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**VxON Photographer of the year 2008***
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Discussion Starter #1
Ive been looking at buying a scorpion decat (about £52)

im trying to figure out if it will be a larger bore than the standard catalyst or if its just a direct replacement. They are very vuage about the whole thing and as such finding info is hard.

anyone know?

would it be a big problem if it was a bigger bore (e.g would the suddent change in diamater going into the centre section cause an issue with exhaust flow)
 

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If your going onto your existing standard exhaust that bore won't make a difference.

What is very important is the CatPipe has a bulge in-it, needs to be similar size to the standard cat. The reason for the bulge is exhausts send a wave effect down them, the bulges send part of these waves back and it helps the gas get sucked out of the engine.

It's why 4-2-1 exhaust manifolds help with low down power, and 4-1 manifolds help with top end power, it's all todo with the bulges and how these effects the waves back into the engine.
 

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Don't know enought about it to say, i'm talking general here, I know the standard manifold is a cast iron mess!

The Lexmaul manifold is apparantly good, Ben Lee gained 4.5bhp top end with improved mid-range pickup. Lexmaul manifold is made of aircraft steel and it's very light when picking up. should get some weight off car on the front. Tomorrow i'm fitting one to a standard CAT, and VX exhaust, ask Saturday i'll know what it's like.
 

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**VxON Photographer of the year 2008***
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Discussion Starter #6
cool yeah im interested to know.

id have thought a whole lot of the gain from an uprated manifold would be taken away by running it into a standard cat?

i will be running a janspeed centre section and back box.... with the lexmaul manifold(downpipe already integrated) which just brings me back to the catalyst problem.

do i keep the standard one... or lose it in favour of a decat :)
 

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The Cat pipes work on Ecotec's. I spoke to someone who worked for AMD (tuning company), he found a second hand cat and cut the center out, said they give 4+bhp. I would fit one but for the MOT.

You would expect the cat to make the manifold pointless, but BenLee runs over 190bhp with the VX cat on throttle bodies so there not that restrictive. Like I say the manifold is also about pules (waves), not just back presure, and i'm expecting better midrange pickup with this item.
 

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I asked my garage about that who I trust, and he said it won't without the CAT on.
 

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Possibly a fine or your car impounded and a fine, etc. Of course that only applies to people that have their car in one piece on the road. If its in bits on axle stands in your garden full of weeds and 3 foot long grass then it comes under environmental, rather than road traffic.
 

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why do people de cat there motors then, how long would the car be impounded for
Supposed to improve performance and most think it's worth the risk! Road side emissions test are very rare (at the moment anyway).

I have a de-cat pipe on my car which seemed to make a differance - whether than was pyscological or not, only a rolling road test would prove! Mine's a Janspeed item that looks like a silencer box. Never even seen a roadside emissions test around here!

Could modify a standard cat - at least then if you did get tested, you could claim the cat was faulty and thank the kind officer for pointing out the problem!
 

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Possibly a fine or your car impounded and a fine, etc. Of course that only applies to people that have their car in one piece on the road. If its in bits on axle stands in your garden full of weeds and 3 foot long grass then it comes under environmental, rather than road traffic. what is siraff on about
you could take the cat insides out on a standard cat then weld a tube though the middle of the cat then this would look like a standard cat from the out side
 
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