1st decat question

ive recently got myself a 1st decat (last thing needed for bpu).. anyway, its just a 3'' stainless pipe, but looking at this picture http://i55.photobucket.com/albums/g151/Azzapics/DSC02285.jpg

it has a hole in the 1st decat, can anyone tell me what its for? and mine doesent have one does that mean i need to get one drilled or what goes in there?

cheers

(ps.. hope fish doesent mind me using his picture)

cat temp sensor?

if so dont worry about it

optional boss for a wideband sensor. Unless you're planning on using one, you don't need it.

optional boss for a wideband sensor. Unless you're planning on using one, you don't need it.

If you don't want to use it then get a stainless blanking plug. I'm sure some of the traders on here will sell them for a couple of quid.

i dont actually have the hole in my decat pipe thats why i was wondering why the one in pic has one. so do ideally do i need to use a wideband sensor? or even better what does one do? im sure i have one already in the cat if the holes come optional on a decat..

Its an additional boss for AFR mate , it normally cost you about £20+ to get that welded in:)

You have a narrowband lambda sensor as standard pre-cat (or pre-decat if you have one). If you want to measure air/fuel ratios then you'll need a wideband sensor and readout, so a boss fitted tothe pipe would be a good idea for futureproofing (i.e. if you want to go to big injectors etc)

but if i didnt use the sensor thing is it bad for the car?

you dont have to have that, specially if you have a J-spec, but AFR is a very good thing to have mate as it gives you very good info all over.

but if i didnt use the sensor thing is it bad for the car?

If you don't use the temperature sensor in the first cat, there's no problem. I've chopped mine off and will take it back through the floor under the drivers seat, then use that grommet to pass the wideband sensor through.

If you're thinking of a wideband, use the search button - there's literally hundreds of posts about them!