Need a quick answer [Archive]

AzCivic

03-14-2004, 09:30 PM

Originally posted by V8killimports
There have been 30+ years of proof.. its a basic TriY header.. I think shelby first used them on the GT350 series.

yeah cause a v8 and a 1.6ltr 4cyl engine get the same benefits from the same mods.

like i said i'd like to see proof, say if you lose 8hp up top only to gain 1ftlb of torque in the low end, that doesnt sound too good to me. but it improved the low end didnt it. or say if there's hardly a difference at all, i'd want which ever one is cheaper.

i know i didnt notice much of anything when i put the dc sports 4-2-1 on my car.

V8killimports

03-14-2004, 10:09 PM

Originally posted by AzCivic
yeah cause a v8 and a 1.6ltr 4cyl engine get the same benefits from the same mods.

like i said i'd like to see proof, say if you lose 8hp up top only to gain 1ftlb of torque in the low end, that doesnt sound too good to me. but it improved the low end didnt it. or say if there's hardly a difference at all, i'd want which ever one is cheaper.

i know i didnt notice much of anything when i put the dc sports 4-2-1 on my car.

I am not talking v8 cs blah blah blah.. I am talking airflow dynamics. 421 is a tri y design.

AzCivic

03-14-2004, 10:22 PM

ok, and what does a GT350 have to do with what works best on a small displacement engine.

furthermore this is barenone the best header out there for honda's: http://www.exospeed.com/engine/bisimoto.htm

hmm its basically a 4-1 design and yet makes power everywhere.

GT40FIED

03-16-2004, 12:58 PM

Originally posted by AzCivic
ok, and what does a GT350 have to do with what works best on a small displacement engine.

Well...the engine size is irrelevent. What IS relevent is that the theory is the same. Sure, the header primary and collector sizes will be different, but the idea is still the same. The 4-2-1 design will scavenge better and produce a better exhaust wave for better and more even flow on all cylinders regardless of the engine. So yeah...what works on a 289 V8 will work on a 1.6L 4 pot motor...just slightly different.

AzCivic

03-16-2004, 01:03 PM

oh god would you v8 fools shut the hell up, your dumb ass pushrod gas guzzlers are not the same as 16v ohc 4 cylinder engines. stop trying to contadict shit when you have no proof as to what these designs do on a honda engine.

GT40FIED

03-16-2004, 02:00 PM

Originally posted by AzCivic
oh god would you v8 fools shut the hell up, your dumb ass pushrod gas guzzlers are not the same as 16v ohc 4 cylinder engines. stop trying to contadict shit when you have no proof as to what these designs do on a honda engine.

Oh forgive me god of the lowly D series engine. I have failed you. Please accept my sacrifice on the altar of candy ass pansy bolt on motors.

Look...I was just saying that the theory is the similar and that...follow me here...in theory the principle is the same. Pushrod, OHC, I4, V8...it's all just engine theory and most engines work in pretty much the same fashion. I guess I am a fool...all those years of engine theory and auto tech classes were just a ridiculous farce. I'm obviously no match for someone whose automotive knowledge is based around a high school tech class, maybe a few books, some driveway tinkering, and pointless online debates. I'm not here to offer you proof...I honestly don't care what your motor will do. I DO, however, know that this design has proven effective on all types of cars with all types of motors with similar (though not identical) results. Also, for your edification, it takes gas to make power so I'm perfectly fine with getting <10 mpg less than you if I can make 3 times as much power. So please, insult the efficiency of my motor...just wait until you hit 600hp to do so.

On a side note: What's with the inferiority complex? I mean...someone disagrees with you and automatically they're a "fool" and you come out guns blazing? My post was not directed as an insult or even at you in particular...merely what I've seen and what I know. You seriously need to stop taking everything everyone says so personally. Otherwise you just come off looking like an asshole. I mean...I'm an asshole...the hours are good and there's no heavy lifting. But I don't run my mouth every chance about random and meaningless shit.

V8killimports

03-16-2004, 03:26 PM

Yea azcivic you are missing the point. 4-1 header REGARDLESS of motor = higher velocity flow. The 4-2-1 = lower velocity. Lower velocity will increase lower end and generally decrease high end, while the other does the opposite. Yea I know your motor has VTeck and blah blah blah, but you know what the real ONLY difference between you 1.(does it really matter)L and my 383 is that my motor is about 4 times the size of yours and makes about 5 times the power.

AzCivic

03-16-2004, 04:12 PM

oh god lemme waste some time and read this stupid crap and come up with a reply and we can go back and forth till the subject is wore out and no one gives a shit or better yet, dont.

but heres on thing that i accidently let catch my eye.
low velocity = low end power :rolleyes:
plug up the exhaust and get mad torque!

guywithastang

03-16-2004, 04:19 PM

AzCivic

03-16-2004, 04:45 PM

i'm just tired of saying something than having some v8 driver who thinks they know everything come on here and contradict what i say almost on cue. "ooooh your engine is soo big, you must know all, i could never go out and buy a v8 car and slap some shit on it and pretend to know half as much as you"

guywithastang

03-16-2004, 05:03 PM

All engines are the same in basic form and will benifit the same way from the same mods. Longer intake runners will create more torque. free flowing exhaust makes more hp, more restrictive exhaust makes more torque. I really feel offendend sometimes when people automaticaly disregard what someone says because of what they own. Are you going to tell John Force he doesnt know how to drag race because he drives a V8 ford?

GT40FIED

03-16-2004, 06:26 PM

Originally posted by AzCivic
but heres on thing that i accidently let catch my eye.
low velocity = low end power :rolleyes:
plug up the exhaust and get mad torque!

Once again...condecend all you want but he's right. It's not about plugging the exhaust...you can free it up a little and still keep a good low end. In fact, most headers made for modern V8s are of the 4-1 design...short or long tube. It's not that they don't benefit from such designs, it's that people have spent so much time working on V8s they've had time to sort of tune the length, tubing diameters, and designs. I4s are, in the grand scheme of things, relatively new to the American performance market so people are still playing catch-up. Maybe instead of dismissing all of us who drive cars with V8s you consider that maybe some of us know our shit. I have yet to see you point out a single reason why a different way works better or why one of us is wrong.

V8killimports

03-16-2004, 07:23 PM

And let me add that as you say you don't give a shit, look whos getting all spun up about something so small. Just trying to teach you something.. that's all.

But yes, believe it or not, depending on how your motor is set up, you always need some backpressure. You don't take a stock 302 and slap on dual 4" exhaust because it'll kill your low end. Granted it would be great for high end power, but that is somewhere a stock 302 will never see anyways. These are very simple concepts and actually basic building blocks for power adding. Not really that complex.

V8killimports

03-16-2004, 09:20 PM

Originally posted by V8killimports
And let me add that as you say you don't give a shit, look whos getting all spun up about something so small. Just trying to teach you something.. that's all.

But yes, believe it or not, depending on how your motor is set up, you always need some backpressure. You don't take a stock 302 and slap on dual 4" exhaust because it'll kill your low end. Granted it would be great for high end power, but that is somewhere a stock 302 will never see anyways. These are very simple concepts and actually basic building blocks for power adding. Not really that complex.

And I think it's funny that you have a 421 header yourself. BTW stickers don't add hp and neither does a big yellow windshield wiper.

AzCivic

03-16-2004, 11:21 PM

Originally posted by GT40FIED
Once again...condecend all you want but he's right. It's not about plugging the exhaust...you can free it up a little and still keep a good low end. In fact, most headers made for modern V8s are of the 4-1 design...short or long tube. It's not that they don't benefit from such designs, it's that people have spent so much time working on V8s they've had time to sort of tune the length, tubing diameters, and designs. I4s are, in the grand scheme of things, relatively new to the American performance market so people are still playing catch-up. Maybe instead of dismissing all of us who drive cars with V8s you consider that maybe some of us know our shit. I have yet to see you point out a single reason why a different way works better or why one of us is wrong.

i've pointed out basically the best header out there for our 1.6ltr engines which is a 4-1 design and makes power all over the rpm range.

AzCivic

03-16-2004, 11:25 PM

Originally posted by V8killimports
And let me add that as you say you don't give a shit, look whos getting all spun up about something so small. Just trying to teach you something.. that's all.

But yes, believe it or not, depending on how your motor is set up, you always need some backpressure. You don't take a stock 302 and slap on dual 4" exhaust because it'll kill your low end. Granted it would be great for high end power, but that is somewhere a stock 302 will never see anyways. These are very simple concepts and actually basic building blocks for power adding. Not really that complex.

thats nice, thanks for telling me somthing i already know, even the ricers are catching on to this one.

after your "low velocity makes low end power" B.S. i really dont care what you have to say.

newsflash its HIGH velocity AT LOW RPMs that makes low end power.

AzCivic

03-16-2004, 11:28 PM

Originally posted by V8killimports
And I think it's funny that you have a 421 header yourself. BTW stickers don't add hp and neither does a big yellow windshield wiper.

i think its even funnier that someone who really doesnt know too much and doesnt have any performance crap done to their civic and who doesnt have a 4-2-1 OR a 4-1 aftermarket header is gonna come on here and tell us whats best.

GT40FIED

03-16-2004, 11:39 PM

Well someone should tell you what's best since you obviously don't have a fuckin clue man. Please...leave the car stuff to those of us who know. And don't think for a second that just because I don't own a Honda I don't have a clue about their motors. I scarecly know where to begin with your arguement that high flow at low rpms gives you torque. It's called backpressure. High flow at low rpms eliminates backpressure which kills your low end so no, high flow does not equal good low end. Pick up a book...read an article...hell, do something. Just don't start with this keyboard bully shit you seem to be so fond of because it's just plain sad.

AzCivic

03-16-2004, 11:51 PM

what, do you think that since you have half the schooling that these retards at Midas do(who cant even put lug nuts on a car with out at least cross threading or over torquing at least a few) that you know all your shit?

GUESS WHAT, your wrong. Show me something ANYTHING that says high velocity of exhaust gasses at low rpms will do anything but help low end power.

GT40FIED

03-17-2004, 12:00 AM

So if I slapped some longtube headers on my car with 2" primaries and 4" collectors and get a shitload of flow...by your logic I'll have insane low end torque? Shit...I'd be lucky if the car moved at all. Once again, my job is not to provide you with information...if you had a clue you'd know all of this by now (perhaps you should've picked up a book or read an article as I suggested). And your comparison between myself and a Midas employee is sorely misinformed. Those guys spend 2 years max at a vo-tech. I, on the other hand, am spending 4 years at a REAL college so when I get out I'll be the guy who tells grease monkeys what to do and how to do it. I'm sorry...but you're wrong. You generally are and that's why everyone says you're wrong and you get your panties in a twist. You pollute every thread you post in with misplaced sarcasm, meaningless insults, and personal attacks on people who say nothing personal to you. My original post was simply an agreement with V8...I wasn't saying you were wrong. Now that you've displayed such rampant stupidity I'll say you are wrong, but that's only because you ran your mouth about shit you apparently know little to nothing about.

Back to the topic: Every engine needs specific specs for it's exhaust but the theory is still the same...get the 4-2-1 and you'll be happier with it.

AzCivic

03-17-2004, 12:13 AM

omfg, if anyone needs to read some articles it you, god help anyone who has you work on their car.

in all your "education" did you ever go over how to get higher velocity of exhaust gases at lower rpms?

dont tell this guys what header is better, I HAVE THE DAMN THING I WOULD KNOW THAT YOU DONT HARDLY GET SHIT FROM IT!

GT40FIED

03-17-2004, 12:30 AM

The reason it hasn't done shit for your car is because to get a noticeable difference you've got have a decent engine to begin with. And actually yes...intake and exhaust velocity were covered in advanced engine diagnostics and performance. Man...if everyone who's got a car that I've worked on is screwed then there's got to be a ton of people out there with problems just waiting to pop up. I work on their car and then 3 years later boom...it breaks down. Fuckin moron.

AzCivic

03-17-2004, 12:41 AM

yeah thats it, other header designs actually make power on my engine but this one doesnt because my engine is too small, that makes perfect sense.

very good, you took a class yet you still didnt say how to get higher velocity at low rpms.

probably.

GT40FIED

03-17-2004, 01:07 AM

Actually it does make sense...some designs are just better than others. And you don't need high velocity at lower rpms. Just look at your factory exhaust this way...it's like going jogging while inhaling through your mouth like normal and exhaling through a straw. Now...you can move more volume without seriously increasing or decreasing velocity. A SLIGHT increase in velocity is good since it will help evacuate the combustion chamber and leave fewer traces of the exhaust products and in some cases will also increase intake velocity as it creates a slight vacuum effect. HOWEVER, and this is where you and I disagree I believe, too much increase in volume and velocity will eliminate backpressure. Most people think of backpressure as a bad thing but it maintains low end torque. Not power...just torque and that's what gets your car moving. A small decrease in backpressure vs. stock is a good thing, but increasing it too much will seriously effect your low end grunt (and I know how you guys love the low end torque those moster D and B series motors make). The design is the main thing here. Whether it's 4-2-1 or 4-1, if the design is poor or the primary and/or collector size is off it's not going to help. If they're too big or too small then you're no better off than when you started.

KwikR6

03-17-2004, 01:25 AM

Originally posted by GT40FIED
(and I know how you guys love the low end torque those moster D and B series motors make).
Torque...what's that?

AzCivic

03-17-2004, 01:26 AM

velocity is KEY, theres no slight crap about it. you still havent answered my question.

GT40FIED

03-17-2004, 02:23 AM

Originally posted by AzCivic
velocity is KEY, theres no slight crap about it. you still havent answered my question.

I've answered your question by telling you it's irrelevent. And velocity, while helpful in small amounts, is detrimental in excessive amounts. Perhaps you just overlooked the last post. You know...where I explained why you were misinformed.

GT40FIED

03-17-2004, 02:23 AM

Originally posted by Black Del Sol
Torque...what's that?

Exactly:thumbsup:

AzCivic

03-17-2004, 02:40 AM

Originally posted by GT40FIED
I've answered your question by telling you it's irrelevent. And velocity, while helpful in small amounts, is detrimental in excessive amounts. Perhaps you just overlooked the last post. You know...where I explained why you were misinformed.

holy crap its obvious you have no freakin clue.

take an engine
-you want air in and out as fast as possible
-for it to get in and out quickly it has to have good velocity
-at low rpms the exhaust should be small in diameter to allow good velocity at low engine speeds(your precious back pressure)
-at high rpms there's more exhaust gasses so the diameter should be bigger to keep from having the gasses back up(what some idiots(including you and v8) think is back pressure)

you cant do both so you make a comprimise between sizes.

BUT ITS ALL ABOUT VELOCITY, now go read up, and take what you learn to show and tell and let all the other future midas workers in on the info.

GT40FIED

03-17-2004, 05:12 AM

So what...you've developed a magic header that's capable of shrinking and expanding at variable rpms? Of course no one header is capable of creating ideal conditions all the time because it's made of metal. Metal that does not bow to your will. The closest comprimise would be stepped headers...but I have yet to see those for Hondas (but I don't follow the Honda market so who knows). And you're right on one note...velocity is the key to engine intake and exhaust...but a controlled velocity. Like I said, by your logic slapping a set of 2" primary long tubes on my car should result in insane amounts of low end power. In reality, they'll fail miserably and produce next to no low end power (something I'll bet you're altogether too familiar with). And I could throw on some 4" pipes because my 3" pipes just aren't doing the job...that'll earn me some points. And I never said anything about backpressure at high rpms...at that point it's your enemy...but that is also a product of camshaft design and timing which another discussion altogether. You seems stuck on comparing me to Midas workers...is there a reasoning behind this? If you think it'll piss me off you're sorely mistaken because I know better...you don't seem to. I think your points are valid in a small-picture kind of way...I'm just looking at the big picture where things aren't always perfect and you find the best possible solution to a given problem.

V8killimports

03-17-2004, 08:27 AM

OMG is this guy an idiot. First off, you say it doesn't do shit to your car. You know why? You are a typical ricer that thought a header would add 40hp to your car when in reality you got maybe 5hp. No header is going to give you more than say a 5% increase, and considering your car makes 100hp on a good day.. well here, lets do the math:

5% of 100
100 x .05 = 5

Ok.. 5 hp.

I am not arguing about this any further. You obviously don't know anything about anything. The fact that you want the highet velocity everything is stupid. Please, take your car, fabricate your self some headers with 3" primaries into a 6"collector and see how your car performs. If your engine can't support exhaust flow like that then it will run like ass and like GT said.. prob won't even go anywhere.

AzCivic

03-17-2004, 08:28 AM

"So what...you've developed a magic header that's capable of shrinking and expanding at variable rpms? Of course no one header is capable of creating ideal conditions all the time because it's made of metal. Metal that does not bow to your will. The closest comprimise would be stepped headers...but I have yet to see those for Hondas (but I don't follow the Honda market so who knows). And you're right on one note...velocity is the key to engine intake and exhaust...but a controlled velocity. Like I said, by your logic slapping a set of 2" primary long tubes on my car should result in insane amounts of low end power. In reality, they'll fail miserably and produce next to no low end power (something I'll bet you're altogether too familiar with). And I could throw on some 4" pipes because my 3" pipes just aren't doing the job...that'll earn me some points. And I never said anything about backpressure at high rpms...at that point it's your enemy...but that is also a product of camshaft design and timing which another discussion altogether. You seems stuck on comparing me to Midas workers...is there a reasoning behind this? If you think it'll piss me off you're sorely mistaken because I know better...you don't seem to. I think your points are valid in a small-picture kind of way...I'm just looking at the big picture where things aren't always perfect and you find the best possible solution to a given problem."

so what, now you agree with me?

and didnt i say you have to make a comprimise?

and whats this "velocity in controlled amounts" junk? you want the most velocity you can get!

i'm not sure what you need on your car, seems like every aftermarket header out there for the 5.0 has 1 5/8" primaries and a four into one design.

AzCivic

03-17-2004, 08:32 AM

Originally posted by V8killimports
OMG is this guy an idiot. First off, you say it doesn't do shit to your car. You know why? You are a typical ricer that thought a header would add 40hp to your car when in reality you got maybe 5hp. No header is going to give you more than say a 5% increase, and considering your car makes 100hp on a good day.. well here, lets do the math:

5% of 100
100 x .05 = 5

Ok.. 5 hp.

I am not arguing about this any further. You obviously don't know anything about anything. The fact that you want the highet velocity everything is stupid. Please, take your car, fabricate your self some headers with 3" primaries into a 6"collector and see how your car performs. If your engine can't support exhaust flow like that then it will run like ass and like GT said.. prob won't even go anywhere.

does it make you feel real cool to come on a honda board and call everyone ricers? talk about not having a life. lemme follow your lead and visit some mustang or camaro site and call everyone ignorant red-necks.

hello, smart ass, did you not read where it says the smaller diameter is going to give a higher velocity a low rpms? of course according to you the less velocity you can get a low rpms will result in the best torque right? stupid moron. you better stop arguing cause you have no clue.

V8killimports

03-17-2004, 09:21 AM

Originally posted by AzCivic
does it make you feel real cool to come on a honda board and call everyone ricers? talk about not having a life. lemme follow your lead and visit some mustang or camaro site and call everyone ignorant red-necks.

hello, smart ass, did you not read where it says the smaller diameter is going to give a higher velocity a low rpms? of course according to you the less velocity you can get a low rpms will result in the best torque right? stupid moron. you better stop arguing cause you have no clue.

Dude you are an idiot.. read the entire post. Less diameter = higher velocity = low end.. Larger diameter = lower velocity = high end. You have it ALL backwards and have NO clue what anyone is talking about including yourself.

I have been here for awhile and get along with most people.. they are not ricers, but you are. And you know it.

And there are many headers avail for the "5.0" otherwise known as 302 otherwise known as small block ford. You can get 2" primaries if you want into a 4" collector. And I am not even sure if you know what a primary on a header is.

AzCivic

03-17-2004, 09:59 AM

Originally posted by V8killimports
Dude you are an idiot.. read the entire post. Less diameter = higher velocity = low end.. Larger diameter = lower velocity = high end. You have it ALL backwards and have NO clue what anyone is talking about including yourself.

I have been here for awhile and get along with most people.. they are not ricers, but you are. And you know it.

And there are many headers avail for the "5.0" otherwise known as 302 otherwise known as small block ford. You can get 2" primaries if you want into a 4" collector. And I am not even sure if you know what a primary on a header is.

Originally posted by V8killimports
Yea azcivic you are missing the point. 4-1 header REGARDLESS of motor = higher velocity flow. The 4-2-1 = lower velocity. Lower velocity will increase lower end and generally decrease high end, while the other does the opposite. Yea I know your motor has VTeck and blah blah blah, but you know what the real ONLY difference between you 1.(does it really matter)L and my 383 is that my motor is about 4 times the size of yours and makes about 5 times the power.

nice way to contradict yourself which of course would make you the idiot.

oh finally you catch on to what i've been saying(well you got it partly right anyway) and then somehow try and turn it around like thats what you've been saying.

sorry a ricer would just sit here and act like your the all knowing cause you have a fast car, i on the other hand wont let you spread obvious bullshit.

and i dont give a crap what headers are available for the damn 5.0, but you look real smart cause you were able to remember how many cubic inches a 5.0 has, very good you get a gold star.

KwikR6

03-17-2004, 10:24 AM

Guy's this is a good discussion, but we can do without the name calling...don't get this thread locked.

GT40FIED

03-17-2004, 01:52 PM

Don't worry...I'm through debating this. You know the old saying, never argue with a fool...people won't be able to tell the difference.

V8killimports

03-17-2004, 02:27 PM

Originally posted by GT40FIED
Don't worry...I'm through debating this. You know the old saying, never argue with a fool...people won't be able to tell the difference.

Exactly

AzCivic

03-17-2004, 03:56 PM

so v8 are you really that blind that you cant see your TOTAL contradiction, which proves you dont know what your talking about???

AzCivic

03-17-2004, 03:57 PM

Originally posted by GT40FIED
Don't worry...I'm through debating this. You know the old saying, never argue with a fool...people won't be able to tell the difference.

way to take the easy way out of a debate.

AzCivic

03-17-2004, 04:02 PM

GT40's thinking: some velocity is good, not too much though we dont want the air moving too quickly.

v8's thinking: low velocity = low end power, no wait high velocity makes low end power... no hold on low velocity makes high end power. duuurrr i'm not sure :banghead:

does that about sum it up?

maybe this(your lack of knowledge) is why you hang out at a small honda website rather than debate on a site that actually has v8 cars or better yet a large honda site where theres plenty of people not afraid(hello hstuners are you there?) to have a little debate.

GT40FIED

03-17-2004, 04:19 PM

Originally posted by AzCivic
way to take the easy way out of a debate.

Oh...my apologies for not wanting to continue a debate with some who is obviously wrong and refuses to admit as much. But I'm sure in all your years of schooling in automotive theory and practice that your knowledge has far surpassed my own. What's that? You HAVEN'T gone to school for such things? Well...you'd never know it by your pompous know-it-all attitude. As for "taking the easy way out", you yourself said (and I quote) oh god lemme waste some time and read this stupid crap and come up with a reply and we can go back and forth till the subject is wore out and no one gives a shit or better yet, dont.. I had this discussion with one of my professors today who's been racing, wrenching, and teaching for the past 50 years. His response to your theory of CrAZy L0w 3Nd Fl0w= Mad L0w 3Nd P0W3r..."that's one of the most uninformed things I've ever heard". He then went on to sarcastically comment that if that were the case then everyone would just pull their headers off altogether and run around without any exhaust. So call it taking the easy way out...you're wrong...you can't prove to me otherwise...but I'm not going to argue about something I know I'm right about with a fool who thinks his garage tinkering is in any way equal to my actual education.

AzCivic

03-17-2004, 04:33 PM

that was before the whole thing really got started, but now its going so dont wimp out now.

either you didnt really ask this knows everthing, done everything, or you asked it wrong or he's just about as dumb as the manager over at midas.

the reason you dont run with out a header is that with out it you couldnt take advantage of exhaust scavaging that a properly designed header allows for(get this it HELPS INCREASE THE VELOCITY OF THE EXHAUST GASES) now i know this sounds crazy to a highly educated man(what are you in your first year?) as yourself but its true.

AzCivic

03-17-2004, 04:37 PM

here's another way to put it, read it slowly and let it sink in:

"In order to understand how the merge collector works, you must first know why one exhaust system can generate more torque and horsepower than another. The ability of a header/exhaust system to maintain exhaust gas velocity has a tremendous impact on realizing maximum torque and horsepower. Any significant changes in the system such as baffles (mufflers) or collectors will have an impact on exhaust gas velocity. The large area change seen at the transition from the primary tube to the collector causes an immediate reduction in exhaust gas speed. This reduction in speed decreases the efficiency of the system thereby reducing scavenging ability. Scavenging ability is the key factor to which an exhaust system is evaluated. The more efficient the system, the more air/fuel mixture that can be pulled into the combustion chamber. Obviously, the greater quantity of air/fuel mixture that can be burned, the more torque and power potential the engine has."

copied and pasted from dynatech's website.

AzCivic

03-17-2004, 04:41 PM

copied from magnaflow's website for your reading enjoyment:

BACKPRESSURE = TORQUE?
An old hot-rodder's tall tale: Engines need some backpressure to work properly and make torque. That is not true. What engines need is low backpressure, but high exhaust stream velocity. A fast-moving but free-flowing gas column in the exhaust helps create a rarefaction or a negative pressure wave behind the exhaust valve as it opens. This vacuum helps scavenge the cylinder of exhaust gas faster and more thoroughly with less pumping losses. An exhaust pipe that is too big in diameter has low backpressure but lower velocity. The low velocity reduces the effectiveness of this scavenging effect, which has the greatest impact on low-end torque

AzCivic

03-17-2004, 04:51 PM

and some more, this time from yawpower.com:

Velocity refers to the speed at which the exhaust gasses are travelling. The exact speed is not important to this discussion, but an uderstanding of how velocity affects exhaust flow is. There are two ways that velocity can be increased. One, by decreasing the cross sectional area of the orifice that the gasses are flowing through. (Making the headers or exhaust ports smaller) Two, by increasing the volume of air that is flowing through the orifice. (Increasing engine rpm) Velocity will increase proportionally with an increase in rpm. In other words, if you double the rpm, the velocity will also double. Velocity is inversely proportional to an increase in cross sectional area. Doubling the cross sectional are will halve the velocity, and halving the cross sectional area will double the velocity.

Velocity is important for one simple reason. Inertia. Websters dictionary describes inertia as "The property of matter by which it retains its state of rest or velocity so long as it is not acted upon by an external force." In other words, once it is moving, it will continue to move until some external force stops it. If you apply this theory to the gasses in the exhaust system you can see that once they have been accelerated by the pressure in the combustion chamber, It will take a given amount of energy to stop them, and even more to cause them to reverse direction. Since energy equals mass times velocity squared, you can see that doubling the velocity of the gasses will quadruple the amount of energy required to stop them. This is important because the flow of exhaust gasses is not steady. During each exhaust cycle, the gasses are accelerated, and decellerated rapidly. Often in the forward and reverse direction.

AzCivic

03-17-2004, 04:53 PM

just a little reasoning behind exhaust wraps from autospeed.com they seem to realize the benefits of high exhaust velocity:

High Energy Exhaust Wrap is woven from the finest insulating materials available, and can withstand temperatures in excess of 600 degrees Celsius. When wrapped around engine exhaust pipes, the High Energy Wrap can reduce under bonnet temperatures by as much as 80%, preventing heat related damage and helping to increase horsepower by reducing intake temperatures. High Energy Exhaust Wrap keeps the exhaust heat inside your exhaust pipes to maintain exhaust gas velocity, increasing combustion chamber scavenging and therefore horsepower.

AzCivic

03-17-2004, 04:58 PM

some more about header wrapping and its benefit to exhaust gas velocity from srcinc.net:

Wrapping the headers also serves two other important functions. Low rpm engine performance will be increased due to the higher exhaust gas velocity. This is due to the fact that cooler exhaust gas temperature result in a smaller exhaust gas volume and resultant lower exhaust gas velocity at any given engine rpm. Because both intake and exhaust valves are open at the beginning of the intake stroke, exhaust gas reversal can occur at lower rpms thereby reducing engine performance.

AzCivic

03-17-2004, 05:02 PM

hey these people want to slow down the velocity to eliminate "jet effect" (thrust) from the exhaust of a turbine generator:

Perhaps the most important part of the entire power train is the expansion bellows. Since there is very little practical difference between a gas turbine and a jet engine, the expansion bellows employs Bernoulli's principle to decrease exhaust gas velocity and therefore eliminate jet effect at the turbine exhaust. Without this expansion bellows, the turbine would impart undue thrust against the remainder of the unit. The exhaust gases are now at approximately 1000o F., and are routed by the exhaust bellows into the second section of the train, where thermal energy will be extracted by the heat recovery system

AzCivic

03-17-2004, 05:04 PM

hmmm Borla's got the right idea(copy and pasted from thier website):

Velocity and uninterrupted flow are the real performance-making factors

AzCivic

03-17-2004, 05:06 PM

someday you may ask yourself why do headers sometimes have a special coating??

well HPC(high performance coatings) has the answer:

Performance gains from increase exhaust gas velocity, improved airflow, and reduced ambient under hood temperature

AzCivic

03-17-2004, 05:08 PM

micron exhaust systems(some bike company) also seems to under stand, from their website:

The end result is a stronger pressure wave for scavenging and minimal loss of exhaust gas velocity, both of which translate to MORE HORSEPOWER!

GT40FIED

03-17-2004, 07:10 PM

All that just to miss my point entirely. Of course velocity is important...but by your logic, as I said, a totally unrestricted exhaust would be the best way to go. This isn't the case. Ok...say you still want to take advantage of scavenging...why not just run straight headers and no pipes? This works well on RACE cars but not on street cars since racecars could give a shit less about low end power. This taken from "How To Build And Modify Intake And Exhaust Systems":

In the past, many racers have gone to extremes in reducing exhaust back pressure. On the surface this might seem quite logical, but for street applications it is quite ineffective. While it is important to create exhaust gas velocity, for all intents and purposes in street applications it is important not to get carried away. While racers will benefit geatly from an extreme reduction in back pressure (such as dirt 1/4 mile track racers in the south in the sixties and seventies who let gases escape from the cylinder head directly), street cars will not benefit from such modifications. The best comprimise is a high flowing header of suitable length and diameter while not going overboard in an attempt to eliminate back pressure altogether.

I honestly think you've ignored most of what I said and are just one of those people who like to hear themselves talk. Go around and quote all of the exhaust manufacturers you want...most of what you posted doesn't really refute what I've been saying and you also have to take into account that they'll say anything because they make the assumption that dumbass wannabe "tuners" won't know the difference. This is the same reason they tell you that you'll get 20hp from a header swap. As for my professor...that's right...keep comparing people to Midas employees. Especially a guy who's spent his entire life around cars. The funny thing about it is that I'm sure that most Midas employees would dwarf you in their mechanical knowledge.

V8killimports

03-17-2004, 10:00 PM

Please please please AzCivic.. go slap on 4" dual no muffler exhaust and see what happens.

Of course less restriction is better to some extent. Why don't you see any of us running open headers? The only real reason to do it is the badass sound they make uncorked. Why don't I slap on a 1150cfm dominator carb? maybe 2 of them with a sheetmetal tunnelram intake? maybe race ported and polished large valve heads?? You just don't know a damn thing about motors. Not that I know all that much, but my sister knows more about an engine than you do. Nobody cares what you do with your car.. I can see now that you are simply bitter towards the 421 header because someone knew you were a ricer and knew you would believe that the $500 header you bought would give you 40hp when it maybe gave you 5 hp.. please leave the big boy stuff to people over the age of 8 and stick to painting your interior like a mcdonald's restaurant, and your single windshield wiper.. thanks.

AzCivic

03-18-2004, 01:52 AM

Originally posted by GT40FIED
All that just to miss my point entirely. Of course velocity is important...but by your logic, as I said, a totally unrestricted exhaust would be the best way to go. This isn't the case. Ok...say you still want to take advantage of scavenging...why not just run straight headers and no pipes? This works well on RACE cars but not on street cars since racecars could give a shit less about low end power. This taken from "How To Build And Modify Intake And Exhaust Systems":

I honestly think you've ignored most of what I said and are just one of those people who like to hear themselves talk. Go around and quote all of the exhaust manufacturers you want...most of what you posted doesn't really refute what I've been saying and you also have to take into account that they'll say anything because they make the assumption that dumbass wannabe "tuners" won't know the difference. This is the same reason they tell you that you'll get 20hp from a header swap. As for my professor...that's right...keep comparing people to Midas employees. Especially a guy who's spent his entire life around cars. The funny thing about it is that I'm sure that most Midas employees would dwarf you in their mechanical knowledge.

nononoNO! wtf dont you understand, I NEVER EVER said a big ass exhaust is best, omfg i cant believe your throwing out shit and saying thats what i said. I SAID VELOCITY IS IMPORTANT, YOU DONT GET GET VELOCITY WITH AN EXHAUST THAT TOO DAMN BIG, holy shit did you skip over everything i wrote.

VELOCITY, VELOCITY, MOTHER F'ING VELOCITY.

you said a little is good, too much is bad. I said NO, velocity is key to making power.

AzCivic

03-18-2004, 01:59 AM

Originally posted by V8killimports
Please please please AzCivic.. go slap on 4" dual no muffler exhaust and see what happens.

Of course less restriction is better to some extent. Why don't you see any of us running open headers? The only real reason to do it is the badass sound they make uncorked. Why don't I slap on a 1150cfm dominator carb? maybe 2 of them with a sheetmetal tunnelram intake? maybe race ported and polished large valve heads?? You just don't know a damn thing about motors. Not that I know all that much, but my sister knows more about an engine than you do. Nobody cares what you do with your car.. I can see now that you are simply bitter towards the 421 header because someone knew you were a ricer and knew you would believe that the $500 header you bought would give you 40hp when it maybe gave you 5 hp.. please leave the big boy stuff to people over the age of 8 and stick to painting your interior like a mcdonald's restaurant, and your single windshield wiper.. thanks.

and i dont even see why you keep posting you have about as much knowledge on the subject as a ricer that you keep talking about, is it that you used to be one or are one for that matter just with a different car. i wonder if your chevy has gay ass MSD stickers, and a calvin pissing on a Ford symbol.

and please dont tell me what i think and what i do with my car, most people on here know my car isnt rice, so shut up. and if your sister knows so much maybe you should ask her for advice before posting on here.

GT40FIED

03-18-2004, 04:52 AM

Originally posted by AzCivic
nononoNO! wtf dont you understand, I NEVER EVER said a big ass exhaust is best, omfg i cant believe your throwing out shit and saying thats what i said. I SAID VELOCITY IS IMPORTANT, YOU DONT GET GET VELOCITY WITH AN EXHAUST THAT TOO DAMN BIG, holy shit did you skip over everything i wrote.

VELOCITY, VELOCITY, MOTHER F'ING VELOCITY.

you said a little is good, too much is bad. I said NO, velocity is key to making power.

Look...I'm not argueing that velocity is a bad thing. But you have to take other factors into consideration. Things like volume and pressure waves. Say you have a given exhaust that has a super high velocity. At a lower rpm this could be beneficial under the right conditions. The problem is at higher rpms it will become problematic as the pressure waves will begin to basically run into each other causing them to back up. So you can't design a header around low rpm velocity. But then again you can't design it around high rpm power unless it's a race header. This is especially important with small displacement engines like Honda's since they can't really benefit from an H or X pipe that can even out these waves in a true dual exhaust system. So what do you you do? You design a header whose purpose is to give decent flow and velocity down low without over doing things but has the capacity to flow more at higher rpms. It's all trial and error I suppose but the velocity on the low end can't just run rampant or else you won't have the benefits that come with higher rpm power. I'm also a bit curious...a few posts back you said that even though your 4-2-1 header didn't make the power you desired, other designs did. My curiosity stems from wondering why you'd stick with an inferior design if other products work better. Hell...I've swapped heads on my car 3 times because the pieces I bought didn't suit my purpose well enough...so why should I stick with them? I'm talking practicality here...not balls to the wall power. We're talking about a street car that can't benefit from the logic of race cars that can throw caution to the wind.

V8killimports

03-18-2004, 07:49 AM

Azcivic doesn't know shit.. any one ting you do with your car will affect all other components. He's the typical guy that would put a tunnel ram on a stock 305 chevy and wonder why it runs like shit.

AzCivic

03-18-2004, 10:55 AM

Originally posted by GT40FIED
Look...I'm not argueing that velocity is a bad thing. But you have to take other factors into consideration. Things like volume and pressure waves. Say you have a given exhaust that has a super high velocity. At a lower rpm this could be beneficial under the right conditions. The problem is at higher rpms it will become problematic as the pressure waves will begin to basically run into each other causing them to back up. So you can't design a header around low rpm velocity. But then again you can't design it around high rpm power unless it's a race header. This is especially important with small displacement engines like Honda's since they can't really benefit from an H or X pipe that can even out these waves in a true dual exhaust system. So what do you you do? You design a header whose purpose is to give decent flow and velocity down low without over doing things but has the capacity to flow more at higher rpms. It's all trial and error I suppose but the velocity on the low end can't just run rampant or else you won't have the benefits that come with higher rpm power. I'm also a bit curious...a few posts back you said that even though your 4-2-1 header didn't make the power you desired, other designs did. My curiosity stems from wondering why you'd stick with an inferior design if other products work better. Hell...I've swapped heads on my car 3 times because the pieces I bought didn't suit my purpose well enough...so why should I stick with them? I'm talking practicality here...not balls to the wall power. We're talking about a street car that can't benefit from the logic of race cars that can throw caution to the wind.

Originally posted by AzCivic

you cant do both so you make a comprimise between sizes.

now your repeating what i've already said.

the reason i haven't switched to anything else was because originally i planned on going turbo, but now money is becoming a concern so i'll probably just go with nitrous, and switching to a different header that'll benefit an extra 4hp on top of the 2 i got from the first one isnt cost effective.

AzCivic

03-18-2004, 11:03 AM

Originally posted by V8killimports
Azcivic doesn't know shit.. any one ting you do with your car will affect all other components. He's the typical guy that would put a tunnel ram on a stock 305 chevy and wonder why it runs like shit.

Originally posted by V8killimports
Yea azcivic you are missing the point. 4-1 header REGARDLESS of motor = higher velocity flow. The 4-2-1 = lower velocity. Lower velocity will increase lower end and generally decrease high end, while the other does the opposite.

Originally posted by V8killimports
Dude you are an idiot.. read the entire post. Less diameter = higher velocity = low end.. Larger diameter = lower velocity = high end. You have it ALL backwards and have NO clue what anyone is talking about including yourself.

and i guess we should all trust you? your dumbass cant even get what YOU'RE saying straight.