SE550 at 6400' elevation
 

Noob question..

i took my SE out over the 4th of July weekend. I had it out at Gold Lake (Plumas County, NorCal) and Donner Lake. Put a few more hours on it while waiting for appointment to get all the issues addressed.

I was pretty stoked about one thing. I've never surfed. Nobody on the boat had surfed, yet I got up on the third try! Can't wait to spend some more time on it.

With 6 people in the boat and full ballast, should the boat be able to get on plane? I tried it in wake board mode (cruise on) and with the cruise off. Wide open throttle at either setting would net 3800-4100 rpm, nice view of the sky and like 16-18mph. Seemed to run fine when empty.

Just curious. If that's normal then thank goodness I have the 550 not the 450. About 1/2 the time I'm in the Sierras.

I have had mine at 4200 feet with no issue, but Gold Lake and Donner, those are up there. If you plan on being up that high a lot, you will want to re-prop.

John

Which prop are you using on the SE550 2773 also are you adding more weight then stock ? I have a 2016 SE450 in NorCal with the 2775 prop and i want to get a little more aggressive prop since i have bigger bags and lead in the boat. It really comes down to do you want to go faster or have a better out of the hole response while weighted and surfing. Actually going to call ACME and see what the next step is over the 2775 Prop ( SE550 High Altitude prop ).

https://www.wakemakers.com/supra-wak...oat-propellers



Just spoke to ACME and if you are looking for the next step up from the 2775 prop it would be the ACME 2951. Each prop step up you are going to loose about 1 - 2 mph on your top speed.

https://www.wakemakers.com/acme-2951-propeller.html

Not sure about the 550 but my 450 will not plane out with 6 people and full stock ballast, and that's in TN with no real elevation and an ACME 2079

Matt

Which gas octane are you using ? I was talking to someone yesterday and they did say if you are running just 87 it will make a little less power and you should run 89 or higher especially at higher altitude.

One thing to thing about if you have a full tank of gas ( Supra SE holds 83 Gallons ) 6.4lbs per gallon X 83 + 522.9 pounds. It definitely seems to pull out of the hole with 1/2 of tank of gas much better.

I just pulled the trigger on the Acme 2951 for my second prop to keep in the boat. Typically we don't do a ton of cruising around and mainly float or are surfing. Once i get it i can report back and give some feedback.
https://www.wakemakers.com/acme-2951-propeller.html

Wakemakers is the cheapest for props that i have found and they don't do coupons or discounts on props.

Dave,

I only run 93 and occasionally 93 no ethanol. Definitely a lot more weight in there with a full tank. I was told by SC that their new prop recommendations for the SE is either the ACME 2775 or OJ 945. Not sure if that is for the 550 as well but they told me those were the best for mine. I upgraded to the 2079 in the offseason so maybe one day I will go with one of those.

Thanks for the info!

I'm pretty surprised to read that the 550 is having problems using 93 octane, one would figure that some of the HP being lost due to elevation would be mitigated by the forced induction.

Either way, it's a pretty big no-no to run anything except premium fuel in supercharged engines.

Where'd you see that?

There are labels on the engine and there is info in the manual. Here is a screen shot from the 2017 Indmar manual. I got this from the 2017 Raptor engine manual page 2-3 on the Indmar website.

Very intelligent and interesting convo!

I was at the Indmar factory in May, and interviewed them. That was one of the questions. The answer was clear, always use high octane in the Supercharged engine or you will have problems.

Lovely California. Can't get good gas here, it's all 91 octane and oxygenated.

What I need is a Cummins conversion! 1200lbs of motor, all the torque to swing a HUGE prop, great fuel economy. Just a little smelly...

Yeah - If I could put the non DEF, non DPF 5.9 Cummins from my pickup in my boat, that would be rad. Just run FAE. Engine makes a lot of heat, though, so I'm not sure how well suited it would be to the fairly tight confines and low airflow of an engine compartment sized like that of my boat. Still the low RPM torque and power seems like it would be just the ticket for a surfing-focused boat.

Cooling the Cummins wouldn't be all that difficult, just would require a pretty large heat exchanger and a big impeller to pull the water in. Heck they already have Marine versions of many of their engines.

https://cumminsengines.com/showcase-...rine&#overview

Here is the 6.7L cummins that has been marinized. Looks like it does not have DEF, and judging by the video it looks like it has a water to air intercooler.
https://youtu.be/stIV94vrMiI

now just takes some $$$