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Old 19th August 2007, 23:28   #1
yuv
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Default CNG savings, a MYTH???

Hi All,

I recently posted a similar thread on LPG and I was saving only 1.5k approx a month, which is peanuts.

The only practical option seems to be CNG, but then again when I do the math, I just dont see any substantial savings in CNG aswell.

Current daily running = 50kms a day.
Current FE = 10kms(avg)
Current daily fuel cost = Rs. 250/- approx

LPG daily running = 50kms
LPG FE = 12kms(avg)
LPG fuel cost = Rs. 90/- approx

Total savings in a month = 4800/-.... seems good enough.

But after 1 year, engine work due to CNG.... costing 50-60k approx.
So all savings gone in engine work. And then there is the initial 50k investment.

So at the end of 1 year.... I end up saving nothing?

Alternate fuels.... are they for real???
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Old 20th August 2007, 09:49   #2
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I'll give you a counter example. Our family Xeta CNG runs at about 1.1-1.2Rs/km courtesy CNG. 8 months, 15k km.
Without CNG, it runs at above Rs 4/km.
The kit cost ~50k for OEM fitment (closed loop, lambda, warranty) et al.
You do the math.

People who say it needs Engine work are misling you. For optimum performance, its good to have the car running on petrol a few kms now and then ;else as taxi walas told us, the fuel pump *can* go bad/engine become too dry - these were all issues with carb Omnis/M800s(back in '00). Haven't heard of such issues with current crop of cars: seen everything from Optra to City to even a Lancer running on CNG.
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Old 20th August 2007, 10:09   #3
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Quote:
Current daily running = 50kms a day.
Current FE = 10kms(avg)
Current daily fuel cost = Rs. 250/- approx

LPG daily running = 50kms
LPG FE = 12kms(avg)
LPG fuel cost = Rs. 90/- approx
I thought the fuel efficiency drops with CNG and LPG. YUV,Your figures show just the opposite.
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Old 20th August 2007, 14:19   #4
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Thanks Phamilyman... which kit are you using? Any special precautions that you are taking.... like changing oil more often, etc.

Also, the reason why CNG is such a hit with taxi's and auto's... is because the cost of engine refurb is very small... compared to say a C class car in my case. Many taxiwala's just replace the engine for 10k from chorbazaar.

I also hear that CNG is a big hit in delhi compared to Mumbai.... Why??

Abhilash - FE increases with CNG and decreases with LPG.
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Old 20th August 2007, 17:05   #5
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My CNG santro zip+ used to give 80 paisa to 1.00 rs per km. Never had any issue with it except the A/C autocut feature which is inbuilt the car, but even that was not a very serious problem.

Used to change oil and the filter at 10k kms and thats all. Other than that every other thing was normal. Gonna fit a kit in Esteem now. Have heard that the performance is very nice in esteem.
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Old 20th August 2007, 17:06   #6
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a. Delhi has better availability than Mumbai. No nuisance of long queues/ waiting behind troubling autowalas.
b. My mom's m800 got it at ~25k km, and we sold it at 90k km. Only problem was that two years petrol wasnt used so fuel left inside went bad. During services when it was used till the end, it led to fuel pump going bad. But car ran always on CNG, so it wasnt a problem So much for engine going bad.

Now with xeta, ~10-20 km a week (or whenever bro remembers) is driven on petrol. That is about it.

CNG is half the cost of LPG. What other reason would you want for it to be a hit?
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Old 20th August 2007, 17:29   #7
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Thanks for sharing your experience Phamilyman

Quote:
Originally Posted by phamilyman View Post
CNG is half the cost of LPG. What other reason would you want for it to be a hit?
How is CNG half the cost of LPG though? I think LPG retails at 26 and CVNG at 22.

Thanks Again.
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Old 20th August 2007, 17:37   #8
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CNG is sold in kgs while LPG is sold in litres,
CNG(1kg) gives 20% more F.E. than petrol (1l).
But,LPG gives 10% lesser F.E. than Petrol. (both litres).
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Old 20th August 2007, 23:53   #9
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Thanks for clarifying that Nitrous.

I think the moot point is the savings...

so Im looking at Rs. 22/- for approx 12-14kms(CNG).... compared to Rs. 26/- for approx 6-8kms(LPG)... therefore CNG wins thumbs down on this count.

Engine wear & tear and maintenance is another issue.... but then again, if I maintain my car well, change oil, oil filter, air filter, etc regularly.... I see no reason why CNG should harm the engine at all.

Comments Please.

Last edited by yuv : 20th August 2007 at 23:56.
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Old 26th November 2007, 16:54   #10
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guys can some one tell me what cng kit shd i intall in my zen and what will be the approx cost.
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Old 26th November 2007, 18:50   #11
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Quote:
Originally Posted by bruty View Post
guys can some one tell me what cng kit shd i intall in my zen and what will be the approx cost.
1) Carb or mpfi both 35k. KIT - landi renzo, s.p.a Italy + Power (TAP) - 5k extra OR TAP - 3k extra. Inclusive of registration charges.

2) carb or mpfi both 36k. KIT - bedini (shrimankar) + power (TAP) - 5k Extra OR TAP 3k extra. Inclusive of Registration charges.

TAP = Timing Advanced Processor (Pickup and things solved by this, reduces spark plug and wires wear and tear)

POWER = TAP of landi. costs more because of good quality.

I am using landi without power. I am really happy with performance.

MODIFICATIONS : Try (CUTOUT) Stopping of fuel pump when the car switches on gas. So when car starts and turns to gas the fuel pump shud stop its work. this will solve a lot of maintainence cost.

Drying of fuel pump is major cost of maintenance.

PEACE
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Old 26th November 2007, 19:40   #12
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I don't know much about alternate fuels; but I was recently in Delhi and I hired a Esteem cab from Airport to Delhi Station. The guys stopped on the way to fill CNG. In Delhi CNG costs Rs. 19.50/kg. When I asked the driver about the Fuel Economy, he replied ~20 Km/kg. When I asked him about the performance, he said that the performance goes down by a large degree, just because the car was new (it was the new Esteem with clear lens headlamps etc.) it had some juice left. A year down the line, the performance left is un-bearable and usually a re-build is required.
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Old 26th November 2007, 19:57   #13
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Dooms day,

Like I wrote above, I am a long standing CNG fan. My mom's car did some 70-75k km on CNG. Fuel pump drying was an issue then. Today with lambda kits, it isnt an issue. bhai's car has done some 21.5k km in one year on CNG (on CNG within a week of purchase!).

if CNG was really that useless, would the cab walas be using it? cmon!!

The juice issue is simply because of them cheapskates NOT installing lambda sensor (read bmd's post above).

Then again, I have also worked in this sector so I pretty much know this business inside out. Rest, you can google

Last edited by phamilyman : 26th November 2007 at 20:00.
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Old 26th November 2007, 20:35   #14
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Quote:
Originally Posted by doomsday View Post
I don't know much about alternate fuels; but I was recently in Delhi and I hired a Esteem cab from Airport to Delhi Station. The guys stopped on the way to fill CNG. In Delhi CNG costs Rs. 19.50/kg. When I asked the driver about the Fuel Economy, he replied ~20 Km/kg. When I asked him about the performance, he said that the performance goes down by a large degree, just because the car was new (it was the new Esteem with clear lens headlamps etc.) it had some juice left. A year down the line, the performance left is un-bearable and usually a re-build is required.
You shud hav asked him to join a driving school and remove that dehli made crap from his car if it dies so soon. Happy riding.
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Old 26th November 2007, 22:40   #15
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Quote:
Originally Posted by phamilyman View Post
Dooms day,

Like I wrote above, I am a long standing CNG fan. My mom's car did some 70-75k km on CNG. Fuel pump drying was an issue then. Today with lambda kits, it isnt an issue. bhai's car has done some 21.5k km in one year on CNG (on CNG within a week of purchase!).

if CNG was really that useless, would the cab walas be using it? cmon!!

The juice issue is simply because of them cheapskates NOT installing lambda sensor (read bmd's post above).

Then again, I have also worked in this sector so I pretty much know this business inside out. Rest, you can google
Quote:
Originally Posted by bmdesai1987 View Post
You shud hav asked him to join a driving school and remove that dehli made crap from his car if it dies so soon. Happy riding.
As I mentioned in the first line of my post, I know pretty much nothing about alternate fuel systems and how they work. Except for the fact that CNG has significantly higher octane rating than petrol. Hence, some suggest a bump in compression for optimal combustion of CNG by the engine.

@phamilyman: Do you need a special Lambda sensor for a CNG system? Coz nowadays every car comes with a Lambda (o2) sensor. Is it because the o2 percentage in CNG emissions can be different from those in traditional fuels, and hence the fuel, ignition timing. AFR etc.has to be altered? This would require an ECU remap also. Is this also bundled with the kit?
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