I was curious on something. Previous to my new exhaust i had the stock size piping (1 7/8") and i had my AFR dialed in to run at 12.8- 13. Since i upgraded to a 2.5" exhaust when i go WOT or close to it the AFR seems to stay at 14 -15 still. I have read adding headers you have to readjust the SAFC for afr as it changes. But i have read adding headers richens your exhaust so you have to take out fuel or make the readings on the SAFC into the negatives. Would this be the same for adding a bigger exhaust minus headers. Keep in mind im running..Sotck manifolds-gutted precats- testpipe- 2.5" exhaust- flowmaster muffler. So what im wondering would i have to readjust and add fuel or reduce fuel?

 

Do you have a wide band? I'm interested in this as well since I have the same setup minus the safc.

 

yes i have an AEM. Thats where i was getting my readings. Used to be in the 12.5-13 now it stays at 14-15 all the time.

 

I think you you need to add fuel. You went from 12 parts of air to 1 of fuel to 14 to 1. Or is that backwards?

 

thats correct. Im just wondering y headers u need to lean it out and with me adding a bigger exhaust i would need to richen it. Unless the bigger exhaust is making the engine suck in more air but the fuel is the same in that respect i guess adding more fuel would be the right approach

 

My car has always been rich, even with the 3" MAF. It was when I went with the LRMAF when it decided to get lean.

 

At first i thought the SAFc wasnt working correctly. Ill try adding fuel and see what happens