Replacing the stock delivery valves in your 12 Valve can substantially increase the low end power and fueling, in turn aiding in turbo spool up. The 191's are one stage above the stock 181 delivery valves on the later model 12 valves to aid in fueling larger injectors.
*All Industrial Injection Performance Products Are Not Legal For "On-Road", "Off-Road", or "Dual-Use". These Products May Only Be Used In " Dedicated Competition Use Only" Vehicles. Compliance With State and Federal Emission Standards Is The Consumer's Responsibility.