what is a decat?
- Thread starter skiba
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Hi Skiba,
Just found this thread.
Try here: http://www.scoobycity.co.uk/phpBB2/index.php
I beleive it is a good community with lots of info.
I know "bloomers" on there.
MSN me if you need any thing else.
ICE
Just found this thread.
Try here: http://www.scoobycity.co.uk/phpBB2/index.php
I beleive it is a good community with lots of info.
I know "bloomers" on there.
MSN me if you need any thing else.
ICE
or if your a bit hardcorejust rip the whole exhaust off and go single silencer side exit stylee ) or if your mad fit a straight thru although plod dont like these i found out to my cost with the old nova
mine is straight pipe from the manifold back to the single rear silencer (OMP Motorsport, group N) touch loud, but good fun
Decatting a Scooby makes a huge difference, mainly because there are 3 cats on the bugeye Impreza, one in the up-pipe, one in the downpipe, and one in the centre section of the exhaust.
The downpipe cat makes the most difference, it's massive and very restrictive, it is also just after the turbo so impedes spool.
The downpipe cat makes the most difference, it's massive and very restrictive, it is also just after the turbo so impedes spool.
The trouble with the wrx is it has three cats, all of them hideously restrictive.
One in the up pipe, one in the downpipe and one in the centre section.
If you went for a Prodrive downpipe that would be a 200 Cell cat, prettyy good but the up and centre ones are still in there, so no gains will be made.
What you really need to do is get an up pipe (magnex) and then fit a 3" exhaust system with a 100 cell motorsport cat or a complete decat if you like.
If you use the latest Miltek system then the motorsport cat is in the centre section away from the turbo, this helps it spool up a bit quicker.
However, on these cars it is inadvisable to do all that and not have a remap done at the same time, you'll be getting boost spikes and possibly running leaner than you want to be.
This can be particularly bad for the engine.
Andy
One in the up pipe, one in the downpipe and one in the centre section.
If you went for a Prodrive downpipe that would be a 200 Cell cat, prettyy good but the up and centre ones are still in there, so no gains will be made.
What you really need to do is get an up pipe (magnex) and then fit a 3" exhaust system with a 100 cell motorsport cat or a complete decat if you like.
If you use the latest Miltek system then the motorsport cat is in the centre section away from the turbo, this helps it spool up a bit quicker.
However, on these cars it is inadvisable to do all that and not have a remap done at the same time, you'll be getting boost spikes and possibly running leaner than you want to be.
This can be particularly bad for the engine.
Andy
The cat is there in an attempt to reduce emissions.
In most cases (post August 92) the car will not pass the emissions test if it does not have a cat. However, that does not mean it is illegal to not have a cat!
It's a bit of a tricky area!
Most people I know have their cats in place for the MOT, then remove them afterwards. Of course, if you are pulled over by the DVLA/VOSA, and they decide to do a full emissions test there and then, you could fail!
But, you could also fail if you do have a cat in place, if it's degraded or has fallen apart!
The act of fitting a decat pipe in itself is not illegal - but you will have to bear in mind that if you do get pulled over for a spot-check, you could fail the emissions test.
In most cases (post August 92) the car will not pass the emissions test if it does not have a cat. However, that does not mean it is illegal to not have a cat!
It's a bit of a tricky area! Most people I know have their cats in place for the MOT, then remove them afterwards. Of course, if you are pulled over by the DVLA/VOSA, and they decide to do a full emissions test there and then, you could fail!
But, you could also fail if you do have a cat in place, if it's degraded or has fallen apart!
The act of fitting a decat pipe in itself is not illegal - but you will have to bear in mind that if you do get pulled over for a spot-check, you could fail the emissions test.
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Soldato
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The trouble with the wrx is it has three cats, all of them hideously restrictive.
One in the up pipe, one in the downpipe and one in the centre section.
If you went for a Prodrive downpipe that would be a 200 Cell cat, prettyy good but the up and centre ones are still in there, so no gains will be made.
What you really need to do is get an up pipe (magnex) and then fit a 3" exhaust system with a 100 cell motorsport cat or a complete decat if you like.
If you use the latest Miltek system then the motorsport cat is in the centre section away from the turbo, this helps it spool up a bit quicker.
However, on these cars it is inadvisable to do all that and not have a remap done at the same time, you'll be getting boost spikes and possibly running leaner than you want to be.
This can be particularly bad for the engine.
Andy
I have a 100-cell in the downpipe myself. But my understanding of using a cat in the cat-pipe (on newages) or centre section is that it doesn't work as effectively, so seriously tuned cars could still fail an emissions test? Not a problem on cars with normal power though.
M
:/
the turbo will give out NO emmissions... the engine its attached to is a different story tho
