evo_soul

I promised to open up the discussion on headers and provide a bit of information for those who dont know much about exhaust flow and want to get caught up and join the discussion.


~~~ Preamble

When it comes to discussions and only debates about headers, the one debate you will come across in searches is the debate over 4 - 1 headers vs. 4 - 2 - 1 headers. Its important to realize the fundamental differences between the two. Both make power. Both could be used in any setup. Both are likely to please with the end result. But if you are doing a car build up, say for max TQ, or maybe Max HP, you gotta be aware of what direction you are going in with all the mods you buy. Personally, being an owner of a CVT equipped Lancer, I know that my primary focus is low end TQ. The logics or school of thought may differ from others, which is fine. Everyone has a different goal, but mine looks at the Lancers engine as a TQ machine, meaning TQ for me is #1. Specifically because running a CVT you know that it operates in normally within the 1500 - 2500 range 85% of the time. Raising the TQ curve can give you a noticable bump in performance that can be felt even before you hit the dyno for verification. Second point, look at the dyno sheets, if you look at the manufacturers HP / TQ power at the crank. And then look at those aftermarket sheets showing much improved TQ numbers, some that even match or surpass the HQ numbers.

Now I encourage everyone to weight in on this topic, about what your goals are for your car and what it is your trying to improve. My quest for low end TQ has been difficult, because the media (mags and online tuning sites) in my opinion continues to drive home the focus is only on HP, HP, HP. but when you stop to think about it, its really TQ that wins the day. I have been eagerly awaiting a 4-2-1 header for months. I was glad to see RRM's 4-1 header when would provide a great overall performance increase and impressive HP numbers. But my search for a 4-2-1 option continues, but maybe maybe not for too much longer, there is some buzz that by next year more aftermarket vendors will join the fight and introduce more exhaust options. for both the 2.4 and 2.0 lancers.

I will be performing a head to head shootout with a custom 421 header and the well known and vetted RRM Header.


For those who want to getting into the header debate, there is a specific reading that I recommend that keeps things in plain enough english so that everyone can get caught up. Now as I say with every sourced reading, try not to take it as the final word, or even a 100% correct, some are theories, with even referencing to support itself. I believe it to be informative, and should make you want to go out and learn more with further research.

~~~~Recommended reading :
http://www.team-integra.net/sections...sp?ArticleID=2
written by Michael Delaney

If you have been tuning for a while, then you know once you say honda or acura you know exactly where we are going. Hondas or known for great high RPM HP performance, but a complete dead horse interms of TQ. You have to know how to drive flat out and how to corner and keep those RPM's high. Many vendors have been trying to address this TQ problem with more targeted upgrades, in this case a 4 2 1 header.
This article has great information and I suggest you read all 5 pages and join the debate.


~~~~Further thoughts
I have made the request to two vendors to think about creating this option I think a 421 header if it can be done correctly would further boost low to mid range performance. Hurdles to overcome, the positioning of the CAT and distance from the exhaust manifold may limit options. in some cases longer piping solutions further help with design and performance, this leaves ideas open on a Header + Cat + Back complete solutions with an approved Catalitic coverter, but once you start messing with the cat your warranty could come into question. Second, 421 headers are more difficult to manufacture, and more can go wrong. a 4-1 header maybe easier to get into. RRM has launched its header sometime ago with a very low, almost none existent trouble history. I heard of one issue and that was resolved almost over night, which is typical of the entire line of products. When your this close to the pulse of the community its very easy to manage your RMA's and product planning.


Share your comments, agree, disagree or just dont understand. Share them... the bigger the discussion the better

mikron15

Thank You for your insightful and well thought out discussion on Header.
I am a total newbie when it comes to this subject and your post has helped me understand a lot more about it. Just for clarification, the first pic on the left, is it a 4-1 or a 4-2-1 header?

evo_soul

both images are of the 421 header. I respect the vendor structure and do not have permission to post images of R R M 's header. perhaps Rock will weigh in on the topic. if you have specific questions about the 4_1 header look for the R R M header thread. in the meantime as soon as I get home I will post back to back headers from some other cars. but someone not to long ago did a how to install of the R R M header with well detailed pics. great job.

Defcon5Es

iTrader: (5)

yeah i would like to have the 4-2-1 headers than 4-1 headers. 4-2-1 headers are more balanced than 4-1. IMO

evo_soul

well, the length of these pipes will limit the performance difference between the two pipe styles. This is because our exhaust ports are on the rear of the engine instead of at the front (nose). that in itself is a bonus in some cases. So this 421 is more like a hybrid variant. longer lengthss for both styles would cause a more diverging performance difference

Bawb3

Interesting. The most I do with my car is drag racing atm, but I don't do it very often because the car is still too slow, and sad to say, somewhat embarrassing at the track. Having low end TQ helps off the line, but once you get going, you're winding the car out to at least 5.5-6k rpm. So for my purposes the RRM 4-1 header will probably be fine. Either way, this car REALLY needs a header because its a PZEV.

evo_soul

so can anyone tell me if there is a PZEV 4B12? just curious

cRc`22

iTrader: (1)

im pretty sure the 4b12 is only 4b12 no pzev or fed just 4b12.. lol

GTS_Rob

ya, no pzev 4b12

evo_soul

makes you wonder why mitsu even made a PZEV version, I did an emissions test on my fed spec 4b11 and the emissions were amazingly low.

EngRWW33

I wish I never heard that darn 08 PZEV!!!!

BABYGOTBACK

iTrader: (1)

EVO_Soul: With all the exhaust modifications and testing you have done on the Lancer, do you feel like the stock header is that restrictive? Is it enough of a restriction to go with the RRM, or would you recommend working on other aspects of the motor for gaining tq??? Thanks again for all your great knowledge and dedication for all of us to read and use to our benefit!!

evo_soul

Thank you for the kind words,

To answer your question, and keep it simple, the top too most important upgrades you can ever make for your car I think are
1. the Cat-back or in our case the Axle back exhaust
2. 4 - 2 - 1 or 4 - 1 header upgrade.

Even thought I was so impressed with the INJEN CAI air intake, when it comes down to it, its all about the greater good and capacity. Its true that when it comes to cars with VVT aka Variable Valve Timing *Honda's and Mitsubishi's to name a few, intake air upgrades can make a great difference. But exhaust side upgrades on average are the things that win the day. namely in the TQ side of things. Of course other factors like factory exhaust and intake design may conflict with what I just said, in years past I have been shell shocked to see crazy dynos on Integras or RSX -S cars where CAI or V2 Options just blow the doors off other upgrades.

Getting back in line with our current generation Lancers, there is way more Capacity for performance gain once you have an axleback, that upgrade is compounded further to the positive side when you add a properly flowing header design.

Now I am know I am answering your questions in reverse but bare with me. Stock header design is always going to be poor when it comes to what manufacturers put into our cars. It comes down to Money, cost of materials, failure rates. Second, and I was even horrified to hear this not sure if it was a rumor or not, but someone mentioned that our header design was changed last minute to actually reduce crank HP by a few horses, to meet emissions limits set by world wide markets. Dont know if it was true, but I can definatly see it happening if they were more concerned about Emissions.
Stock Header designs are not optimized for proper 4 cyl. pulse flow. Idealy what you want in a optimized header is there to be order and harmony when each piston fires, as each fire, the pulses go down the exhaust manifold pipes and one after and collect along they down into one pipe, as I mentioned about the 4 2 1 headers, they would collect from 4 pipes into 2, travel a bit further then collect from 2 to one. But a 4 - 1 header does the job all the same, just with better numbers in the HP department. Now thats in the perfect world, flash back to the stock headers of the past and present.

if you get a good look at a factory header you can see that the lengths of exhaust manifold pipes are all wrong, what you end up getting is collisions you get some pistons working harder then others to get its pulse down the line and on to the down pipe. if you look at the image below, you can see a side by side comparing of the two types of headers, performance aftermarket header vs. factory. Now in some cases, some manufacturers mostly Japanese design some pretty decent manifolds all things considering, but still looking at the design you can still see the pipes that are uneven in length, look at 1 and 4 vs. 2 and 3. Now I know I am super simplifying this example, and not taking into consideration firing sequence pairing, but you get the idea. But the over all point of this example is to get a header that has the piping perfectly balanced so there is no congession in the exhaust system, and back up, could potentially harm overall HP performance. Something that most if not all honda owners would say is the number one RULE. Get that exhaust flow out of that exhaust system as fast as possible.




I want you guys to go around and read up from different sources, but at the same time be grounded in the fact that there is more then one theory for what makes better flow or performance. What is a golden rule for a honda guy isnt the same thing for a Mitsu guy.

Honda's and Mitsu's go about making power in very different ways. In most cases for hondas, and forgive me for making the sweeping generalization, but mostly, the goal is to go all out in the HP department, exhaust flow is balanced for exhaust volecity and these leads to handicapping Low and mid range TQ power. This is why you will constantly hear that back pressure and deliberate resistance bends are just foul and dirty words. Not to be spoken.

Mitsu's if you study the charts are very much dependant on balanced levels of back pressure, where TQ is more valued paticularly in the low and mid ranges. Personally this is why in the 4 cyl. world, EVO's are unbeatten because they are just disgusting when it comes to low end pull. Now I am not putting down hondas in any capacity, a well seasoned honda driver that knows what he is doing, able to keep his car in the high RPM zone is able to hold his own. But thats a debate left for another day.

getting back on topic, you might find the following sites fun readying, so long as you take what is said with a grain of salt and remain grounded that our engines work differently then others. then you will still be able to fully understand the situations you encounter.

http://www.hondatuningmagazine.com/t...est/index.html


Did any of that make sense, most of this was crafted on my cell phone PDA while I wait for my girlfriend to finish shopping, lol too much time on my hands eh?

Bawb3

Here are some comparison pics from an 02 Lancer RRM header vs Stock. To further emphasize what Evosoul said about header design.

From a How-to thread created by Green_Bandit.







You can tell that thing is very restrictive just by looking at it.

evo_soul

revisions to the 4 2 1. so far so good I get my hands on it by the end of next month