Mishri

Right you'll need to retune after any other mods. So you might want to wait till you do everything you want.

also, you can datalog your car and see where your AFRs are since you have a wideband sensor, that will tell you how far off you are from where a dyno tune would get you. or if you wanted to you can just put it on a dyno and see, that usually costs $100.

why dont you ask these questions in the 2005-2010 section? someone migth be abel to tell you how much they picked up from a dyno tune.

Stone629

No, you do not need to wait to tune after you do headers, etc. The first thing I did was tune my car (knew I was doing LTs eventually so had him go ahead and turn off rear O2's). I didnt do headers until several months later. Simple bolt ons will not throw a PCM controlled car's tune off. It will simply gain power. Your car's PCM is more than capable of making those adjustments to keep the car where it has been tuned to be. Parts like headers will not make the car run rich or anything (assuming the pre-tune was done correctly). The only mods you need to re-tune for are major mods like cams, F/I, nitrous, etc. All this is straight from my dyno tuner's mouth, not me.

Put it this way. You go get your car tuned. Your tuner bumps up the timing as much as safely possible, turns off any torque management or whatever nannies that you may not need, adds fuel or air where needed, etc. Ok, you're car is now tuned as aggressively as he felt should be done. Alright, you drive down the road and it pings a few times. No big deal, drive it a little longer and your pcm will add fuel where it is trying to ping and it goes away. Thats what it does, 24/7. Alright, now you go get yourself some headers and install them. For the first 30-40 miles the car smells rich. Do you need a re-tune? NO! Let the car adjust for it. Thats what it does. Your car is already tuned, so there is nothing more your dyno tuner can do to help. He has already maxed you out, so the headers are just added HP. I have always tuned first! Its by far the best gain for the money, period. My car ran a 12.5 with a lid, cat-back, and a tune. My TBSS gained 25 RWHP and half a second from just a tune. My S197 picked up something like 28 from an intake/tune. I've had hypertech tunes, Diablo, SCT, etc before. They suck, period. They are just good enough so you can safely run what you got, nothing more.

Mishri

I've read completely different info.. for example, you gain pre-tune whp, but you gain a ton more after a retune, like you might pick up 5-10whp off of headers w/o a tune, with a tune you pick up 20-25whp (talking about the 3 valve for instance) thats what about every report ive read said. doing mods without a tune is a waste of money. on the s197 exhaust is the only mod you can run w/o a tune that benefits from having a tune. others that get power from a tune, like CAI and CMDPs will cause a lean condition and limp mode. I'm not sure about the throttle body, perhaps that too.. anything that changes the intake can cause it to go too lean, exhaust however isn't a problem.

The big question here is on the 4.0 s197 does a dyno tune pick up much more whp than a canned tune from BAMA, from what i've read tuners like brenspeed and bama on the 05-10 mustangs get it pretty close to where it needs to be, not leaving much left on the table, people aren't picking much up off of a dyno tune, making it as much of a waste of money as a throttle body.

You can always call that shop that specializes in mustangs and see what he says about gains, then try to talk to local people who did an e-mail tune then a dyno, see what they thought.

Stone629

Exactly. What you're confused about is the order in which it needs to be done. My car will gain 15-20 RWHP with or without a tune, its been proven (not trying to get into exact gains, every car is different). You're not going to be able to run more timing or whatever simply because you add headers, pulleys, or an intake. Once you tune your car, it is tuned, end of story, Unless you're camming it, FI, nitrous, etc, there is absolutely NOTHING more your tuner can do for you after you add something like headers vs pre-tuning. If you want the biggest initial gain for your new car for less than $500 ($300 in my area), just tune it FIRST. Do your bolt-ons as your funds allow.

Mishri

you can adjust your fuel trims, especially in the 05-10 mustangs taht dont have wideband o2 sensors. Thats why they go into limp mode as soon as it gets out of range(too lean), you cant do a CAI without tuning your fuel for it on the s197. I believe that is also why they are able to add timing, with more air and fuel they can throw a little more timing at it but i coudl eb wrong, that could be done with the 93 octane tunes already, but i know the part about fuel is correct, getting the AFR where it should be with the less restrictive intake/exhaust. udps obviously cant be tuend for just like a driveshaft or gears, doesn't change the engine at all, just delivery of power. but for engine mods, yes i believe in a retune after every mod that changes how much air or fuel is moving through it.

the 11+ mustangs do have a wideband o2 sensor though and it can adjust fuel delivery even with a bigger change in intake/exhaust, like a cai didn't throw a code on my 11+, and with higher octance gas it automatically advances timing. (part of that is the ECU too) but an untuned for cai would put my 07 in limp mode.

Stone629

The S197 is the exception concerning the intake. Those cars only need a 2% change in intake flow to throw that mode. Headers will not have that effect on them (or gain jack for that matter on the 3V) with or without a tune.

What you're not understanding about tje A/F is that once you do headers, you dont need a tuner to adjust for them. The change in air flow, etc is well within the car's parameters to adjust for. By the time you install them and drive to your dyno shop, the PCM has already made the appropiate corrections. I'm telling you man, once you are tuned, thats it. There isnt anything else a tuner can do for you after a few bolt ons. There's nothing left to adjust that the car can't take care of itself.