crapsack

iTrader: (9)

I have the cali emissions and I read this from one of the stickies:

"On CA emission 99's Front pre-cat built into header, two extra oxygen sensors to monitor pre-cats (total of 4), Swirl valve in intake to improve emissions. Special aftermarket Y-pipe required and only 1 pre-cat can be removed."

Im assumming pre-cat means before the standard cat, there a two, and one on each manifold. correct me if im wrong.

So why can only one be removed?
How restrictive is this emissions equip?
Whats the difference between CA y-pipes and non CA Ypipes besides the extra O2 sensor spots?

maximazation

iTrader: (11)

the pre-cats are before the main cat, and its purpose is to limit pollution and pass smog checks during start-up when the engine is cold.

i never knew only one could be removed on the 99 with cali spec.

the pre-cats are restrictive, thus aftermarket y-pipes making so much power when the pre-cats are removed.

ronin22357

iTrader: (14)

The front bank precat cant be removed. it has an o2 sensor before and after it

crapsack

iTrader: (9)

are you saying that pre cat cant be removed and replaced like the main cat? Is there any way to get both the precats out, like with headers?

crapsack

iTrader: (9)

Anybody know?