Uneven Length Header? - Performance Forum

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Uneven Length Header?
Tuesday, July 23, 2013 3:06 AM
Did some Google searching and found a post or two on a prelude enthusiast site about mimicking Subaru's iconic boxer rumble sound, as most know, this is attributed to their uneven length header's, of course, having a uneven length header would lose you 2-5hp, but gain you that 'Subaru' sound, and more displacement offering a little more depth (2.4 LD9 would probably be better than the 2.2 Eco, as opposed to what I think the Subaru's have... 2.5's?), of course due to the firing order, you'd have to have uneven length piping from the outer 2 or inner 2 pots. And it would have to be custom fabricated.

Link to aforementioned thread: http://www.preludeaustralia.com/forum/archive/index.php/t-51129.html?s=9c8d704cfc6edf7480f313b0b523ed36

Thoughts? I've always loved that sound personally, some hate it, some others like it, etc etc.




Re: Uneven Length Header?
Tuesday, July 23, 2013 3:33 AM
retarded






Re: Uneven Length Header?
Tuesday, July 23, 2013 3:46 AM
Unequal length header on a L61 or Ld9.....doesn't equal subaru sound. Most of that sound is from the Boxer motor. Could you get a little rumble sure, but you would have to make sure the exhaust waves are out of phase. The reason no one makes these is because it is either a lot of trial and error, or WAY more math than most people want to do.

You could get closeish if you make a 4-2-1 header, and pair the correct ports together, but you need to ensure the waves are out of sync......or synced together. This is bad for scavenging, and against most "good practices" for header design. Also, you would probably need some custom cams...or large cams to help with the sound.


In my opinion....not worth the time or effort at all.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: Uneven Length Header?
Tuesday, July 23, 2013 3:57 AM
I'm a hater.

I hate the subaru sound... it sounds like a misfiring piece of crap.

my new shirt:






Re: Uneven Length Header?
Tuesday, July 23, 2013 9:52 AM
If you want your car to sound like a Subaru get a Subaru.



Re: Uneven Length Header?
Tuesday, July 23, 2013 12:48 PM
-MD- Enforcer wrote:Unequal length header on a L61 or Ld9.....doesn't equal subaru sound. Most of that sound is from the Boxer motor. Could you get a little rumble sure, but you would have to make sure the exhaust waves are out of phase. The reason no one makes these is because it is either a lot of trial and error, or WAY more math than most people want to do.

You could get closeish if you make a 4-2-1 header, and pair the correct ports together, but you need to ensure the waves are out of sync......or synced together. This is bad for scavenging, and against most "good practices" for header design. Also, you would probably need some custom cams...or large cams to help with the sound.


In my opinion....not worth the time or effort at all.


+1 for knowledgeable reply.

This has been what I've been seeing around online about the subject, and obviously gains have been had by switching to even length headers.

Thanks.



Re: Uneven Length Header?
Tuesday, July 23, 2013 1:30 PM
Its not just the uneven length headers that make it rumble. Its the uneven firing order compared to a typical 4 cylinder.

Read that.

So ya what Mikes saying would probably work if you could do the math the sync the exhaust pulses but seriously a waste of effort IMO.





Re: Uneven Length Header?
Tuesday, July 23, 2013 2:39 PM
I know, /also/ being attributed to the header. But it'd be alot of work, just curious.







Edited 2 time(s). Last edited Tuesday, July 23, 2013 2:41 PM


Re: Uneven Length Header?
Wednesday, July 24, 2013 3:09 PM
Why is this in the "Performance" section when the intention is less performance? This clearly belongs in "Audio and Electronics"




I have no signiture
Re: Uneven Length Header?
Wednesday, July 24, 2013 7:12 PM
ive heard some LD9's sound pretty "rumbly" i think the sound to which you refer technically should be called "bubbly". dont get me wrong i like the way subie's sound too but i would never sacrifice performance to get that kind of sound. i would however sacrifice performance to quiet an exhaust down and or get it deeper sounding though. but id still run an electric cutout right after the collector to get the performance when i really wanted it.



RIP silver car. You will be missed.
Re: Uneven Length Header?
Sunday, August 11, 2013 2:56 AM
You want rumble ,just weld on a throaty sounding muffler and call it a day!


BLACKMANTIS

Re: Uneven Length Header?
Sunday, August 11, 2013 2:58 AM
Or ,and this is just an idea ,you could record the sound of a Subaru boxer engine and play it on your radio while driving to work everyday!That would be your cheapest option.


BLACKMANTIS
Re: Uneven Length Header?
Sunday, August 11, 2013 11:55 PM
Brian wrote:Its not just the uneven length headers that make it rumble. Its the uneven firing order compared to a typical 4 cylinder.


Just switch 2 plug wires around



"If I'm not back in 5 minutes...just wait longer"
Re: Uneven Length Header?
Monday, August 12, 2013 7:30 AM
My LD9 sounds exactly like a Subaru boxer when it has a bad spark plug.

Try that route. Might hinder performance but shouldn't be much.





BeardLife / Club Awesome Reject Blog
Re: Uneven Length Header?
Monday, August 12, 2013 9:41 AM
Patrick Coulter wrote:Did some Google searching and found a post or two on a prelude enthusiast site about mimicking Subaru's iconic boxer rumble sound...of course, having a uneven length header would lose you 2-5hp, but gain you that 'Subaru' sound


Yep, let's make a car's exhaust sound like a faster car, even if it hurts performance.






Re: Uneven Length Header?
Monday, August 12, 2013 4:34 PM
Qwik2k2z24 wrote:My LD9 sounds exactly like a Subaru boxer when it has a bad spark plug.

Try that route. Might hinder performance but shouldn't be much.


Same as when a eco throws a follower lol.
Re: Uneven Length Header?
Saturday, August 24, 2013 1:35 PM
Mine kinda has that subie sound when slowly cruising through a parking lot but that's about it. The only thing I like about a Subaru is that sound. Other than that I'm not a fan of them. But to each their own
Re: Uneven Length Header?
Tuesday, August 27, 2013 9:28 AM
it can be done with really unequal length, it a sound "alike" turbo would be hard





Re: Uneven Length Header?
Tuesday, August 27, 2013 9:45 AM
Jamon wrote:it can be done with really unequal length, it a sound "alike" turbo would be hard

Solved



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