Mercury 115 ProXS 4 stroke

[RangerRic]

Anybody running or have performance info/thoughts for the new 4 stroke 115 ProXS ?

Sorry wrong forum -

[PECo]

I recently bought a 2017 Triton 179 TrX with a Mercury 115 Pro XS that has the standard gearcase, NOT the Command Thrust gearcase. The motor came with a 20 pitch Laser II three-blade prop. The boat felt bogged down when coming out of the hole and the motor never got close to 6,000 rpm, let alone the 6,300 for which it's rated at WOT. I swapped out the Laser II for a 19 pitch Spitfire X7 four-blade prop. I think that the Spitfire X7 should have been the OEM prop. The boat comes out of the hole much quicker and acceleration is much more linear. A couple of days ago, I found some smooth water on the Connecticut River and, fully loaded with 450 pounds of fishermen and 20 gallons of fuel, the boat ran at 50.4 miles per hour GPS. The river was running high and there was a lot of floating debris, so I failed to take note of the rpm at top speed, but I glanced at the tach and it looked closer to 6,000 rpm than I had previously seen it. I have only 5.6 hours on the motor, so I figure that I'll get more out of it as it breaks in, and the air and water warm up.

[RangerRic]

That 50+ is mighty good for a yet-to-be-broken-in 115.
Congrats!

[bassin70]

I've got the 115 Command Thrust on '17 Ranger 175, 24 Tempest I've topped out with everything perfect and full tanks/load and me 48mph, can hit 46 anytime. No plate. Sips the fuel too.

[RangerRic]

Sounds like a lot of prop for a 115 - speed looks good, though.
Are you getting around 5800rpm at WOT? Any plans for a plate?
Always wondered about plate effectiveness at under 150hp and
I am running a 2 stroke 115 sans plate, myself.

[Lowerider58]

Sounds like a lot of prop for a 115 - speed looks good, though.
Are you getting around 5800rpm at WOT? Any plans for a plate?
Always wondered about plate effectiveness at under 150hp and
I am running a 2 stroke 115 sans plate, myself.

The Command Thrust gear case has a different gear ratio and is geared to turn the higher pitched props.

[JOE54]

and larger diameter too

[RangerRic]

re: Command Thrust: Thanks for the info - sounds like that could boost performance.

[PECo]

Since my last post, I've added a port-side console and fishing seat to my boat, so it's a little bit slower, now. Here's a screen shot of my VesselView Mobile from a recent trip, fully loaded with 450 pounds of fishermen and at least 13 gallons of fuel:


Here's a prop slip calculation using that data:

[Javelin 180]

So is the Command Thrust suppose to be faster ? Or what is the difference ?

[JOE54]

much better prop selection also with this gear case

[PECo]

So is the Command Thrust suppose to be faster ? Or what is the difference ?

Command Thrust is the new name for Mercury's Bigfoot lower unit. Basically, Mercury took the lower unit from a 150 and put it on the 115, so that it could run larger diameter props. The gear ratio goes from 2.07:1 on the standard gearcase to 2.38:1 on the Command Thrust gearcase. The Command Thrust lower unit weighs a little more (four pounds, I think) and the torpedo is larger, so it creates more drag. In automotive terms, it trades some horsepower for more torque. Theoretically, it could get out of the hole faster than the standard gearcase, but would sacrifice some top end speed.

My boat has the standard gearcase and, although it's on the bigger side for the motor with a length of 18-1/2 feet, beam of 91 inches and hull weight of 1,202 pounds, it gets out of the hole just fine with a Spitfire X7 19-inch pitch four-blade prop and still pushes the boat at 48-1/2 miles per hour, fully loaded. But, as always, your mileage may vary.

[jaymaharg]

I have a 2017 Triton TRX 179 with the Merc 115 Pro XS Command Thrust. Currently running a Tempest Plus - 24 pitch. Pretty much same boat as PECo but CT lower unit. These numbers are based on speed over ground from my Lowrance GPS. The claimed weight before adding people, gear and fluids is claimed to be just above 1200 lbs. I run tournament ready with a full tank on this run (26 gal) - I had run about 2 miles before opening it up.

I run at 6000 RPM and my speed is 53 mph. Hole shot is pretty good too but it's a 115 so I knew I'd trade some for efficiency. I've run the numbers for the CT lower unit based on my numbers and depending on what I am looking for, it has me at 23-25 pitch. I've been looking at a Fury 24 as they claim to have the best hole shot, minimal drag due to blade thickness, and increased top end speed. The prop calc thinks I can get 57.8 mph max, hell - at 53 now, if the Fury picks up a couple and the hole shot is better I think I'll settle.

Based on other anglers I have spoken with - the CT lower unit can give a performance gain and I anticipate that is mainly driven by the use of other props (from the 150+ classes) and where the gearing has shifted to compensate and realize the potential.

Anyway you look at it - my Merc is super quiet, very torquey (4-stroke trait), sips fuel, plenty of power to run at 40+ mph all day, can't think of a single complaint - maybe no more filling oil? ha, no...