Exhaust Header - Explained
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- เผยแพร่เมื่อ 6 ส.ค. 2013
- What are exhaust headers? How does an exhaust header increase horsepower? What's the difference between a 4-2-1 header vs 4-1 header? This video explains how exhaust headers are used as a portion of the exhaust to increase horsepower, by using long piping and larger diameter piping, as well as a larger diameter collector.
Product Link:
Yonaka Headers - www.yonaka.com/Yonaka_Headers_...
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You have to understand the basics to understand it all. Some videos are simpler than others, ultimately (hopefully) it provides a good understanding of the overall system.
First, I like your channel, and i'm subscribing, so don't take this the wrong way :-) but...
You missed the science behind the main reason for using an aftermarket header... it is *Not* the larger diameter header piping (although that *can* help... or hurt... "sometimes").
The main rationale for a header is to create an equal length of piping from start to finish for each of the individual pistons on the engine.
Why?
- The pistons fire in very rapid succession, and when each piston releases it's exhaust gases into the exhaust system, it represents a pressure spike in the exhaust system. Each of these pressure spikes seeks to equalize pressure by expanding down the exhaust pipe, eventually exiting the exhaust.
- At the rate of piston firing in typical engine use, any given piston's exhaust pressure spike has not yet dissipated before the next pressure spike from another cylinder arrives (more noticeably so at higher rpms). So the pressure spikes from the cylinders start to overlay each other, kind of like people waiting in line to go through a ticket booth. This generates exhaust gas pressure, and the higher the pressure, the more it creates back-force on the engine's pistons which push out the exhaust, robbing power.
- While larger diameter exhaust components are helpful for reducing gas pressures in the exhaust, thus reducing resistance to the engine's job of forcing exhaust out and in turn the amount of power it takes to pump the exhaust out... there is another factor at play which a header is specifically designed to address: *The spacing of each cylinder's exhaust pressure spikes in the exhaust system.*
- In a typical original equipment exhaust manifold, the goal is often to use as little metal as possible (cheaper/lighter), and take up as little space as possible, while getting exhaust to the catalytic converter as quickly as possible so that it heats rapidly, reducing emissions for legal reasons. This results in exhaust manifold piping where the pistons nearer the catalytic converter having a shorter distance to travel to enter the main exhaust, and pistons further away from the catalytic converter having a longer distance to travel ("unequal exhaust path lengths").
- The pistons fire in a cycle where each piston's exhaust has equal timing between it and it's neighbors, so at any given RPM, the exhaust pressure spikes are occurring at equal intervals. But when they travel through piping of different lengths, these exhaust pressure spikes can end up closer or further apart when they reach the catalytic converter and remainder of the exhaust. If you want to go back to our people waiting in line analogy, imagine two people side by side in line, both trying to get through a ticket booth which is only one person wide, at the same time.
- A header is designed *specifically* to reduce (short header) or eliminate (full header) that timing differential, by making the length of pipe for each cylinder going to the catalytic converter identical, or nearer to identical than stock. So that your people waiting in line to go through the ticket booth (spikes of gas pressure in the exhaust which must dissipate to reduce exhaust pressure) are in a nice single file line which moves through the ticket booth efficiently.
(( For reference, when you see an engine's power band (in both HP and Torque) following a curve where you get diminishing power returns at higher RPM, that downward curve (which seems to prevent an engine from continuing to ramp upwards in power at higher RPM's) is very heavily influenced by the resistance of gas movement. Friction, and oscillating weight such as pistons, valves, & rods also affect it, not to mention losses in the drive chain taking it to the wheels. But back to gas movement... If you tuned the *entire* breathing system of a car, including: filter, intake, throttle body, intake manifold, valves, valve timing (cam), exhaust ports, header, cat, and cat-back... you could shift the peak of an engine's power output several thousand RPM's higher, allowing it to climb to a significantly higher peak, at much higher RPM, before diminishing returns bring it back down, and also provide a broader power band which helps reduce time spent shifting gears. BUT most of these components *by themselves* offer very little benefit, because the stock components are like a whole set of bottlenecks, and power gains are minimal when you only remove some of the bottlenecks. A header is the glaring exception though, as it can help *any* exhaust system move air significantly more efficiently. Although from a labor standpoint, if you're installing a header, you probably should do the whole exhaust anyway. Similarly a turbo or supercharger has a very strong single-upgrade benefit because it can brute-force it's gains through a restrictive throttle body & intake manifold. ))
*** Header Advantages ***
Headers can reduce exhaust pressure *significantly*, or more accurately reduce variances in exhaust pressure, so that any given diameter of exhaust piping, catalytic converter, muffler, etc. can work most efficiently. At low RPM where exhaust pressure is minimal, there are little to no power gains, but at high RPM's a header will make any exhaust system have much more efficient gas movement, keeping exhaust back pressure to a minimum. A good header can help reduce the need for excessively oversized cat-back tubing, reducing weight and improving ground clearance. It also makes a smoother sound at the exhaust. While a un uneven rumble may sound cool, a smooth deep exhaust note is the sound of efficient air flow.
A header can add more power (by itself) by increasing the efficiency of even a stock exhaust system, than a cat-back can. It's also much more of a pain to install though.
*** Header Disadvantages ***
Headers add weight. All that extra piping is more metal for your car to carry around. For normal driving in the 500-2500 RPM range, headers will weigh more than they're worth. Which is one of two reasons they aren't factory equipped.
Headers put more travel distance between the engine and the catalytic converter (another minor help for reducing exhaust pressure), but that makes the Cat take longer to heat up after starting an engine cold... and that will make your pollution emissions significantly less favorable. Some schemes that auto makers have tried to overcome this issue is to put a mini-catalytic converter in each header pipe, or to electrically heat the Cat at startup. Some performance Cats are designed to somewhat alleviate this concern with more pure platinum coating, etc.
Another possible disadvantage is that some exhaust headers have oversized piping, but if the exhaust ports on the engine block are smaller, that creates a sudden change in exhaust diameter... while the explanation is quite a bit more in depth, in simplest possible terms, you can think of sudden squared off changes in exhaust diameter as being "very NOT aerodynamic" in terms of moving gas through a tube with minimal resistance. Conical changes in diameter are not problematic, but squared off changes in diameter are not good. Large diameter header tubing on standard diameter exhaust ports could potentially rob a bit of power even at low RPM. I'd recommend getting standard diameter piping on the header (matching the factory engine block ports) *OR* milling out the engine block to match the header diameter if you want really big pipes (milling the exhaust ports is probably only worth it if you're going to increase the engine's gas pressures with a turbo or supercharger). For similar reasons (avoiding abrupt changes in pipe diameter), I'd recommend a low-resistance performance catalytic converter with nice gentle funnel shapes fore and aft, a low resistance muffler, and to avoid using a resonator. Likewise, the design of a header's "collector" (where the pipes come together) is crucially important as well.
ALSO:
A 4to2to1 header will perform well *on a 4 cylinder engine* for piston ignition sequences of: 1-3-4-2 and 1-3-2-4, but less well with ignition firings of 1-2-4-3, 1-4-3-2, and 1-2-3-4. Meanwhile a 4to1 full header will perform equally well with any ignition sequence. This is all due to getting the people going through the ticket booth as equally spaced and spread out as possible. If two neighboring cylinders in the right or left pair of a 4to2to1 header fire one after the other, then that creates additional pressure on one side in the 2-pipe stage of the header. Personally I think a 4to2to1 header is the better choice, being generally lighter, and having staged collection (merging of pipes), but only *IF* the ignition sequence on your car is one of the two sequences with which it can perform to it's best potential.
In terms of parts & labor, it's almost always cheaper to get a car with a larger displacement engine than it is to tune a smaller engine to be more powerful. However, I get the hobbyist interest. And with gasoline at around $3/gallon, 100,000 miles at 20mpg is $15,000 in gas, while 100,000 miles at 30mpg is $10,000 in gas. I doubt you'd usually see that large of a gas mileage difference, but there can definitely be some back-loaded savings on tuning a smaller engine. Plus "the engine in the car you already have" is always priced very attractively.
kathrynck What a comment! I have another video going into a bit more detail. :) Performance Exhaust - More Horsepower
You have WAY too much free time on your hands.
Very interesting to read, thanks!
So 180° parrallel twins would benefit from header pipes of significal difference in length.
As would those 4 valve singles with double header pipes.
Altough I would guess one had to be so much longer that the backpressure would be worse than any gain from airflow.
Maybe in connection with different diameters? ...
kathrynck Fantastic comment. Thank you so much for taking the time to write up this lengthy explanation. I feel much more informed after watching the video and reading this comment. Kudos to you both.
kathrynck ummmm Is there anything you left out" damn that's a bloody mouth full!!!. so to my question I asked I might as well ask you!. what do you think about a ceramic header?? gee's you know you're shit pretty damn well.
Finally someone who doesn't swear by turbos. Engineering at it's finest indeed! I love the mathematical breakdowns, really helps me understand the concepts of these videos. Very good work, mate! Cheers!
Haha turbos are pretty awesome though!
But with a turbo you are turning exhaust energy that is normally just wasted to pressurize the air coming into the engine. Therefore making a denser and more packed air/fuel charge, to make more HP. Out of any mods a turbo will give you the most hp for the price. I can spend like 2-3k building an N/A car and make like 300whp (just an example). Or turbo it for about the same price and make 350-400hp (depending on strength of stock engine components and psi). A turbo is like turning your shit into gold, now who wouldn't want to do that.
Engineering Explained would headers help my turbo car
the one every car has headers...lol
the one you probably mean would "performance" headers help.
Your honestly a huge help man. I'm really into cars but I have literally no one to teach me anything about them. I thank you for these videos even tho learning from them is looked down upon by others. They still help me and inspire me.
***** Glad you enjoy the videos, and can learn from them! Why is learning from these videos looked down upon?
Engineering Explained I honestly don't know. I tell my friends that I'm learning from them and they laugh at me and I've seen comments on other car videos of people just making fun of people who learn from them. But I honestly don't care as long as I'm learning about something I am really inspired to do.
Interesting. Well Yonaka, Nitrous Express, Shell (world's second largest company), Nissan, and many others still to come have all used my channel as a method of teaching about various items, suppose that provides some credibility no? Anyways, happy to hear you can learn from them. Negativity will always exist. :)
Engineering Explained probably just machismo-driven ignorance. In their minds, you gotta be out there busting your knuckles and getting your hands greasy. Classroom instruction doesn't count.
emmanuel big facts
Appreciate the suggestions! I do have videos on cam lift, multiple valvetrain videos, but many of your other suggestions I am limited on. Cheers
Yes, sometimes curves are put in to keep the length of the pipes equal, could also be done for space constraints.
Header comes directly from the engine head, it's the first tubing the exhaust goes into after leaving the cylinder head. The downpipe is directly after the turbo (exhaust side).
Thank you so much for all of your explanations. I've learned about cars and machinery in general with your videos more than with any other resources. Again, thank you so much, I look forward to more of your videos!
You should also touch on aspects like
- Sequential vs non sequential pairing of 4-2-1. There was an Exup Valve on a header that would switch between the two pairings.
- Long tubed primaries vs short tubed primaries. Some headers will split the primary secondary length 50/50 but I've seen some primaries that are closer to 60% of the length perform like a 4-1, while still reaping the benefits of the 4-2-1.
- Then there are collectors that have venturies/choke points in them to alter their performance.
- Stepped headers and stepped port vs port matched head -> header
marry me
Thanks, glad you like the videos!
Actually, I am an engineer, working in the professional world..
Hi i have a question i have a 206 gti s16 136hp and 190nm torque now my goal is to get 190hp but thing is its light and im not aiming at gettin more top speed intead i like accel 0-180kph my ive got a blok thats going to be refurbished in a few weeks i orderd a sport cat 200 cells janspeed catback exhaust a 4-1 header ist going to get a rc head witch has bigger valves and its ported have to disable vvt tho and like itb but what to do with cams and cam sprockets is it worth it to forge the blok high compression pistons etc ?
@@LB83. the amount of compression would depend on if your installing forced induction. The compression would depend on how much boost you plan on running if you go that way. High boost would generally require a bit lower compression to avoid blowing the motor from increased stress. If you are going to be running a naturally aspirated setup id get higher compression im not sure how much it would help you gain in terms of actual power sure compression is good for power but probably wouldn't give you that gain your looking for best option from what I read a bit higher compression ratio upgraded fuel pump maybe a bit larger injectors. I wouldn't be running without vvt this would rob you significantly of power. Header setup and free flowing exhaust put a better intake plenum thats higher flowing and a larger throttlebody as well as a higher flowing air filter (sidenote throwing this at the car without a tune would 100% throw codes, the car would most likely not run as the computer would be very confused with what to do with the new hardware get a piggyback ecu or a new ecu and get it tuned. That in mind you would make plenty of power
Depends of course on the engine, number of cylinders, and size of the engine. If you check out my video on catbacks I give a fairly vague rule of thumb about how it may work. Likely need additional videos on this kind of topic in the future.
Most of what I saw only differed by a few hundred RPM, and most of the time it seemed the 4-1 did a little bit better. Definitely didn't pool a very large sample of dynos though, so it'd take a bit more to reach more conclusive decisions. I hope to get more into it over time.
Perhaps, if it's really heating up the engine bay a lot/the intake manifold. Also most exhaust manifolds have a heat shield, and this requires removing it so it could potentially help.
I've been going through a lot of your videos. You're an excellent teacher. You teach like how I teach others.
I'm going to school to teach and while I don't know what topic specifically, but I do know that I will remember the style of your teaching for sure!
You sound like Melvin from the movie Madagascar
lmfaooo
Dead you fucked the video up for me
LMAO whyyy
You mean david swimmer xD
*Melman
Once I get into tuning my car and actually swapping out components, I'll be doing some dyno tests for sure, and will certainly explain them. It may be a while until this time though, saving up for a new car so my Integra can become a project car.
Interchangeable terms yes, "header" seems to be more common here when referring to aftermarket parts.
Hey just wanted to say great video's, I have been building motors for awhile now and you explain it better then most of the guys I have learned from. Keep up the great work!!
I love the quality you put in your videos. If i never saw your subscriber count, i would have thought you had a million subs
Dude thank you for these videos, you do a great job of explaining and making good sense of how things work. Especially a car enthusiasts such as my self thats at an amatuear level with understanding how things work it makes sense!!! aYou my friend have gaing a new subscriber
Thanks for subscribing!
Nice job on this video. You really should discuss the primary pipe length as it is the single biggest factor for the tuned header. A shorter pipe length move the peak torque higher up the RPM band while a longer pipe length moves this down the RPM scale.
You explain very well about the topic! I'm enjoying your series!!!! Really good!!
Actually there are some headers that do this, but I think the reasoning lies in creating the scavenging effect, and having the pulses create a low pressure zone which acts like a vacuum. Things wouldn't exactly line up well if it were to all join at once.
I haven't really been upgrading it, primarily due to a lack of time. If I put any of these parts on there will certainly be a video.
Just gotta say, i love your videos, Im a first year Freshy engineer on a Formula SAE team and these are such a great way to get introductory information. Keep up the good work!
Caleb Hille Thank you! Glad you enjoy it. Best of luck with your college career!
i just want to say thanks for making these videos, its greatly appreciated and keep it up!
I like that you talked a bit about the types of collector designs. If you look at some of the nascar cup car headers, they have various designs including 4-1 and 4-2-1 for each cylinder bank, as well as various pipe diameters of each step. It's really just tuning based on the track they're running, but it's surprising to see so many different configurations.
Back pressure is not needed, velocity is what you want. Check out my video "how exhaust systems increase horsepower." Here I discuss the balance, you may not have enough power to warrant a larger exhaust, thus it may actually reduce performance slightly.
Thanks for all the great videos! Very well explained and informative. Could you please make a video for the secondary air injection system! Thx
My old Porsche 944S had a 4-2-1, also known as a Tri-Y exhaust system. It sounded pretty good and seemed to flow pretty well.
Yes, this fits B series motors, and my Integra has a b18b1.
Absolutely, it's not as simple as saying this component gives this much power. Everything works together.
Thank you for not having any video intros and just going straight to the point.
can you do a video on long tube vs shorty headers?
awesome vid.. i have a 2014 veloster turbo.. will buying a aftermarket header increase my performance
Great vids and love watching them.
I just have a question.for an A/T car to remove the catalytic will it gain or lose power since there will be little to less back pressure? And how about fuel economy?. thanks!
Great video, I was able to translate all of this to my motorcycle because it too has an in-line 4 cylinder engine, as well as exhaust headers. It's a 2008 Yamaha R6.
Same thing, many aftermarket companies simply refer to replacements as headers.
So ceramic coated or painted with something like VHT? Which is better in terms of performance and longevity?
Thank you for taking the time to explain this!
I like your videos man because you're giving me an idea on witch mods I should get on my car to gain more horsepower so I can have more fun on the roads. Nick
A looked at a variety of companies when I was still in school. Yes, definitely difficult to get into the automotive industry. I like where I'm at.
With the power band shift - that's not because of the way the headers are built, but because of their length - in a N/A car there are wave effects occurring in the exhaust that help scavenging around some RPM range, and that depends on header length. As 4-2-1 are in most cases longer they help in lower RPM range (also there are compounded effects from each joint point so 4-2-1 have a wider torque range).
Either you read a few pages or u watch this guy. The physics behind it is important to know for your next step in truck or car mods! Thanks bro
I like how you kept it simple and to the point. Thanks
Thanks for putting this up bro, I remember asking about this couple weeks ago.
ZOMG Thank you. I agree with both you and Jose on this matter, straight to the point, no time wasted. Love your videos man.
Love your videos and i respect that you are an engineer with knowledge, however we all work in the "professional world".
Hey great videos. I have watched nearly all of them and am impressed with the explanations. I was wondering if you could explain a fwd manual transmission as those seem to be a bit different than regular manual trans. Thanks
Been waiting for an explanation of this these bad boys! Thank you sir
Man litterally all the info I need to know you have, thanks man haha just learning and learning.
alright alright, i thought i might see maybe one or 2 of your videos in my life of yours but evidently thats not the case now.... damn it you earned yourself a subscribe....keep up the great work
We need more engineers like you thank you for all your work
Yes, if you're only using this for city driving rather than at a track where you stay near the higher RPM.
I'm sorry if I didn't catch it in the video but what bearing does the length of the headers have on back pressure? From what I have gathered from info online and my experiments with my 36-year-old 350cc single cylinder bike, reducing back pressure to a very low amount results in large gains at high revs (just like you said about shifting the peak output up the rpm band) but a drop in low end output. How does the header length fit into this?
Siddharth Rajkumar it doesn't explain in this video, but he does refer you to another video of his. Basically, when the exhaust reaches the collector, the cross sectional area increases suddenly before tapering down to the larger diameter. When the high pressure pulse of gas expands like that, it sends a lower pressure wave back up along the pipes until it reaches valve. Imagine taking a long, light spring, then suddenly yanking on one end. You'll see a wave go from one end to the other where part of the spring is stretched, and the remainder is still at rest. If you can time it so that wave reaches the valve just as it's opening, the backpressure will effectively be lower. However, this only gives a boost when your rpm is at a certain level, and will actually decrease torque when it isn't at the correct rpm, due to higher pressure before the wave hits
Thank you very much for explaining the item. can you please tell us what are the risks that may happen after installing it.
Great vid as always. Thanks for the education. Have u considered having a quick quiz at the end of ur vids...might be a good idea
Any chance we can get some info on High Airflow catalytic converters and if its even worth it? CA legal of course...
Yes, and updates along the way. Haven't even started to be honest.
Really enjoy your videos! If you do install the parts you've been getting, make a video!
Not sure yet. If I don't turbo it I may.
What about equal and unequal headers??? What are the differences except from the design?? I'm an Impreza STi owner so you understand why I'm asking and I would be glad to learn more... Keep up the great work!!!
great short detailed info! quick question ... with a 370z, what would U do to get best hp gains without forced induction? cheers in advance
justin
Haha very welcome. I get a comment or two every now and then saying "you need a video intro." I disagree - I'm here to teach and an intro is simply a waste of time. Hence "hello everyone and welcome" is my intro. Glad to see the method is appreciated.
I have a civic 1999 LXi with a stock engine of D15z4(87hp). You mentioned that an upgrade to a 4-2-1 header won't help in this kind of small engine. So, how can I add more kick or more HP into this? I don't want a turbo package upgrade as this is expensive. I just want to see other options if there are. Please advise.
Yep
These videos help me so much. I am working on designing an "ideal car" because I'm fifteen with nothing better to do, and I want to have experience in designing cars if that's what I end up doing for a career. I'm thinking v10 or v12, 3.0 liter 1990's f1 style. Awd, with torque vectoring, and turbo charged. I'm also working with an Ohio state university student with a Chrysler internship on redesigning the way valves work and move, because I really hate how restrictive they are. The goal of the car is pure acceleration. I think I'll be relatively relaxed with top speed. Let's say a goal of 200 mph (hah got you there). Because of acceleration being our goal, we'll use the 2014-2015 f1's hybrid engines as a reference point. I recall you going over a new turbo technology you saw at an event. We'll combine that new tech with the split turbo technology of f1, to keep the intake cool. Since I'm a group B rally enthusiast, let's put a twin screw super charger after that turbo.
What about Longtubes vs short tube headers?
Very clear and informative, thanks for the video:)
Thanks great explanation. Does the O2 sensor detect any issues that is sends back to the computer?
Hey Mate,
Could you do one for a turbo vehicle?
I have heard many mixed things from both forums and experts all contradicting each other
Cheers, keep up the awesome vids love them
Hi, I've been looking across TH-cam but can't seem to find any videos on the benefits of using exhaust heat wrap. Would love it if you could do a video explaining the pros and cons of it.
Many thanks
Is there a specific equation that you could use to determine the best, most efficient diameter tube to use based on engine and desired horsepower/torque? For example, if you have a 5.7L Hemi and want to produce 500ft/tq. What diameter tubing would be best?
I am thinking about replacing my exhaust header in my 2014 miata with a GWR roadster sport street header (catted). Would I be able to feel the difference in performance and is is worth the money and time?
Please advise. Great videos by the way.
Thanks
I apologize if you covered this, If you want to replace your stock exhaust header with something with larging piping, how would you connect the larger piping to where it connects to the engine? I'm guessing it has a specific diameter. I didn't know if there was another piece you would connect to make it fit or not. I love you videos I'm learning so much.I also have a vw rabbit a/t 2007 2.5 that I would like to start fixing up.
do you have a video the explains the benefit between sequential firing order vs non-sequential piping on exhaust header, like a Honda since you use a B-series.
okay so hears a question for you that I've always wanted to know. i drive a subaru and the have a 4-2-1 exhaust header. now in theory if i ran duel exhausts from both sides of the motor basically covering the header system to a 2-1 would that increase power efficiency and whatnot? I'm VERY curious to know.
I don't know how to send private messages with the new google+, but oh well. I have the same car as you, 99 integra gs, and I have a few questions. So I've replaced the stock exhaust with the same Yonaka Catback system you've shown in your video. I'm planning on replacing the headers with the same Yonaka headers you have in your video, so all that's left is the cat.
Like you said the collector pipe diameter is 2.5" and the product description says it won't fit the stock cat. Yonaka also makes a high flow cat that has a 2.5" inlet and outlet diameter, which matches the headers. The problem is the Yonaka catback exhaust is 60mm in diameter, which is less than the 2.5" outlet for the cat.
My question is, will the 60mm Yonaka catback system bolt onto the 2.5" Yonaka cat without any grinding or modifications? In other words will it fit properly?
The header is not a simple bolt on, there will have to be some fabrication/welding to get it to fit with the exhaust.
Do I need to eliminate the catalytic converter if I'm installing short headers ? If so saving myself at inspection. I'm planning on installing "DC Sports 4-2-1 Exhaust Headers" for my Si sedan. Thank You
Great explanation of the torque shift of 4-2-1 vs 4-1.Thanks
Noobie question. I've heard that when installing an after market exhaust header, you also need new fuel injectors. I just want to confirm if this is true or not and what would be the best way to go about shopping for them?
I drive a 2013 Dodge Dart Rallye 2.0 automatic.
thank for your video and i have some questions to ask
1) For 4-1 and 4-2-1 exhaust system, which will have better air flow but lower air velocity?
(from what you draw i think should be 4-2-1, but still need your clarification on it)
2) how does the air flow and air velocity of exhaust system affect the torque band shifting?
(of cause in your graph did show the result of torque shifting, but i really need you further explanation on that)
just fyi for those in the dark. Primary tube size is always given for the outside diameter not inside diameter.
you are awesome dude!!!
What headers would you recommend for a 03 eclipse gts v6? I have an invidia n1 exhaust
Plan on doing any videos showing us the completed vehicle when the time comes? I'd be interested to see what all these nice parts do to it performance wise when all is said and done.
Can you do comparison for ceramic coating for exhaust headers and some kind of thermo isolation tapes for more performance of engine? Is it true, cost-effect, etc.
great video , but i want to ask about the relation between back pressure and header ,
2- why we loss torque from the engine when there a leakage on exhaust system ?
You should do a vid explaining the difference between DOHC- SOHC and OHV (Highlighting disadvantages and advantages between them if there are any) ---- by the way keep up the great work
Great explanation! I have yet to read all the comments/questions here but I would like to ask, if you install a 421 aftermarket headers, is it necessary to PORT Match it to your head or would it make a difference?
i have so much questions, my first question would be; on a 2013 Altima. I want to make it faster with a nice sound to it. It is completely stocked no mods on it what so ever. Where should I START?
i got a question, so which headers contribute to a Louder exhaust sound?
Larger diameter pipes or Smaller?
4-2-1 or 4-1 ?
if u can answer that, that would be great!
thank you
im planning to remove my resonator and upgrade my pipes into a stainless steel 2.5in pipes and change my stock muffler into a freeflow muffler.. my question is can i gain a horsepower into it?? thanks for more info you shared
my cat. converter is build in with exhaust header. is it a big disadvantages to mod anything with engine, turbo?
I have a 99 Honda Civic si B16 engine what is yonaka also a good brand?
Could you please show me this same video as well as the manifold precat with a 2003 Nissan Altima.2.5 thanks
hello, i want to ask, why 4 stroke exhaust header always use a straight pipe than use a divergent cone like a 2 stroke exhaust (without baffle), i just run a simulation in cfd program compare a straight pipe and a divergent cone same length, same area and same environment preassure (divergent area 2, two times area 1). it shows divergent cone makes more volume flow rate and more gas speed than straight pipe, it mean less force to push air out from the cylinder. but why i never see people use divergent cone as a header? i just see them use in tail pipe section.
can you explain it in next video? wait for your reply. thank you
No, it's simply routed that way to expel the exhaust gas at the back of the vehicle.
I want a Subaru UEL header like rumble but can't because I have no exhaust manifold, is it possible to get the same rumble effect I make one pipe on the catback longer than on the other side?