Backpressure BS
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From: Louisville, KY
Originally posted by tuchy
Backpressure is needed to fill the pipes and keep airflow going smoothly.
Backpressure is needed to fill the pipes and keep airflow going smoothly.
JBLsilver01,
Wrong also. No headers at all and it would still run. Not optimally, but it would still run.
quiksilver,
You are correct here. It is scavenging that's highly desirable.
Tuned headers promote scavenging, thus reduce boost pressure because it doesn't have to fill on top of already burned exhaust gases.
Just wanted to get you guys stirred up a little. But still feel a little bummed because after reading all these posts on exhaust and how we need exhaust pressure, I felt that I would get a LOT of opposition here.
Bring It!
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From: Plano, Texas
air1kdf
Not to take away from the topic, but I noticed where you are from and got to thinking about home.
My whole darned family is from out there. And there are a crapper load of them.
Have you lived there very long?
And to stay on topic. Isn't the exhaust really more about flow velocities?
Rocks
Not to take away from the topic, but I noticed where you are from and got to thinking about home.
My whole darned family is from out there. And there are a crapper load of them.
Have you lived there very long?
And to stay on topic. Isn't the exhaust really more about flow velocities?
Rocks
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Joined: Jul 2001
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From: Hammer Lane
Previous posts on subject......
https://www.f150online.com/forums/sh...=flowmaster%2A
https://www.f150online.com/forums/se...der=descending
https://www.f150online.com/forums/sh...=flowmaster%2A
https://www.f150online.com/forums/se...der=descending
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From: Louisville, KY
Rocks,
We moved here in 98 and love it here. For us this is home.
Back to the topic. It's not about flow velocity at all. Just how well the combustion chamber can get rid of spent gases. Some systems do a better job than others.
Quote
"The more restrictive the exhaust flow, the more power the engine has to use. Therefore if we reduce the restriction by adding a header, less power is required to push out the exhaust. That "extra" power now can be used at the wheels to accelerate the car."
On a SC engine backpressure is killer on the exhaust side. The less the better. Even to the point that headers without collectors yield better results than with them.
So as far as the muffler question. Mufflers don't add HP, but they can reduce HP. So the winner is... Get the system that has the highest flow rate (if the noise level is exceptable).
We moved here in 98 and love it here. For us this is home.
Back to the topic. It's not about flow velocity at all. Just how well the combustion chamber can get rid of spent gases. Some systems do a better job than others.
Quote
"The more restrictive the exhaust flow, the more power the engine has to use. Therefore if we reduce the restriction by adding a header, less power is required to push out the exhaust. That "extra" power now can be used at the wheels to accelerate the car."
On a SC engine backpressure is killer on the exhaust side. The less the better. Even to the point that headers without collectors yield better results than with them.
So as far as the muffler question. Mufflers don't add HP, but they can reduce HP. So the winner is... Get the system that has the highest flow rate (if the noise level is exceptable).
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From: CORAL SPRINGS, FL. USA
Re: Backpressure BS
Originally posted by air1kdf
Funny how I hear all of you guys talk about how the L just loves backpressure. Just to be clear about this, that is a completely false statement. The closer the backpressure gets to 0 the more power the L will have. Now scavenging is a completely different story. Flame away
I'm ready to defend this to the death of it.
Funny how I hear all of you guys talk about how the L just loves backpressure. Just to be clear about this, that is a completely false statement. The closer the backpressure gets to 0 the more power the L will have. Now scavenging is a completely different story. Flame away
I'm ready to defend this to the death of it.
Hows about this: The further from 0 you go the better?? In the negative spectrum, that is! Thats what scavaging is.
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From: Louisville, KY
Mondo1,
That's not what scavenging is. Ever hear of an AR (anti reversionary) header? Why do you think that Dragsters use open primaries for? Do you know the reason for a collector? Because you want the maximum, just put a potatoe in your exhaust, that gets you the maximum scavenging right? Hah, get a clue. You have no idea how exhaust theory works with a SC engine, or any engine for that matter. I suggest that you read this whole post over again, and try to learn something.
That's not what scavenging is. Ever hear of an AR (anti reversionary) header? Why do you think that Dragsters use open primaries for? Do you know the reason for a collector? Because you want the maximum, just put a potatoe in your exhaust, that gets you the maximum scavenging right? Hah, get a clue. You have no idea how exhaust theory works with a SC engine, or any engine for that matter. I suggest that you read this whole post over again, and try to learn something.
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Joined: Mar 2001
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From: CORAL SPRINGS, FL. USA
Lets see......opposite of back pressure= negative back pressure which = scavaging.How else can you explain negative backpressure, Einstien?Your AR header explanation describes scavaging to a tee.And the funny thing about it is that your so wound up about giving anyone an arguement that you don't even realize it.! You better read your own posts or go back to school to learn to read.This website is full of guys like you who are so insecure with themselves that they are ready to pounce on anyone who quotes them....like its some challange or something.Chances are I've been buying headers since you've been in diapers..(and I don't mean in the last year or so either) So chill...we all believe you think you know what your talking about!
Last edited by Mondo1; Oct 26, 2002 at 09:23 PM.
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From: Tampa, Fl
Originally posted by MRBBQMAN
Mondo tried to get past his "airness" with a quick theory on scavaging, but like those before him,he was quickly "belittled", or something
Mondo tried to get past his "airness" with a quick theory on scavaging, but like those before him,he was quickly "belittled", or something
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From: Louisville, KY
Hey, I said to the death. I just can't figure why anybody would say that that is what scavenging is.
I'm a little surprised by you guys though. There is still something that hasn't been mentioned yet. I'll give you a hint, it's the reason that long tube headers have marginal performance gains.
I'm a little surprised by you guys though. There is still something that hasn't been mentioned yet. I'll give you a hint, it's the reason that long tube headers have marginal performance gains.