exhaust question
Thread Starter
New Member
Joined: 12-01-05
Posts: 73
Likes: 0
From: Lancaster, PA
exhaust question
This is going to seem like a newb question, but i would like to put dual exhaust on my cobalt, but i dont want to void the warrenty. I would like a dual exhaust system, anybody know where i can find a good one and how to not void the warrenty?
Banned
Joined: 12-18-05
Posts: 17,838
Likes: 1
From: North Jersey
A) You can't do a dual exhaust on a 4 cylander
B) Exhaust doesn't void the warranty.
you can have a splitter custom fabbed, that's about it. please search, as there's several threads about this topic
B) Exhaust doesn't void the warranty.
you can have a splitter custom fabbed, that's about it. please search, as there's several threads about this topic
Banned
Joined: 12-18-05
Posts: 17,838
Likes: 1
From: North Jersey
no... a dual exhaust would be exhaust pipes coming from 2 seperate banks of cylanders... a 4 cylander car doesn't have 2 banks of cylanders... you can get a splitter, or run a muffler with an extra pipe out of it, but it's not a dual exhaust, technically. i guess, there's the possibility of going with a custom exhaust manifold to accomodate a true dual exhaust, but i don't see why anyone would want to do that
Senior Member
Joined: 08-17-06
Posts: 3,795
Likes: 0
From: Rochester Hills, MI
no... a dual exhaust would be exhaust pipes coming from 2 seperate banks of cylanders... a 4 cylander car doesn't have 2 banks of cylanders... you can get a splitter, or run a muffler with an extra pipe out of it, but it's not a dual exhaust, technically. i guess, there's the possibility of going with a custom exhaust manifold to accomodate a true dual exhaust, but i don't see why anyone would want to do that
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
Senior Member
Joined: 09-26-06
Posts: 9,753
Likes: 0
From: Marlton, NJ
Then you don't know about the complete lack of backpressure burning up cylinders, as well as any bottom end you may have had, unless you are pushing massive amounts of HP. You could do a wannabe dual exhaust which would be single from manifold/header dualed out somewhere around the cat or after the cat. Not sure about space under the car. Performance won't get any better with this setup as opposed to a nice mandrel bent single exhaust though.
Senior Member
Joined: 02-25-06
Posts: 3,246
Likes: 0
From: Dacula, Georgia
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
Backpressure is resistance to flow. Go jogging for 2 miles with your nose taped closed and breathe through a drinking straw, then explain to me how that's good.
Too many people confuse backpressure with velocity. When you lose velocity in an exhaust system, then you lose scavenging. When you lose scavenging you lose flow. When you lose flow, you lose power. Backpressure causes you to lose flow also, which causes a loss in power.
BTW, lose the person comments. It causes me, along with other people to lose respect for you.
Senior Member
Joined: 02-25-06
Posts: 3,246
Likes: 0
From: Dacula, Georgia
Anyone who thinks backpressure is good is an idiot.
Backpressure is resistance to flow. Go jogging for 2 miles with your nose taped closed and breathe through a drinking straw, then explain to me how that's good.
Too many people confuse backpressure with velocity. When you lose velocity in an exhaust system, then you lose scavenging. When you lose scavenging you lose flow. When you lose flow, you lose power. Backpressure causes you to lose flow also, which causes a loss in power.
BTW, lose the person comments. It causes me, along with other people to lose respect for you.
Backpressure is resistance to flow. Go jogging for 2 miles with your nose taped closed and breathe through a drinking straw, then explain to me how that's good.
Too many people confuse backpressure with velocity. When you lose velocity in an exhaust system, then you lose scavenging. When you lose scavenging you lose flow. When you lose flow, you lose power. Backpressure causes you to lose flow also, which causes a loss in power.
BTW, lose the person comments. It causes me, along with other people to lose respect for you.
in theory you are correct, in physics your wrong.. you have to have backpressure to a certain exstinct or nothing will happen...
i serously doubt my respect will go down from flaming dumb comments
Senior Member
Joined: 02-25-06
Posts: 3,246
Likes: 0
From: Dacula, Georgia
and this goes in hand with a backpressure discussion how? if you want to discuss engine math and equations we can... or we can continue backpressure
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
Who said anything about engine math and equations?
Here's a quote from myself I posted at *************** that helps explain, followed by a link to a post here, at CobaltSS.net where a few people, including myself, explain where the backpressure myth originated.
https://www.cobaltss.net/forums/show...hlight=exhaust
Putting any type of restriction in the exhaust system (a muffler) will also change the timing of the pulse waves. Again, this has to be matched perfectly in order to gain maximum power. It requires a lot more time and money than a lot of us have. Normally we'll settle for "good enough".
Regardless, the muffler still adds resistance to flow even if a minute amount. This restriction will change the power levels in certain engines if the restriction is high. If there is any power increase anywhere in the RPM range after adding a muffler, then there's another variable that was overlooked while tuning the exhaust for said engine.
Here's a quote from myself I posted at *************** that helps explain, followed by a link to a post here, at CobaltSS.net where a few people, including myself, explain where the backpressure myth originated.
https://www.cobaltss.net/forums/show...hlight=exhaust
The key to a performance exhaust system is to provide as little backpressure as possible while still keeping exhaust velocity up.
The exhaust system, in any car, must match the desired output of the engine it's attached to. It's one of the pieces of the "combination" of parts, and should be treated as one.
Are you building a street engine and plan to use a low RPM cruise range? Or do you plan on a high RPM engine in a drag car? Is the car heavy, or light? Is it FWD, RWD, or AWD? Automatic or manual transmission? Etc., etc.
There's an interesting thing that happens in the exhaust system called pulse wave scavenging. For every high pressure exhaust pulse wave, there's an equal and opposite negative pulse wave that follows the exact path from the moment the high pressure pulse leaves the tailpipe. In theory, it flows right back up to the exhaust valve from which it came and is ~180* out of phase with the high pressure pulse.
The negative pressure creates a "pocket", for lack of a better term, which the next pressure wave will see as soon as the exhaust valve begins to open. This helps pull the exhaust out of the cylinder (scavange), reducing pumping losses.
The "in theory" part is using a "perfect" exhaust system. But, in reality this 180* moment only happens within a very narrow RPM range, usually a range of 500-1000 RPMs at the most. Have you ever noticed how certain cars have that "sweet spot" in the RPM range where the exhaust sounds perfect. That's the RPM range I'm talking about.
There are two things that effect when that RPM range is reached. Exhaust length and diameter. Changing either of those individually will alter the pulse wave timing. The length because it effects when the high pressure wave will reach ambient pressure (the end of the tail pipe), and the diameter because it will change the velocity of the exhaust flow and therefore also effect when the high pressure wave will reach the tail pipe.
The exhaust system, in any car, must match the desired output of the engine it's attached to. It's one of the pieces of the "combination" of parts, and should be treated as one.
Are you building a street engine and plan to use a low RPM cruise range? Or do you plan on a high RPM engine in a drag car? Is the car heavy, or light? Is it FWD, RWD, or AWD? Automatic or manual transmission? Etc., etc.
There's an interesting thing that happens in the exhaust system called pulse wave scavenging. For every high pressure exhaust pulse wave, there's an equal and opposite negative pulse wave that follows the exact path from the moment the high pressure pulse leaves the tailpipe. In theory, it flows right back up to the exhaust valve from which it came and is ~180* out of phase with the high pressure pulse.
The negative pressure creates a "pocket", for lack of a better term, which the next pressure wave will see as soon as the exhaust valve begins to open. This helps pull the exhaust out of the cylinder (scavange), reducing pumping losses.
The "in theory" part is using a "perfect" exhaust system. But, in reality this 180* moment only happens within a very narrow RPM range, usually a range of 500-1000 RPMs at the most. Have you ever noticed how certain cars have that "sweet spot" in the RPM range where the exhaust sounds perfect. That's the RPM range I'm talking about.
There are two things that effect when that RPM range is reached. Exhaust length and diameter. Changing either of those individually will alter the pulse wave timing. The length because it effects when the high pressure wave will reach ambient pressure (the end of the tail pipe), and the diameter because it will change the velocity of the exhaust flow and therefore also effect when the high pressure wave will reach the tail pipe.
Regardless, the muffler still adds resistance to flow even if a minute amount. This restriction will change the power levels in certain engines if the restriction is high. If there is any power increase anywhere in the RPM range after adding a muffler, then there's another variable that was overlooked while tuning the exhaust for said engine.
Banned
Joined: 12-18-05
Posts: 17,838
Likes: 1
From: North Jersey
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
I wasn't going to say anything because I assumed you were Canadian. They spell things a little different than Americans. Like the word "colour", "color".
Then I saw you're from NJ and thought I'd just try to let you know.
I still mispell Camaro (Camero) sometimes, and I've owned 5 of them. LOL
Senior Member
Joined: 08-17-06
Posts: 3,795
Likes: 0
From: Rochester Hills, MI
FTmfW!!
Last edited by 07SSCharged248; Jan 30, 2007 at 08:34 PM. Reason: Automerged Doublepost
Senior Member
Joined: 09-17-06
Posts: 551
Likes: 0
From: Earth
[QUOTE=07SSCharged248;798038]Well then you Balt ,might go the same route as my cavy did.. Have fun.[quote]And what happened to your Cavalier, exactly?
I proved that theory wrong with factual information, yet you and your boyfriend still think I'm the idiot?
FTmfW!!
I proved that theory wrong with factual information, yet you and your boyfriend still think I'm the idiot?
Thread
Thread Starter
Forum
Replies
Last Post