[1100D]

Originally Posted by chetanhanda

Apart from the gain of BHp with the staright thru pipe.. the tone of the exhaust also changes .. sounds much better also.

By this "straight thru pipe" you mean a perforated pipe inside an outer chamber. What will be the length of the pipe and the outer diameter (assuming that the perforated pipe itself is of the dia of the inlet and outlet)

[chetanhanda]

Originally Posted by 1100D

By this "straight thru pipe" you mean a perforated pipe inside an outer chamber. What will be the length of the pipe and the outer diameter (assuming that the perforated pipe itself is of the dia of the inlet and outlet)

nope !!
No outer chamber, just a straight thru pipe.
Dia of pipe = dia of inlet and oulet ..same throughout
length of pipe = the length of the cat = distance between flange at inlet and flange at outlet
The straight pipe has flanges of same dimensions as the flanges on the original cat, so I simply replace the cat using the original bolts and bushes.
Just take care of the measurements .. if fit is not perfect u can hear a hissing sound from the joints at inlet/outlet from leakage..

[1100D]

Originally Posted by chetanhanda

nope !!
No outer chamber, just a straight thru pipe.
Dia of pipe = dia of inlet and oulet ..same throughout
length of pipe = the length of the cat = distance between flange at inlet and flange at outlet
The straight pipe has flanges of same dimensions as the flanges on the original cat, so I simply replace the cat using the original bolts and bushes.
Just take care of the measurements .. if fit is not perfect u can hear a hissing sound from the joints at inlet/outlet from leakage..

And Also the Pipe is not a perforated one. Right?

My Idea of a straight thru was more aligned to a "glass-pack" as they call it in US.

[chetanhanda]

Originally Posted by 1100D

And Also the Pipe is not a perforated one. Right?

My Idea of a straight thru was more aligned to a "glass-pack" as they call it in US.

yes dude u r right ... not perforated.."desi test pipe" is a bit diff
that glass pack concept is valid for the "muffler"..
for cat the straight thru concept is a "test pipe" with a bung for the fake sensor i.e o2 simulator.

[ananthkamath]

That article does answer a few questions. Namely, removing the cat is worth roughly 5 hp on a 150 hp engine. Considering you can make that extra 5 hp using simple breathing bolt-ons and proper tuning alone, I doubt its prudent to remove the cat. Doesn't make much sense to me.

[1100D]

Originally Posted by chetanhanda

yes dude u r right ... not perforated.."desi test pipe" is a bit diff
that glass pack concept is valid for the "muffler"..
for cat the straight thru concept is a "test pipe" with a bung for the fake sensor i.e o2 simulator.

Do we get O2 simulators in India?

[HKS]

Originally Posted by ab1xlr8

hi guys,
removing the cat con will have negligible effect on the horse power gains in a normal road car, my advice to increase power will be to block the E.G.R valve,which comes with most modern engines

I doubt EGR's come in new SI engines. It comes in almost all diesel engines though.

[abhik]

Post edited by the Team-BHP Support : Please do NOT use more than two smilies per post. Thanks

Originally Posted by ananthkamath

That article does answer a few questions. Namely, removing the cat is worth roughly 5 hp on a 150 hp engine. Considering you can make that extra 5 hp using simple breathing bolt-ons and proper tuning alone, I doubt its prudent to remove the cat. Doesn't make much sense to me.

I would completely agree with you ananth, 5hp on a 150hp engine if taken proportionally will further reduce with a 100hp engine and so on and such gains can be attained by bolt-on add ons like a high-flow filters etc.
But of-course the question then arises on MONEY factor!!
Which does matter to most of us a lot. Removing a cat con and getting a bolt-on kit would have a huge difference in terms of money for the same hp gain. But again replacing the cat con with a straight through pipe which even if called as a "custom" pipe would end of the day still be a "juggard" hence reliability issues.
But i still want to do it!! Anything for "BUTT DYNO"so guys where can i get a straight pipe to replace my Ikon's cat con in delhi.

As far as pollution norms are concerned, if you guys have notice, our vehicles pollute way way lesser than specified measures.
To qoute an example my stock Ikon 1.6(2002 BS2) measures 0.01 CO to a permissible limit of 0.5 so removing the cat con shouldn't be a problem.


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[chetanhanda]

Originally Posted by 1100D

Do we get O2 simulators in India?

I dont think so. You would need them if you had a second O2 sensor.
How many cars in India have 2 O2 sensors to monitor the cat's health ?

Originally Posted by HKS

I doubt EGR's come in new SI engines. It comes in almost all diesel engines though.

EGR system is present in petrol engines also not just diesel engines.

Originally Posted by abhik

I would completely agree with you ananth, 5hp on a 150hp engine if taken proportionally will further reduce with a 100hp engine and so on and such gains can be attained by bolt-on add ons like a high-flow filters etc.

@abhik ,the comparision should not be taken literally and used as a direct formula for calculating gains in our cars.
Let me explain my point..
All these figures depend on the design of the cat and how well the entire exhaust is designed and the nature of the cams so I dont agree that a blanket statement can be made like this.
If an OEM cat is well designed the gain will be negligible, you should not compare dyno charts on some other engine to your engine and say "aha x gains on that = y gains on mine"

Originally Posted by abhik

But of course the question then arises on MONEY factor!!
Which does matter to most of us a lot.
Removing a cat con and getting a bolt-on kit would have a huge difference in terms of money for the same hp gain. But again replacing the cat con with a straight through pipe which even if called as a "custom" pipe would end of the day still be a "juggard" hence reliability issues.

abhik relax.
This is just a hollow pipe there is nothing complex to it, if it was a header I'll say dont even think about it, but for a hollow pipe concept of "jugaaad" and "reliability" should hardly be a concern.
Dude , do you know if you have second O2 sensor for checking the cat's health ? You wouldn't even get a MIL light if you didnt have one. Did you read all the previous posts ?

Originally Posted by abhik

But i still want to do it!! Anything for "BUTT DYNO" so guys where can i get a straight pipe to replace my Ikon's cat con in delhi.

As far as pollution norms are concerned, if you guys have notice, our vehicles pollute way way lesser than specified measures.
To qoute an example my stock Ikon 1.6(2002 BS2) measures 0.01 CO to a permissible limit of 0.5 so removing the cat con shouldn't be a problem.

If your car has a very restrictive cat then you will see some difference in terms of exhaust tone and top end.
The extent of this difference depends on how bad your cat is in the 1st place as compared to a straight through.

It's not guaranteed that you will see a difference , just try it , if it works.. great! if not then lets save the environment and keep our cats on.

[abhik]

@chetanhanda
hey Bro! thanks so much for the info i do wish to try out the change and see how much of a difference it makes to the cars performance but the Ikons exhaust seems more restrictive, hopefully so is the cat-con.

BTW if you could help me, as i was wondering that removing the cat-con, which nomatter what car, does create a certain amount of back-pressure. By losing the cat-con which would also mean loss of back-pressure but would that be good because as per my understanding a certain amount of back-pressure is required right?

[abhik]

Guys Please help me on where i can find or get a straight pipe made for my Ikon 1.6 Rocam

[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
following photo provided by vip3r

[abhik]

Originally Posted by chetanhanda

Dude , do you know if you have second O2 sensor for checking the cat's health ? You wouldn't even get a MIL light if you didnt have one. Did you read all the previous posts ?

The Ikon has just 1 o2 sensor located in the header so i guess that shouldnt be a problem

[rohan_fonseca]

Hey that belongs in the ice section!

[chetanhanda]

Originally Posted by abhik

Guys Please help me on where i can find or get a straight pipe made for my Ikon 1.6 Rocam

I dont think you can get it off the shelf.

Originally Posted by abhik

@chetanhanda
hey Bro! thanks so much for the info i do wish to try out the change and see how much of a difference it makes to the cars performance but the Ikons exhaust seems more restrictive, hopefully so is the cat-con.

Originally Posted by abhik

BTW if you could help me, as i was wondering that removing the cat-con, which nomatter what car, does create a certain amount of back-pressure. By losing the cat-con which would also mean loss of back-pressure but would that be good because as per my understanding a certain amount of back-pressure is required right?

Lets call it "back-pressure" for lack of simpler terminology which we can relate to easily.
Yes we need some amount depending on what kind of power you want.
We had discused this earlier,try going though this if it helps, its an "over simplified" description how your free flow exhaust affects the kind power band of the car w.r.t cams etc.
post#139 http://www.team-bhp.com/forum/413214-post139.html from another thread
There is more to it but to make it simple some stuff has been left out.