Advice on cat removal

NathanD

Member
Hi Guys,

I have browsed the forum before, but only just signed up...

My Mrs has a Astra Convertible Linea Rossa. I've changed a few bits, and current it has some GT3 oval tailpipe backbox.

Its due for an MoT and I'm having a brand new cat back system made, as it nearly failed last year. The question is, the Z22SE in the convertible, does have two cats right? a pre cat in the manifold, and then the big fat main cat?

Following this, if I remove the big fat cat, will the car pass an MoT?

Engine-wise its standard apart from a Vectra Scoop, deristricted airbox and K&N panel filter..

Any advice welcome!

Thanks
 

Sjdickso

Staff
Depending on year some of the later cars didnt have a pre cat, only way to find out is drop it and have a look, you can safety remove this and not fail a MOT.

The main cat you need in place for a MOT, you get sports cats 200cpi which should pass the MOT but can cause Engine management light to pop on due to the faster flowing gases and the second 02 sensor.

Hope this helps.
 

NathanD

Member
Hi, thanks for your advice,

Oh thats interesting, it's 2004 so no doubt one of the later ones, so will have to check it out further. any other ways to find out?

I can always pop a sports cat in there, and yes, good point about the EML light!
 

m4rtin

Regular Member
Im sure yours wont have a pre cat then, mines a 53 plate and doesnt. if you are going to get a sports cat, i think you can get a spacer for the 02 sensor so you dont get an eml light.
 

evocarlos

Stupid Bollocks
Staff
ive took mine out and fitted a lambda elbow dont get an eml now even with the charger fitted
will wait and see what happens on its mot :)
 

NathanD

Member
Thanks for the replies guys, double checked yesterday and it doesnt look like it has a pre-cat, so will buy a 200 cell sports cat and pop that in there.

Thanks for the heads up evocarlos - will get a spacer, or elbow for the post cat lambda ;)
 

corsaZ22se

Senior Member
I havent fitted any kind of spacer and never had any problems with eml in 70k+ miles (y)
got the 200cpi cat from courtenay sport
 

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Remap Services
Trader
ive took mine out and fitted a lambda elbow dont get an eml now even with the charger fitted
will wait and see what happens on its mot :)

As Evocarlos said, I have a lambda Elbow on mine and a decat pipe, no eml, however it will still fail the MOT with it removed, so will need to find a friend at a MOT station who would overlook it (if you remove it :) )
 

Opel2.2

Member
Whats this elbow you talk of? Going to remove my cat completely soon and want to fool the eml light. Is there a cheat plug like the egr thing I bought of here when I blanked off the egr?
 

evocarlos

Stupid Bollocks
Staff
Whats this elbow you talk of? Going to remove my cat completely soon and want to fool the eml light. Is there a cheat plug like the egr thing I bought of here when I blanked off the egr?
took my cat off ages ago had problems till i fitted the lambda elbow on the 2nd sensor
http://www.ebay.co.uk/itm/Lambda-Sp...005&prg=9063&rk=0&rkt=6&sd=161210562183&rt=nc

it takes the tip of the lambda sensor out of the gas flow so the 2 sensor readings are different that way the EML stays off :)
 

Opel2.2

Member
Thanks guys I'm building a track car so don't need to worry about emmision's just noise. Will I gain much power?
 
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