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Originally Posted by redfire But then why are people going for free flow filters and exhaust to increase low end torque? What I understand, for example, a stock petrol swift with OE air filter and exhaust manifold is never able to catch up one with a free flow filter and good exhaust system with headers. Isn't manufacturers doing this for cost cutting / emission norms, efficiency or detuning? Or are you saying that a moded car is not really having any advantage in low end torque, but just a feeling of it due to more free revving engine which reaches higher RPMs faster than a stock car? I really would like to know as I am planning for a FFE. |
OEM Filters and Exhaust are designed for optimum efficiency as they are strictly bound by emmission norms and have to produce a product for a mass where 90% of the people, nomatter what car you might be talking about, will pop the question-"Wo Sab to theek hai! Par mileage kya hai gadi ki?" Hence everything is designed for FE as priority and performance is compensated with good handling etc. in short comes as secondary.
(Please keep in mind the above is only being reffered to car being produced for the majority audience and not aimed at a specific niche. Eg: Cars in the 3.5lacs to 5lacs segment.)
What you said was correct in terms of manufacturers detune or more appropriately have a conservative attitude because of - "cost cutting / emission norms, efficiency etc."
And the above also concurs with what RedMM said but it is not that modding a car with an FFE and a high-flow filter reduces the torque...its just how you mod it, how you design an FFE to give you what you want, to do what you want it to do to maximize output of the small throttle bodies, cams, heads and other restriction which one might not want to mod early on. Ofcourse at the end of the day a TB can be enlarged, cams and heads can be replaced, ported, pistons polished and what not.
A wrongly designed FFE, headers will reduce surely torque or top-end because there design restrictions to keep in mind.
An oversized air-filter does not necessarily mean your car would be faster, the extra air being fed in will not be used as there is a limit to the volume of air which can be used/combusted by a specific engine.
Similarly an undersized one will leave the engine gasping for air.
So modding means enhancing performance but it should be backed with knowledge about the correct way to mod.
Last edited by abhik : 24th June 2008 at 16:48.
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