RomRaider

Hi,
I have my JDM 03 sti project and had to buy a used sti downpipe to pass the emissions. Ive been scaling the maf and retarded timing while doing this. The maf scaling at idle and cruise is good only corrections of about 0.75 so the scaling is good. However during smog i got co2 emission of 0.5 and and the reuqired value to pass emissions is about 0.2-0.25. The co2 emissions is measured at idle.
My question is does the ignition timing affect the emissions at idle to 1000rpm. I also noticed that the target closed loop afr is 14.37 insted of 14.7 this is due to the CL fueling Target Compensation A (ECT) map making it more rich adding -0.221 afr during idle. I find it odd that the CL Fueling Target Compensation (ECT) Disable map is set 245F so that table never gets disabled hence running rich. Would it be sufficient to advance the Ignition at idle and set this disable table to a bit under operating temp such that closed loop target becomes 14.7 or should i approach it differently.

Any other ideas on how to lower idle co2 and pass my emissions. Any feedback and help is appreciated.

yes if you dont have enough ignition timing your emissions will be poor so throw some timing back in then see how your emissions look. Also make sure the cat is fully up to temp and if that doesn't do it then you may have just bought a bad cat and it will need replacing.

as for the compensation tables, you can always open up a comparable USDM or EDM car (UK 2.0 STI also had emissions targets and cats so might be a closer match) and you can compare the values there for some inspiration.

Thanks as allways bludgod for the help. Ill set the timing at idle and cruise back tto oem map and ill compare it with the EDM maps. Lets hope it passes it so i can finnaly have it back on the road.

So It seems here we see that the EDM sti has zeroed out the compensation tables to have 14.7 instead of target, overall the EDM runs leaner with less compensation during warmup. Any special reason for this, does it ahve to do with fuel quality? I believe that Japan has better fuel quality to be fair.

ignition timing at idle and low rpm is also much more advanced compared to JDM. I wonder why this big difference, does somebody know?

I Hope its okay that i post my findings like this still new to forums.
I will try to apply this and hopefully the emissions will pass, i wonder how this car passed emissions previously

the answer to pretty much all your questions is going to be emissions targets - the EDM car will have a much tighter limit to achieve vs the JDM car and it has to do it on a range of fuels available across europe.