Sorry, stupid EL vs. UEL question...

[ft86me]

Originally Posted by Tromatic

I'm sure it's right in front of my face. Feel free to call me a dope but at least provide a link. The stock car has an EL header, which is why it does not sound like a typical boxer, correct? The various UEL headers are what would make the FR-S sound like a typical Boxer, correct? I DO NOT want it to sound like a typical boxer, so I need to look at aftermarket EL headers, correct? Thanks!

here is what I have. HKS EL header, motiv OP, motiv front midpipe with high flow cat, ark catback.

http://web.stagram.com/p/707997224129277089_31758082

here she is on the dyno a while back with a 9psi pulley before i went with the 11psi pulley on the vortech
http://web.stagram.com/p/682623034882797191_31758082

hope this helps.

[wtrxprs007]

Originally Posted by ET86

They do, I hate spiders.

I hate spiders with a burning passion

[wparsons]

Originally Posted by chiefshayan

IIRC, a lot of cars are unequal length. The rumble is present because of how Subaru puts the engine together. The UEL header promotes the boxer rumble. Even an EL header on an STI will still have the boxer rumble.

The reason the Subaru exhausts have such a pronounced burble is because of how unequal the runner lengths are. Most stock manifolds are slightly unequal, but Subaru boxers are VERY unequal.



It will?

[ame="https://www.youtube.com/watch?v=zkJ9MaEdWcY"]2012 STi sedan with EL headers and Greddy Evo 3 exhaust - YouTube[/ame]

[ame="https://www.youtube.com/watch?v=0CwgnWmtwgI"]2011 sti stock exhaust manifold vs perrin equal length manifold - YouTube[/ame]

[ame="https://www.youtube.com/watch?v=sGdcre_3Mx4"]2012 Subaru Wrx Un Equal and Equal Length Headers before and after - YouTube[/ame]

[chiefshayan]

Originally Posted by wparsons

The reason the Subaru exhausts have such a pronounced burble is because of how unequal the runner lengths are. Most stock manifolds are slightly unequal, but Subaru boxers are VERY unequal.



It will?

Subaru's have a characteristic sound because they have a horizontally opposed four cylinder engine, also known as the "boxer" engine. Hence the term boxer rumble. UEL only promotes the sound, EL is a bit more raspy and hides the rumble but it's still evident. Both cylinders on one half of the engine fire, then the other 2. This causes the exhaust pulses to not be evenly spaced, which creates the Boxer Rumble.

Think about it, it's not called the "UEL rumble".. it's the BOXER rumble

[mike the snake]

Well, my car has zero rumble with EL. If you closed your eyes it sounds like any inline 4.

I'm pretty sure it's more about the crank timing than the cylinder layout.

The rumble comes from the unequal length header.

With the equal length header, the exhaust note is:

[ame="https://www.youtube.com/watch?v=ryXsn7fLV-M&feature=kp"]7-UP Commercial featuring Geoffrey Holder - YouTube[/ame]

Originally Posted by chiefshayan

Subaru's have a characteristic sound because they have a horizontally opposed four cylinder engine, also known as the "boxer" engine. Hence the term boxer rumble. UEL only promotes the sound, EL is a bit more raspy and hides the rumble but it's still evident. Both cylinders on one half of the engine fire, then the other 2. This causes the exhaust pulses to not be evenly spaced, which creates the Boxer Rumble.

Think about it, it's not called the "UEL rumble".. it's the BOXER rumble

[husker741]

Originally Posted by mike the snake

Well, my car has zero rumble with EL. If you closed your eyes it sounds like any inline 4.

See, this is why I don't want an EL header. Everyone has their tastes, but the only 4 cylinders that sound good to me are these Boxers and the Fiat 500 Abarth. Any other Toyota, Honda, or whatever I-4 engine/exhaust just sounds like shit to me.

If my car didn't sound the way it does with my exhaust mods, it would've stayed stock and quiet.

[chiefshayan]

Originally Posted by mike the snake

Well, my car has zero rumble with EL. If you closed your eyes it sounds like any inline 4.

I'm pretty sure it's more about the crank timing than the cylinder layout.

The rumble comes from the unequal length header.

With the equal length header, the exhaust note is:

I disagree, but it doesn't matter. I'll be open open dump/wastegated pretty soon so I won't even be able to hear myself think when driving, let alone my exhaust

[mike the snake]

I was referring to the exhaust note or frequency. Our cars still sound very unique I think with either type of header.

Originally Posted by husker741

See, this is why I don't want an EL header. Everyone has their tastes, but the only 4 cylinders that sound good to me are these Boxers and the Fiat 500 Abarth. Any other Toyota, Honda, or whatever I-4 engine/exhaust just sounds like shit to me.

If my car didn't sound the way it does with my exhaust mods, it would've stayed stock and quiet.

[chiefshayan]

Originally Posted by mike the snake

I was referring to the exhaust note or frequency. Our cars still sound very unique I think with either type of header.

I agree with that. I wouldn't recommend an EL header for our cars, sounds out of place to me. But exhaust is very opinionated. I think UEL is the way to go for N/A

[wtrxprs007]

Originally Posted by chiefshayan

Subaru's have a characteristic sound because they have a horizontally opposed four cylinder engine, also known as the "boxer" engine. Hence the term boxer rumble. UEL only promotes the sound, EL is a bit more raspy and hides the rumble but it's still evident. Both cylinders on one half of the engine fire, then the other 2. This causes the exhaust pulses to not be evenly spaced, which creates the Boxer Rumble.

Think about it, it's not called the "UEL rumble".. it's the BOXER rumble

No actually, in a 4 cylinder engine, whatever the layout of it is, only one cylinder will fire at a time then the next and so on. You also just said "boxer rumble" and then said "UEL promotes the SOUND" hmm... Then the exhaust is what promotes the BOXER RUMBLE.

Boxer engines do have their own characteristic sounds too but it's the exhaust and exhaust piping that does the music.

[FormulaD1988]

Originally Posted by wtrxprs007

Boxer engines do have their own characteristic sounds too but it's the exhaust and exhaust piping that does the music.

This. It's the order in which the cylinders fire in a flat engine: LLRR (1,3,2,4). UEL runners make the "pulse" more pronounced. However, there's a video of a s2k on Youtube running custom fabricated UEL headers that has a similar pulse, albeit a lot higher pitched.

[wtrxprs007]

Originally Posted by FormulaD1988

This. It's the order in which the cylinders fire in a flat engine: LLRR (1,3,2,4). UEL headers make the "pulse" more pronounced.

Exactly what I was trying to say but couldn't really word it. Thank you

[w00t692]

Originally Posted by nelsmar

Boxers don't have a sound...

And if you don't want the UEL sound don't get one. Unfortunately there really isn't much out that seems to perform well enough to justify the cost for el. All of the good performing headers seem to be UEL

Also these cars are quite raspy with a el header so if you are you okay with lots of rasp you may want to keep the oem header or get a very well muffled exhaust.

Nope. Look up a youtube video of an sti with the perrin EL header.

[wparsons]

Originally Posted by chiefshayan

Subaru's have a characteristic sound because they have a horizontally opposed four cylinder engine, also known as the "boxer" engine. Hence the term boxer rumble. UEL only promotes the sound, EL is a bit more raspy and hides the rumble but it's still evident. Both cylinders on one half of the engine fire, then the other 2. This causes the exhaust pulses to not be evenly spaced, which creates the Boxer Rumble.

Think about it, it's not called the "UEL rumble".. it's the BOXER rumble

No. How much boxer rumble do you hear in any of these?

H6 swapped impreza (still a boxer)
[ame="https://www.youtube.com/watch?v=wqnuj58lFQI"]EFI Logics Track Car - YouTube[/ame]

Older 911 (yes, those are boxer engines too)
[ame="https://www.youtube.com/watch?v=WMXH6I9ray0"]'89 Porsche 911 Carrera dyno run - twin exit exhaust - YouTube[/ame]

New 911 (yep, still boxers)
[ame="https://www.youtube.com/watch?v=20xhYn1QnCA"]Porsche 991 Carrera S Dyno Test and Tune Exhaust Bypass Pipes - YouTube[/ame]

Yet another 911 (again, still a boxer)
[ame="https://www.youtube.com/watch?v=-UQ-Psx0ZgU"]Porsche 993 RSR 2 61 litre twin turbo dyno - YouTube[/ame]

There are two main reasons the (non FRS/BRZ) Subaru 4 cylinder boxers sound so different.

1) The stock manifolds are VERY UEL and merge the ports right at the head instead of having individual runners for each cylinder.
2) They have different firing orders than most engines, and fire both left cylinders then both right cylinders.

The firing order combined with the manifold design is why they rumble so much stock. If you swap out to an EL manifold you'll definitely get rid of the rumble.