Kitty Kat question

[Black_Mamba]

This is more geared toward the 6.0L guys. Question is will I see more performance with or without the cat? I am already running without the cat and like the way it is performing and the way it sounds but if I get more performance from haveing the cat in then I'm game. Now I now my MPG will go back up to 20 MPG but this is with stock exhaust and the programmer, currently 18 MPG was 15 before intake, but this is not a issue. I just want more bang for my buck with what I have already. Injectors and Trans are going to be replaced sometime next year so that is out of the question.

 

[powerboatr]

mine is still in with a mbrp 4 " exhaust. milege only changed slighty, but .. what feel likes quicker spool up or less restrictive breathing is the only real advantage i feel
i get 16 at 72 mph with 430 gears

 

[DaveBen]

That is very good mileage for 4:30 gears. Most get that mileage with 3:73 gears so you are doin good.

Dave

 

[powerboatr]

dave
the trade off hits at 77 mph and above, it drops sharply to 14

but its still better than my 7.3 with 4.10 gears

 

[JohnBoyToo]

Someone on another site in a land far away in a time past
did testing and determined that at the strip or on the rollers, there was negligible difference with the properlly mounted cat...
(meaning trim the inlet and outlet to match your exhaust pipe so as not to have a bottleneck)

Only difference I noticed on the 03 Ex was that the cat would mute the turbo whine just enough to knock the obnoxious levels down a bit - my neighbors appreciated it !

 

[powerboatr]

when i had all mine apart, i can tell you that the cat on my 06 looked more like a big screen to catch large chunks of debri
i shined my 4 cell mag light right through it to the other side on my iddy bitty hand not real bright but i could see the light
sooooooo with that said
i probalby could have gotten away with just a new down pipe that was not bent like a pretzel.
i also a ULEV sticker on my radiator support.
I have only once had her blow any kind of off color exhaust out the back.
but the turbo lag is Dangerous from a 2-3 mph off throttle rolling start
when the power comes on it comes ON and BAM your gone.
i feel better now

 

[Black_Mamba]

This was what I was looking for finally. Thank you all. Guess I'm going to leave mine out then. Now decideing if I want to go with the SCT XCal2 for the tranny tuning or more.