I have a 12 5.0 that I rarely drive,...once a week at most. I have ordered the bassani catback with x pipe and was thinking of long tube headers as well but ran into some questions. This is my first mustang and I am an aircraft mechanic but don't know much about gas engines so please forgive me lol. I was wondering if installing headers will void your powertrain warranty? And if I do headers is it a must to have a tune? What's the negative about not tuning? I apologize if there's some cool guys here who are annoyed with the questions

 

I run a 93 tune on stock exhaust, Flowmaster 40 Series Mufflers, and the cats punched with the cat casings still intact. I notice a slight power drop off of the line but this could be because of the JLT 110mm Ram-Air intake I have on stock plugs. I also have stock headers and the car is outrageously FUN to drive. My car came to me without a warranty because I purchased from the original owner who got the car brand new. I can tell you that the "race tune" has my car running rich and when I first power the car up and might give it a rev, I'll get some small backfires due to unburnt fuel still sitting in the exhaust. After the car is fully warmed up it goes away and subsides but I can only imagine that potentially being an annoyance if running the car untuned. Another thing to remember is that you are putting money into aftermarket parts, isn't it ideal to get the most from them by having the car tuned for it? I know with the exhaust you are surely going to have issues with the check engine light of you don't shut the 02 sensors off..

 

That poor car - you must drive it more! Seriously though, welcome to the forum. As with any mod to your car, your warranty is not automatically voided. The dealer/Ford has to show that the modification you made contributed to whatever issue may or may not happen. So if your lower control arms fail, it's going to be hard to blame that on headers. But if you install a bad tune that leans out the engine too much and blows it up, that would not be covered.

I'm not sure about needing a tune or not with the headers but I would think to get the maximum power out of them, the answer would be yes.

 

Definately need a tune with long tube headers or you'll get a CEL and not get the hp benefits of the new headers. Also, in case you haven't already read about it the install is a pain in the azz.

 

You need the tune or it runs lean. I've got long tube and full exhaust. We put my car on the Dyno at Brenspeed to check Air Fuel Ratios to be sure. I am running an email tune from Steeda and it's actually runs a tad rich but tha is okay. With a full exhaust the throttle response is sickening fast.

My first Dyno runs had me at 418/395 SAE corrected on a dynojet in mid summer. Later in the fall I put down about 430/405. ( Need to verify exact # but I am not home). The car has ran a few high 11s but I have extensive suspension work. I need to practice launches since most of the runs are low 12s at about 116-119.