it up.
The CNG system has 2 adjustments Idle/off idle and flow under load. The trick is to adjust the flow to get the max HP without a stumble off idle or under low load 2100 RPM. Now it pulls hard no more slipping the fun part of the kit is you can be driving it on just diesel and click the CNG switch and it feel like someone hit you from behind..
I have taking some pic and will add then over the week end.
Bob Mann
 

Rickstah

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Good information, thanks, Bob. Could this mean others could have dial-in issues such as clutch slippage once it was installed and set, I assume, to your baseline specs?. I sent you a PM, but when you say "trick", does that mean it will be a situation of having to change the flow during different driving conditions, or will it be proportionate to throttle position, for example? A set-it-and-forget-it would be nice. I missed the part about performance increase, just thinking about fuel econ, lol. a CNOS system! :)
 

RNDDUDE

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It would seem that the biggest advantage of CNG is it costs less per BTU than diesel or Gasoline....
 

thebigarniedog

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Why even say that....shouldn't you be supporting the alternative fuel being as you are the administrator of the alternative fuel board? I think its pretty amazing that you may only have to visit the pump for fuel once a month. I've looked into the conversion and every way I work it out, it pays for itself in a year..all of the above factors included. I might try it out over the next few months on my 2000.
I got this one as well .......

The thread title is not "wow, you can run your car on cng and diesel" or the like. The thread title is about getting 120 mpg. The sub-plot of this superlative claim is that the OP will be selling a kit so you too can do this. All of this strikes a similar cord to infomercials which throw the same type of pitch: "There is a secret", "it is easy once you know that secret" and of course "anyone can do it with this kit". I would expect, no I would insist that someone throwing that kindov stuff out there in such a dramatic fashion would be challenged.

I would also expect that the OP who threw it out there would be ready to back it up "with the math" rather then trying to offload a bunch of kits onto the the "true believers" that infomercials cater too on a regular basis.
The bottom line is that if it works, great --- you should be able to handle the tough questions. But wait, there's more ....... If you want too start a thread with a dramatic claim without being able to answer the questions then expect the members of this Board to call you on it. So before the OP starts with a few easy payments of x and just paying extra shipping and handling, lets deal with the math and the testing regiment.
 

CNGVW

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Many TDI Jettas and a Beetle Race car run 2010 jetta tdi cup car build roadrace
As I laded it out in the post the car was driving 60 mile round trip and used only .52 GAL of diesel. The math is very easy here 60 x 2 = 120 miles using .52 GAL x 2 make up one GAL.
Bio Diesel is not GOD sent and not the solution for everyone. Natural Gas is at the lowest it has ever been and it burns a lot cleaner then Diesel. I invent a lot of thing and sell a lot of stuff mostly around clean energy products. And listed as one of your Trusted TDI Mechanic I have not asked anyone to buy a kit.
I do build and sell VW and Audi,s converted to CNG BI-Fuel cars using a Auto Gaz kits from Poland I am a importer for the systems.
Once the TDI system is installed and adjusted after a few drive and tune sectioning you never have to adjust again. As I said you are more than welcome to drive it.
Bob Mann
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
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Sterling, Massachusetts. USA
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idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
VW diesel gets 12,000 miles per gallon of diesel on a biodiesel blend.

No conversion kit, no cargo space loss, a cost of 8 cents per mile (because I buy retail with road use fuel tax included) or 2.5 cents per mile (for home brew).

p.s.: It's spelled conversion
 

Ludicrous Speed TDI CUP

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Northern IN
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2010 TDI Cup, 06 Jetta TDI
Sounds interesting... Doesn't some of the big diesel trucks use propane injection for power?
I'm sure CNG would be similar...
Heck.. I'd like to see pictures and more info!
Good going if it works as stated...
~Scott
 

nord

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My uneducated opinion only...

From what I understand either propane or NG mixed into the diesel system result in a more complete burn for fuel oil. In other words more complete use of the available energy. Thus increased economy in fuel used for miles traveled.

Propane injection is an old standby and it works from what I can tell. The same being true (I assume) for CNG. The problem I see is that the propane system I noted is used more for diesel trucks. My Dodge Cummins has lots of room for an extra tank or pressure vessel. My Jetta doesn't!

For me it comes down to a matter of room and numbers. My Jetta costs just under ten cents a mile for fuel which I feel is very reasonable. The question then becomes whether the cost of a conversion and the loss of room makes economic sense. Further, I'm not too sure that I'd want a bottle of CNG riding inside the cabin with me.

So... To each his or her own. The idea has merit without question. Test donkeys bear out this fact. I'd just be more comfortable with a somewhat more refined storage and delivery system.
 

nicklockard

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SOLD 2010 Touareg Tdi w/factory Tow PCKG
My uneducated opinion only...

From what I understand either propane or NG mixed into the diesel system result in a more complete burn for fuel oil. In other words more complete use of the available energy.

How can the fuel be burnt more than 100%?

A regular diesel engine, even a non-turbo IDI from the 1980's, burns 100% of the fuel, effectively.

I'm not arguing against NG. If it's a cheaper fuel per btu, and it can be made to function with the engine safely and reliably, then clearly it is a valid alternative fuel.

I just don't think it can 'burn more efficiently'. Maybe 'burn more cheaply' for a given heat value.
 

CNGVW

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Wksg

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I know practically nothing about alternate fuel systems. It seems surprising that you can just feed in CNG to a diesel engine and have everything work well. Combustion conditions much change, emissions, etc.

The OP mentioned .51 gallons of diesel and 1.2 GGE CNG. This works out to 38.5 mpg if it was all diesel. If the car got 45 mpg on diesel alone, it looks like the overall efficiency has been reduced by introducing the CNG, which would not be surprising at all.

This is not to say it is not cheaper to run that way - surely it is given the current low price of natural gas. 1.2 GGE is 127 cu ft, 1.27 therms, which would cost (at my house) just about $1. So the 0.51 gallons diesel + 1.2 GGE CNG is about $3, around $.05/mile. That's about 30% lower cost per mile than I pay right now...

One thing I don't quite get, the OP mentioned home fueling cost at $0.40/gal, that doesn't add up to me. At the station, 1.2 GGE (1.27 therms, compressed) is $1, which is just right for $0.80/therm natural gas, and I don't think it's any cheaper in MA than it is in MI. So even if you are fueling at home, how do you get down below $1/GGE CNG?
 
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