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Old 22nd February 2008, 01:23   #16
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Originally Posted by hellspawn View Post
And how do you know who is good and who decides which "headers" manufacturer is good?Because you wont get to know unless you have spent some time with the car.Also,the damage to the engine we are talking about is noticeable only after a long period of time.
Well, if you're asking about me specifically, don't worry, I've got my information down pat.

As for a regular person, I'd expect him/her to do what anyone does. Research. Look around and see who is the best. That's what professionals do, they make things well.

And let me tell you, if headers are badly designed, they will fry your engine in 10,000 km just as easily as they will in 50,000 km. With the way some of us drive, 10,000 km is 3 months worth of driving.

Zubair, as in Ali Jung? He's doing cars now?!
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Old 22nd February 2008, 03:02   #17
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Originally Posted by v1p3r View Post
Well, if you're asking about me specifically, don't worry, I've got my information down pat.

As for a regular person, I'd expect him/her to do what anyone does. Research. Look around and see who is the best. That's what professionals do, they make things well.

And let me tell you, if headers are badly designed, they will fry your engine in 10,000 km just as easily as they will in 50,000 km. With the way some of us drive, 10,000 km is 3 months worth of driving.

Zubair, as in Ali Jung? He's doing cars now?!
No,Im not talking about you,but a regular person....without the aid of team-bhp.
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Old 22nd February 2008, 04:29   #18
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i guess not zubair is the owner of a shop near hbr layout but he aint no expert he has a good collection of cars but all ruined

and sorry in the earlier post when i rotte running i meant ruined by all unwanted mods


red metallic rims on a blank endaviour

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Old 22nd February 2008, 05:37   #19
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this is real nice reading
Stuff you wish you knew about intake manifolds - Ultimatecarpage.com forums

Waiting To Inhale - TPI - GM High Performance - July 2000 - ThirdGen.org

cheers
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Old 22nd February 2008, 07:24   #20
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http://www.team-bhp.com/forum/techni...its-worth.html
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Old 22nd February 2008, 13:28   #21
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I guess, the discussion here is about exhaust headers.. not intake manifolds.. the second link is a nice read neverthe less..

Here is what i know about headers :
the Header/ exhaust manifolds main job is to suck the exhaust gases from the cylinder during the exhaust stroke. The issue here is how well the header sucks the air out of a cylinder..This is important because performance of the engine depends on how clean the charge is inside the cylinder. It is also important to create a negative pressure gradient inside the cylinder by sucking out the air so that fresh charge is sucked in to the cylinder for the next power stroke. Another issue is that the time duration the exhaust valve is open depends on the RPM the engine is running. So typically at lower RPMs the exhaust valve is open for a longer duration and at higher RPMs exhaust valve is open for shorter duration. So a header design is always dependent on the RPM range and the amount of waste gas to be expelled. Bigger primary pipes help in expelling larger quantity of gas at high RPM and smaller dia pipes help at lower RPM. This is because you should visualize the exhaust gases passing through the pipe as a series of pulses (because of opening and closing of exhaust vlaves) at high RPM, there are more pulses in the manfold and a larger dia pipe helps in pushing the pulses towards the rear more efficiently. The pipe dia must be so chosen that the velocity of these pulses is not slowed down for peak performance. So a header provides for smooth and unhindered flow of hot gases from the engine to the rear of the car..But there are 4 cyliders and only 1 pipe at the end. How does this merge together..This is called a collector. Design of a collector is crucial for header design as exhaust pulses from 4 cylinders collect in to one pipe. A collector must be designed in such a way as not to hinder velocity of gases in the pipes. Here is where a skilled fabricator puts in his magic.
Now typically, every header is desigend for improving performance at a certain RPM range, short primary tubes help in faster expulsion at higher RPM and longer primaries help in low RPM performance but this affects high RPM performance.
I read some where that best headers are "NO HEADERS" but it is not practical considering city driving because the noise would be too loud.
here is nice link for further reading: HEADERDESIGN.COM - Header Design Concepts
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Old 22nd February 2008, 13:56   #22
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Headers can be installed and do not affect the cat cons. Headers will not damage the engine.

Unless done by a dunce who doesnt understand what headers mean!
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Old 22nd February 2008, 14:23   #23
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Quote:
Originally Posted by redfire View Post
Good thread, was waiting for it. Would like to know the effect of headers from the Gurus. Also, is it possible to install headers without removing catcon? I am planning headers but don't want to remove catcon. Can we fix the catcon anywhere else than the manifold?
The headers are the first part of the exhaust and does not affect the cat con which is mostly installed in the mid / rear end of the exhaust systems.
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Old 22nd February 2008, 14:36   #24
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The pulses from the head travel at the speed of sound ,and are made to return during overlap of the valves to help scavenge.And are very effective in multi cylinder engines,each cylinder being at different strokes can compliment the others.The dia and length are changed to suit the required wave length and return time required.Previously in F1 the intake runners lengths were varied with RPM until they were banned.They work on the same header principle.
cheers
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Old 22nd February 2008, 15:11   #25
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Originally Posted by headers View Post
The headers are the first part of the exhaust and does not affect the cat con which is mostly installed in the mid / rear end of the exhaust systems.
Isn't the cat con installed just behind the exhaust manifold due to the reason that cat needs to heat up rather quickly to be efficient.

I remember in Mag's car the header is followed by the intermediate pipe and then by the muffler.
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Old 22nd February 2008, 15:48   #26
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Quote:
Originally Posted by Sankar View Post
Isn't the cat con installed just behind the exhaust manifold due to the reason that cat needs to heat up rather quickly to be efficient.

I remember in Mag's car the header is followed by the intermediate pipe and then by the muffler.
The cat con is usually right after the headers and before the muffler / free flow section.

Some cars have the cat con in the muffler section too.

The cat con design is dependent on the type of car and the volume of exhaust gas etc etc. There is no single cat for all cars and thats why they are prohibitively expensive for a small carbon structure cage sitting inside your tiny enhaust.
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Old 22nd February 2008, 15:49   #27
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i was just visualising the valves slapping against the seats when there is no back pressure at all and the damage it can cause to valve stem as well as the seats.but all F.F.E. are not like that ,they improve the flow of exhaust gasses but not open exhaust fully.
gurus you have a major role here to be responsible enough to clarify the doubts.
ram
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Old 22nd February 2008, 16:45   #28
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Originally Posted by ram_hyundai View Post
i was just visualising the valves slapping against the seats when there is no back pressure at all and the damage it can cause to valve stem as well as the seats.but all F.F.E. are not like that ,they improve the flow of exhaust gasses but not open exhaust fully.
gurus you have a major role here to be responsible enough to clarify the doubts.
ram
I'm not a guru but just my two paise...

Backpressure does not cushion the valves slapping against the seats. It does all the time and the valve seats are designed to take the pounding. A badly designed exhaust can increase the operating temperature of the engine and heat is what's going to destroy the exhaust valves and the seats.

For the exhaust to work it doesn't need backpressure. A good exhaust is all about sound waves and harmonising the pulses... the pulses are used to scavenge the exhaust gases from the cylinder. If the pipe harmonics ain't right the headers would scavenge fresh mixture along with the burnt gases and some badly designed headers would push back the burnt gas back into the chamber before the valve closes.

A properly designed header should help scavenging the burnt gases from the chamber and help in sucking in a bit of extra the fresh mixture during that gap of valve overlap and at the same time preventing it from going out through the exhaust valve by pushing it back into the cylinder. These are done by sound waves or pulses.

The connecting of pipes from different chambers at some specified length and in some specified order is to utilise these negative and positive sound waves/pulses to scavenge and fill up the chamber.

The only damage a poorly designed exhaust can do to the engine is through excess heat. Heat is what kills the valves and the seat.
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Old 22nd February 2008, 17:47   #29
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oh ,is it the heat that was destroying the valves.isnt heat generated almost proportional to the rpm at which the engine is running,more heat-more fuel-more rpm.like more fuel is fed at lower gears when power is required and the engine rpm is also high.and more heat is also generated and used.so does it mean that a guy travelling at high rpms can damage his valves even without a F.F.E.
and does it mean that a guy with a F.F.E.driving at sedate rpms is safe and he wont have his valves blown.

ram

Last edited by ram_hyundai : 22nd February 2008 at 17:48.
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Old 22nd February 2008, 18:48   #30
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Quote:
Originally Posted by alias View Post
zubair u mean hot...some thing

well the guy is experenced alright but only in ruining good cars thats all i can say
Please elaborate! i would love to know more!
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