30 Degrees F motor/water box temp reduction, reduces intake air temps by about 15 Degrees F, 85% less water going to water box which increases acceleration noticeably, decrease in temp helps balance fuelling at ECU since water temp sensor is located in exhaust water jacket so rich condition late moto fade is eliminated.
I had the R&D kit on my ski. It broke because it used the stock water exit as a water intake which caused a failure, and a tow up the river. I usually like R&D stuff. I then got Trey’s kit. It is much better. Noticeable difference in performance. Also almost no water in the exhaust and somehow runs cooler. Easy directions, obviously well thought out. — Jason from Facebook
We spent many hours testing in test tank and on water with many sensors on motor two summers ago when Mike Kelberer came to me complaining his ski was fading 1/2 way through motos.
Thanks Trey StJohn @ MPS for the water reroute/pipe dry out kit. Made my SXR 1500 total different machine! After my ride I went to blow the typical 2 gallons of water from the water box, instead one dixie cup! Popped the hood - motor cool as a clam! THANK YOU! I was a little sceptical putting this one on - NOT ANYMORE! Genius status for the peeps that figured that out.— Tina from Facebook
In my engineering opinion the OEM cooling routing on the 15F motors is one of the oddest things I have seen in my 35+ years in the jet ski world, hence the SXR1500 Water Re-route Kit.