[CARDEEP]

I guess the issue re high petrol consumption in a CNG-ed car that you are facing is because of the sequential kit. If you can rev the car a bit when you approach the 1st signal or stoppage (provided it is not too far from your starting point) your problem can be solved.

My friend who introduced me to CNG in automobiles, does have a sequential kit in his Accent & City Vtec makes sure to rev the car a little higher after he has belted up, so that the car comes on CNG before he moves.

The kit in my car is a non-sequential one so I have to select the fuel I need the car to be driven on. If I want good acceleration, I prefer the petrol, but, for daily usage I use the CNG & on Fbd-Ggn & other highways, my car averages 26-28 kmpkg, whereas on Fbd-NOIDA route (with heavy traffic) it is 21-22 kmpkg, & petrol usage (generally) is like what @ptaneja has mentioned.

Hope this helps...

[ptaneja]

Originally Posted by LithiumSunset

Hmmm, is something amiss in my Car?

Even I had not bargained for this 0.3 litres per KG of CNG and that is exactly what has upset my calculations. I have a detailed log of every fill that I have made over the last 15 odd months of ownership, both Petrol and CNG. In fact the actual consumption of petrol is 0.5 liter per KG of CNG, but I have discounted the quantity of petrol used in my out station trips.

Is there someone whom I can talk to? Any other resident TBHP expert out there? Please help me clear my doubts..

I wish I could cleanse my veins of this 'Sadashiv Peth' blood and just enjoy the car! [Oh shoot, I've given away my closely guarded identity, but from the tenor of this thread, it must have been obvious much earlier...]

The only questionable entity here is that the switch-over from Petrol to CNG doesn't happen when a certain RPM is reached, but this happens when a particular temperature is attained in engine. So if we consider this phenomenon, then frequent short trips(wherein engine doesn't get much of time to heat up) should cost you more petrol than a lengthy one ...does this hold true ?

Also, I have sent in a request to Maruti to clarify the doubt we have - I doubt if they respond to web queries, but lets see....

[maglev]

Originally Posted by ptaneja

I will not go deeper into economics and inflation - but for me running 1700-1800 odd kms/month on CNG costs approx 3000 to 3500/month. Had it been petrol it would be almost double.

The only thing I can't digest is the fact that .3ltrs of fuel is consumed along with CNG ? This has NEVER happened to me in the last 4 years of CNG ownership for any of my cars on CNG. A mere 200rs worth of petrol lasts months...months.

Maybe a different setup with company fitted kits ?

Whatever be the reason, I have never come across a person who fills up BOTH CNG and Petrol ...

I totally agree with you, I dont even remember the last time i filled petrol in my Ritz. Post CNG at 4K KM I have had a full tank thrice and thats it. The car currently has done around 55k KM. My car is practically never driven on petrol. Petrol is only used for starting up and a little revving to about 1500 engine rpm is enough to convert to CNG.



P.S.: My car has never gone beyond NCR (Except once to Agra), I get the driver to fill up every day before he leaves for home. Average daily run is around 75km.

[LithiumSunset]

Originally Posted by Deeps

What is your usage pattern of petrol? I've been on CNG for the past 5 years over 2 cars. I've followed the practice of running 5 kms on Petrol on the first trip of the day and starting on petrol all the time (this happens automatically).

Do you follow a different petrol usage pattern - discounting the outstation trips scenario.

I definitely do not run the car for 5 km on petrol. As I have said earlier, its practically impossible to start the car on CNG, so it always starts on petrol and switches over.

Originally Posted by CARDEEP

I guess the issue re high petrol consumption in a CNG-ed car that you are facing is because of the sequential kit. If you can rev the car a bit when you approach the 1st signal or stoppage (provided it is not too far from your starting point) your problem can be solved.

My friend who introduced me to CNG in automobiles, does have a sequential kit in his Accent & City Vtec makes sure to rev the car a little higher after he has belted up, so that the car comes on CNG before he moves.

The kit in my car is a non-sequential one so I have to select the fuel I need the car to be driven on. If I want good acceleration, I prefer the petrol, but, for daily usage I use the CNG & on Fbd-Ggn & other highways, my car averages 26-28 kmpkg, whereas on Fbd-NOIDA route (with heavy traffic) it is 21-22 kmpkg, & petrol usage (generally) is like what @ptaneja has mentioned.

Hope this helps...

Nope this does not help!!! But jokes apart, I too follow a similar pattern to yours, the car will usually switch over to CNG within a couple of hundred meters, unless the revs are forced to be low due to traffic. But a quick rev up does switch the car over to CNG.

Originally Posted by ptaneja

The only questionable entity here is that the switch-over from Petrol to CNG doesn't happen when a certain RPM is reached, but this happens when a particular temperature is attained in engine. So if we consider this phenomenon, then frequent short trips(wherein engine doesn't get much of time to heat up) should cost you more petrol than a lengthy one ...does this hold true ?

Also, I have sent in a request to Maruti to clarify the doubt we have - I doubt if they respond to web queries, but lets see....

You are right, the rev up will not switch over unless the temperature has reached the required level. My trips are not very short. I am averaging about 30 km per day overall, but I don't drive every day. So the day I drive its usually 60km or even more of stop less drives, meaning I am not running small errands.

I doubt you will get a reply from Maruti, but thanks for trying. What I will need is the ear of someone responsible in the company.

Originally Posted by maglev

I totally agree with you, I dont even remember the last time i filled petrol in my Ritz. Post CNG at 4K KM I have had a full tank thrice and thats it. The car currently has done around 55k KM. My car is practically never driven on petrol. Petrol is only used for starting up and a little revving to about 1500 engine rpm is enough to convert to CNG.

P.S.: My car has never gone beyond NCR (Except once to Agra), I get the driver to fill up every day before he leaves for home. Average daily run is around 75km.

I did a quick calculation, if you have filled three tank fulls (say 120 liters) for 51000 km and filled CNG @ say 23 km per KG, you may have filled about 2220 kg of gas, making it about 0.05 liter Petrol per KG of CNG, which is clearly FIVE times less than my figures!

Now I am really worried. So either my petrol tank has a leak, or something else is amiss. I know the car has a decent Petrol mileage. I got over 15.5 kmpl for a highway run.

Ab kya karen!

[maglev]

Originally Posted by LithiumSunset

I did a quick calculation, if you have filled three tank fulls (say 120 liters) for 51000 km and filled CNG @ say 23 km per KG, you may have filled about 2220 kg of gas, making it about 0.05 liter Petrol per KG of CNG, which is clearly FIVE times less than my figures!

Now I am really worried. So either my petrol tank has a leak, or something else is amiss. I know the car has a decent Petrol mileage. I got over 15.5 kmpl for a highway run.

Ab kya karen!

My car consistently gives around 16-17km per kilo (City + 100% A/C) & around 20-21 km per Kilo (Highway + 100% A/C).
The day I got my car converted to CNG, prices were jacked up to Rs: 29/- per kg in New Delhi.


Your post got me thinking and worried at the same time, thinking because of why and worried because I thought there was something wrong with my car.
Well the reason for the difference in consumption is simple, the difference is in the approach used by the factory fit kit and the aftermarket install.


After market kits switch to CNG mode after a certain RPM is reached. So even in the coldest of climates, if the vehicle is revved beyond the already set conversion RPM, it will convert to CNG mode. Irrespective of engine temperature.
The Factory installed kits dont do this, these kits will only switch to CNG mode once the engine reaches its normal operating temperature. Because of this these cars end up using more petrol. So if this happens in your car, then this should be a possible explanation.


P.S.: I was reading about Maruti's I-GPI tech. This info was sourced from one of those reviews.

[LithiumSunset]

Originally Posted by maglev

My car consistently gives around 16-17km per kilo (City + 100% A/C) & around 20-21 km per Kilo (Highway + 100% A/C).
The day I got my car converted to CNG, prices were jacked up to Rs: 29/- per kg in New Delhi.


Your post got me thinking and worried at the same time, thinking because of why and worried because I thought there was something wrong with my car.

This changes your Liters per KG consumption a bit.

Here is another owner of an SX4 Green car reporting almost exactly the same figures: http://www.******************.com/fo...html#post53519. (I don't think the link is going to work because it's for a rival(?) site. *Mods please moderate as per your policy).

Although his mileage is also lower, at about 17 or 18 kg per kg. I know even for my infrequent trips I get almost 23 km per kg (without counting the petrol consumed).

[ptaneja]

Well for a change Maruti did replied back - and rather quickly. Moreover, got 4 different calls for this query - one from Maruti customer care, Maruti Tech Team, another from Apra in Gurgaon, yet another one from Rana Motors Service head. I am summarising their deduction in nutshell -

In short - "Usage of petrol on company fitted CNG kit would be more than third party sequential kit"

From all the sources the response is exactly the same - that, this is by design behavior wherein instead of switchover at RPM, it switches over only when ambient temperature has reached in engine. This results in the car running on petrol for the initial 10/15mins of driving - more so in winters than in summer. This holds true for all sequential kits company fits in SX4/Alto/Wagon R etc.


Email response from Maruti -

Dear Mr. Puneet,
We are in receipt of your e-mail dated 03/03/2012 regarding your query about petrol consumption while using CNG mode in your Maruti SX4 CNG.

We would like to inform you that as vehicle designed the vehicle is run on three different modes.
1. First mode is auto mode in which vehicle will start on petrol mode and later gets converted into CNG mode on its own.
2. Second is petrol mode in which vehicle will start and run only in petrol
3. Third one is Forced CNG mode in this vehicle will start and run only in CNG.

Auto Mode is normal recommended driving mode by MSIL for all CNG vehicles. For starting the vehicle in this mode petrol is required for which you need to ensure availability of petrol in the fuel tank all the time. In this process small amount of fuel will consumed at the time of starting of the vehicle in Auto Mode. This usage depends on how long it takes for the engine to reach optimum temperature for CNG combustion.

We are also advising our Regional Service Manager Posted at NEW DELHI (Phone 011- 46782086/ 87) to call for detailed inspection of your vehicle and for resolution of your query.

In future correspondences, please quote the above subject reference number.
Assuring you of our best services always.

Thanking you,
Yours Sincerely,

Manish Kumar
(Sr. Manager, Service - 3)
Maruti Suzuki India Ltd
CC : RSM- N1U


Looking at the above explanation, and the explanation given to me on the phone, we can conclude safely that your car is not at fault - but rather it's by design. Watching this petrol consumption, I am happy that I have invested in top end ZXi and would have them install a sequential kit as an add-on - atleast I would have to fill up Rs.200 petrol once in 6 months.

[Jignesh]

Originally Posted by LithiumSunset

I definitely do not run the car for 5 km on petrol. As I have said earlier, its practically impossible to start the car on CNG, so it always starts on petrol and switches over.

Now I am really worried. So either my petrol tank has a leak, or something else is amiss. I know the car has a decent Petrol mileage. I got over 15.5 kmpl for a highway run.

Thank you LithiumSunset for all the calculations & clarifications.

Originally Posted by ptaneja

Looking at the above explanation, and the explanation given to me on the phone, we can conclude safely that your car is not at fault - but rather it's by design. Watching this petrol consumption, I am happy that I have invested in top end ZXi and would have them install a sequential kit as an add-on - atleast I would have to fill up Rs.200 petrol once in 6 months.

Thank you Puneet, for the explanation, clarifications & taking an initiative in writing to Maruti. After reading this thread I almost made up my mind to buy a Diesel Car, because consumption of 0.3 litres of Petrol per 1 kg of CNG seems very costly to me.

But now it seems it is almost clear that company fitted CNG Kit turn to CNG mode after particular Engine Tempreture is reached whereas the aftermarket CNG Kit switch to CNG mode at particular RPM.

LithiumSunset, shall I suggest you one thing? My father always start the car in the morning & leave it in idle mode for couple of minutes. Only when the heat indicator goes up till quater high, he will engage 1st gear & move the car. This can probably help in your case so that Engine is heated before you move & it switches to CNG mode sooner.

Thanks,

[ptaneja]

Originally Posted by Jignesh

LithiumSunset, shall I suggest you one thing? My father always start the car in the morning & leave it in idle mode for couple of minutes. Only when the heat indicator goes up till quater high, he will engage 1st gear & move the car. This can probably help in your case so that Engine is heated before you move & it switches to CNG mode sooner.
Thanks,

Most welcome - i had to dig deeper into this as in near future I would be converting my SX4 to sequential kit too.

I doubt if this trick will make a difference ... it's the engine temperature that matters - and the rate at which temperature increments is not dependent on whether the car is in motion/driving or stationary. Infact I think it would be opposite - a car in motion will heat up quickly rather than a stagnant 800/1000RPM hummming ....

[LithiumSunset]

Originally Posted by Jignesh

LithiumSunset, shall I suggest you one thing? My father always start the car in the morning & leave it in idle mode for couple of minutes. Only when the heat indicator goes up till quater high, he will engage 1st gear & move the car. This can probably help in your case so that Engine is heated before you move & it switches to CNG mode sooner.

Thanks,

Originally Posted by ptaneja

Most welcome - i had to dig deeper into this as in near future I would be converting my SX4 to sequential kit too.

I doubt if this trick will make a difference ... it's the engine temperature that matters - and the rate at which temperature increments is not dependent on whether the car is in motion/driving or stationary. Infact I think it would be opposite - a car in motion will heat up quickly rather than a stagnant 800/1000RPM hummming ....

Absolutely great work, Puneet. I think we can lay the beast to rest and simply enjoy the car the way it was built!

Jignesh, when I am running out of the house to get into the car, I am usually in a hurry! Who's got the time for that extra 2 minutes of warming time, and I too believe that running the car will heat it up faster and let the fuel do some 'work' for being burnt! I do take care not to race from cold starts, and I usually need to reverse from where it is parked to get to the main road, and there I get my 2 minutes. Then the first signal is literally 150 meters away and like it happens to everybody its never your signal, you have to wait it out!

Puneet, maybe I can send a mail to somebody too, could you PM me the mail ID from where all the follow-up happened? There is no harm in getting it checked, though from the looks of it nothing is going come out of it.

[vharihar]

I am looking to buy a new SX4 VXi (manual transmission, petrol). Today I went to Pratham Motors in Bellandur ORR in Bangalore.

I was told by the sales people that there is a 30-45 days waiting period for 2012 SX4 Vxi. Saying that, they were trying to convince me to go for a new 2011 model, at a cash discount of about Rs 15,000 compared to the 2012 model.

Questions:
- Is it true that the petrol, manual transmission 2012 SX4 VXi has a 30-45 day waiting period? I thought only diesel models had such a long waiting period
- If I were to go for a 2011 model, what should be the cash discount that I should try to negotiate?

[ptaneja]

hahaha ....someone willing to do the calculation again ... ? since our lovely govt has raised the price of CNG YET again by 1.7rs/Kg. Though on the longer run -

9kgs on average fillup in one visit - 15.3rs/trip extra
3 trips/week - 45rs extra/week
4 weeks/month - 180rs increment in monthly run.

If I compare the above with projected rise of petrol prices in coming week or so ( 4rs/litre as per news channels ) then we are let off cheap !!

Pheeew ---its tough being optimistic and positive every time !

[Jignesh]

Originally Posted by ptaneja

hahaha ....someone willing to do the calculation again ... ? since our lovely govt has raised the price of CNG YET again by 1.7rs/Kg. Though on the longer run -

Hello Puneet,

What CNG Prices are increasing by Rs. 1.75 again? Is this today's (breaking) news?

I believe just last month CNG Prices were increased by Rs. 2 & now again an increase of Rs. 1.75?
Also as rightly mentioned by you, Petrol prices are definitely going to increase in days to come (after election results) this means cost per KM for Petrol & CNG cars will increase further.

I wonder how long will Petrol users compensate for Diesel consumption?

Also after seeing today's election results, I feel government will not dare to increase Diesel prices till 2014 General elections..

Thanks,

[ptaneja]

Originally Posted by Jignesh

Hello Puneet,

What CNG Prices are increasing by Rs. 1.75 again? Is this today's (breaking) news?
I believe just last month CNG Prices were increased by Rs. 2 & now again an increase of Rs. 1.75?

Rates were revised yesterday night midnight. Present rate is 35.45/Kg.
A mere difference of 5rs/KG with respect to diesel ?

[Jignesh]

Originally Posted by ptaneja

Rates were revised yesterday night midnight. Present rate is 35.45/Kg.
A mere difference of 5rs/KG with respect to diesel ?

Hello Puneet,

Thank you for the clarification.

So at a difference of merely Rs. 5 / 7 between per Kg of CNG & per litre of Diesel it clearly seems that for new car buyers it makes more sense to go for Diesel Cars. Also spending Rs. 40000 in installing a new CNG Kit does not seem to be a viable option, because you stand to lose the boot space in your Car. Specially for hatchback owners installing a CNG kit means loosing the entire Boot space.

I don't know whether it is a right place to discuss, but just inviting opinion from others, should one buy a second hand diesel car?

Thanks,