4-1 vs 4-2-1 Headers – What is the difference? What makes more power?

A question we get a lot is: What’s the difference between 4-1 headers and 4-2-1 headers? Which header design is better and which header makes more power? It’s not that easy of an answer, and we’ll explain below the differences to help you decide what is best for your car, because really, the answer is: it depends. These headers are for a 4 cylinder or an 8 cylinder car, and we’ll go into more detail below.

4-2-1 Headers
As the name implies, the headers start from 4 pipes that merge into 2 pipes and those merge into 1 pipe. You can see from the headers on the right how this design plays out. For most cars, this design produces more mid range power with the sacrifice of top end power. Mid range power is great for the street since when you drive you usually do not rev your motor close to redline. Instead, you keep the revs somewhere in the middle, usually shifting at 3-6K, and this is where the headers shine. Do note that not all 4-2-1 headers produce more mid range power at the expense of top end. Some high quality headers are able to improve top end as much as they improve the mid range. This is more the exception than the rule as most headers that are 4-2-1 do produce more power in the mid range, so the “seat of the pants” and “butt dyno” make these headers feel stronger since the power band isn’t as high in the RPM range. This goes the same for both 4 cylinder and 8 cylinder applications. Since on a V8 the headers are 4 cylinder per side, you would simply have two 4-2-1 headers, one on each side.

4-1 Headers
4-1 headers are designed so that all 4 exhaust pipes merge into one. In most dyno tests, this produces the most top end power since it usually offers the best flow characteristics for the engine at high engine speeds. 4-1 headers usually move the power band up, which makes the bottom of the RPM band feel a bit weak and the “seat of the pants” feel might not be as strong as a 4-2-1 header. However, dyno tests have show that at low RPM there is very little difference in power. The 4-1 headers usually have less back-pressure than the 4-2-1 header and customers have stated their cars seem louder at high RPM with the 4-1 headers. Most headers that are street legal or CARB legal are usually of the 4-2-1 design but there are exceptions. You can see the design of the 4-1 headers in the picture on the right.

Which headers offer more ground clearance?
Since 4-2-1 headers merge into 2 pipes before they merge into one, there is usually more ground clearance here. You usually have only 2 pipes under the car instead of 4. You can see the difference in ground clearance from the pictures of the headers above. Vibrant headers offer great ground clearance with the 4-1 and 4-2-1 design.

27 comments
  1. i have a 92 cx hatch that has a d15b7 ingine and i was wonderin what kind of headers should i get as well as cams and intake mani

        1. lol. i agree. i had a 01 civic ls and it had a d17a1 woorr. I was thinking why the f**k didn’t they put a k-series in the 01-05 civic it would have been a awsome car.

    1. Lmao. You have no idea what you’re even asking. There’s no such thing as “true dual headers”. There’s no such things as “headers” for a 4 cylinder engine, either. It’s a single header. Being single, there’s no possibility for dual anything. You have 4 pipes into 1 single exhaust pipe. Done.

      “true” Dual EXHAUST consists of one exhaust pipe per header. Since a V engine has 2 headers, you can have “true” dual exhaust by keeping each side of the exhaust seperate from the other, effectively giving you seperate exhaust systems. On a 4 cylinder, that’s impossible. You only have a single header. Unless you make 2, 2-cylinder headers and run those as you would on a V8, then you cannot have true dual anything on an inline 4 cylinder engine.

      1. “True Dual Exaust” consists of “1” exhaust manifold/header per exhaust ports of the HEAD!! No such thing as a “V” engine having two headers that you attach headers to!!

  2. I got a 2000 civic sir , b16a2, put 4-1 headers now almost feels like hits vtech early and you can barely notice ,
    Vtech kicking in , is this normal or could there be an issue

      1. you are overreacting no one usually cares if some says headers when it’s meant to be singular like you know what the fuck he meant right why you gotta be an asshole and try making him feel stupid, it’s different if you want to correct him like.

        Hey man if it’s a 4 banger its singular only one set of tubing.

        Dont deal, was I a dick NOOOOOO help your comon man you could create a better world for yourself instead of trying to one up everybody.

  3. I`m driving Ford laser TX3 1.8 (1992) Front wheel drive. BP N/A Engine.. My question is, can i use 4-1 header (shorter type)

  4. I hav a Mitsubishi gsr 1998 model… what tweaks shud I get for my engine to be more fuel efficient yet stil hav d power/speed when I need it…

    1. Put a turbo on it and a change the piston And the connecting rods exactly for turbo set up and put an oil supply to the turbo and back to oil pan

    1. Get the Megan Racing 4-1 for that’s for the 06+ Accent, You’ll have to make a custom catback system, and the weird “bent” pipe that comes with it is useless for 02-05, but the header itself bolt-on for 02-05 1.6L Accents…

  5. Ano po ang maganda para sa honda covic97 hesders full exhaust po b na 4 2 1 or 4 1
    Ano po ang impact po nito . low budget tnx and God bless

    1. Ang 4-2-1 header ay okay pang daily driving. Mas mararamdaman mo ang power sa mid range. Sa 4-1 naman, mas maramdaman mo ang power sa high end which is more advantageous kung sa race track ka, mas maingay pa ang tunog. One more thing, kung sa California ka nakatira, the only choice you have is 4-2-1. Its the only CARB legal header available. Ang 4-1 ay hindi CARB legal. Sana ay nakatulong ito.

  6. The explenation on 4-1 and 4-2-1 is it like on golf 1and 2 does that count for carb and fuel injection and the L ,A or G cam and 288

  7. I have 4.2 v6 f150 heritage i went with k&n intake, shorty headers, and jet programmer any other tips as far as coils plugs etc i tried maf sensor and tb from jet but the 4.2 often gets left out

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