bad idea to decat downpipe my 04' sti ?
17 September 2008, 02:39 PM
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bad idea to decat downpipe my 04' sti ?
what will be the effects if i fitted a decat downpipe to my car? would it run like a bag of nails? im aware of the mot business and the light coming on but what about damage to engine and suchlike. i already have a decat pipe after the downpipe and then an h&s system.
dan
dan
17 September 2008, 02:43 PM
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you will make some nice power gains, as for a re-map, quite possibly so, in order to get best out of it.
MY mate on his Evo replace his OE downpipe for a decat and it made 35hp more...thats how restrictive they are!
MY mate on his Evo replace his OE downpipe for a decat and it made 35hp more...thats how restrictive they are!
17 September 2008, 03:34 PM
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If you fit the decat pipe, after 100 miles you will more than likely get a CEL light on and the car will also not perform as it should. I had it done and had to wait a week for my map... once mapped the difference was night and day 
17 September 2008, 04:32 PM
#7
You won't get too much of a power increase as the ECU will still be using it's fuel / ignition maps. Spool up will be better and the noise will change 
You are likely to get CEL P0420 (cat below efficiency)
For best results de-cat and re-map so the ECU can do it's proper job and not the strangled effort that left the factory !!!
Shaun
You are likely to get CEL P0420 (cat below efficiency)
For best results de-cat and re-map so the ECU can do it's proper job and not the strangled effort that left the factory !!!
Shaun
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17 September 2008, 08:07 PM
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HT04 'view my scooby', jesus christ mate is there any square inch on your car that hasn't had something added or changed? 
not a bad idea to decat the downpipe by the way, i just struggle to see the point nowadays with very good sports cat downpipes available.
fair play if you want to squeeze every last bhp out of your car, but unless you're doing that you won't lose that much over a full decat and you be legal aswell
not a bad idea to decat the downpipe by the way, i just struggle to see the point nowadays with very good sports cat downpipes available.
fair play if you want to squeeze every last bhp out of your car, but unless you're doing that you won't lose that much over a full decat and you be legal aswell
18 September 2008, 05:13 PM
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TBH the overboost etc is a problem. Those posting saying the ECU is pulling back boost just goes to show that doing this without a map is not good for the engine. Remember the ecu is acting because it has spotted something going wrong and is trying to correct it rather than preventing it happening.
Not worth the risk IMHO
5t.
Not worth the risk IMHO
5t.
18 September 2008, 06:17 PM
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Got one of those on my classic - been through two MOTs so far (one on standard map, one with remap) with no problems - think the remapped time was actuallly a bit better on emissions. I put it on after using a decat downpipe (standard map), and to be honest I didn't notice any difference in power (or noise) after the change.
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