MY08 wrx hatchback exhaust components - rumble

[Bakerwrx]

So I recently bought an MY08 impreza wrx hatchback.

I also promised my girlfriend that it would stay standard.

However, I promised that before I realised that the hatchbacks are super quiet and don't have that famous impreza rumble :(. So I will be changing my promise to it will remain relatively standard :).

She has no idea about cars so I'm safe doing all the suspension and brakes etc without her being any wiser however I want more rumble too without it being so loud that it upsets my neighbours and the gf.

On to the exhaust.

How many components does my exhaust system consist of?

Manifold > turbo > up/down pipe (with cats in?) > mid pipe > back box ??

what parts are best changing to get more power/noise?

I get that there are multiple cats to contend with also. Ideally I'd like to have one in place so it will still reliably pass the mot without swapping up pipes every time. Is this possible?

I also want more induction roar. From what I have read changing to a cold air induction kit won't release any extra horses as the standard airbox is so good and I'm fine with that. Noise is key. Also I understand this will make my recirculation valve louder which would also be good.

I also realise that whatever I change needs to be done ideally at the same time as a remap so no need to hammer that home.

Cheers for the help.

[stants]

Not sure about the sections on hatch but usually up pipe, down pipe centre/mid and back box,

You could go for a cat back system deleting one of the cats which would still keep you legal and wouldn't require a remap,best of speaking to Jay, Alex or aucky as they are hatch owners and have changed various parts of ye exhaust

[Xander]

Hay, Mine is loud, not crazy loud but louder than stock its noticeable inside but doesn't do my head in. People do know when I have pulled up outside there house though.

If you just want more sound pop to a local exhaust place and get the back box removed and replaced. A simple axel back system will give you a better sound without being to much.

If your going for performance get the hold system replaced.

There are 2 cats in the stock system one in the down pipe and one under the car. You also have a centre resonator and the huge final resonator.

So far my system is stock down pipe and then full 3 inch back I have removed the second cat and thats the point it got much louder. I also have a centre resonator and smaller rear resonator.

I will be going in later in the month for the down pipe to be replaced with a bell mouth and 3 inch pipe so will be full 3 inch system. I am having a 100 cel cat put in this will keep the noise down a little and hopefully keep it legal-ish.

I also need to get a remap done as it drives a little funny at the moment.

I shall post some photos later.

Thanks

Alex

[Xander]

 

[Ryan85]

I have full decat n only back box it's loud but not overly loud much louder before when I had str8 thru lol but before I had decat it was reasonable n sounded loud to hear the flat four rumble without waking the neighbours every morning

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[Bakerwrx]

So if I go for a cat back system like the invidia n1 (Street version) http://www.tarmacsportz.co.uk/GB/Invidia_WRX_HATCBACK_N1_STAINLESS_STEEL_TIP_CAT-BACK/HS08SW5GTP_.aspx

That will have a centre resonator and back box but will delete the 2nd cat. That should make it nicely louder and with a remap a little quicker too.

Then I'll look for a 3" downpipe with a cat in.

[Xander]

No the n1 will go from the second cat back the down pipe would delete the second cat.

I would look at getting a custom one mate the n1 was on my list but it's crazy loud and melted someone's bumper on here.

Also cheaper to go custom and its fitted for you. I went custom and when it's all finished it will be 3 inch turbo back with 100 cel cat and second cat delete total £800 or £650 if I have a full decat.

--

I make Films for businesses and people. I also make websites.

[Ryan85]

Mine is custom preferred it that way meant when I had my full decat I was easily able to add a box to quite it down to a level close to my needs where as a bought aftermarket is wat it is

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[Bakerwrx]

So if both cats are in the down pipe I need to get a down pipe with only one cat in?

Is there a lambda sensor after the second cat or just after the first one?

Anyone know a good custom exhaust place around Cambridgeshire?

[Ryan85]

Something like this is wat u want

http://scoobyworld.co.uk/catalog/product_info.php?cPath=24_207&products_id=2071&osCsid=aged3tifan66i9isk3ldjgdml7

As for sensors can't remember off top of my head and as for custom exhaust places not to sure I have a powerflow on mine had no problems

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[Ryan85]

Think cobra sport do a 3" with a high flow cat but can't be sure mines full decat

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[Bakerwrx]

Ah so the stock downpipe is 2-piece with a cat in each.

Also ideally I want 3" from turbo back?

[Ryan85]

Yh standard downpipe is 2 pieces and mine is 3" tapered down to 2.5 due to my local powerflow not doing 3" but at min not planning on running enuff power to need 3" but sure if u Google few places local to u they should be able to accommodate ur needs my decat came as one piece

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[Bakerwrx]

What are the power limitations of a 2.5" exhaust over 3"?

[Ryan85]

Not to sure few ppl I spoke to have sed up to 350-400 2.5 is fine n exhaust place told me not much difference in sound so suited me mines bout 280ish at fly wi no problems

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[Bakerwrx]

Ah right Yeah 2.5 is absolutely fine for me too. Doubt I'll be going over that sort of power as it unlikely I'll change the turbo.

Can buy a 2.5" 2nd decat pipe and get the rest of the system in 2.5" too then custom made :).

Does single or full decat show a check engine warning light? Does a remap remove this?

[Ryan85]

Both cats removed brings up warning light but after removing both cats map is needed anyway which is when light can be turned off don't think 2nd cat removal turns light on but not sure on that sum1 with more knowledge than me on here will no that

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[Bakerwrx]

Ok so can I get a cat back system and 2nd decat fitted and still drive it safely without over boosting or do I need a remap at that point?

[Ryan85]

Wunt like to say for definite as not to sure but sure sum1 can advice u on that

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[Bakerwrx]

My only other turbo car in the past was an mr2 turbo and that came with a 3" nur spec turbo back exhaust fitted from the previous owner and that used to overboost and hit the fuel cut. Didn't have it long enough to get it mapped though just took it as a part ex.

[Ryan85]

Concentrating more on looks at the min me cos subaru seemed to give up its just an rx with a scoop in bonnet looks wise well that my opinion anyways

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[Ryan85]

Don't see many of those on road these days before I bought my hatch I had few Renault sports n an astra 888 so new to subaru

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[Steveuk260.Esq]

Thought I let you know that the famous subaru rumble is mainly because of unequal headers, this has been changed to equal headers in later subaru models think it's 2005+ but don't quote me on that.

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[savage bulldogs]

Unequal length Headers cause the burble as the exhaust gasses hit the upipe at different times compared to equal length Headers

I'm not sure what year subaru fitted equal length Headers across the whole UK & jdm range but A friend of mine has a (04 ish) jdm sti blobeye .which comes with equal length Headers as standard and even with a 3" miltek turbo back it doesn't burble

it does sound better than the standard set up but it sounds more like a straight 4 than a boxer burble

If it's not broke .....upgrade it

[Ryan85]

Learn summat new every day always wondered why my m8s classic burbled n mine dint although just drove car n gotta say it's a gd noise burble or not especially when u get up in revs still a distinct sound but that been sed basically with hatch u lose the burble and the four pots the styling is idle cheers subaru lol

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