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-   -   Mercury's Turbo Engines (https://www.offshoreonly.com/forums/general-boating-discussion/221481-mercurys-turbo-engines.html)

alexgr8 02-21-2010 08:22 PM


Originally Posted by Rexx (Post 3051828)
Again, it has already been done at 9000 rpms. Do the research before raising the "it can't be done" flag. By the way, have you blown up a drive at 9000 rpm? Wondering where all this experience comes from. Oil lubed Bearings and gears of turbine engines run thousands of hours at 22,000 rpms

Turbines do not have gears turning that rpm that are vertical and horizontal. Do you know if those little boats were using a gear box let alone a brova 1 etc.

I feel where you are coming from but the truth is there are people with more money and time then us. Cant reinvent the wheel here.

No i have not blown a drive at 9k but seen many blown at 6500rpm. due the math.

Rexx 02-21-2010 08:39 PM

There is a tremendous science to bearings and gears. I've been involved with these details for many years in aerospace. Some drive transmissions I've worked have lasted over 20,000 hours in tightly optimized packages. Coatings and precision is everything in the world of longevity. I would be happy to share some wisdom. How about a coating that is 95 Rc hardness with coef. of friction at 0.09? Chrome is 70Rc and 0.2 coef. Friction. Chrome also likes to peel and Flake, especially at high temps. Gear cutting techniques like undercutting of the pitch diameter do worlds to reduce noise and heat. Some nicely ABEC classed bearings can handle very high loads at very fast rpms.

Regardless of the endless possibilities in refinement, Australian guy already ran a 900 hp triple, now he is setting up a Quad turbo rotor based on previous success. I'm sure he dealt with many naysayers along the way!

JasonSmith 02-21-2010 08:48 PM


Originally Posted by Rexx (Post 3051844)
There is a tremendous science to bearings and gears. I've been involved with these details for many years in aerospace. Some drive transmissions I've worked have lasted over 20,000 hours in tightly optimized packages. Coatings and precision is everything in the world of longevity. I would be happy to share some wisdom. How about a coating that is 95 Rc hardness with coef. of friction at 0.09? Chrome is 70Rc and 0.2 coef. Friction. Chrome also likes to peel and Flake, especially at high temps. Gear cutting techniques like undercutting of the pitch diameter do worlds to reduce noise and heat. Some nicely ABEC classed bearings can handle very high loads at very fast rpms.

Regardless of the endless possibilities in refinement, Australian guy already ran a 900 hp triple, now he is setting up a Quad turbo rotor based on previous success. I'm sure he dealt with many naysayers along the way!

If you want to truly do something for the marine industry take all that smart guy sh!t you are spouting off & make Bravo XR gears last longer than a few hours in high HP applications.

Rexx 02-21-2010 08:52 PM

Yes, in our turbine engines we indeed have tapered roller bearings and beveled gears running thousands of hours under max load @ 22,000 rpm. Our engines run horizontal in a hellacious vibratory environment and very high rotational inertia/gyroscopic effects. An these bearings are not small either.

Ball bearings for turbos....that is old news. I worked on magnetically levitated bearings 14 years ago to replace failing roller bearings.

I'm not BS'ing here. Aerospace techniques would revolutionize the marine industry. Just look at how the old (1960's design) t-53 lycoming push go-fast boats past the 200 mph mark with great reliability!

If you say it can't be done, then I'll know that you won't be doing it and will be the first to remind me if I ever take on the endevour.

Rexx 02-21-2010 09:12 PM

Yes, the australlian dude used a bravo xr on the 900 hp/9000 rpm triple rotor. I can see the issue of not passing 6500 rpms with a big supercharged v8. Excessive torque is the issue there. IMCO already makes upgrades for the bravo to handle the big v8 beasts. High torque puts huge gear teeth bending into the gears. High torque also causes bearing positional changes which not only affects bearing wear, but higher contact stresses on the gear teeth.

All this is why I firmly believe a higher rpm/lower torque/higher horsepower is the better direction to go.

Brad Zastrow 02-21-2010 09:12 PM

Didn't the auto manufacturers abondon rotary engines because of the poor gas mileage? I think a big hp rotary has to really consume fuel.

JasonSmith 02-21-2010 09:19 PM


Originally Posted by Rexx (Post 3051858)
Yes, the australlian dude used a bravo xr on the 900 hp/9000 rpm triple rotor. I can see the issue of not passing 6500 rpms with a big supercharged v8. Excessive torque is the issue there. IMCO already makes upgrades for the bravo to handle the big v8 beasts. High torque puts huge gear teeth bending into the gears. High torque also causes bearing positional changes which not only affects bearing wear, but higher contact stresses on the gear teeth.

All this is why I firmly believe a higher rpm/lower torque/higher horsepower is the better direction to go.

IMCO uses Mercruiser stuff in the SC drive. They break. They break a lot.

BigSilverCat 02-21-2010 11:14 PM

1 Attachment(s)
the turbos mercury is using on there twin turbo engine may be able to supply the 1300 hp but they would probably have to redesign the engine to make much more.. we have tried small turbos before and they make really good power to a point and then they cannot supply enough air...

now this turbo will supply enough air to do however much hp we want.. ok come on with all the stuff about how we will not be able to spool it.....

BigSilverCat 02-21-2010 11:19 PM

4 Attachment(s)
while im borred tonight i might as well put up a couple things i'm making for this twin turbo engine..

here is a little idle air valve block to hold two idle air valves in a small package that will be on this engine.. if any other engine builders need an idle air block let me know and i can make you one of these..

Young Performance 02-21-2010 11:27 PM

2 Attachment(s)
Looks nice Tyson, but already got one.:drink:

Top center of the first pic. Uses a little K&N filter. I tried the brass, stone looking filters but they get clogged up with belt dust to easily.


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