Evo Forum

[Warrtalon]

As I said above, you don't have to get tuned for an exhaust. There is much more to life on an Evo than the exhaust. yes, it is a fundamental building block, but there are many other areas to mod that make you faster, and many of those other mods DO require a retune. You don't normally get a flash first, because you don't want to have to reflash multiple times if you can avoid it, although with Dynoflash, mail-in reflashes are only $100 - not a big deal.

A flash reprograms your ECU and is able to directly control every ECU parameter, such as rev limiter, high/low octane fuel trims, high/low octane timing, launch control, fuel cut, idle, etc etc. The flash reprograms the code directly and can be reflashed at anytime to anything you want.

A piggyback intercepts the signals going to the ECU, then modifies them. For instance, in the case of AFRs, a piggyback will intercept the MAF signal (air flow), change the value, and thus cause the ECU to think there is more OR less air crossing the MAF, which in turn changes the AFRs however you want. With a crude piggyback, such as the SAFC, doing changes in fuel like that indirectly cause changes to the timing based on the ECU's preset timing tables. More sophisticated piggybacks, such as ECU+ and Xede, are able to more directly affect timing, but not as directly as a flash. Piggybacks cost much more, but they do allow you to tune yourself granted you have the proper monitoring devices and know-how. The worst is when people spend $1000 on a piggyback then pay someone else to tune it - that's just a shame.

With the flash, unlike in the past, you can now maintain multiple maps (race, street, drag, valet, stock, etc) and flash them in yourself whenever you want if you get the new flashing cable and free software. That used to be the flashes only deterrent - one map that couldn't be changed. Now, that is a thing of the past, so flashes are really the ultimate tuning method.