Just bought a 255LPM Walbro Fuel Pump and a Fuel Pressure Regulator, just wondering what a good setting would be for best performance and best fuel economy. For a 91 Civic 1.6L

 

Best performance and fuel economy setting is to put the stock unit back on. Adj. units are crap and will do more harm than good.

 

I agree. The stock fuel pressure will be best for mileage because Honda optimized the design for mileage in the first place. If you change the fuel pressure, the ECU will just fight back by changing the drive to the injectors.

Also there's nothing wrong with a stock pump, it pumps way more gas than the engine can ever use.