rule of two for a new cat?
 

i'm not quite in this situation yet, but i soon hope to find myself there. i have purchase a cat-back, dp, and intake kit. soon, these will all be installed and the car retuned via an Apex'i PFC. if i then decide that i want to add a hi-flow cat (possible birthday present from my parents and fiancee) do i need to have my car retuned after adding the new cat or does the "rule of 2" still apply? i'm not sure from what i've researched if only applies for the first 2 mods to the air-flow or if it applies the entire way through modding :beerchug: thanks guys.

*bump*

Why not just wait to install everything THEN tune it? :)

Just have the tuner run a slightly more conservative fuel map than he normally would, a hi-flow cat doesn't make THAT much more power than the stocker.

BTW, it's a little silly to bump your post after only an hour at 4:30am....

Yah, what he said. Tell your tuner that you plan to put a high-flow cat on the car, and ask him to tune for it.

it wasn't 4:30 AM here, i'm in MD so there's a time difference and i just didn't wanna have to page down through the forum searching for my post to bump it again during lunch, so i bumped it when it got near the end of the page.

If you tune a bit conservative you will not need to tune again. Otherwise you will need to tune again. Wait till you get all of them and then tune the car

I agree that you should just wait to do it all and then have it tuned. You can never know how a product is gonna act on a car. You may end up not tuning conservative enough and blow your motor, or you will tune too conservative and not have a good tune job.

I was under the impression that the base map that comes preprogrammed into the PFC is pretty well suited for intake/dp/catback. I am in the same situation as pugg57. I have an intake/dp/catback/pfc w/ unaltered map. I am wondering if this base map is conservative enough to add a HFC w/o additional tuning.

Thanks,
Tony