1988 242 ls?
08-19-2019, 09:15 AM
#31
Im sure you guys remember a while back when user zackevans6.7 was looking at this boat.
https://www.facebook.com/marketplace/item/618002172053281/
Look at the block and verify that is has 8.2 on it. It isnt impossible that someone put the mag mpi intake on the 330hp 454. We have seen stranger things happen. Your speed is dead on what a 330hp engine pushes these boats with a 23 mirage plus at 4800rpm. That works out to a 21% slip which isnt too bad.
I dont want to seem like an ass, but I dont want you to be mislead either. The 502 mag mpi was a 435hp 8.2(502 ci) engine. That power would easily push you into the low to mid 60s with a full tank and a few friends on board.
https://www.facebook.com/marketplace/item/618002172053281/
Look at the block and verify that is has 8.2 on it. It isnt impossible that someone put the mag mpi intake on the 330hp 454. We have seen stranger things happen. Your speed is dead on what a 330hp engine pushes these boats with a 23 mirage plus at 4800rpm. That works out to a 21% slip which isnt too bad.
I dont want to seem like an ass, but I dont want you to be mislead either. The 502 mag mpi was a 435hp 8.2(502 ci) engine. That power would easily push you into the low to mid 60s with a full tank and a few friends on board.
try hitting the tilt button a few taps when at full trim. You could have the trim limit set too low. That may get you a few more mph 🤔
Last edited by oconnor marine; 08-19-2019 at 09:24 AM. Reason: More to say
08-19-2019, 01:08 PM
#33
Registered
Blue vs black= an original blue hp500 was a 500hp 502: black could be pretty much anything really. Blue was the high performance where black was the normal engines.
Slip is the percentage of "slip" the prop has. In a perfect world with 0% slip a 21 pitch prop would travel 21" in one complete revolution. Slip is the actuality that it does not. Slip is good and bad read more in this link.
https://teaguecustommarine.com/teagueblog/how-to-correctly-determine-propeller-slip/
Slip is the percentage of "slip" the prop has. In a perfect world with 0% slip a 21 pitch prop would travel 21" in one complete revolution. Slip is the actuality that it does not. Slip is good and bad read more in this link.
https://teaguecustommarine.com/teagueblog/how-to-correctly-determine-propeller-slip/
08-19-2019, 01:13 PM
#34
Platinum Member
Platinum Member
iTrader: (2)
The black engines are GM industrial engines that have been marinized by Mercruiser (as well as other OEMs). They use production line parts that are pretty much interchangeable with their automotive/light truck cousins. The "Magnum" engines are the higher-performing offerings before getting into the "blue" engines.
The "blue" engines are custom-built by Mercruiser's performance line, Mercury Racing. They are blueprinted and hand-built using aftermarket performance parts.
The engine in the boat is the standard Mercruiser "black" set up that someone painted with Mercury Racing's blue paint (or a color close to it anyway).
TZ
The "blue" engines are custom-built by Mercruiser's performance line, Mercury Racing. They are blueprinted and hand-built using aftermarket performance parts.
The engine in the boat is the standard Mercruiser "black" set up that someone painted with Mercury Racing's blue paint (or a color close to it anyway).
TZ
08-19-2019, 01:35 PM
#35
Platinum Member
Platinum Member
iTrader: (2)
21% slip isn't awful, but it isn't all that great either.
A number of things can contribute to slip: prop condition, drive condition, boat bottom, drive trim, water conditions.
My 242 ran 50-54 with a 23 Mirage Plus and a 454 Mag in flat-calm water. But she ran 57-58 in a good chop. What I'm getting at is that these boats need choppy water in order to reduce the wetted surface in order to get speed. I suspect that water conditions are a part of your issues.
A number of things can contribute to slip: prop condition, drive condition, boat bottom, drive trim, water conditions.
My 242 ran 50-54 with a 23 Mirage Plus and a 454 Mag in flat-calm water. But she ran 57-58 in a good chop. What I'm getting at is that these boats need choppy water in order to reduce the wetted surface in order to get speed. I suspect that water conditions are a part of your issues.
