Discussion in 'Engine Compartment' started by ProBiker, Feb 23, 2011.
@gurjinder, Italia-Linea, I am not sure what those last posts are supposed to mean. Do we need to tune our engines to flout pollution norms? Normally I think factory settings are *way below* what is required by law, (as seen on the certificates about the actual reading vs the allowed limit) , so there is a lot of margin for improvement and still be a responsible citizen. Let's not just chop off a filter, but add a better filter.
btw, what is the tuning/remap required to improve the low rpm/low gear drivability. My car is a PITA in bumper to bumper traffic.
no, if you read the posts carefully it was just a mockery of how the authorities are serious about issuing pollution certificates.
the current norms in india have a lot of tollerance to factory actuals as all our cars are Euro 4 complaint. they pollute very less. if you are providing your engine with better air and perfect fuel qty at right time of acceleration then it pollutes less.
Even if your car is euro 4 and you floor the pedal it will pollute like hell.
so a tuning process of engine is not to flout any pollution norms. its a process of bettering the power output of the engine
The cat is of no technical use in practical terms. Mother nature completes the reduction/oxidation process within 4 hours without building up H2SO3 and traces of Cyanide. The cat needs for mid range a fairly lean mixture, which leads to higher fuel consumption than necessary compared to engines without cat. This in turn means a higher CO2 output. Nitrous oxide and CO as well as hydrocarbons are not a problem as they are broken down safely in nature. In any case a well maintained combustion process is low on HCs in general.
The DPFs are also a complete waste of time. The are responsible for a 8 to 15% in power drop (depending on the size of the engine, which means that they increase the fuel consumption accordingly. Additionally at the regeneration cycle quite a bit of fuel is thrown at them to burn of the soot/particles.
When the mapping is done properly, smoke will not be detected even under heavy load.
The legal limits from the technical point of view are a farce. Minimum fuel consumption is required to achieve the lowest amount of pollution. This can be achieved with improved air intakes, which are designed to improve low end torque. This improves fuel economy to start with because the power to drag ratio increases. This also allows to shift earlier helping fuel consumption.
The factory map is never a perfect map as it has to cater for too many scenarios. With conditions changing geographically also the required maps change when wanting to achieve the best results.
With fuels having octane ratings in the low 70s to over 100 the ECU software faces the biggest challenge. Altitude, temperature and humidity (an extreme in India because from sea level to the Himalayas). Another of other factors come into play too, but this would go far to far right now.
In essence professional tuning is not about outright power. It is about a package that also considers environmental points. My competitors and myself in Europe have to adhere to very strict regulations (annual technical and pollution inspection, which is required by law). We can do it even if we more than double the specific output of a factory spec.
Regarding the low rpm torque output:
Depending whether it is a normally aspirated or a force induced engine (the design principles vary greatly) an improved AIR is the first stop. The intakes have to be specifically be designed for the car and should not just be some bits thrown together making it a kit suitable for use in a car. Too many points need considering.
The correct re-map will aid the improvement. A re-map alone will show some good torque increase in force induced engines. In normally aspirated engines it is increasing torque very limited without a dedicated AIR.
I am not sure if removing the catalytic converter is the way to go. Yes a cheap alternative, but not so good for pollution. Besides, I heard a free flow is not good for low end grunt. Already the MJD is a pain in B2B traffic.
In India, especially in Bangalore, where our respiratory systems seem to be part of vehicular exhaust, 4 hours will do a lot of damage. Besides, who knows what condition the engine is, why not keep the catcon just in case. I was going through a FFE thread in teambhp and it was mentioned there that one pollution check failed after removing the catcon.
Just to add, my contention here is not that a pollution free FFE cannot be achieved, but as you highlight, we need a lot of tweaking around the ECU map and/or air intake, take measurement and again tweak. I don't think it is a simple matter of removing the catcon and getting around PUC checks. If I were to go for a FFE, I would insist on a local PUC pass before handing over the cheque.
First things first.
What is that mysterious "catcon" just after the turbo in a Multijet?
Its just a soot trapping contraption. Nothing else. It is there so that the exhaust from the diesel engine does not "look" bad. It traps a certain amount of soot. But when flooring the pedal it cannot stop all of it.
It does not cure the exhaust fumes. The toxicity of the fumes will be the same with and without the cat. It's just that the soot will be a bit less.
In any case , the real harm to the environment comes from petrol engine exhaust. That is more dangerous.
i beg your pardon but its not a mere soot trapping device. it plays an important role of oxidation mainly to convert carbon monoxide to CO2 and breaks down toxic hydro carbons to CO2 and Water vapor or H2O.
without the catcon on modern vehicles the world will be a hell to live in.
there are bypass catcons or free flow catcons which are less restrictive and also do the function of reducing toxic gases. they are a bit costly though.
yes a free flow is not always good for low end grunt. for example on my other car when i fitted the FFE i got it designed for low end and mid range torque. so i just lost small amount on low rpms in which i stay for very short time and then mids around 2500 + rpms are very good and highs are almost stock.
i lost the catcon but the muffler is filled with glasswool to an extent that the sound is not too loud.
my car is still within permissible pollution limits according to my city law. i always keep checking it on CO machine.
to compliment to the FFE i also have a free flow air filter. in any case my AIR DUTY on MAF is balanced, so its very less polluting.
the above is on petrol car.
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