Should I get a Warranty -- How many issues have you had?

grandpawmoses

If, after the exhaust and intake mods, everything seems to run okay, there is a cheap way to tell if you're running too lean. Warm up the car, Run it hard for about a mile, shut it down & coast to a safe stop, immediately remove a spark plug and check its' insulator color. Black is too rich, white is too lean, and tan is what you want to see. If it's white, get it tuned immediately.

For what it's worth
Not to justify the cost of a tune but it involves a lot more than just getting the air/fuel ratio to a stoich AFR(about 12.7 AFR for 91+ octane fuel in a naturally aspirated engine). It also involves timing, spark knock retarding, cold cranking enrichment, acceleration enrichment, and deceleration enleanment to name a few. The AFR is adjusted for each cell in a table of throttle positions against engine RPM's. This is done for each cylinder too. The dyno technician really needs to know his stuff and will still take over a dozen wide open throttle runs even with todays computer assisted tuning software. Also, get a copy of the tune or "map" on a thumb drive & keep it. It'll save you some money if you ever need to reflash your ECU.

njobe89

i'll be going to z1 motorsports, everyone seems to agree they are well trusted, but i will ask for that when i go and see them.

is this the general rule for every car or just the Z's? i had a rsx-s before with some bolt on and never did a tune on it or anything and it went fine for the time i had it.

grandpawmoses

Just general for ECU controlled gas engines. Older carbureted engines were adjusted with modifications to the carb jets.

More worthless info
Most all water cooled engines (cars and bikes) have wide band O2 sensors and they do a decent job of telling the ECU to up the fuel with minor exhaust and intake mods. (A water cooled engine has a narrow band of engine temperature and can use a wide band O2 sensor.) They still need adjustments to their "map" (or tune) for timing, etc. to get the maximum horsepower. ("map" should not be confused with "MAP" or "Manifold Absolute Pressure" which is another factor the dyno tech has to deal with.)
Air cooled motorcycle engines have a very broad band of operating temperature and most use a narrow band O2 sensor. A tune is almost always needed with even small air flow mods. I've closely followed Harley Davidsons' transition to water cooled engines on their touring bikes and believe it was an inevitable move by HD. With stricter EPA restrictions looming, it was the only route.