Hey guys, I am still in the process of purchasing some stuff for my F and I was wondering what you guys thought on having cats in or out of the PPE headers. Im sure there is a thread on this but I couldn't find it. I want to make my car to sound great and perform great but I don't want to throw any codes. I have the DES forged exhaust system to go along with whatever I buy, so what do you guys think I should do with my header set up?

 

No cats will give you better sound and performance. There is a simulator included with the PPE headers to eliminate the chance of a CEL.
Most people with headers and exhaust are eliminating there cats but for some it's a moral dilemma or an state emissions issue.
There are plenty of threads on this topic.

 

are you gonna buy your headers new from figs?

 

i'm not an eco nut but gain 5hp never seemed like a good tradeoff for the smell and killing the ozone layer.

 

I don't have headers but I would say go without cats, sounds better. If you are sensitive to noise, add cats. I know an F owner with Joe-z / PPE (WeaponF ;-)), he told me his car sounds pretty quiet with the setup, and he has RandomTech cats. Having cats will decrease your HP, also keep that in mind.

As far as morals go... I live in probably the highest environmentally polluted state in the nation, so what's the point of worrying? If you pass inspection (which I did legally, without secondary cats or mufflers).....that obviously means you passed emissions tests and the car complies.

 

No cats!!! if ur state requires it just put back ur stock exhaust and ur good to go...

 

I just got PPE headers on my car last week and haven't stopped smiling since. It makes the car significantly quicker, I can tell you that!

 

i was really in between PPE and Sikky headers, there is a ton of information on here about the 2 to gain some confidence in your decision

 

FACTS:

Headers and deleting cats - Yes F car will be louder

Yes your F will pull harder and gain more power that you can feel at higher RPM and at higher speeds (and show in dyno)

 

I'm posting this dyno graph once again. My F has PPE headers and a fabricated dual exhaust system utilizing MagnaFlow HiFlow Cats, an X Pipe, GlassPack resonators and modified stock mufflers. The other F, dynod on the same day, has PPE headers, JoeZ Exhaust and no cats. If you look at the power curves, my F makes more power down low and the other F makes mower power up top. Pick you poison. I picked mine.

Lou

 

Having cats and a loss of 13 overall whp is IMO not a good trade off for the smell. The power advantage you had down low is under 3k RPM.. in a drag or race track you'll never see RPM's that low. I suppose you feel the power more on the street but that kind of defeats the purpose of installing a header and exhaust, which IMO is to increase overall power.

 

^^^^And the increased power on the catless F is all above 5.7K. I wanted cats, not for performance, smell or sound or anything like that. To me, it was a personal decision. I just feel like it's the socially responsible thing to do. My friend didn't feel that way, that was his choice.

And not trying to start an argument here, but the question was asked and folks made comments. I thought this visual aid might help put the question to bed.

Lou

 

I went catless for a week before getting highflow cats installed. To be honest, the sound of the Borla with catless PPE is just awesome, I had random people just coming up to me and telling me how good it sounded. And it was LOUD!

However, the smell was pretty bad, and the penalties here in Australia are quite severe if you get caught for not running cats. After putting cats in, I can feel a slight power decrease but it still feels and sounds better than the stock headers.

I am happy now because the sound now suits the character of the car - luxury and performance when you want it. You can live with it as a DD but still get the beautiful sound at WOT.

If I didn't care about getting caught or daily driveability, I'd go catless. The sound was just out of this world.

 

Or keep your stock exhaust and get an electronic cut out. Best of both worlds! Quite when you want and or need it to be and nice and voictrious when you want or need it to be.