New light 200 rumored
- Thread starter xb03fs
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Clarify this for me then: What is the difference between a standard gear/worm/belt supercharger and the air compressor on an optimax?
GotMyAlly
Well-Known Member
The air compressor on an optimax builds pressure in the fuel rail, not the intake like a supercharger would.
The supercharger is like a turbo a power/torque adder, where as the compressor as some describe it is power subtractor...
Its why a 300 XS even with extra displacement isn't as strong as a 300 X and why even thought porting is similar a 200 XS is more promax power than 280 power.........However the XS motors due benefit in throttle response due to direct injection....
Really my preference is a larger displacement motor like the 150 Fourstoke/Yamaha SHO variety, simple, less expensive, reliability with less things to break and of course AS LIGHT AS THEY CAN MAKE IT....if they just add two cylinders to the 150, it could mean a 4.5 L, or if they increase displacement to make a huge 4 cyl that could be cool also.....a 3.5L-4.0L 4 cly wouldn't hurt my feelings if it was light.
Its why a 300 XS even with extra displacement isn't as strong as a 300 X and why even thought porting is similar a 200 XS is more promax power than 280 power.........However the XS motors due benefit in throttle response due to direct injection....
Really my preference is a larger displacement motor like the 150 Fourstoke/Yamaha SHO variety, simple, less expensive, reliability with less things to break and of course AS LIGHT AS THEY CAN MAKE IT....if they just add two cylinders to the 150, it could mean a 4.5 L, or if they increase displacement to make a huge 4 cyl that could be cool also.....a 3.5L-4.0L 4 cly wouldn't hurt my feelings if it was light.
So the optimax actually has air injectors that do run through the back end of the fuel injector via the fuel rail. Its still pushing pressurized air into the cylinder, but not via the intake.
I don't think running up fuel/air pressure to 100+ psi would subtract from the power. Thats actually the same design that BRP (Bombardier) uses in their snow mobile and jet skis, and is how they make so much power from such a small engine.
I don't think running up fuel/air pressure to 100+ psi would subtract from the power. Thats actually the same design that BRP (Bombardier) uses in their snow mobile and jet skis, and is how they make so much power from such a small engine.
TB21
Active Member
The Opti air comp takes like 15-20 crank HP to spin it....It has no air injectors and it is not pressurizing the cylinder , just the fuel rail.
15-20hp to spin a tiny cylinder? That seems a bit excessive. Its just an air compressor. I just looked at my 200XS and it looks like it has air injectors. I'm trying to find the microfiche to find out what merc actually calls them, but there is definitely 2 injectors per cylinder. One is outside the fuel rail and one is between the fuel rail and the head. Again, let me see if I can find a pic for further dicussion.
I've heard of pre 2005 200XS failures because of the lack of rigidity of the mount. I have not read about many of the 2005-6 models which had issues though. Have you? I also have seen some newer opti's with issues.
I've heard of pre 2005 200XS failures because of the lack of rigidity of the mount. I have not read about many of the 2005-6 models which had issues though. Have you? I also have seen some newer opti's with issues.
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TB21
Active Member
It's a fairly good size comp. with a fair amount of displacement , 15-20 may be a tad high , I don't know the exact loss. And the newer engines don't have trouble with comp failures.
Much better for sure but when you hear of a failure it is a failed compressor getting debris in the injections causing the motor to lean out then fail.
Per one of the techs on another website if you dhave not plan to use your boat within a weak it's best to put a few drops of oil in the compressor and try it to prevent rust.
According to some on screamand fly there's are still issues with one of the bearing surfaces being improperly hardened which still causes premature failure
http://www.screamandfly.com/showthread.php?227613-Mercury-Optimax-compressor-failure-Got-pics-of-the-bearing-just-about-to-fail
Per one of the techs on another website if you dhave not plan to use your boat within a weak it's best to put a few drops of oil in the compressor and try it to prevent rust.
According to some on screamand fly there's are still issues with one of the bearing surfaces being improperly hardened which still causes premature failure
http://www.screamandfly.com/showthread.php?227613-Mercury-Optimax-compressor-failure-Got-pics-of-the-bearing-just-about-to-fail
I saw A number that said 80psi output, and it has a regulator, so it can put out max psi at lower RPM's. I'll get some more specific numbers on the pressure vs rpm and map it out. I'm interested to see what its actually putting out, and when. It appears to be the size of a 100-125cc motorcycle cylinder. I also wish I had one to crack open to measure displacement and we could determine the exact hp to crank it over to 80psi (if that psi is accurate).
Thanks for the advice and link on the oil in the compressor.
This is my last hijack of this thread. Just put a stupid turbo on the motor and be done with it :smile
Here is the air injector and fuel injector.
This is my last hijack of this thread. Just put a stupid turbo on the motor and be done with it :smile
Here is the air injector and fuel injector.
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brotherxb03
Active Member
The compressor on a opti mainly fails from lack of cooling due to grass or trash stopping it up, that's why they make a water strainer for it.
ziemer
Active Member
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Probably not, but the 400 lb V6 2-stroke is all but dead as a mass-produced motor from Mercury.
The supercharged 4-stroke is currently the only option and in order for it to be comparable in weight to the 2.5, you have to look at the inline 4 cyl. It stands now at 510 lbs. I'm sure with a light weight cowl and some other weight loss measures they could get it down to 450. 250-300 hp is probably fairly easy with some more boost and ECU tweeks.
I think we're overthinking this... lets just start casting our own 2.5's 
https://www.mercurymarine.com/en/us/unleashed
3 videos and I am going to be optimistic and guess 3 new products...
upping the ante video ...maybe the leaked 400 HP verado seen on the X-Cat
changing the game video...maybe new 4.5 L fourstroke digging at yamahas "gamerchanger" marketing of the SHO motors
Leading the pack video ....some crazy inboard for the poker run crowd.........
Unfortunaly the EPA is not going away. California has already banned all non-DFI/fourstroke motors...really we are lucky it hasn't happened elsewhere.
I am nearing the chance to repower soon so I am hoping for something great under 505 lbs with a sporty
3 videos and I am going to be optimistic and guess 3 new products...
upping the ante video ...maybe the leaked 400 HP verado seen on the X-Cat
changing the game video...maybe new 4.5 L fourstroke digging at yamahas "gamerchanger" marketing of the SHO motors
Leading the pack video ....some crazy inboard for the poker run crowd.........
Unfortunaly the EPA is not going away. California has already banned all non-DFI/fourstroke motors...really we are lucky it hasn't happened elsewhere.
I am nearing the chance to repower soon so I am hoping for something great under 505 lbs with a sporty
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So do you think they will do?
Add two cylinders to 115 class? Doubt it as that's only 3.15 liters
Add two cylnders to 115 class and increase stroke to get higher displacement and keep the engine somewhat short?
Add two xylnders to 150 class motor and have a 4.5 liter huge tall motor
Add two xylnders to 150 class motor and shorten stroke to rev faster.....
Add two cylinders to 115 class? Doubt it as that's only 3.15 liters
Add two cylnders to 115 class and increase stroke to get higher displacement and keep the engine somewhat short?
Add two xylnders to 150 class motor and have a 4.5 liter huge tall motor
Add two xylnders to 150 class motor and shorten stroke to rev faster.....
Bobalouie
Active Member
No, Mercury will do what Merc has done for the last decade: Build a pig fat motor that weighs 550+ lbs with 50 more HP and call it good. Which wont help us one bit. You have to think of Mercury as a bells and whistles company, at least that was the biz model when I was working there. If someone else offers an engine that was 500 lbs and 250 hp, then Merc would design something similar, add some stuff to it and end up at 525lbs and 275HP.
My guess is that with all boats getting bigger, the pontoon market stronger than it ever has been, and the economy being what it is, we are going to see that engine weight doesnt matter to mercury any more since the bigger boats can handle it. Thats where the money is thus thats where Merc will be heading.