8ballvmax Posted April 20, 2012 Report Share Posted April 20, 2012 hi guys i want to lose the cat converter on my 1.4s, i have looked on ebay and seen stainless manifolds claiming its a decat blah blah...... i thought the cat was somewhere in the pipe section???? im very confused ( doesnt take much lol) and i have also seen on flea bay a decat by-pass pipe for around £20?? very confused???????ps not worried about the mot Quote Link to comment Share on other sites More sharing options...
Ashh Posted April 20, 2012 Report Share Posted April 20, 2012 http://forums.clublupo.co.uk/index.php?showtopic=79122 Quote Link to comment Share on other sites More sharing options...
8ballvmax Posted April 20, 2012 Author Report Share Posted April 20, 2012 many thanks mate, still confused as **** lol think i will get me mechanic to sort it lol Quote Link to comment Share on other sites More sharing options...
treblet Posted April 21, 2012 Report Share Posted April 21, 2012 Your car has 2 catalytic convertors. The first catalytic convertor (pre cat) is in the manifold and there is another under the car in the conventional place after the downpipe. Most aftermarket manifolds include a downpipe decat section which will get rid of the second cat and will not have first pre cat at all.Make more sense now? Quote Link to comment Share on other sites More sharing options...
shaunsprules Posted April 21, 2012 Report Share Posted April 21, 2012 Id go to a local metal fabrication workshop and get prices as 90% of the time it's cheaper Quote Link to comment Share on other sites More sharing options...
8ballvmax Posted April 22, 2012 Author Report Share Posted April 22, 2012 cheers now than makes sense many thanks Quote Link to comment Share on other sites More sharing options...
Bazza21 Posted April 24, 2012 Report Share Posted April 24, 2012 which of the cats gives the most restrictions or do both have to go ? Quote Link to comment Share on other sites More sharing options...
shaunsprules Posted April 24, 2012 Report Share Posted April 24, 2012 1st cat more as 2nd it to see if there is a fault with the 1st one, but if u take 1st out and leave second then u will have to clean the codes it will chuck up Quote Link to comment Share on other sites More sharing options...
treblet Posted April 24, 2012 Report Share Posted April 24, 2012 Shaunsprules, I take it you're guessing and you don't really know for sure as there's no way of telling which of the two catalytic converters gives more of a restriction without putting them on a test rig with a micro manometer on either side to assess the pressure drop. None of which I'd guess you have access to.Just because the box it comes in is bigger doesn't always mean it's more restrictive. The monolith inside the tube which is coated with the catalytic material is what causes the restriction. Sometimes the casing can be a lot larger to reduce restriction as it allows more surface area for the monolith to work on. However sometimes it is also possible that a very small case can have a massive restriction as the monolith is very tightly spaced, meaning the air can't all get through as quickly. Quote Link to comment Share on other sites More sharing options...
Thissy Posted April 24, 2012 Report Share Posted April 24, 2012 The pre-cat in the manifold has little restriction. I think 'shaunsprules' is getting confused and mixing up the cat with the post lambda sensor which reads the efficiency of the cat. The conventional cat certainly isn't there to check the efficiency of the pre-cat! So the cat located under the car after the manifold is the one you want to remove. Personally on a 1.4s with no other performance mods i wouldn't bother, if you were getting a performance manifold to then you could justify it.Mike Quote Link to comment Share on other sites More sharing options...
shaunsprules Posted April 24, 2012 Report Share Posted April 24, 2012 (edited) Ohhhhhhhh rite we tbo lambda sensor are for oxygen measurements from the chamber Edited April 24, 2012 by shaunsprules Quote Link to comment Share on other sites More sharing options...
8ballvmax Posted April 26, 2012 Author Report Share Posted April 26, 2012 cheers guys great advice to bear in mind these things are best not rushed Quote Link to comment Share on other sites More sharing options...
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