Carb Zen w/o the muffler

raghuram.cg · 16th April 2006, 12:06

Friends,
Just today - removed the muffler from the 99 ZEN.The exhaust note is racy and there is a feeling of more power when driven.
The engine has done 92K kms..

A few questions
1)Does this affect the engine in any way.I have heard that removing the muffler is detrimental.

2)By what does the FE go down.

3)is it a good idea to just have a straight pipe from the cat con and continue to use the vehicle.

Any thoughts on this would help.

Thanks
Raghuram C G
Bangalore

angelfire · 16th April 2006, 14:34

hi there...
wel one of my friend has tried it out...a straight pipe from the cat...man!!...the exhaust note is amazin....but there is a drsatic drop in FE....thats mostly because the sound`s gonna be so great that you tend to rev a lot.....nd effects on the engine....guess the gurus wil it answer for you...

buzzin_hornets · 16th April 2006, 17:41

Bad idea dude!! get a sport muffler fitted or put the OE muffler back! ur gonna damage ur engine!!!!

Mpower · 16th April 2006, 18:41

Quote:

Originally Posted by buzzin_hornets

Bad idea dude!! get a sport muffler fitted or put the OE muffler back! ur gonna damage ur engine!!!!

Can you explain how ??

raghuram.cg · 17th April 2006, 15:17

Can someone shed more light on this matter.I know that it harms the engine.What actually happens?

Raghu

raghuram.cg · 18th April 2006, 15:52

Seems like al are busy with the Drag at Jakkur on sunday

.Any replies are appreciated on the questions.
Raghu

Fuelled · 18th April 2006, 17:26

Not Sure but i've heard that too free flow a exhaust lets out all burnt gases much quicker from the engine manifold(a set of pipes that collect exhaust gases from the engine cylinder) area..
though this reduces force needed to push out burnt gases.. but it causes the valves to burn out.

If wrong, some one please provide the correct info... cause this question has dogged me too over past some time.

Psycho · 18th April 2006, 17:54

Points to be noted if you remove the muffler:

1) Some engines require a bit of back pressure for the initial torque which is created by the muffler this may also lead to drop in the FE due to free revving
2) Mufflers are meant to reduce noise let them be a freeflow type or a OE

shibujp · 18th April 2006, 18:08

I think the key word here is "back pressure".

When you have a common exhaust manifold/chamber all the cylinders put out the exhaust into the same chamber. Now the firing order in most cars being sequential this causes a situation where you have the exhaust gas from one cylinder in the chamber lowering the difference in pressure between the chamber and the next cylinder due to expel the exhaust. This is what is called "back pressure". the two effects here are

- The pressure in the cylinder is very high compared to the exhaust manifold and enables the sucking out of the exhaust from the cylinder. However the back pressure results in comparitively less exhaust sucked out compared to what will be if you had no back pressure.
- the back pressure kind of cushions your piston head and valves. So this technically entends the life of your engine and reduces wear and tear.
- All restrictive components along the exhaust line contribute to this build up in back pressure i.e your manifold design, the cat con, muffler etc. So removing any of these restrictive components decreases your back pressure.

I think the second point here is what is damaging to your engine. However this might be over a lot of time or mileage. it isn't anything thats gonna happen in a very short period of time. i also haven't seen much issue made of this when I was researching for fitting a free flow exhaust for my car.

Hope this helps.

Drive on!!
Shibu

P.S - i think there was a technical article on back pressure somewhere on this forum but I can't seem to find it. Will post the link when i do.

16th April 2006, 12:06	#1
raghuram.cg BHPian Join Date: Jan 2006 Location: Bangalore Posts: 198 Thanked: 112 Times View My Garage	Carb Zen w/o the muffler Friends, Just today - removed the muffler from the 99 ZEN.The exhaust note is racy and there is a feeling of more power when driven. The engine has done 92K kms.. A few questions 1)Does this affect the engine in any way.I have heard that removing the muffler is detrimental. 2)By what does the FE go down. 3)is it a good idea to just have a straight pipe from the cat con and continue to use the vehicle. Any thoughts on this would help. Thanks Raghuram C G Bangalore
	() Thanks

16th April 2006, 14:34	#2
angelfire BHPian Join Date: Sep 2005 Location: Mangalore/Chicago Posts: 251 Thanked: Once View My Garage	hi there... wel one of my friend has tried it out...a straight pipe from the cat...man!!...the exhaust note is amazin....but there is a drsatic drop in FE....thats mostly because the sound`s gonna be so great that you tend to rev a lot.....nd effects on the engine....guess the gurus wil it answer for you...
	() Thanks

16th April 2006, 17:41	#3
buzzin_hornets BHPian Join Date: Dec 2005 Location: Mumbai Posts: 236 Thanked: Once View My Garage	Bad idea dude!! get a sport muffler fitted or put the OE muffler back! ur gonna damage ur engine!!!!
	() Thanks

17th April 2006, 15:17	#5
raghuram.cg BHPian Join Date: Jan 2006 Location: Bangalore Posts: 198 Thanked: 112 Times View My Garage	Can someone shed more light on this matter.I know that it harms the engine.What actually happens? Raghu
	() Thanks

18th April 2006, 15:52	#6
raghuram.cg BHPian Join Date: Jan 2006 Location: Bangalore Posts: 198 Thanked: 112 Times View My Garage	Seems like al are busy with the Drag at Jakkur on sunday .Any replies are appreciated on the questions. Raghu
	() Thanks

18th April 2006, 17:26	#7
Fuelled BHPian Join Date: Dec 2005 Location: delhi Posts: 252 Thanked: 2 Times	Not Sure but i've heard that too free flow a exhaust lets out all burnt gases much quicker from the engine manifold(a set of pipes that collect exhaust gases from the engine cylinder) area.. though this reduces force needed to push out burnt gases.. but it causes the valves to burn out. If wrong, some one please provide the correct info... cause this question has dogged me too over past some time.
	() Thanks

18th April 2006, 17:54	#8
Psycho Senior - BHPian Join Date: Jul 2004 Location: Bangalore Posts: 1,043 Thanked: 110 Times View My Garage	Points to be noted if you remove the muffler: 1) Some engines require a bit of back pressure for the initial torque which is created by the muffler this may also lead to drop in the FE due to free revving 2) Mufflers are meant to reduce noise let them be a freeflow type or a OE
	() Thanks

18th April 2006, 18:08	#9
shibujp Senior - BHPian Join Date: Mar 2005 Location: Trivandrum Posts: 1,753 Thanked: 3,225 Times View My Garage	Back Pressure I think the key word here is "back pressure". When you have a common exhaust manifold/chamber all the cylinders put out the exhaust into the same chamber. Now the firing order in most cars being sequential this causes a situation where you have the exhaust gas from one cylinder in the chamber lowering the difference in pressure between the chamber and the next cylinder due to expel the exhaust. This is what is called "back pressure". the two effects here are - The pressure in the cylinder is very high compared to the exhaust manifold and enables the sucking out of the exhaust from the cylinder. However the back pressure results in comparitively less exhaust sucked out compared to what will be if you had no back pressure. - the back pressure kind of cushions your piston head and valves. So this technically entends the life of your engine and reduces wear and tear. - All restrictive components along the exhaust line contribute to this build up in back pressure i.e your manifold design, the cat con, muffler etc. So removing any of these restrictive components decreases your back pressure. I think the second point here is what is damaging to your engine. However this might be over a lot of time or mileage. it isn't anything thats gonna happen in a very short period of time. i also haven't seen much issue made of this when I was researching for fitting a free flow exhaust for my car. Hope this helps. Drive on!! Shibu P.S - i think there was a technical article on back pressure somewhere on this forum but I can't seem to find it. Will post the link when i do.
	() Thanks