Hi all,

OK I have used search but am still somewhat confused..

2001 WRX bugeye wagon,
KN filter, Prodrive Down (Sports cat) and rear (decat) pipes, HnS 2.5" main pipe and rear box

Q1) Iv replaced the down pipe and rear cat pipe with MagmaWrapped Prodrive Sports cat down pipe and de-cat rear pipe, I now have a CEL light on this morning. now as far as I can search this should not be an issue and can be ignored or switched off by inserting a resistor somewhere.
What does the light mean?? too hot exhaust? is this correct that I can ignore the light??
I cant find a link to any instructions to insert the resistor, does anyone have the link handy?.

Q2) Im considering replacing the catted up-pipe with a STI OEM unit (de-cat).
Now here Im confused, Iv read some posts saying that you must to get the car re-mapped to prevent damage to the car and others posts saying that the standard turbo (TD04??) is too small to damage the car and the ECU will readjust to suit the now free-er flowing turbo intake.
Will someone please put me straight and tell me whats what.

I dont want to get the car remapped as the costs locally are stupid money.

thank you
Vik

 

You only use the resistor when you change the up pipe. The light you have on now will be because your sports cat has taken the o2 sensor out of its limits. You can have this light turned off.
Your car may not pass its next mot, but some do.
When you change your up pipe ( as i have ) you insert a 2k2 1/4 watt resistor into the EGT wiring plug near the boost solenoid. If you dont you will get a light on for that too. Or you can have that light turned off as well.

 

1 - i believe on a new age there is a sensor that needs a fix to compensate for or summit.

2 - they can overboost on a decat or afk can change (not always the case though) best bet get it on a dyno to be checked out and then go from there. You will however get a much beter driving car with a proper tech 3 remap.

 

I have the up-pipe replaced with an OE STi item(no cat) and i have a decatted mid pipe (after the downpipe but before the centre section). I run with 1 cat only (downpipe) and i posed this question before and was told that the Denso ECU will cope with this ok and not need a remap.

I used the resistor fix to knock the CEL off , i will try and find the link for you.

 

here you go

http://forums.nasioc.com/forums/show...php?p=29126624

no pictures but a description of where it needs to go in post #4

 

Pete,

Iv got the CEL after only fitting the down pipe and removing the rear cat..
The article you linked, isnt it talking about the resistor if you decat the up pipe ???

or am I missing something here.

Vik

ps- good to know that I can remove the uppipe cat and not need a remap..
did you notice a big difference before n after or not much?

 

its not 100% that you will get away with it.

 

noted Tidgy thanks..

Maybe Im asking the wrong question...

What CEL error would occour when removing the Rear cat and installing a Prodrive down pipe (uppipe untouched)??

and what can i do to remove the CEL ??

thanks

 

^ Yes your right, ignore me i didnt notice a difference becasue it was fitted by the previous owner.


Tidgy - what do you mean? How would you know this?

Cheers

 

know folks who had issues despite being told on various sites it would be fine, need to get it checked out to confirm. Just because it appears to be runnign right doesnt mena it is.

 

I answered that for you in my first post. You will get a P0420 code. Cat efficiency problem. You need to access your map and you can turn that light off. Your car will run ok with the light on but may fail its next MOT on emissions.

 

thank you for assisting a fool who didnt read your post correctly

So its not something that I can fix myself... poo, over here AFAIK its a fail if you have any CEL lights on..

Vik

 

You can buy a OBD2 scanner tool that will clear / reset the light for maybe 2 weeks. Enough time pass a test. Or i have heard that if you weld a longer boss on the exhaust, where the o2 sensor screws in , it withdraws the probe from the exhaust gases and doesnt throw the light on.

 

Folks,

Sorry for the hijack but I have a quick question on the same topic.

I have car mapped with prodrive sportscat downpipe and back box. I also have the cat behind the downpipe decatted.

Would decatting the upipe require a map tweak or will i get any benefit without map tweak?

Cheers

 

Ooh touchy subject. If you change a jubilee clip you need a remap so im told

The way i would approach is fit the up pipe ( as i have ) perform the EGT bypass with a resistor, drive the car for a couple of weeks and see if any lights come up. If they do, it will mean you have gone outside correction limits for the o2 sensor etc. Then go see your mapper.
Replacing the up pipe will increase flow and is one less restriction to remove from the exhaust, but there have been tests to show no bhp gain with just an up pipe change.