So a friend of mine said something tonight about how the fuel:air ratio was different in the 11 and 12's than it is from the 08-10's. He was saying that the 11 and 12 run a lot lighter, and thus it would only take a very small amount of modding before i needed to get tuned or else I would have too much air in the mix. Can anyone confirm this? Isn't that something the MAF should sense and adjust for?

 

There is a big difference between AFR at WOT and AFR at idle / cruise. Don't confuse the two.

The '11's and '12's are leaner at WOT.

 

All I'm planning right now is the K&N drop in that I already installed yesterday.

So, are you also saying I should get it tuned after just these two minor changes?

 

I installed a wideband before I put my drop in on in my 2011, and it was high 10's at WOT, cant speak for the catback though. If you're worried install a wideband first

 

I'm familiar with what a wide band does, but not so much on what the information means. Can you say more about what "high 10's" are, and what that means for F:A ratios.

 

AFR=Air Fuel Ratio.. too lean cylinder temps raise causing detonation leading to a blown motor. Too rich you wont make as much power and you'll foul 02 sensors and spark plugs. You want to be in a safe place in the middle, usually mid to low 11s at WOT. Higher the number the leaner. Google stoichiometric

 

The cars should be tuned right from the factory if you want to extract their full potential, but that being said, the stock tune is perfectly safe with a drop-in air filter and a catback exhaust.

Here is a dyno chart w/AFR from a stock 2011 + K&N drop-in like yours:



As you can see it did lean it out slightly, but still within the range of being safe.