what is the truth about exhaust pressure?? I dont know much about exhaust but if anyone knows can they explain the benefits of back pressure and whats bad cause i dont sh**.
You don't want exhaust backpressure, you want exhaust velocity.
The problem people run into when they put 3 inch straight pipes on their 2.2L is that it slows the flow down significantly.
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Any and all back pressure is bad.... The myth comes from the fact that when volume is increased, velocity decreases; the most effecient exhaust will result from zero backpressure and high velocity.
The one place where backpressure actually is important, is in 2 stroke engines; They have no valve in the exhaust, so the gasses are timed to pulse back at the port; That is why 2 strokes have elaborately shaped pipes.
"i promise we won't get drunk, and go out in boat in the dark, stand up in the boat and fire the gun into the air unless we have life jackets on."
So when people say "some back pressure is good" you are saying they are lying?
They should say "backpressure is bad, but you still want small exhaust so the exhaust still has velocity to get the @!#$ out of your engine".
Thats what Im gathering.. am i right?
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yes. You want as little or no back pressure at all. But you also don't want to slow down your exhaust flow by using to large a diameter exhaust tubing. I would stick with 2.25 inch exhaust piping and a free flowing perforated core muffler such as a Magnaflow or Borla. Also, in order to keep the noise down, I would suggest using a perforated core resonator too.
I was always taught that you needed a little bit of back pressure. I thought that you needed a little because if you didnt have enough ur piston rings would fry faster.
you need back pressure to run your engine
would putting a high flow cat and just a muffler on stock piping help the exuaghst flow, or would it be better to buy a cat back system like magnalow?
racing a ford is like racing a fat kid.
cat back systems are a WASTE of money just buy the muffler and have the local shop do it, its so much better and cheaper dont spend 300 0r 575.84 on a borla cat back liek i did i learned the 2nd time around when i just boug the muffler
i wish this jacka$$ that always cruzes where i do would see this post he is always saying get a real exaughst well this would shut him up, plus my 3A racing muffler is the deepest sounding muffler i have heard from any cavy aroubd here plus i get compliments for it not sounding ricey.
oh just like my favorite phrase always says.....
racing a ford is like racing a fat kid.
Quote:
you need back pressure to run your engine
NO YOU DO NOT! If your car has a 2 stroke engine, yes, but IT DOES NOT. Snowmobiles need backpressure, as do chainsaws and other 2 strokes; 4 stroke engines DO NOT.
Pleses, stop filling the .org with false information.
Man, I wish Event was still around!
"i promise we won't get drunk, and go out in boat in the dark, stand up in the boat and fire the gun into the air unless we have life jackets on."
tools, you do not want to lose all of your velocity,,,, if you have the right set up the speed of the gas will actually start to create a vaccum at the engine, to suck out the exhaust gas from the cylinder.... you can do this by getting a nice header.....this piping on the header allows for the pulse from the previuos cylinder to create negative pressure behind it therefore pulling out the next pulse and so on and so on...
my car runs nice i have all stock piping with a pacesetter 4into1 header, with a magna flow catalytic converter, and a dtm quad tip muffler
and to fast plan, by the way the car sounds deep until you do the cat, after that it gets loud as hell!!! trust me i use to get compliments to.....
2000 Dark metallica green cavalier. (2.2 2200) pace setter 4-1 header, magna flow cat, dual quad tip dtm muffler, 1800 watt stereo with satalite radio, momo 16in rims, from rk sport strut bar, rear vibrant strut bar, indeglow gauge cluster along with matching hvac panel, clear corner lenses, altezz tails, vibrant wai, carbon fiber oem style hood, rsm lightened crank pulley....
and soon to be part of my family of which is may car, the rsm supercharger 8psi, waiting until i get time to install it....
"Disarters are just another star falling in my yard."
you want 1-3psi i believe
i red an article on magnaflows site as to what optimal backpressure was
check their site
theL61 wrote:you want 1-3psi i believe
i red an article on magnaflows site as to what optimal backpressure was
check their site
i say no back pressure you want scavenging to pull all the burnt exaust gases out of the combustion chambers as possible.
see ya!
scavanging = backpressure
cant have one w/o the other
That's total bull@!#$! how does opposition to flow equal scavanging?
and another large exhaust company(I believe it was flowmaster or borla; Event used to use the link to shut up these arguments real quick) which plainly stated, BACK PRESSURE IS BAD.
"i promise we won't get drunk, and go out in boat in the dark, stand up in the boat and fire the gun into the air unless we have life jackets on."
of course back pressure is bad the fact is you have to have it to run ur engine. Also to agree with everyone else, to buy a cat-back system is a complete wast of money, around here i can get 2.25 inch exhaust piping from the cat for 100 dollars.
right
you show me a car that runs w/o back pressure then
which would mean basically no pipes
theL61 wrote:right
you show me a car that runs w/o back pressure then
which would mean basically no pipes
what the hell do you think open headers do, you think you have backpressure then? i think not! want some videos to prove that a car can run with open headers/no header on at all?
Backpressure on a 4cyl exhaust is BAD, get that, B-A-D plain english NOT GOOD. What happens when you go to too big of an exhaust the exhaust cools too quickly due to loss of velocity and that can create backpressure and basically not help the cause any, you want to keep the exhaust hot in the pipe for as long as possible. Now for the people that are like "wtf how come i lost power" i doubt you did, you will see a change in the bottom end hp/tq because with more air going out, you need to get more air/fuel in that much faster, and to tell ya the truth, a CAI/WAI aint going to help much
A 2stroke engine is Tuned for powerband by the exhaust, yes a 2 stroke will run with no backpressure, but entirely like a bag of @!#$.
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Giuseppe Barbieri wrote:what is the truth about exhaust pressure?? I dont know much about exhaust but if anyone knows can they explain the benefits of back pressure and whats bad cause i dont sh**.
What the next guy says
Sunfires rule! (Tom) wrote:You don't want exhaust backpressure, you want exhaust velocity.
The problem people run into when they put 3 inch straight pipes on their 2.2L is that it slows the flow down significantly.
craig steele wrote:Any and all back pressure is bad.... The myth comes from the fact that when volume is increased, velocity decreases; the most effecient exhaust will result from zero backpressure and high velocity.
The one place where backpressure actually is important, is in 2 stroke engines; They have no valve in the exhaust, so the gasses are timed to pulse back at the port; That is why 2 strokes have elaborately shaped pipes.
That's good too.
Sandstorm-J wrote:So when people say "some back pressure is good" you are saying they are lying?
They should say "backpressure is bad, but you still want small exhaust so the exhaust still has velocity to get the @!#$ out of your engine".
Thats what Im gathering.. am i right?
Yes, bang on buddy.
kyle shanks wrote:I was always taught that you needed a little bit of back pressure. I thought that you needed a little because if you didnt have enough ur piston rings would fry faster.
Allow me to be blunt... You were taught wrong. Sorry. Santa Claus was a fraud too. Sorry about that as well.
theL61 wrote:you need back pressure to run your engine
No... no you don't.. trust me. I've run my car with no exhaust manifold... and while it's loud as hell, it also hauled major ass.
theL61 wrote:right
you show me a car that runs w/o back pressure then
which would mean basically no pipes
Yup. No pipes. Nothing. Not even an exhuast gasket.. here it is:
It's been done. It's not impossible. It's very possible. Backpressure = bad. End of story.
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Sport Compact Car Magazine gained 10whp on their Civic Project by running no exhaust(only header), versus running a high flow full custom exhaust.
i ran my car with an open header yesterday, and its got 1" 7/8ths primaries and a 3.5" collector. thats right, no mufflers or anything. just that header on a quad 4. its loud, and it runs fast.
its a big exhaust, but its a nitrous motor, so im moving more air than stock.
.
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Wouldnt running open header be bad? Having your valves cool off so quickly...?
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read the 1st couple posts I'm impressed, people are finally learning )
under no circumstance do you want backpreasure.... big exhaust makes for alot of turbulence in the exhaust and crappy flo, it has nothign to do with back preasure
