[carboy]

Originally Posted by bhp_maniac

Most of your queries relies on two things. The kit you are going to use and the installer from where you are getting your kit installed.

So what's a good kit to use for Swift?
And who is a good installer in Bombay?
And how much does it cost?

[bhp_maniac]

Originally Posted by carboy

So what's a good kit to use for Swift?
And who is a good installer in Bombay?
And how much does it cost?

1. Which is your Swift model, BS IV or older ones ? In both cases, the best bet will be go for SI kits. You can go for Lovato or Tartarini.

2. I have no idea about Bombay installers, as I am from Kerala

3. SI kits will cost you around 40K. Lambda kits are on lower side, around 27-30K but not recommended for a swift. Again it depends on your budget and risk taking mentality. Anything other than SI may cause an ECU failure.

[carboy]

Originally Posted by bhp_maniac

1. Which is your Swift model, BS IV or older ones ?

I have a 2007 July Swift VXI.

[bhp_maniac]

Originally Posted by carboy

I have a 2007 July Swift VXI.

Ok, so I guess its the BS III model. All SI kits available on market will be compatible with your car. Also you can use Lambda based kits, but on the risk that there can be an ECU failure. In case of SI kits you will be getting almost same FE and performance as of petrol, but in case of lambda based kits both needs compromise. SI kits completely eliminates the risk of a backfire by isolating gas from air. But in case of lambda based normal closed loop kits, that risk is always there and may lead to even a blown out inlet manifold.

[manishalive]

Originally Posted by bhp_maniac

You can go for Lovato or Tartarini.

Anything other than SI may cause an ECU failure.

What do you mean by an SI kit. And I doubt that any thing else will the ECU of the car. In good old days when fuel injected cars were just comming. The normal kits for carbureted cars was used and the cars ran perfectly fine. With all the electronics what you have is a faster responce time, there by a better responce.

if you can Eloborate on your point, it would be better.

And in my opinion BRC kits are far better in terms of quality and in sheer no of options / accessories, but then it was in the old days, now others might have cought up.

[lucksin]

bho_maniac,

I beg to differ here on ECU blown out. being in delhi is a bliss for CNG as most of my friends and relative and colleague uses CNG and i can vouch that no one ever had a ECU failure with a lambda based kit(except some small tunning issues). Infact manglev have had 3 cars all Lambda based and i too have 3 all CNG converted and as far as i know none ever had even a single glitch with ECU. ZILCH

@carboy : closed loop that is lambda based kits are safe enough in all ways, just get it installed by a reputed installer. i am sorry i have no information about the installer in mumbai, i guess you have do some hard work :P also one of my friend has Swift with Lambda based kit and it works like a charm.

Just to clearify a bit there is a component called Emulator with directly talks with ECU and all it has to do is to emulate the petrol functions. this is my understanding for the past 5 years that i have been using CNG which happend to be a lambda based. and never ever i had even a single issue with ECU. be it Zen or Baleno. also

No doubt Sequential kits perform better but i can tell you there also it backfires and misfires depending upon installation. and about blown out inlet manifold i have yet to see one.

about the kits BRC. GNC, Tomasetto Achille, Lovato etc are some reputed one i have used GNC, Tomasetto Achille and all are good kits.

[bhp_maniac]

Originally Posted by manishalive

What do you mean by an SI kit. And I doubt that any thing else will the ECU of the car. In good old days when fuel injected cars were just comming. The normal kits for carbureted cars was used and the cars ran perfectly fine. With all the electronics what you have is a faster responce time, there by a better responce.

if you can Eloborate on your point, it would be better.

And in my opinion BRC kits are far better in terms of quality and in sheer no of options / accessories, but then it was in the old days, now others might have cought up.

There are mainly two types of LPG/CNG systems.

Open Loop/Lambda based LPG Systems:

In Carburetor based cars, petrol-air mixture is supplied to the engine cylinder. In this case LPG/CNG the system cuts the fuel pump power there by stopping the flow of petrol. The operation is quiet simple, i.e instead of petrol gas is mixed with air.

But in MPFI cars, petrol and air is never mixed outside engine. Instead petrol is injected through injectors which are controlled by ECU. As a result if we are using the LPG system like in the previous case, the ECU will sense that the fuel pump has failed and will give check engine lights and will stop firing the spark plugs. This will result in the car not running even if gas is being supplied. To cover this issue, LPG systems for MPFI cars use an emulator which fools the ECU that fuel is being supplied and thus making ECU to fire the spark plugs. Again, gas is directly injected to inlet manifold which may result in misfiring/backfiring. The result may be a blown out inlet manifold or a failed cat con. Also, ECU will be pulsating the injectors without fuel supply. So we are risking on 3 costly components ECU, injectors and cat con in case of a modern car, neither of which are present in a conventional car. I am not telling that a conventional kit will not work on modern cars, Yes it will work but the risk factor is always high. I am telling this from my experience of failures in my ECU which was caused due to an LPG conversion. But Marutis are using such systems in their Duos.

SI Kits (Sequential Injection):

In SI kits gas is injected as in case of MPFI injection systems. In this case there will be another ECU controlling the gas injection. This ECU will work as a slave of the main ECU. Here, gas is never mixed with air, but will be injected to the cylinders as in the case of MPFI. The result will be a smooth ride as of petrol. Also in conventional LPG systems petrol/gas conversion is being handled by rpm or manual. Result may be stalling issues in cold whether. But in case of SI kits, the ECU will take care of this thing by switching over to gas only when the engine has achieved operating temperature. Also the switching will be cylinder by cylinder which will give a smooth transition that the driver will never know whether he has changed petrol/gas. These kits are being used in Xeta LPG, Spark LPG, Santro Eco etc.

Regarding BRC kits, I forgot to mention in the previous thread. Yes, BRCs are widely used.

[lucksin]

Originally Posted by bhp_maniac

There are mainly two types of LPG/CNG systems.

Open Loop/Lambda based LPG Systems:

MPFI cars use an emulator which fools the ECU that fuel is being supplied and thus making ECU to fire the spark plugs. Again, gas is directly injected to inlet manifold which may result in misfiring/backfiring. The result may be a blown out inlet manifold or a failed cat con. Also, ECU will be pulsating the injectors without fuel supply. So we are risking on 3 costly components ECU, injectors and cat con in case of a modern car, neither of which are present in a conventional car. I am not telling that a conventional kit will not work on modern cars, Yes it will work but the risk factor is always high. I am telling this from my experience of failures in my ECU which was caused due to an LPG conversion. But Marutis are using such systems in their Duos.

First of all the Gas is not getting injected directly in fact its getting mixed with the air in throttle body of the engine and then it goes in through the valves. correct me if i am wrong that is why we install MIXER to mix the gas with air right at the starting of throttle body.

misfire/backfire only happen if access of gas in injected with low spark. which happens in SI kits as well.

"about ECU pulsating the injectors" i am not able to understand this. so what you say is in-case the car is running fine and suddenly the car is out of gas then the engine will keep on pulsating the injectors ?? well My car gets turned off the moment there is no gas.

[manishalive]

Ok by SI you mean LPI (Liquid propane injection), I got it now.

Again, gas is directly injected to inlet manifold which may result in misfiring/backfiring. The result may be a blown out inlet manifold or a failed cat con. Also, ECU will be pulsating the injectors without fuel supply. So we are risking on 3 costly components ECU, injectors and cat con in case of a modern car, neither of which are present in a conventional car. I am not telling that a conventional kit will not work on modern cars, Yes it will work but the risk factor is always high. I am telling this from my experience of failures in my ECU which was caused due to an LPG conversion. But Marutis are using such systems in their Duos.

Many of the MPFI cars are not direct injection and the mixing does take place outside the cylinders. I could not understand why gas fed into manifold will result in backfiring, no way. And catalytic converter is in down stream of the exhaust line and in any case (normal or SI kits) the by products of combustion will be the same, how that will result in its failure. Also please note that the Injectors do not pulsate when the car is running on GAS and it is this that causes the check light to glow and thus the use of emulator. Again since the Injectors are not functioning there is no reason for their failure. ECU will be doing its function as always from the signals from various sensors and emulator.
Please note failure of Injectors could be due to different reason (LPG is corrosive in nature and that is probably due to methyl mercaptan used for odor)

SI Kits (Sequential Injection):
Here, gas is never mixed with air, but will be injected to the cylinders as in the case of MPFI. The result will be a smooth ride as of petrol. Also in conventional LPG systems petrol/gas conversion is being handled by rpm or manual. Result may be stalling issues in cold whether. But in case of SI kits, the ECU will take care of this thing by switching over to gas only when the engine has achieved operating temperature. Also the switching will be cylinder by cylinder which will give a smooth transition that the driver will never know whether he has changed petrol/gas. These kits are being used in Xeta LPG, Spark LPG, Santro Eco etc.

How do you inject the LPG into the cylinders? Do you drill holes? Going by that there will be two injectors in the head. As far as I know the LPG is injected in the manifolds. For smooth ride do you mean to say carbureted cars were rough and mpfi are very good? I doubt that. I t all depends on the state of tune. However the response time for electronic systems is miles better than mechanical ones. I have not seen any issues in cold weather. The air fuel ratio in the conventional system is controlled by 1. Engine vacuum and secondly by mixer. Further the air fuel ration is also controlled by the lamba feed back mode (close loop). In normal kits also the transition to gas is very smooth and it switches only after a certain period or rpm.

Having said all this I do agree that SI kits are better than the normal ones, but that do not necessarily mean the normal system is bad for the car.

[saintsinner]

I have a BRC SI on my Indica Xeta since the last 2 years. And yes, holes are drilled into the manifold.

Here are some pics -

1st Pic - The BRC ECU

2nd Pic - The Reducer

3rd Pic - The Fuel Rail, the controls the gas being injected through the 4 pipes. Also has the temperature sensor.

4th & 5th Pic - The four pipes are then connected to the manifold by drilling and screwing in a small injector

More than the pipes there is a huge amount of wiring harness that needs to be put in the car.

[Deeps]

@Sainsinner: what kind of performance and efficiency do you get. I have a xeta running on the tata approved bedini kit with lambda and advancer. There is a definite loss of torque relative to petrol and i get about 17 kmpkg of cng with 100% AC and city driving.

[saintsinner]

^^The performance is good, pickup is much better than other CNG cars i have driven. the refinement can be felt too. I can't tell the real mileage as my office up down is 25 kms both ways, plus i spend quite a lot of time in a standing car with AC on. i usually get about 16km/kg that includes about 2-3 hrs of the idle AC usage. When driving to the other part of delhi or so its like 18 km/kg. Also, its been 10,000 kms since the car has been serviced, maybe that effects the mileage too.

Where is your temperature needle in stop and go traffic on a very hot afternoon? Mine crosses the half mark and the AC trips at times.

[bhp_maniac]

Originally Posted by lucksin

First of all the Gas is not getting injected directly in fact its getting mixed with the air in throttle body of the engine and then it goes in through the valves. correct me if i am wrong that is why we install MIXER to mix the gas with air right at the starting of throttle body.

misfire/backfire only happen if access of gas in injected with low spark. which happens in SI kits as well.

"about ECU pulsating the injectors" i am not able to understand this. so what you say is in-case the car is running fine and suddenly the car is out of gas then the engine will keep on pulsating the injectors ?? well My car gets turned off the moment there is no gas.

What you are telling is correct. Gas is mixed with air at the beginning of throttle body. Regarding misfire/backfire in SI kits backfires in inlet manifold may be very very rare since gas is not mixed with air, but in normal kits its always possible since gas is present right in the throttle body. Once in my Xeta, a backfire happened which spoiled the inlet manifold, throttle body and also the air filter. It happened due to the presence of gas in inlet manifold, and due to the huge amount of heat in inlet manifold. But my damage was over with that. I have a friend of mine, who lost his ECU also with such an incident, his was a 2004 Santro. I know one other Xeta owner who had lost his air filter twice due to such backfire.

Pulsating the injectors:

I meant about petrol injectors. Injectors are nothing but solenoid valves controlled by ECU pulses. By pulsating, I meant that ECU will be commanding the injector solenoid to open, but without fuel since the fuel pump is not powered while running on gas. That is the reason why your car will stop if you run out gas while running, even though your injectors are pulsating. In case of SI kits, the ECU will do the duty of automatically switching to petrol if you run out of gas I guess. Somebody with an SI kit can validate this.

[Deeps]

Originally Posted by saintsinner

Where is your temperature needle in stop and go traffic on a very hot afternoon? Mine crosses the half mark and the AC trips at times.

I've had my car since Dec 2006 and its been on CNG since Jan 2007. Even in the worst of heat and traffic conditions, the temp needle went only upto halfway. but recently, i've noticed that it goes very slightly above the halfway mark...but the AC does not trip. I suspect that there may be a coolant leak somewhere.

[bhp_maniac]

Originally Posted by saintsinner

I have a BRC SI on my Indica Xeta since the last 2 years. And yes, holes are drilled into the manifold.

Here are some pics -

1st Pic - The BRC ECU

2nd Pic - The Reducer

3rd Pic - The Fuel Rail, the controls the gas being injected through the 4 pipes. Also has the temperature sensor.

4th & 5th Pic - The four pipes are then connected to the manifold by drilling and screwing in a small injector

More than the pipes there is a huge amount of wiring harness that needs to be put in the car.

Thats a very neat set up. Dreamy stuff. Can you just confirm on two things.

1. How is the petrol/gas switching. Is it butter smooth ?
2. Where there any problem of misfire/backfire