
Originally Posted by
mmmkay
I was running the 3337 (16x15 with 0.075 cup) on my 2020 SL400. We run full ballast, 500 lbs of lead (all towards the back to get the nose up to about 9.5 degrees), and a crew of 6-8 adults. Had no problems surfing 11.4 mph at 3k feet of elevation (3750 RPM +/-150 at depending on load and pitch), but fully weighted on a hot day we could not plane out. We don't wakeboard so this is not usually a problem for us. But, we took the boat up to 5k feet of elevation and it could barely hold 10.0 mph fully weighted. We came prepared and pulled the boat out to put on a 3409 prop (16x13 with 0.150 cup) and it solved all of our problems! Shockingly surf RPM is exactly the same but we have more holeshot, it gets up to speed faster, is much more responsive, and if we hit a wave it can easily temporarily rev above 4k to maintain speed (something the 3337 could not do). We can even slowly plane out fully loaded at 5k feet now. I was not expecting that out of the 400 motor - thank you Supra Launch! Fuel efficiency for surfing is also slightly improved - went from averaging 7 gph to 6.5 gph. Even though it's running the same surf RPM, the motor sounds like it's not working as hard and is slightly quieter. Top speed dropped from 37 to 34 mph so fuel efficiency while cruising at 25 mph (3800 RPM vs. 4100 RPM) has gone down but it's a small price to pay for a WAY better set-up. I highly recommend the 3409 for anyone with the 400 motor and 1.76 transmisison. I was originally planning to only use this prop when we were boating at elevation but we're leaving it on all the time now. Even at 3k feet it's a noticeable difference and much better.
This is awesome, sounds like the 16x13.9 .105 cup will be a good choice under 2000 feet
Sent from my iPhone using Tapatalk
2021 Supra SA 400
2018 Supra SA 400 (SOLD)
Michigan