Hi Thinking to get myself a full de-cat(down pipe and mid-section), without the remap. but will this make the car use lot more petrol than it should?? or is it better to keep a cat in, if so which one?

Will a remap fix the above question?? please advice...

thzz...

 

You may find that without a remap you find you have 'flat spots' in the rev range. The newage ECU has compensation maps which it can fall back onto if it thinks something is not quite right. You may also experience overboost. I don't know if that would mean more fuel I suppose it depends how you drive it.

You may also get a CEL after removing the downpipe cat, this can be removed using a CEL fix or by raising the tolerance of the sensor when remapping.

This info is from advice from a mapper when i asked about decatting a bugeye WRX - I should imagine it would apply to STi although you dont have an uppipe cat to start with.

You should be able to remove the mid section alone without any probs.

 

Oh... thats makes more sense to me now.. I will do more research on this thx...

 

I would also be careful decat'ing without a remap... because you may find your engine is running lean which could end up costing ££££'s.

My advice would be to get it remapped ASAP and to drive it carefully in the meantime. Many people only fit their decats when they are about to get a remap for this reason, and a friend of mine melted a hole in a piston by not getting one in time in his Bug STi.

 

which one is the best to de-cat?? how many cat i need to pass the MOT?? thx