You are looking at custom machined Del West one piece forged Titanium valves. This full set of 24 Valves (12 Intake and 12 Exhaust) come with custom titanium retainers (24 pieces) and titanium keepers (48 pieces). Keepers are also called "Locks" by some engine builders.
Rallyroad.net is the only place you will find these Titanium Valves! Retail price for a new titanium valve from a company like Del West is over $100 each. Normally, a set of titanium valves with retainers and keepers would cost more than $2750.
These valves have been re-machined from slightly larger larger Del West valves used in the Honda Indy Engine Program. Valve head surfaces have been machined with a custom profile while the valve stems retain their original Chrome Nitride and moly coatings.
Titanium valves are extremely durable and generally weigh 40% less than steel valves. The decrease in weight allows a stock valve spring to be used in place of a higher rate spring or after-market dual valve springs. The benefit is increased horsepower due to camshafts requiring less force to depress the intake and exhaust valve springs. The decrease in valve train mass reduces the tendency for the valves to "float" during high rpm events.
Stock Intake Valve = 48 Grams
RR Titanium Intake Valve = 29 Grams
Stock Exhaust Valve = 48 Grams
RR Titanium Exhaust Valve = 29 Grams
Stock Steel Retainer = 8 Grams
RR Titanium Retainers = 5.5 Grams
Rally Road Inc. has worked with cylinder head and valve experts to create a valve head profile to maximize air flow. Upon close examination, the intake valve has a different head profile than the exhaust valve. Intake valves have a sharp edge to promote air flow from the top side of the valve. They exhaust valves have a rounded edge to increase air flow from the bottom of the valve out the exhaust port. The custom machined titanium retainers are a "snap fit" into the valve spring to eliminate harmonics which can be caused by sloppy fitting retainers (the OEM retainers we test fit had a sloppy fit). It may be overkill for the RPM range that the M5X series engines operate within, but it is this attention to detail which we take pride in providing.
Compare the price of these Titanium valves, retainers, and keepers to the other options available and you will realize what a bargain these are. Ferrea® Titanium retainers alone will cost $350+. Stainless valves do not offer the weight savings and increased RPM range provided by Titanium valves.