Exhaust simple question...
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Im getting a bit
with the exhaust "bits" as in what i need, is there 3 cats on my bug? 1 uppipe 1 down pipe and 1 cat pipe? plus a mid box or am I way off? Iv been told by the previous owner its got ported " headers" WTF is that lol and can I prove it ?
cheers lee
with the exhaust "bits" as in what i need, is there 3 cats on my bug? 1 uppipe 1 down pipe and 1 cat pipe? plus a mid box or am I way off? Iv been told by the previous owner its got ported " headers" WTF is that lol and can I prove it ?
cheers lee
Std a Bug WRX (not STi) does indeed have 3 cats as you say. See here:-

You'd need to get under the car and take a photo of the headers (bolted to the underside of the block halves), for us to see if they've been changes to tubular - and, usually, equal length - jobs...

You'd need to get under the car and take a photo of the headers (bolted to the underside of the block halves), for us to see if they've been changes to tubular - and, usually, equal length - jobs...
Last edited by joz8968; Aug 3, 2011 at 06:36 PM.
Ported headers are the OEM headers which have been gas flowed for better performance........so will look normal
http://scoobytuner.com/graphics/ExhuastDiagram.jpg
is a diagram of the bug WRX
Shaunh
http://scoobytuner.com/graphics/ExhuastDiagram.jpg
is a diagram of the bug WRX
Shaunh
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Cheers lads cleared it up for me, so basically a turbo back exhaust plus an uppipe to fully decat, is there a good amont of torque/hp doing this b4 a remap? cheers lee
Oops, sorry you said ported, not tubular.
But yeah, basically for up to 400bhp:-
*A set of harvey's OEM ported headers (if yours aren't) + OEM ported uppipe (harvey will advise on uppipe type/size etc.)
* New Age pattern bellmouth decat d/p (replaces the OEM 2-part dual-cat job), plus decent system.
Can use either a 2.5" or 3" d/p + system for upto 400bhp.
For over 400bhp then need to have the 3" exhaust parts, plus a move to equal-length tubular headers/uppipe...
Changing to the above exhaust parts will maxmise any power gains in the remap.
But yeah, basically for up to 400bhp:-
*A set of harvey's OEM ported headers (if yours aren't) + OEM ported uppipe (harvey will advise on uppipe type/size etc.)
* New Age pattern bellmouth decat d/p (replaces the OEM 2-part dual-cat job), plus decent system.
Can use either a 2.5" or 3" d/p + system for upto 400bhp.
For over 400bhp then need to have the 3" exhaust parts, plus a move to equal-length tubular headers/uppipe...
Changing to the above exhaust parts will maxmise any power gains in the remap.
Last edited by joz8968; Aug 3, 2011 at 06:56 PM.
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Oops, sorry you said ported, not tubular.
But yeah, basically for up to 400bhp:-
*A set of harvey's OEM ported headers (if yours aren't) + OEM ported uppipe (harvey will advise on uppipe type/size etc.)
* New Age pattern bellmouth decat d/p (replaces the OEM 2-part dual-cat job), plus decent system.
Can use either a 2.5" or 3" d/p + system for upto 400bhp.
For over 400bhp then need to have the 3" exhaust parts, plus a move to equal-length tubular headers/uppipe...
Changing to the above exhaust parts will maxmise any power gains in the remap.
But yeah, basically for up to 400bhp:-
*A set of harvey's OEM ported headers (if yours aren't) + OEM ported uppipe (harvey will advise on uppipe type/size etc.)
* New Age pattern bellmouth decat d/p (replaces the OEM 2-part dual-cat job), plus decent system.
Can use either a 2.5" or 3" d/p + system for upto 400bhp.
For over 400bhp then need to have the 3" exhaust parts, plus a move to equal-length tubular headers/uppipe...
Changing to the above exhaust parts will maxmise any power gains in the remap.

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Would this be any good for a decat? http://www.ebay.co.uk/itm/SUBARU-IMP...item3368f0b3f9 cheers lee
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Wrap a tape measure round it to find the circumference.
Then do this calc:-
diameter = circumference divided by 3.14159
That'll give the outer dia. -- so subtract about 6mm (c.3mm for each opposing sidewalls thickness) = inner diameter. Simples
Then do this calc:-
diameter = circumference divided by 3.14159
That'll give the outer dia. -- so subtract about 6mm (c.3mm for each opposing sidewalls thickness) = inner diameter. Simples
Last edited by joz8968; Aug 4, 2011 at 04:51 PM.
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That'll give the outer dia. -- so subtract about 6mm (c.3mm for each opposing sidewalls thickness) = inner diameter. Simples
Last edited by joz8968; Aug 4, 2011 at 04:51 PM.
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MY BAD!
I thought you said uppipe!!! LOL
It's this static air and heat -- I need a lie down.
Obviously yes, it will be either 2.5 or 3 inch for the exhaust sytem - a quick measure will confirm
If it is a 3", check to see if the downpipe/centre section flanges isn't a reduced 2.5" one....
I thought you said uppipe!!! LOL
It's this static air and heat -- I need a lie down.

Obviously yes, it will be either 2.5 or 3 inch for the exhaust sytem - a quick measure will confirm

If it is a 3", check to see if the downpipe/centre section flanges isn't a reduced 2.5" one....
Last edited by joz8968; Aug 4, 2011 at 05:02 PM.
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LOL no worries appreciate the advice m8ty, find out more about this car everyday, its got a KnN panel filter, SS catback and an LMA(?) BOV but never been mapped? So im thinking uppipe and downpipe....jobs a good en.......for now lol
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