I am not sure what the correlation is but I have noticed much better gas millage since installing 200 cell fabspeed cats on my 997s. If I am easy on the gas I get close to 20mpg city and over 30 on highway. Prior to installation I was getting 15/23. Anyone have a clue what thats about?

When I do punch it the cats sound pretty good, provide a little power, and a noticeable change throttle response. Good mod.

As an install note I would recommend taking off the bumper and heat shields first. Also unclip the O2 sensors from the engine bay, remove airbox first then unclip them from the right and left side, this will give you some slack and allow you to properly remove the existing cats.

Would be nice if the cats came with install notes from fabspeed, hint hint...

Tuber

 

That would be great! I plan to do cats when my warranty is up (maybe earlier if I figure out it won't be a big deal), and I'd love the extra mpg.
I'm disappointed that my 06 C2S gets worse mileage than my old 964, which has some mods.

 

I put 200 cell AWE cats on my Targa last year, and never noticed any change in mileage. But I did love the sound of them. I agree with your recommendation about unplugging the sensors etc.

 

Tuber- are those CARB approved, or will you have to swap them out when you smog it?

 

I don't think any high flow cats are approved, but I understand that some will pass the smog test if you take the car for a spirited run immediately before testing it.

 

Who cares? New cars are exempt from smogging for 7 years.

I added the fabspeed cats also, and I think my mileage has gone down... because I'm always stomping the gas to hear the music!

 

I am not sure? But the guys at fabspeed say no problem with Cali emissions. I should find out. LOL. But I have noticed a consistant 18-20 city and now 27-29 hwy. Very strange?????

 

They must have increased that, as I think it used to be 4 years. Very VERY cool!

 

So, FWIW, I just went to get my Fabspeed-equipped 997S smogged here in CA and it would not pass. No CARB-approved stickers on the pipes, and Fabspeed has done nothing to provide them.
It's outrageous. Unless I've missed something and Fabspeed is willing to help (two years back, when my 200 cell Fabspeed-equipped car failed the smog test, Fabspeed did nothing for me in numerous phone calls and I had to spend $700 to have the exhaust system swapped to pass the test) I do not recommend them for purchase. At least here in CA.
V

 

Unless any after market mod comes stamped or with a sticker in CA. no pass smog.
FYI...New cars do not require a smog check in their first 6 years since the original date of purchase. When selling a car 4 model-years old or newer you are not required to obtain a smog check.

 

hard to believe

 

downhill in neutral with a tailwind might do it

 

When I had my VF SC and NHP 200 cell cats I got 30mpg on the freeway when just cruising.

 

That would be about 35% increase. Hard to believe and almost impossible, but I hope you are right.

As long as you are happy, let it give you the increase.

 

I live by Mulholland Hwy, I get 40+ MPG..............................









as soon as I reset my gauge at the very top of the mountain and before going downhill. jk