View Full Version : Precat question
joff-turbo-nova
22-10-11, 05:29 PM
Hi all,
Just taken the exhaust off the Z20LET in the Astra Coupe and I peered down the downpipe into the precat expecting to see a cell structure of some sort and got this view :-
http://i2.photobucket.com/albums/y15/joff-turbo-nova/Exhaust0001.jpg
Its empty and you can see all the way through to where the pipe exits at the bottom.
Is this standard or has someone been playing with this before I got it?
Joff
honeycomb has been bashed out, precat is not need in the uk iirc
it will still pass the emmisions test without it, but the MIL may come on with a ''catalyst efficiency below threshold' code stored in some cases.
yep someone has removed the middle. As said, not needed in the uk, but eml may illuminate with it removed.
can space lambda out with a few washers if eml comes on
joff-turbo-nova
22-10-11, 07:03 PM
It was running fine with no ECU lights on, just wondered if this is a normal pipe as it doesn't have a flange below the precat like most of the Z20LET's I've seen .
Its NOT like this ....
http://www.lmfvauxhall.co.uk/image.php?type=T&id=1121http://www.lmfvauxhall.co.uk/image.php?type=T&id=1121
Joff
How is it connected to the CAT then? Sleeve joint?
I'm sure some coupes didn't have a separate precat, the cat and precat was one unit
Some had an all in one downpipe so the precat wasnt seperate. You wont need the precat for emissions as said and it wont show a eml if you still have the standard cat doings it job.
Definatly been smashed out though, and get you lambda sensor changed! Running a bit lean by looks of that exhaust
9.9/10 times the precat will NOT trigger the EML. Its purely there to get rapid light off on the NEDC for emissions BS.
Most of the time they cause the cast manifolds to crack, so bin them :)
joff-turbo-nova
22-10-11, 08:12 PM
Some had an all in one downpipe so the precat wasnt seperate. You wont need the precat for emissions as said and it wont show a eml if you still have the standard cat doings it job.
Definatly been smashed out though, and get you lambda sensor changed! Running a bit lean by looks of that exhaust
I think its the LED light making the soot lighter than it really is, its quite dark really in normal daylight.
joff-turbo-nova
22-10-11, 08:15 PM
Some had an all in one downpipe so the precat wasnt seperate. You wont need the precat for emissions as said and it wont show a eml if you still have the standard cat doings it job.
Definatly been smashed out though, and get you lambda sensor changed! Running a bit lean by looks of that exhaust
Yes its all in one ...
http://i2.photobucket.com/albums/y15/joff-turbo-nova/Exhaust0002.jpg
No flange joint ...
http://i2.photobucket.com/albums/y15/joff-turbo-nova/Exhaust0003.jpg
Joff
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