Re: What's a free flow exhaust ? Quote:
Originally Posted by shelleve Hi All,
I couldn't find any information about this through my search on tbhp. Mods please move this post to correct thread if I am posting it i a wrong thread. I have a polo 1.6 and the engine is very sluggish and I thought going with the basic mods i.e. a CAI and FFE will add that extra punch which is required. However, one question about FFE which I would like to ask is the O2 sensor. In Polo the O2 sensor is placed at the conjunction of all the 4 pipes coming from the cylinders. Now if I choose to go for FFE with 4X2X1 where would the O2 sensor be put. A lot of people mentioned that for them it was placed on 2nd cylinder or 1st cylinder, but thats not the right way of doing it. Is it? As that would cause some cylinders to run lean/ rich. Also if I put the same at the cross section where are the 4 exhaust pipes meet then will it not be too far from the cylinders, as the O2 sensor works on the exhaust gas temperature to trigger a voltage. Also, after installing FFE what will happen to the pollution check which I have to get done in Delhi, would that be hampered? Not really sure if my facts are correct here, but some guidance would be great. Also, please guide which FFE is the best, and where can I get it done in Delhi?  |
Your doubts are bang on, shelleve!
Positioning the o2 sensor in any other fashion than the aoem fitment is guaranteed to sense not the best readings for oxygen content in ex gas. So you are guaranteed to get lower efficiencies. Infact I am also running my GETZ on one with the lambda sensor on just one cylinder. My modifier shabber had already made one out for me and I did not gabble him with my lambda sensor knowledge and spoil his day!
And you rightly put it, all the AOEMS in euro 4 are running close couple cat cons for the only reason to get fast operating temperature for the thermocouple, they are all using zirconium catalyst for sensing oxygen! So positioning the lambda sensor in downstream is only going to delay the o2 signals to engine ECU and allow the engine to run on its standby logic which again deems that your combustion efficiencies go for a toss.
Passing Indian exhaust norms is a breeze, it still certifies u an euro 2, with 0.05% CO and 750 ppm HC which is a pity! Even my Carb ZEN passes it  . So no worries on it! |