[ananthkamath]

Originally Posted by chetanhanda

Lets call it "back-pressure" for lack of simpler terminology which we can relate to easily.

You know chetan, this is something to think about. I used to think that backpressure is something of an old wives' tale, but after having seen atleast 10 SAE papers which talk about backpressure, I'm not so sure now. It isn't something that has been invented in the aftermarket. OE engineers talk about it too, so it is definitely the correct term.

[chetanhanda]

Originally Posted by ananthkamath

You know chetan, this is something to think about. I used to think that backpressure is something of an old wives' tale, but after having seen atleast 10 SAE papers which talk about backpressure, I'm not so sure now. It isn't something that has been invented in the aftermarket. OE engineers talk about it too, so it is definitely the correct term.

That's great ; if its good enough for SAE...it's more than enough for us.
I remember: you, me and Psycho had a nice long "discussion" on this back in 2005.

Dug up my old post from 2005

Originally Posted by chetanhanda

in short low back pressure = higer top end ..

[gandabacha]

does removing the cat con effect the average compared to wad is was wid the ffe system wid cat con ???? is it helpfull for more on low/mid or high range ?

Note from Mod : Please take the time to type out your posts in full words as per Team-BHP rules. Avoid the use of SMS language (wid = with, wad = what, etc), and please take the time to read Team-BHP's rules before posting any more.

[Zenster]

hi friends, I own a Zen 2001 old model. I recently had the clutch overhauled and the head-gasket changed on my car. post that i drove it for about 20kms and the car decided to stall after a speed-breaker. I tried starting it and giving some raise and see if it comes back to life but nogo. I then called the MASS guys (Smart Cars in my case) then came to the site and opened the nuts for the exhaust under the engine bay. The Car started up and remained ON. He then drove it back to MASS saying that there is something stuck in the exhaust system.

At the MASS the supervisor suggested checking the Cat Con. The mechs opened the Cat Con and found the Silica block completely clogged and also broken to pieces. One of the Piece of that block was stuck in the exhaust pipe as well. They then proceeded to break the block in pieces and removed it comepletly. one the Cat Con has become straight hollow pipe. I was told that the Cat Con needs cleaning at 50k kms (I have done 55k) and removing the filling will not cause any harm.

From what is read here, it causes some increase in Power and i can feel it in the pick-up and top-end burst. But my question is that will it cause any sort of harm to the engine or any other system in the car in the long run considering i do a 50kms run everyday? what will be the effect on FE (I get around 15kmpl in city) ? Also when i get the PUC done. what do i expect in the result and any probs that can come in that?

Please reply soon as i dont know how good or bad this change to my car is .

Awaiting a quick response. Thanks in advance.

[Zenster]

No Replies from any experts? Is everyone so busy ? :(
Please respond guys? I need to get my head cleared before i get behind the wheel later today?
HEELLPP

[Atlblkz06]

The condition of the Cat does not affect your engine. You wont do any harm to it by driving it. However, make sure you get it fixed ASAP. Your car's pollution level will be elevated till you fix it.

Removing the Cat gives you a small boost in HP along with a HUUUGE boost in pollution.

Here is my thinking:
You want to remove your cat? Fine, but let me know if you're willing to route a part of the exhaust back into your car. No but you want me, the guy behind you to breathe it right? Well I dont want to breathe in your highly toxic CO and unburnt hydrocarbons because you want an extra 5 HP. I dont want cancer!

I think it's the driver's responsibility to run a car with a Cat. If I had the power to enforce this - I would make cats mandatory on all race cars as well. It's simply not worth the damage to US, not to mention the environment.

This is also why I HATE auto rickshaws. They produce absolutely ungodly amounts of pollution.

Two-way reduction (from Wiki, edited):
*2CO + O2 → 2CO2
CO (Extremely toxic) -> Carbon Dioxide

*CxH4x + 2xO2 → xCO2 + 2xH2O
CxH4x (Nasty smelling Unburnt hydrocarbons) - > Water and CO2!

Originally Posted by Zenster

No Replies from any experts? Is everyone so busy ? :(
Please respond guys? I need to get my head cleared before i get behind the wheel later today?
HEELLPP

[Atlblkz06]

Originally Posted by chetanhanda

Just FYI .. photo of a cat from the Indian swift.
hmm..doesn't it look restrictive now ? doesn't look very "free flowing" to me
Attachment 1909

Going by your face, I hope this is a joke. Merely looking at it and saying "it doesn't look free flowing" makes absolutely no sense at all!

Depending on the type of Cat, the surface area could be MUCH larger than what you see. (3D air path - goes in, then up to filter, then out)

[amit_mechengg]

Originally Posted by Zenster

No Replies from any experts? Is everyone so busy ? :(
Please respond guys? I need to get my head cleared before i get behind the wheel later today?
HEELLPP

i dont think this will affect your engine at all. the same thing happened in my alto and the MASS people cleared all the burnt debris from inside the CATCON and fitted it back. now some parts have flown off in my end can and making rattling noise. but i have observed increase in pick up.
regarding the backpressure i am sure the header design solves that purpose well.

[HappyWheels]

Originally Posted by Zenster

...From what is read here, it causes some increase in Power and i can feel it in the pick-up and top-end burst. But my question is that will it cause any sort of harm to the engine or any other system in the car in the long run considering i do a 50kms run everyday? what will be the effect on FE (I get around 15kmpl in city) ? Also when i get the PUC done. what do i expect in the result and any probs that can come in that? ...

Isn't this what gets done for FFE?

Yes, you will notice some pick-up increase and some more power. I do not think that your engine will be harmed.

With regard to PUC, I think you might just be able to get thru.

[amit_mechengg]

PUC in india is just a gamble, and the whole chain of polititians and RTOs get profited by this. i dont remember a single time i have taken my car to check the PUC. whenever i go on my bike to fill petrol guys come running with the PUC receipts and i hand over 90 rs to him and get 3 certificated of 3 vehicles without physically showing the cars.
when you take a car they will charge you 70rs and when u go on a bike they will charge you 30rs. certificate issued is same.

[jassi]

well i have an ffe and the catcon is removed and my vehicle is almost the same as far as emissions go - i have two puc certs from the same place (hyundai service station), before ffe and after ffe, and the readings are almost the same. Infact the hyundai guy said that ffe (no cat con) will hardly affect emission readings as the engines these days are very refined
On the split side, my 0-100 times have dropped by a few seconds

[Zenster]

Thanks all you guys, I knew i could bank on T-Bhp as always. I was told a lot of what you guys have mentioned by the MASS Supervisor but then i just cant trust these guys blindly and hence revived this thread.

Once again, thanks for the clarification. For now i keep an eye on the PUC numbers so that no one gets Cancer from my joy-ride (seriously)..And enjoy the lil boost in pick-up and the new music from the exhaust note.

Take care friends cheers:

[HappyWheels]

Originally Posted by jassi

...Infact the hyundai guy said that ffe (no cat con) will hardly affect emission readings as the engines these days are very refined ...

It is a 2001 model vehicle, hence my comment that it might just get thru. The age might go against it.

Originally Posted by Zenster

... For now i keep an eye on the PUC numbers so that no one gets Cancer from my joy-ride (seriously)...

Thanks for the concern! (seriously)

[bblost]

Originally Posted by amit_mechengg

PUC in india is just a gamble, and the whole chain of polititians and RTOs get profited by this. i dont remember a single time i have taken my car to check the PUC. whenever i go on my bike to fill petrol guys come running with the PUC receipts and i hand over 90 rs to him and get 3 certificated of 3 vehicles without physically showing the cars.
when you take a car they will charge you 70rs and when u go on a bike they will charge you 30rs. certificate issued is same.

I dont know about Pune.
But in Hyderabad the number plate of the vehicle is photographed and printed on the PUC certificate.

[HappyWheels]

Originally Posted by bblost

...But in Hyderabad the number plate of the vehicle is photographed and printed on the PUC certificate.

Same process here at Bangalore also, in most of the places. Definitely in authorized serviced centers. But you can still get a test receipt written out from the local petrol pump tester.