is the nissan altima 2002 2.5L engine the same as the QR25? I am trying to install a turbo kit on an ALtima 2002 2.5L
The 2002 2.5 L is the QR25DE. Good choice on your turbo kit and good luck on installation.
Fuel management is the most important and also the most complex item with turbo charging. There are several ways to perform fuel management:
Management options are diverse. The cheapest option is the Rising Rate Fuel Pressure Regulator which automatically adjusts the fuel pressure according to the boost pressure; this is the most affordable way to provide the proper amount of fuel to a turbocharged engine, but are not the best. Digital options are the next step up, which include SAFC-II, AFR, and E-Manage. These are not terribly expensive, and provide the best fuel management for the money. These units digitally manage fuel flow, and provide excellent variability for the money. The next option is a chipped ECU. Jim Wolf Technology is the most famous provider of this service, but these are quite expensive and not user-reprogrammable. The best option is, of couse, stand alone fuel management. Stand alone is a complete ECU replacement. Companies such as AEM sell their EMS units which provide exactly what the name promises, All Engine Management. Stand alone is quite expensive, but can support extremely high horsepower applications while providing the greatest level of tuning flexibility.