Jump to content
Ultimate Subaru Message Board

How to: Incressing Boxer rumble? (EA82)


Recommended Posts

Been wanting to increse the sound of my wagon somehow, but wasn't sure how to do it with out making my own exhaust. Now I know this might sound like a redneck Idea, but would adding a small hole in the muffler bring out the sound or make it sould like crapola? I would be sure to make the hole on the side so no hot air is blowing onto the body, just wanted some ideas. I can here the rumble when the engine has aload on it at lower RPMs but I would like it more pronounced.

 

And before someone says it, I do need my Cats (Emissions in lower WI)

 

Or my other idea, what muffler has anyone use that does such and isn't a PITA to install (Retrofit) Does anyone know if theres a Thruster muffler out there that would work (Still need to weld, I know that)

 

But how does the hole idea sound to you guys? my muffler already has some rot spots (Might just help it along Lol)

-Tom :)

Link to comment
Share on other sites

you can cut the muffler off and replace it with a turbo muffler.... no need to weld just get muffler clamps and your golden

 

The EA82T muffler is diffrent then the stock EA82 muffler? I heard they are the same? Anyhoo, So hell, if I buy a Turbo muffler, the bends for the pipe and the flange are the same, so it should bolt right in, correct?

Thanks for this idea!

 

-Tom

Link to comment
Share on other sites

The "rumble" is not due to the boxer engine design - it's due to the unequal length headers Subaru uses. This also decreases power - so more rumble = less power. You can make it louder - just lose the muffler. I run straight pipe on my lifted wagon - stock exhaust. It's not that loud..... but I don't drive it every day either.

 

GD

Link to comment
Share on other sites

Ya know, GD, you've been saying that for as long as I have been on here, and I have doubted that since day 1. Think of the sound of a WRC car, how they have a phenomenal deep rumble, even through the turbo, then take a look at this-

 

subaru-header1.jpg

 

That's equal length there.

 

FWIW, it is the firing order of the boxer that makes the sound. A lot of VWs around here have the Baja-Bug style exhaust, with -you guessed it- equal length pipes, and they have a growl to them.

Link to comment
Share on other sites

Rob, oh I was thinking he ment a cherry bomb (Can't run those in WI, due to they get old and start shooting hot fiberglass out so I've heard)

 

Niku, its SPFI.

 

GD, yes I know the unequal headers play a part in it but that can't be all..? Does't have anything to do with firing order? I can't cut the muffler off either (State law:rolleyes: ) Well if I would loose power I wouldn't want to do that either, hmmm..

 

Well its all good reads, I'll think about what I can do (Or just leave it as is)

 

Thanks guys!

-Tom

Link to comment
Share on other sites

Nah GD speaks the truth. I have a buddy up at Uconn that has an STI. He bought it with equal lenth headers on it and it sounded like a honda i kid u not. He couldnt take it so he put a stock Y-pipe (unequal lenth) on and got the boxer rumble back but lost something on the order of 30hp.

Link to comment
Share on other sites

4x4_Welder, Thats what I was thinking.. Thanks :)

 

So if the unequal headers take away power, why did Subaru use them and still do IIRC?

 

-Tom

 

I'll jump in before GD on this one, IIRC, it increases scavenging and allows for

proper back pressure so you don't burn valves and have decent low end grunt.

 

Twitch

Link to comment
Share on other sites

Yeah it has a grownl but I think he means the distinctive sound of a Subaru Boxer. I know I can tell one without looking :banana:

 

I know the EA82 will never push out the true "Boxer sound" like the EJs but theres some rumble hidden, cause my video camera picks it up and you do here it inside (Dunno what it sounds like outside going down the road @ 3k?)

 

-Tom

Link to comment
Share on other sites

He couldnt take it so he put a stock Y-pipe (unequal lenth) on and got the boxer rumble back but lost something on the order of 30hp.

 

Dyno proven or seat of the pants?

 

Subaru uses unequal length headers because they are cheap to engineer and manufacture. 90% of the engines Fuji makes are more about smooth, quiet operation rather than out and out performance. To have an equal length header actually do its job, a lot of CFD and math needs to be put into the design to achieve the desired effects. This is money that can be saved by making a header that simply merges two seperate exhaust flows into a single pipe (Then split it again on newer ones for the 100% pointless dual mufflers).

 

Subaru's Group N challenger, the STi Spec C, uses a twin scroll turbocharger which has a similar effect as EL headers in that it is more efficient at extracting power from the exhaust pulses. I'm not sure if that car uses EL headers.

 

The "boxer rumble" or deep bass-like boom is not a Subaru only thing. The poorly yet cost effective headers Subaru uses do make it more pronounced, but like many have mentioned already, air-cooled VWs also emit a classic boxer burble. Follow any Porsche and you will hear the deep rumble from their posteriors. Based on this we can conclude that despite all the different styles of exhausts, port design, bore/storke ratios, fuel systems or induction tuning, all horizontally opposed engines make something like a "boxer rumble".

 

As for how you can enhance it, uncork the exhaust (Not the intake) and make the headers MORE unequal. Beyond that I have no idea.

Link to comment
Share on other sites

Now that I think of it, the Displacement plays a big part in the rumble (1781cc) with adittion to the unequal headers, Firing order has nothing to do with it.

 

Lol I've seen that civic (Talk about a fart can) Haha

 

Caramanos, Thanks!

 

Carfreak, yep I know this. thanks for the added info!

-Tom

Link to comment
Share on other sites

The firing order does have an effect on the sound - but not the rumble.

 

As the engine fires 1,3,2,4 - left, left, right, right (or is it right, right, left, left)? with a 4-2-1 header or siamese ports on the EAs, only the second ignition on each side benefits from scavenging.

 

Apparently that's what produces the characteristic offbeat boxer sound.

Link to comment
Share on other sites

Rob, oh I was thinking he ment a cherry bomb (Can't run those in WI, due to they get old and start shooting hot fiberglass out so I've heard)

 

Niku, its SPFI.

 

GD, yes I know the unequal headers play a part in it but that can't be all..? Does't have anything to do with firing order? I can't cut the muffler off either (State law:rolleyes: ) Well if I would loose power I wouldn't want to do that either, hmmm..

 

Well its all good reads, I'll think about what I can do (Or just leave it as is)

 

Thanks guys!

-Tom

 

well if its spfi then i say block off your resonators in the intake so that its just a single pipe running with out big boxes or tubes with empty space in them, it'll give you a bit more rumble but not from the rear end of the car. of course SPFI intake may be like that i dont know. i notice mine has quite the doo doo doo doo doo doo sound when i am crusing if i step on it though it becomes a giant hiss as the exhaust gasses escape the now HUGE hole in the manifold. i havent taken any of the reasonators off but it does make these types of injected motors a bit louder, did it to a friends legacy once and man was it loud.

 

a good tune up, make sure ignition is good and everything will have an effect on it too, i hit a sweet spot and it made the doo doo doo doo doo sound more pronounced and my milage got better too so mabe it was just outa wack when i got it.

Edited by Niku-Sama
  • Like 1
Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...