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By-passing cat

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rotti

Post subject: By-passing cat

Posted: Fri Jul 04, 2008 9:29 am

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Location: Leicestershire
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If I wanted to bypass my cat, for purely experimental reasons of cause, can I use a straight peice of pipe or will i have to buy a box ie magnex bypass kit?

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onslack

Post subject: Re: By-passing cat

Posted: Fri Jul 04, 2008 9:35 am

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Joined: Sun Mar 06, 2005 6:10 pm
Posts: 22224
Location: Somewhere

you could go to a place( magnex dealer i think) and get a de-cat pipe made up or if again its like the 1.6 zetec, cut the cat off, weld a bit of pipe(make sure its the right length and bore etc.) then put back in place

if you can get a spare cat just incase for MOT's etc

might be easier to get a de-cat pipe made up tho, your looking at about Â£50+- i'd say

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DANIELP1991

Post subject: Re: By-passing cat

Posted: Fri Jul 04, 2008 6:04 pm

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Joined: Fri Sep 21, 2007 12:55 pm
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Location: Blackwood, south wales
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i want to de-cat my car, apparently 1.4s go a lot better without the cat!

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rotti

Post subject: Re: By-passing cat

Posted: Fri Jul 04, 2008 6:15 pm

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Joined: Thu Jul 03, 2008 6:46 pm
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Mine can't go much worse! :wth:

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DANIELP1991

Post subject: Re: By-passing cat

Posted: Fri Jul 04, 2008 9:00 pm

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Joined: Fri Sep 21, 2007 12:55 pm
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Location: Blackwood, south wales
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same ere m8

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zetecsi16v

Post subject: Re: By-passing cat

Posted: Sat Jul 05, 2008 2:37 pm

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Joined: Thu Apr 10, 2008 10:28 pm
Posts: 33

Im putting a four branch manifold with full exhaust system minus the cat on my fiesta this wednesday,I will let you no how good the power gain is, I been told it will be allot better but to be honest i don't think it will effect top speed much but will give the si that extra power it lacks.
I will let use no though if its worth the money for the extra gain.

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DANIELP1991

Post subject: Re: By-passing cat

Posted: Sat Jul 05, 2008 2:58 pm

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Joined: Fri Sep 21, 2007 12:55 pm
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Location: Blackwood, south wales
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i cud get a janspeed manifold for my 1.4 si but not sure if it will make much difference.

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fonfe

Post subject: Re: By-passing cat

Posted: Fri Jul 11, 2008 6:15 pm

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Joined: Tue Jul 08, 2008 8:14 pm
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Location: high wycombe
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dont expect big gains from not having a cat, but it will make a small difference to an extent though, its a bit like the air filter myth gain; you tend to think its going faster because you can hear it more but its not actually made much difference if you get what i mean. now on a turbo car yes it will make a considerable difference but compared to n/a dont hope for that much. better off for the money just fitting a larger capacity engine or at least buy mods that will fit a larger engine should you decided to upgrade later on.

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DANIELP1991

Post subject: Re: By-passing cat

Posted: Fri Jul 11, 2008 6:34 pm

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Joined: Fri Sep 21, 2007 12:55 pm
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Location: Blackwood, south wales
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well said!!, thats 1 reason y im getting air filter and exhaust so its louder so it feels faster!! lol

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Tweek

Post subject: Re: By-passing cat

Posted: Fri Jul 11, 2008 7:31 pm

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Joined: Mon Aug 28, 2006 11:28 pm
Posts: 297
Location: Gloucester
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I've got a Magnex bypass, it's just a downpipe with a front silencer on but I got it bundled with a system I bought lol. It doesn't make a great deal of difference but it's worth doing if cheap enough. There is slightly more poke when snatching the throttle.

It definitely does make a difference though, the cat's a fairly big restriction in the exhaust, removing it removes that restriction.

With the Magnex bypass, you get hardly any noise anyway

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fonfe

Post subject: Re: By-passing cat

Posted: Sat Jul 12, 2008 5:16 pm

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Joined: Tue Jul 08, 2008 8:14 pm
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Location: high wycombe
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to an extent it is how it sounds i must admit. i took the si for a road test for the first time earlia this morning and it felt so so slow! then i looked at the clock and realised i wasnt actually going that slow im just used to hearing the batch firing on the escort and the really loud exhaust on the gfs zs.... think im gonna have to make it a tiny bit louder just for my own reasurance cz i can hardly tell if the engine is running or not at the moment in it!

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Post subject: Re: By-passing cat

Posted: Sat Jul 12, 2008 5:19 pm

Jap Crew

Joined: Tue Dec 21, 2004 6:24 pm
Posts: 11189
Location: In the Shires
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Magnex have gone out of business so if you want a new one then get it quickly.

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fonfe

Post subject: Re: By-passing cat

Posted: Sat Jul 12, 2008 5:28 pm

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Joined: Tue Jul 08, 2008 8:14 pm
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Location: high wycombe
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when did that happen??

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Post subject: Re: By-passing cat

Posted: Sat Jul 12, 2008 5:31 pm

Jap Crew

Joined: Tue Dec 21, 2004 6:24 pm
Posts: 11189
Location: In the Shires
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Only just. along with Peco.

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fonfe

Post subject: Re: By-passing cat

Posted: Mon Jul 14, 2008 6:50 pm

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Joined: Tue Jul 08, 2008 8:14 pm
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Location: high wycombe
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dam it i just gave away what could of been an antique back box in a few hundred yeaers!

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rotti

Post subject: Re: By-passing cat

Posted: Tue Jul 22, 2008 5:08 pm

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Joined: Thu Jul 03, 2008 6:46 pm
Posts: 24
Location: Leicestershire
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Ok, so I've decided to go the cheap route with this one and just smack out all the filler in the cat and put it back on, as read in the "guides" section. I grew some balls today and did a 0-60 test. Warm car, flat road. To be honest I'm far to ashamed to put it on here but it was terrible. If its not the cat holding it back then I'm at a loss and looks like I'm binning the engine or car.

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sk8xtrm

Post subject: Re: By-passing cat

Posted: Tue Jul 22, 2008 5:57 pm

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Joined: Thu Mar 23, 2006 11:29 pm
Posts: 1818
Location: South wales
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Its dependant on engine how it affects it...for example i no with my 2ltr and a lot of 2ltr zetecs that have has a de-cat you would lose lower torque but would increase Bhp slightly at higher revs. Basically you wont have as much pressure there at low revs to get it going quicker...yet when you get to high revs its more free flow so does help slightly.

even if you smash the cat out the air will swirl in the empty chamber...try just a pipe. it might make a little diffrence

and it wont be as raspy.

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rotti

Post subject: Re: By-passing cat

Posted: Tue Jul 22, 2008 6:18 pm

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Joined: Thu Jul 03, 2008 6:46 pm
Posts: 24
Location: Leicestershire
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Bottom end is ok......ish, its mid range, see my flat fiesta thread. Above 3rd gear its a waste of space. But having not driven a healthy 1.4si its hard to compare.

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sk8xtrm

Post subject: Re: By-passing cat

Posted: Tue Jul 22, 2008 7:01 pm

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rotti

Post subject: Re: By-passing cat

Posted: Wed Jul 23, 2008 10:46 am

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Joined: Thu Jul 03, 2008 6:46 pm
Posts: 24
Location: Leicestershire
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I'm nowhere already mate. we are talking 28 secs for a 0-60! :banghead:

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