Header/Sidepipes vs headers true duals
Burning Brakes
Joined: Jul 2015
Posts: 823
Likes: 57
From: Austin TX
Apparently you never understood it back in the 80's. You're trying to claim that you want a restriction so the exhaust gas can keep putting downward pressure onto the piston instead of exiting the open exhaust port? Exactly how much of a restriction or how much backpressure are you adding to cause that to happen? 
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
OP, you can be entertained by the "arguing" but a simple search will tell you the sidepipe primaries are too long to be effective.Get an appropriate size under car header and squeaze in an H/X pipe somewhere. I have always liked the 3 inch race bullets for sound.
Wanted to say as well, a simple head and cam swap can tax a small primary header quickly, a big header may not be tuned for off idle scavenging but it is less detrimental on the low end than too small corking things on the top end.
Wanted to say as well, a simple head and cam swap can tax a small primary header quickly, a big header may not be tuned for off idle scavenging but it is less detrimental on the low end than too small corking things on the top end.
Last edited by tt 383; Dec 9, 2015 at 07:37 PM.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Do you have any understanding of these scientific principles you claim no-on reads? Do you have test data that shows adding only backpressure adds power? Do you have any data that shows backpressure helps? NOT how tuning the flow and length helps even though it results in a smaller size of pipe. How backpressure ALONE helps.
Here I'll help you out. Look at the end of the post with the butterfly flow restriction tests vs dissuser tests. Any backpressure added hurt.
http://www.mustangevolution.com/forum/f312/t296628/
Here's a good explanation of the whole concept.
http://forums.mightycarmods.com/show...why-it-s-wrong
I suggest you do some reading. Use Google and find more information. Then, you can claim you understand something instead of just going on about how it's been that way forever even though you couldn't explain why it's been that way forever.
You actually want a vacuum occurring at the correct time and in the correct location to help suck the exhaust gases out of the engine. You do not want a restriction to the exhaust gases flowing out of the engine.
Last edited by lionelhutz; Dec 9, 2015 at 09:03 PM.
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
Do you have any understanding of these scientific principles you claim no-on reads? Do you have test data that shows adding only backpressure adds power? Do you have any data that shows backpressure helps? NOT how tuning the flow and length helps even though it results in a smaller size of pipe. How backpressure ALONE helps.
Here I'll help you out. Look at the end of the post with the butterfly flow restriction tests vs dissuser tests. Any backpressure added hurt.
http://www.mustangevolution.com/forum/f312/t296628/
Here's a good explanation of the whole concept.
http://forums.mightycarmods.com/show...why-it-s-wrong
I suggest you do some reading. Use Google and find more information. Then, you can claim you understand something instead of just going on about how it's been that way forever even though you couldn't explain why it's been that way forever.
You actually want a vacuum occurring at the correct time and in the correct location to help suck the exhaust gases out of the engine. You do not want a restriction to the exhaust gases flowing out of the engine.
Here I'll help you out. Look at the end of the post with the butterfly flow restriction tests vs dissuser tests. Any backpressure added hurt.
http://www.mustangevolution.com/forum/f312/t296628/
Here's a good explanation of the whole concept.
http://forums.mightycarmods.com/show...why-it-s-wrong
I suggest you do some reading. Use Google and find more information. Then, you can claim you understand something instead of just going on about how it's been that way forever even though you couldn't explain why it's been that way forever.
You actually want a vacuum occurring at the correct time and in the correct location to help suck the exhaust gases out of the engine. You do not want a restriction to the exhaust gases flowing out of the engine.
The other thing that is wrong is you are reading a mustang site. You can forget about anything those guys claim
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Of course, jump right to the stupidity of discounting and make fun of the link that has dyno graph proof how you are wrong.
I shouldn't have expected anything less since you have no proof, not even an attempt at an explanation why.
Last edited by lionelhutz; Dec 9, 2015 at 10:12 PM.
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
Well even better, we all know that DYNO's NEVER lie!!
You come across as someone who has gathered all your info off the internet (where half the posters are clueless as well). I've learned the majority of what I know in the last 30 years talking to other racers in the staging lanes while waiting to race, and actually DOING it at the track, over and over and over. I guarantee you that will will learn ALOT more practical knowledge that way...
Having a Mechanical Engineering degree and 25 successful years in the engineering field help, but I don't like to play that card much if I don't have to.
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
I think to an extent, he doesnt know what he is actually saying... Anyone with a degree should know backpressure is a measure of restriction, so it is not good for making power/torque. I think and I could be wrong he is thinking like 454, but I think he was talking more to do with the valve events side of things, not scavenging. Again, scavenging is based off of airflow, and the VACUUM it creates, not PRESSURE.
Last edited by tt 383; Dec 9, 2015 at 11:08 PM.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
OMG!!! A DYNO GRAPH!!
Well even better, we all know that DYNO's NEVER lie!!
You come across as someone who has gathered all your info off the internet (where half the posters are clueless as well). I've learned the majority of what I know in the last 30 years talking to other racers in the staging lanes while waiting to race, and actually DOING it at the track, over and over and over. I guarantee you that will will learn ALOT more practical knowledge that way...
Having a Mechanical Engineering degree and 25 successful years in the engineering field help, but I don't like to play that card much if I don't have to.
Well even better, we all know that DYNO's NEVER lie!!
You come across as someone who has gathered all your info off the internet (where half the posters are clueless as well). I've learned the majority of what I know in the last 30 years talking to other racers in the staging lanes while waiting to race, and actually DOING it at the track, over and over and over. I guarantee you that will will learn ALOT more practical knowledge that way...
Having a Mechanical Engineering degree and 25 successful years in the engineering field help, but I don't like to play that card much if I don't have to.
As I said, can't explain it it yet claims to be the expert by putting down proof....
Your dyno lies comment is ridiculous. A dyno is a perfect tool when doing back to back runs to determine what effect changes have on a vehicle. Just further shows you have no leg to stand on so you have to resort to discrediting.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
As I said, can't explain it it yet claims to be the expert by putting down proof....
Your dyno lies comment is ridiculous. A dyno is a perfect tool when doing back to back runs to determine what effect changes have on a vehicle. Just further shows you have no leg to stand on so you have to resort to discrediting.
Your dyno lies comment is ridiculous. A dyno is a perfect tool when doing back to back runs to determine what effect changes have on a vehicle. Just further shows you have no leg to stand on so you have to resort to discrediting.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
I don't really care because the the backpressure believers are about as bad as religious zealots.I just don't want other people falling for their un-explainable crap.
And I agree with the post a few up. Any decent mechanical engineer would know you don't want to purposely add any kind of restriction to the flow of exhaust.
I will also say that any decent engineer would know that there is a technical explanation for what occurs. The excuse that it's just the way it is and no book smarts can explain it is nothing but pure BS.
You believe it and have claimed your an engineer so why can't you explain it?
Last edited by lionelhutz; Dec 9, 2015 at 11:29 PM.
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
LOL, going away with your last comment claiming that you're right is certainly proving you're the bigger" man.
I don't really care because the the backpressure believers are about as bad as religious zealots.I just don't want other people falling for their un-explainable crap.
And I agree with the post a few up. Any decent mechanical engineer would know you don't want to purposely add any kind of restriction to the flow of exhaust.
I will also say that any decent engineer would know that there is a technical explanation for what occurs. The excuse that it's just the way it is and no book smarts can explain it is nothing but pure BS.
You believe it and have claimed your an engineer so why can't you explain it?
I don't really care because the the backpressure believers are about as bad as religious zealots.I just don't want other people falling for their un-explainable crap.
And I agree with the post a few up. Any decent mechanical engineer would know you don't want to purposely add any kind of restriction to the flow of exhaust.
I will also say that any decent engineer would know that there is a technical explanation for what occurs. The excuse that it's just the way it is and no book smarts can explain it is nothing but pure BS.
You believe it and have claimed your an engineer so why can't you explain it?
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
Well not many people can explain it. Even engineers. There's people that think they understand and attempt to explain it. But truth is no one can.
By the way, when are you guys going to come get this little punk justin beiber? you can have him back.
By the way, when are you guys going to come get this little punk justin beiber? you can have him back.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Do you know why we have some of the most power, lowest emission and most fuel efficient engines today? Engineering of the engine and associated systems. As examples, Intake manifold simulations to create better intakes. Head and combustion chamber simulations to create MUCH better heads and piston crowns. Exaust simulations to create better exhaust systems. The simulations go as far as simulating the air and fuel mixture from the injector or carburetor going through to the chamber. It's not voodoo science that can't be explained or a case of it being "learned in pit lane".
You claim that no-one can understand it explains why you don't.
Advanced
Joined: Feb 2013
Posts: 93
Likes: 6
Now see what you created cable, another pipes vs duals and exhaust war...
That was my 81, it had the combination you described above.
Long tube Hooker Super Competition hedders, 2,5 duals and Flowmasters.
That would be the correct description of what it did, definitely very mean and very loud.
BUT - that was with a Hardcore Engine.
Solid Cam, Dart heads, high revs / no low end.
Supersweet grumpy idle and it really screamed - goosebumps.
I think both pipes and duals will sing you a sweet song each one in its own way, but with a stock motor will not be same fascinating.
Keep in mind the Flowmasters don`t have the deepest tone if that is something you`re looking for.
Last edited by EASYGEAR; Dec 13, 2015 at 07:26 PM.
Le Mans Master
Joined: Oct 2010
Posts: 6,929
Likes: 842
From: melbourne florida
2023 C3 of the Year Finalist - Modified
My goodness all these posts all this arguing and too broke is yet to chime in!
If you think back pressure helps your car at low speed smash your pipe 3/4 closed with a hammer and drive it only at low speed.why do you guys argue over stuff like this none of you will convince the other because changing your mind admits your wrong.
Back pressure never helped anything.
If you think back pressure helps your car at low speed smash your pipe 3/4 closed with a hammer and drive it only at low speed.why do you guys argue over stuff like this none of you will convince the other because changing your mind admits your wrong.
Back pressure never helped anything.
Burning Brakes
Joined: Jul 2015
Posts: 823
Likes: 57
From: Austin TX
Where was that? I didn't see it in either of the links. I did see however that the author of the first post notes the importance of velocity. He also knows that the same thing that creates velocity - a smaller pipe or other restriction - also creates backpressure. The two are inseparable. He goes on to say "Thus if your powerband is located 2-3000 RPM you'd want a narrower pipe than if your powerband is located at 8-9000RPM." In other words, the greater backpressure produced by a narrower pipe equates to increased low end torque.
Like I said, it's all about speed and pressure.
Like I said, it's all about speed and pressure.
Race Director
Joined: Jan 2005
Posts: 11,011
Likes: 166
From: Milford Michigan
So Lionel, what's your point? Why don't all Vettes, Challengers, Camaros, Vipers, etc. come from the factory with dual 4" exhaust then? Have you ever heard of flow velocity? You should work for Borla & change all their performance systems to 3.5" or 4". Let me 'splain it again to you, then you can "correct" me & tell me I'm wrong. Diesels hate backpressure so bigger is better, but gas engines require a proper diameter system to maintain flow velocity, & if the system diameter is too big & too free-flowing, a gas engine will lose bottom-end & midrange performance. Now tell us all this is a load of crap. I have logged hundreds of hours of conversations with racers, musclecar builders, doing it myself, engineers at Ford & Chrysler, etc. to get to the point where I am today. I have logged an extensive history of knowledge & you are basically saying the flow velocity data is garbage. Please share your real-world experience with us all - we are waiting. We want to know what you know.
Last edited by Chambered; Dec 14, 2015 at 12:18 AM.
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
Racer
Joined: May 2011
Posts: 484
Likes: 10
From: Newcastle NSW
So, I have studied mechanical engineering and have a PhD in physics. Moreover, my PhD involved (in part) the expansion of gases through restrictive apertures. Without a doubt, the one who is correct here is Lionel. Backpressure is an unfortunate side-effect of sizing pipes for 'ideal' flow velocity and scavenging. It, in and of itself, is not beneficial.