We've tested this on the dyno few times with our demo car.
Deleting 2ndary cat does not do much since o2 sensors are not working properly or not functional.
Sure you can still make the bungs and use defoulers to avoid the check engine lights (still pass emissions without problems) but Lambda motor and ECU works on all combination of things like I told you on the phone last time.
It really needs monitor proper water temp and Cat temp in order to perform the set A/F ratio.
We do not change any of A/F ratio when it's cold start and everything is warmed up good to go.
That also means if o2 sensors are not sensing properly, ECU will not be reading right still thinking it's still at cold start.
For our demo car adding stock cat back on added about 12rwhp compared to straight pipes.
Also if you look at the stock cats, they are very well made almost like aftermarket highflow cats.
Deleting 2ndary cat does not do much since o2 sensors are not working properly or not functional.
Sure you can still make the bungs and use defoulers to avoid the check engine lights (still pass emissions without problems) but Lambda motor and ECU works on all combination of things like I told you on the phone last time.
It really needs monitor proper water temp and Cat temp in order to perform the set A/F ratio.
We do not change any of A/F ratio when it's cold start and everything is warmed up good to go.
That also means if o2 sensors are not sensing properly, ECU will not be reading right still thinking it's still at cold start.
For our demo car adding stock cat back on added about 12rwhp compared to straight pipes.
Also if you look at the stock cats, they are very well made almost like aftermarket highflow cats.