Is this causing a loss of power

[james1986fox]

Ever since I emptied my 1st set of cats and deleted my 2nd set I get a code PO171 for Bank 1 Running Lean and it I was getting a missfire on cylinder 8 but after I installed a tune the missfire code went away and never came back but I still get the PO171. Is this causing me to lose power cause it sure feels like my car was faster when I first got it when it was stock. Now I have tune, cai, 4.10s and just doesnt seem fast enough.

For some reason I think it has to do with me getting the 1st set of cats emptied but please help me out with your opinions I need to be fast again

[Stranger in the Black Sedan]

what on earth was the purpose of deleting primary cats?

[james1986fox]

I thought it would make my exhaust more throaty

[Stranger in the Black Sedan]

did it? .

[offroadkarter]

Hollowing out cats will decrease power, because the exhaust will start to circulate and collect in there, making it a restriction...

Theirs no point in "hollowing" out a cat, you might as well straight pipe it if you want to really stick it to mother earth...

[DEFYANT]

Loss of back pressure will hurt performance.

[Raudermaster]

+1 with the above. Just get a set of high flow cats and put them as your only set and you'll be fine. Hollowing out the primaries with just F with your performance.

[Stranger in the Black Sedan]

the "high flow" cats probably have the same monolith spacing as OEM. the name is really a misnomer, they were high flow compared to a pellet cat..... some of the more expensive cats really do have better spacing or shorter bricks to flow better but the cheaper ones aren't anything special

[james1986fox]

Loss of back pressure will hurt performance.
how badly will it hurt performance, so if i put some high flo cats in place of the emptied ones will i see a big difference

[Stranger in the Black Sedan]

a lot of the "performance" cats are no different than stock, a ceramic monolith of similar construction and dimensions, you really should not have ruined your cats

[Raudermaster]

What we're trying to say is, having cats is better than no cats in some applications.

[ctrlraven]

Get some high flow cats to put on and make sure your O2 sensors are plugged up where the first set is.

[JACook]

Loss of back pressure will hurt performance.

A common misconception. What actually hurts performance is the loss of flow
velocity. Exhaust backpressure is never a good thing.

[babbage]

Your old cats used to be worth about $200 CASH. Not worth a cent now, also it is illegal to run in the US without them.

[james1986fox]

Could a bad o2 sensor be the cause of my check engine bank 1 lean code

[james1986fox]

Also the shop said they hollowed out the first set of cats how can I prove that they did I cant tell by looking at the piping, can i check something with sct live link

[james1986fox]

Could a bad o2 sensor be the cause of my check engine bank 1 lean code
I know someone knows the answer too this

[Glockafella]

Also, your tune will be highly affected by exhaust work like the kind you described...better get your tune tweaked

[Glockafella]

A common misconception. What actually hurts performance is the loss of flow
velocity. Exhaust backpressure is never a good thing.



I have a 2006 Kawi ZX10R that could prove this statement wrong