boxer enigne noise.

[Guest]

hey guys as you all know wrx / forester /legacy . have a very nice boxer engine noise , now i have are wrx and every wrx version 1-7 ive ever seen has the very nice noise , i live down a short street and there is are v7 ra spec c very close my meh about 20 meters away , hes sounds very arresive and nice like the rest of them , but mine is not quite the same , is very quite for what it is , and it does not have the sound that the rest of the wrx have ,

ive herad the v1-7 have it , but havint heard the 8-11

what im wondering is that - is this just my wrx thats like this or is it like this with the v8 and up wrx ???

is BT spec c like this as well ???

[WRXER]

Enjoy the sound, you just have equal length headers which is a good thing that is stock, dont de-tune to unequal so as to get the rumble.

[Shale]

 Spec C said:

very bothered that i dont have what the rest off them/uses have !

:'( are very left out wrx here :'(

Boxer engines are divided into two banks; two cylinders pointing to the driver's side, two pointing to the passenger's side (hence the term 'boxer' - it looks like two boxers punching each other as the pistons move in and out). The exhaust gases exit on the bottom of each head (you have a head facing each bank of pistons).

You have a pipe leading off each exhaust port. These wrap around and join into one pipe.

Because they join into two, then into one, you get a different sound depending on where and how they join. IIRC the boxer burble is simply because one side is SIGNIFICANTLY shorter than the other, and the gases are clashing.

This sounds cool, but it's not the BEST way of getting power.

'Even' headers or 'tuned' headers that everyone talks about is getting both sides exactly the same length, including calculations for bends (which have a huge effect). Evenness is godliness in cars, and the balanced exhaust note's flatness shows how smooth the exhaust flow is. This is another reason it's so easy to bleed safe extra ponies out of the GDB, like your Spec C.

I come bearing google image search!

Even length headers, top...vs stock uneven length headers on the bottom.

FURTHERMORE! Twin scroll turbos do not allow the burble. This is an area I know nothing about though...so someone else can fill you in there.

In short though - your car will be faster from stock, like we keep on saying over and over, because of little things like this.

[funkytown]

also Unequal but tuned headers.. like shale said.. notice how short the left hand piping is. These have a throb like v1-7 although quite a different note.

[Guest]

I haven't seen any evidence that equal length headers make any more power than unequal length headers.

On a turbo subaru.

[Joker]

[Simon C]

The twin scroll OEM GDB headers are apparently one of the best balanced designs out there, hard to improve on unless you're seeking really serious top end power.

And I understood that equal length was desirable if you were after quicker spool. Of course, if you have bigger fatter pipes for high flow, it'll take longer to pressurise them so aftermarket equal length may not necessarily reduce lag over factory.

[Guest boostin]

The EJ25 turbos still run the early style very unequal headers right up to current V11.

[BC5RA]

 Shale']

[quote name='Spec C said:

very bothered that i dont have what the rest off them/uses have !

:'( are very left out wrx here :'(

/quote]

Boxer engines are divided into two banks; two cylinders pointing to the driver's side, two pointing to the passenger's side (hence the term 'boxer' - it looks like two boxers punching each other as the pistons move in and out). The exhaust gases exit on the bottom of each head (you have a head facing each bank of pistons).

You have a pipe leading off each exhaust port. These wrap around and join into one pipe.

Because they join into two, then into one, you get a different sound depending on where and how they join. IIRC the boxer burble is simply because one side is SIGNIFICANTLY shorter than the other, and the gases are clashing.

This sounds cool, but it's not the BEST way of getting power.

'Even' headers or 'tuned' headers that everyone talks about is getting both sides exactly the same length, including calculations for bends (which have a huge effect). Evenness is godliness in cars, and the balanced exhaust note's flatness shows how smooth the exhaust flow is. This is another reason it's so easy to bleed safe extra ponies out of the GDB, like your Spec C.

I come bearing google image search!

Even length headers, top...vs stock uneven length headers on the bottom.

FURTHERMORE! Twin scroll turbos do not allow the burble. This is an area I know nothing about though...so someone else can fill you in there.

In short though - your car will be faster from stock, like we keep on saying over and over, because of little things like this.

Shale

Those headers you have chosen as an example are not Equal length, they in fact Uneven length.

You will find that Equal length headers are not perfectly equal.

[Guest]

Ok this is a better example of what Shale was trying to get. This is a 250T Equal exhaust manifold (top) and Forester Turbo unequal (bottom)

Hope this helps clarify the basic principle which Shale was trying to convey

[wildturkey]

 Qwerty said:

I haven't seen any evidence that equal length headers make any more power than unequal length headers.

On a turbo subaru.

same here.......i hear lots of talk about them giving up 8-12 kws but i haven't seen the hard evidence.........point me in the direction of some articles?

[Shale]

Yeah my bad. It was a quick google image search, certainly not a comprehensive one... this is what happens when you post after waking up at 5:45am

But thanks for updating with a correct image ;D

[BC5RA]

You either know or you don't.

If you don't know then don't post.

No offense.

Equal length vs Unequal length vs Stock is as much about where the power is made rather than how much.

[madmike]

 BC5RA said:

You either know or you don't.

If you don't know then don't post.

No offense.

Equal length vs Unequal length vs Stock is as much about where the power is made rather than how much.

I have equal length on my RS.

Cause it make it sound like an evo bro......

I found that i come on boost earlier and don't seem to drop off so much up top..

[BC5RA]

Some say that boost is produced later, some have your opinion.

I've driven a few setups that included aftermarket headers; the best conclusion I can draw is a before and after set on a GF8 V6 STI, stock to semi-tuned length.

Boost was slower to ramp; this was most likely due to no heat wrapping.

[Guest boostin]

When I had the equal length 250T headers on mine I reckon it had full boost 500rpm earlier, and revved out a lot quicker. They were heat wrapped though, about 3 layers.

[Guest]

I have seen some comparison with 4-2-1 vs 4 - 1 headers

The 4-2-1 were spooling 500rpm earlier all else being equal.

[BC5RA]

 Qwerty said:

I have seen some comparison with 4-2-1 vs 4 - 1 headers

The 4-2-1 were spooling 500rpm earlier all else being equal.

This is what I've seen as well.

Pretty hard to conclude all in all.

[subiv5]

I have aftermarket header's on my Sti, they arn't heat wrapped tho. Boost spools up pretty early as it is, is it worth heat wrapping them?

[BC5RA]

 subiv5 said:

I have aftermarket header's on my Sti, they arn't heat wrapped tho. Boost spools up pretty early as it is, is it worth heat wrapping them?

I suppose it comes down to whether you want to pull them off.

Turbos like heat for spool.

[Joker]

and engine bay doesn't like heat.....

heat for spool? I'm listening

[BC5RA]

Heat = energy

The hotter pre-turbine exhaust gases are the greater the velocity.

(others will answer it more technically than I)

[subiv5]

 BC5RA']

[quote name='subiv5 said:

I have aftermarket header's on my Sti, they arn't heat wrapped tho. Boost spools up pretty early as it is, is it worth heat wrapping them?

/quote]

I suppose it comes down to whether you want to pull them off.

Turbos like heat for spool.

Yea just tied back what looks like a portion a some sort of wiring loom as the outside plastic cover of them had started melting. They look a little rough tho so thinking I might get replace them back to the standard ones

[funkytown]

 BC5RA said:

Heat = energy

The hotter pre-turbine exhaust gases are the greater the velocity.

(others will answer it more technically than I)

yup this is totally correct, hotter means the same amount of air in the same space, but expanded further so it has to flow faster, faster flow means turbo spools faster, (same theory as not running a real fat uppipe, keep the velocity up).

Also the same as a cold night air contracts, and you get more oxygen parts per standard volume causing car to run faster.. more o2 means more explosive

[Joker]

so ya wanna wrap the pipe - keep energy/heat in and not warm up the bay eh... (softening plastics/fluids)