LoftyMan

iTrader: (1)

Hi guys,

I have been looking through the forums for an answer to my question but have not come up any the wiser. The Blobeye Wrx STi I am looking to pick-up tomorrow has a full Prodrive kit fitted etc.

What I am trying to understand is, how many 'cats' are in the prodrive exhaust system?

I have listened to it idling from behind the car and sat inside. What im looking for is that lovely burble to just be louder while driving in the lower revs and idling.

I am a complete novice at this and I do hold my hand up to say sorry for these questions but I hope I can learn now and not have to keep asking silly questions.

Am I right in saying the prodrive exhaust system consists of the downpipe, centre pipe, backbox and tailpipe? Can I simply replace the tailpipe with a larger 3 inch to get the louder burble?

Any help as always is appreciated.

Beastie

iTrader: (2)

You can replace the centre section with a straight through pipe. Then you get much better burble. Done this on both my 99ppp and 2006sti ppp with good effect. :

Believe on your car only down pipe cat left.

LoftyMan

iTrader: (1)

Excuse my ignorance but the centre section is behind the backbox? How do I replace it with a through pipe? Is this a garage job? What sort of cost?

Thanks

cster

If I were you, I would stick with what you have until you get used to your new car.
After a couple of months and a bit of time on here, you will have a better idea of what mods you may wish to make.
Changes to the exhaust system may require a remap at circa £500.
Other areas for modding would include braking and suspension.
Exhaust system consists of;
http://www.subaru-impreza.org/forum/...t-diagram.html
Details may vary from one model to another.

stealthy1

Hi there.I have a 2005 sti ppp,the major cat which is left on your car is the down pipe cat,this is the most restrictive of the cats and you would need a remap if to decat this section due to boost spikes.
A straight through centre section replaces the silencer,this joins from cat pipe(which now has no cat in due to prodrive pack) and the back box.easyto fit yourself but I'm sure a garage would not charga anymore than £20.this option is the cheaper one and for the time being would increase the lucious burble (and cabin noise!)

LoftyMan

iTrader: (1)

Thanks Stealthy.

Would you recommend a centre section to replace the silencer? I would have a look at maybe fitting it myself but if I can get a good deal I may get garage to do it.

That sounds like what I want because I just love the low burble so would like to make it that bit louder

stealthy1

Yeah,I would recommend a centre pipe.got an afterburner section on mine,made by Hayward and Scott for scoobyworld,very good quality.I like the sound of the prodrive backbox,not too loud,although it is a little restrictive to most aftermarket ones.
Definatelly look into a decat d/p and remap,car sounds and runs really nice.easily reach 330bhp without needing other mods.
Enjoy mate!!

2bitpython

I have definitely joined the forum at just the right moment - I was wondering, like LoftyMan, about options and practicalities of changing the ppp exhaust to get a better burble (I have an 05 STi ppp and literally like the sound of a Nur Spec system).

But I know little about the mechanicals, terms or right questions to ask, so I'm glad LoftyMan posted this as it's a great start point for me.

All the replies to the post have been really helpful to get me underway on my learning curve; and thanks cster for the exhaust system link, dead useful - now I understand better what words mean what bit of metal!

Stealthy1 we have the same car - I'm intrigued by what you've done to yours. Afterburner?! I don't mean to take this thread off topic, so if you're happy to talk about your mods and this is the wrong place to do it, just tell me what the proper channel is

In any event, cheers all.

TonyBurns

iTrader: (3)

Your downpipe on your specific PPP STI is a sports cat, its not that restrictive tbh, if you replaced the standard cat with a sports cat you would need a remap due to the ammount of flow that goes through a sports cat over the standard item.

Tony

urban

iTrader: (1)

The PPP downpipe has a sports cat, and itsn't really that restrictive.
I think you may be confusing this with the original factory downpipe.

I was informed by a well known mapper that changing the PPP downpipe to full decat would only achieve maybe 10 - 20bhp

stealthy1

I wasn't aware that prodrive changed the downpipe,I have been miss informed,nice one.
10-20 bhp ain't bad hey!?every pony counts!

TonyBurns

iTrader: (3)

I think he means 1 or 2 bhp

Tony

greatgonzo

iTrader: (1)

Personally I would leave the centre section alone as this cuts out the drone and cabin noise (although it's the cheaper option). I would sell the Prodrive Box (£70-£120) to adds funds to a quality after marker back box like a Hayward & Scott or a blitz. but thats just my opinion

53

iTrader: (41)

Swap out the centre pipe for a straight through pipe and it will be perfect Revs more freely without the silencer in the centre pipe and will sound spot on

urban

iTrader: (1)

I definately didn't mean 1 or 2.

But having said that my post might be a tad confusing.
I was told that a remap on the 05STI PPP when I had it typically was 330-340bhp - it actually worked out to be 337 on average.
And if a full decat remap was done, it would be typically 340-350bhp.

So I'm sorry, my mistake - not anywhere near another 20bhp, 10 maybe.
Either way, not worth the money and effort - never mind the hassle come MOT time

greatgonzo

iTrader: (1)

have you replaced yours on the spec D?
I have full decat with Prodrive BB and find it drone's a little,do you think thats down to the centre section (resonated). I do think that the 2 litre has more of a burble than the 2.5

53

iTrader: (41)

You get less drone without the resonator (silencer) The Prodrive BB can drone at bit IME depends what you're used to I guess Put the Standard STi box back on

I have sports cat and then straight through to the STi Backbox and it's perfect

LoftyMan

iTrader: (1)

Does anyone have any links to a good straight through centre section to replace the one on my prodrive exhaust?

Am I right in saying theres 2 fairly simple options:

1. Replace centre pipe with straight through, or;
2. Just replace backbox and exhaust tip from prodrive to say a blitz nur spec?

I dont want to have to remap the car or anything, I just want that burble to be a little louder and deeper. (Nothing silly)

Thanks

Pink_Floyd

Either will increase the volume. I'd be inclined to do both

53

iTrader: (41)

Just do the centre pipe, look in the GB section H&S do a straight through centre pipe, easy to fit Blitz will rob a small amount of torque due to the change in bore size

LoftyMan

iTrader: (1)

I cant find a group buy for this. Can you point me in the right direction

greatgonzo

iTrader: (1)

Sold the original sti BB, someone on Ebay offered silly money so i couldn't resist
Scoobyworld do one with a sports silencer (like the old cherry bomb) could be good for me what im after is a bit more burble with out more cabin noise, dont want to change the Prodrive box as its only a year old and I like the look and keeps with the discreet theme

greatgonzo

iTrader: (1)

http://www.scoobyworld.co.uk/catalog...roducts_id=448

53

iTrader: (41)

do the centre pipe then, will drive better anyway

Lofty ....

https://www.scoobynet.com/group-buys...group-buy.html

Ignore the end date, Ian at H&S is always good for a snet discount

acstua

iTrader: (1)

bah im tryin not to spend money atm, but all this talk of centre pipes and burble is getting me ready to get the plastic out again :d

although the car being relatively quiet is a bonus sometimes heh

Zaim

iTrader: (3)

I'm reading this with interest as I've got all the parts to replace the exhaust on my WRX i.e. sports cat on downpipe and then replacement for the rest and finally a Prodrive backbox. Currently all this is sitting in my shed awaiting a fuel pump and decat up-pipe, then a session with a mapper.

My question is can I fit the backbox and centre pipe now without requiring a remap?

53

iTrader: (41)

^ Yup

Andy03STI

I just removed my prodrive backbox and fitted h&s backbox instead with milltek straight through centre section. If anything the h&s backbox is quieter than prodrive one but louder when driving. Just need to save up for a remap and can fit decat pipe.

Hilla

Can anyone confirm what bore the Prodrive backbox is?

Cheers!

stealthy1

2.5" pipe to 4" tail pipe