The new Solas Concord YS-CD-11/15 blows away the performance of your stock impeller! Large blade area and superior hub design deliver increased acceleration and top speed. This 155mm diameter, YS-CD-11/15 The YS-CD-11/15 Solas Concord Impeller is also used in our Yamaha FX HO Stage 1 Performance Kit. impeller is designed for modified Yamaha applications with 1.8L HO engines.