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-   -   What's a free flow exhaust ? (https://www.team-bhp.com/forum/technical-stuff/2173-whats-free-flow-exhaust-8.html)

Guys,i have often come across this question some threads as to whether we can make FFE's more environment friendly and more importantly so that the car does not fail at the PUC test.
Can sport catalysts be a solution?These are catalysts with more greater flow rate than normal catalysts because of the larger chamber size and is as efficient as a normal cat.

Here is the link to the article
Power gains from a sports catalyst

So what to the pundits think?Also will fitting such a catalyst will not really make the exhaust "free flowing" anymore?

PS Its a nice site for learning the basics of tuning.

how important is the primary muffler in an FFE?
im running a straight pipe in my car and am really happy with the top end. the low and mid range has slightly gone down though.
so would a primary help?
P.S i got my FFE done at BAR.

wildchild by saying primary muffler did you mean the Auxiliary Muffler ? If yes the Auxiliary Muffler is the one which reduces the sound at the end can. This usually has glass and steel wool.

Usually most installs would have an expansion chamber instead of the auxiliary muffler. The expansion chamber is usually installed after the header.

I would recommend that you go back to the installer and the car tuned once. If the power isn't up to your expectation, then check for leaks in the headers.

thanks mate! going to pay him a visit today.

what exactly does an expansion chamber do? and what is an auxilary muffler?

and why is it called 4-2-1 or 4-1 for FFEs. whats the relevance?

My Spark's muffler is kind of broken due to rust (will post a pic soon). The OEM muffler costs around 3k+.

1. Should i go for OEM / Aftermarket muffler ?
2. How much will an aftermarket muffler cost ?? warranty ??
3. I want my vehicle to be rev freely and not get restricted. Does an aftermarket muffler allow this ?? or i need a full FFE ?/

Hi, i would like to go for a FFE on my i20 Asta Crdi, Let me know which one to choose ? without harming my machine. Someone suggested me Rimmers Bolt on stuff, i am not much into this FFE thing but still i need a decent sound on my ride.

Are we not required by law to fit a catalytic converter in our cars or to rephrase the question, is it not illegal to remove the cat con?
Will it cause my car to fail a PUC test and more importantly will my car become less green if I fit an FFE?

Hari

I am sure this topic will have been discussed somewhere on the forums, though I was unable to locate the exact threads. So mods, if this topic has been discussed, please merge this thread with the right one.

Is it possible to only fit exhaust headers on a car, without touching the catcon and other components? Will it provide more power than the stock exhaust manifold setup?

To the best of my knowledge replacing the manifold with headers should allow the exhaust gases to flow with less restriction and this will ease up the load on the engine. I am also aware it will be lesser than a complete FFE. However I am only interested to know if simply moving from manifold to headers will produce any improvements. And if yes, how much?

Hi,

Let me split and address your last update in parts.

"Is it possible to only fit exhaust headers on a car without touching the catcon and other components?"

Answer is Yes, if the B (catcon) and the C (endcan) are in good condition because
after all the tuners try to replicate the set up and fabricate them accordingly.
@performance gurus: Please correct me if i am wrong.

Will it provide more power than the stock exhaust manifold setup?

This should be answered by the performance gurus and i will be closely monitoring
the thread. Although i believe this has nothing to do with the end can as it has the
muffler placed and retaining it will have the exhaust note muted similar to stock
though you can have the end can fabricated and muffler designed to have a muted
exhaust note.

You can also follow the below thread to understand the impact of removing the catcon to achieve an performance gain.

http://www.team-bhp.com/forum/techni...its-worth.html

Hope this helps.

Cheers,
Ayyappan

Thanks Ayyappan for the answer. I am not at all interested in removing the catcon. The only mod I am looking for is to replace the exhaust manifold with headers, maybe make it a bit quieter in the process too. As yet I haven't had any trouble with the existing exhaust system in terms of rattles or any other issues. All the PUC checks are being carried out on time and the readings are quite good.

The only objective in this exercise for me is to see if by using exhaust headers I can get x number of horses more from the existing engine. This increased power may help in better acceleration or maybe better AC performance. And this x number of horses will then be compared to the cost of making the mod and that's what will influence my final decision.

I have spoken to several people regarding this who are into mods and they have all given me similar opinion.
You cannot just fit and endcan which make a growling noise and claim that you have a FFE. The entire exhasut system needs to be changed right from the header to the muffler to get performance gains. Obviously, the CATCON has to be removed. You cant have both ie perfromance as well as FE/ meeting emission norms.
Decide what you want at the end of the day FE / performance and then go about it.

Err, is the endcan the same as an exhaust manifold/headers? I guess not, though I am not an auto expert. To the best of the knowledge I have gained from the internet, the job of the exhaust manifold is to collect the exhaust gases from the cylinders and pass them onto the exhaust pipe which will take them out of the vehicle. An exhaust manifold can be replaced by headers, which have an independent pipe routed from each cylinder to collect the gases. The headers, by design, are supposed to allow easy passage of the gases to the tailpipe. So my logic is if I replace the stock manifold with headers (maybe custom made), I should get some performance increase. I am not interested in fully replacing the exhaust, getting the catcon out or getting any particular exhaust notes.

If my above reasoning is correct, simply by replacing the stock manifold with headers, I should get x amount of performance boost. I need someone to confirm if the above reasoning is correct, and if yes, give me an approximate idea about the improvement, i.e. will it be 1%, 5% or some other figure.

Hi, have a quick question on FFEs. Gurus, please help.

Can the sound be tuned in such a way that at idling and in normal city driving, the sounds stay as stock. Post 3000 - 4000 RPMs while redlining, the meaty exhaust note comes into picture.

Is such a kind of setup possible. Kindly Assist.

Thanks

Raj

Is this for your Gypsy? Remember the multiplication rule. If the gypsy is a 1L, your exhaust should be atleast 5L in volume. So do calculations accordingly. Also, make sure you dont alter the diameter of the pipe much. Max you should go to is 1-3/4inch. I have seen people have MASSIVe 2-3 inch pipes etc and it is all nonsense. also, dont have an exhaust tip. It helps a little trust me.