That's why I run a stock 28 B1. Less stress. (and better acceleration)

If he was going to do that then there would have been no reason to to install an 800HP engine.

Pat, we have not been able to be with the Y2K this past week.:(.. I am hoping to run her Thur. with the new XR upper.

Kendle, Tom I tried a 30 and the boat only ran upper 80's and way over the 5500-5600 Max RPMS. We had a 32 on her and she ran 92 @ about 4900 RPMS. My thoughts are we can take the 32 down to a 31ish or whatever it takes to get her at 5500 rpms., while also picking up speed. As for drives we are looking at the Max Worx set up for next year. If not a spare XR will be in order. Lets see how the new upper fairs.

I said until he figures out what to do. An XR is not going to hold up and no fun being far from home when it blows.

Gary ever try a hydromotive ? PE / Fast Eddie / Superstious use them. When my boat had a bravo drive the stock non lab bravo props worked best. I never tried a hydro.

Sure K, I got you. You've been there and done that...

I believe that Gary like most of you fellows that bolt big power up to a Bravo drive know the risk...:grinser010:
I also know G well enough that to suggest holding the throttle back to the power level he had before he spent all the time and $ on the 800 just isn't going to happen...:rolleyes:
G doesn't travel all that far from home and he's got Seatow and Boat US towing...:eek:

Hey G.
The 30p B1 prop you ran was a labbed prop, right?
The 32p B1 prop is a stock prop, right?
Run a stock 30p vs. a stock 32p and see which one is closer. They are typically 400rpm different but I have read the 32p B1s can vary a lot.
Then send the prop you like better to BBlade or Merc to be labbed. A prop can be altered to run ±300rpm.

Like others have said, you may also want to try some Hydro props. 30p QIV, 30p QIV-X, 29p P5-X.

Have fun and be safe!

I understand, my engine was built to run at 6000+ rpms. I did not know you where running stock rpm range. I wish I could have suggested building it to handle more RPMs. You would have loved it. Alot more flexability. I could run 90+mph with a stock 28 Bravo1. Ask if your bottom end will handle more rpm's after broken in. That would be a big plus in my opinion. If your worried about increased wear, it's not a big deal as long as you have the parts in there that will take it. :)

Pat, Mike, I did speak with Hydromotive, I for sure want to give one a try.

. Pat you are correct the 30 was a labbed prop. The new 32 is not labbed, so I hope to resume testing tommorow!!!!:grinser010:

Gary I Ran A 5 Blade Hydromotive On The Kryptonite And It Worked Great ,,And I Tried A Bunch Of Props,,I Still Have That XR Drive For Sale If Your Interested

Thanks Tom, I was not aware that the more top end RPMS avaiable would Reduce the prop size, someting I will check out with the motor builder. I thought the faster RPM motors would need rebuilds sooner ???

I bet the motor has a hydrolic cam. Thats Y the lower rpm range. My 540 likes 5900

Gary, I bet if you tried 5 different Merc 30's. You would get different results from each one. All props are not the same.

Dont mean to change the subject, but has anyone had any luck with a labbed merc Maximus. I have aB1 and a Max both 26P and want to get one labbed for the Y2K but cant decide on witch one, they both have good pros and cons. B1 4800RPM 69MPh GPS and the maximus is the same speed @4600.

Thanks John, getting my hands on a bunch of props is not as easy as the time merc racing had the box of props at Superboat to try out, I did not forget about your xr drive, I want to see how my mine holds up.:grinser010:

[QUOTE=Superbabi;2618196]Thanks Tom, I was not aware that the more top end RPMS avaiable would Reduce the prop size, QUOTE]


Higher rpm does not reduce prop size. The faster you spin the prop the faster you will go. Spinning a smaller prop faster may be less strain on the drive as apposed to spinning a larger prop slower.

Maybe, but not likely.
Torque is Torque no matter how you slice it.

One other thing to consider is the higher the RPM the more friction and heat which can hurt the drive too.

I highly doubt that spinning a 28p B1 at 4000rpm vs. a 30p B1 at 3733rpm vs. a 32p at 3467rpm makes much of a difference.

Now if you change the slip of the prop significantly, that could change things. A 5 blade will in all likelihood be harder on a drive than a 4 blade on and off the throttle...

I run a hydrolic cam but using good valvetrain control (jesel rocker assembly, custom cam, ect) Here is what I used http://www.jeselonline.com/v2/index.php?categoryid=12

I also had my Mustang spinning 6600 with hydrolic but that's not same as a boat.

Torque at 4000 rpm is not the same at 5400 rpm, where his builder said he wants WOT. I'd rather run a 28p B1 at 5400 rpm than a 30 at 5400 or a 32 at 5400 or any 5 blade for that matter. Sure he can spin a 28 to 6000 (just don't do it), but he won't blow the drive.

My point is why run a large prop and go WOT and blow the drive???? With that motor it is obviously not a matter of if!! Unless money is no object then by all means....run it like you stole it.

Use a smaller prop, don't go over 5400, enjoy the boat untill another drive option is figured out. Or, pull some power out of the motor. That's what I would do, and it's just my meaningless .02 cents. What do I know! :rolleyes:

I don't know about all the anylizing about how much a XR will take. I only have proof my set-up has withstanded 800hp since late 2005 including a 100 mile offshore race and I still have not done anything but change oil. I still think it has alot to do with throttle control more than anything. I always have one hand on the throttle. If you want to just hammer the sticks and forget about it then you better spend the big bucks on a massive drive.
Yes, a smaller pitched prop will have less stress than a larger pitch prop at the same rpm. It's obvious as small props push less water a the the same prop speed than larger props do.
Therefore my 28p has less stress than a 30p prop at 5400rpm, however the 28p probably has the same amount at 6000rpm. The same goes for cruising speed I would think.
The increased rpm and heat come into play with a smaller prop as said before, but that is negated by cruising just a little slower. But hey, I haven't had to worry about that yet.

All this talk about drives. Who uses what for drive oil ? Thats a big factor. Ive tried Amzoil and it expanded out of the overflow can where merc oil didnt. Dont know if thats good or bad but im back to merc with the new drive. Thinking about going to mobil 1 synthetic. That has to be worth a few since my drive hold like 10 quarts.

Kendal HP (Power) varies as a function of RPM since it is a calculated value from Torque and RPM.
The Torque produced by the engine is what is depending on the power curve of the engine.
In this case with 5500 rpm being the red line, your statement is probably correct, the engine does likely make a little more Torque at 4000 than at 5500. For sure, it makes a lot more Power at 5500rpm.
Your also saying that spinning a 28p prop at 5400 engine rpm (3600rpm at the prop) creates less load on the drive than if you spin a larger prop i.e. 30p or 32p at the same rpm; also true.

My statement was that a 28p spinning at 4000rpm (6000engine rpm) does not likely create less load on the drive than a 32p spinning at 3467rpm (5200 engine rpm); Bigger prop less rpm but propotional to the smaller prop at higher rpm... Same Speed as a Result...

We are not debating the same thing...:ernaehrung004:

K, your suggestion that G holds the power back to the level he had before is a little strange to me.
Don't you have like 750HP hooked to an XR? I know you put the hammer down from time to time.
Superbabi turned a 29p B1 at 5400 engine rpm with the 600sci.
No way could one of us get behind the helm after bolting in a new engine and not run it...:party-smiley-004:
Gary knew the risk of bolting 800HP to his 280hour old XR and I'm sure he's not surprised it went boom. Now with the new XR drive he'll see how much his stomach and wallet can take before he holds back with his throttle hand...
My guess is that he has already hammered it again...:eek:

Does this mean we're going to start thinking about surface drives again? ;)

You guys are Fuuunnny!:D Gary, just run it like ya stole it! (almost).

Zup, I run Merc oil.

Wise Guy !!! lol lol

Who luvs ya !

Pat, first part of your statement, very true, I did run hard. I also knew my XR was tired. We just put another 5 hours on the new upper and new parts lower, I have been running only 3000-4000 max for the time being.:( I guess we will have another winter project ( New Drive ). :D

[QUOTE=Pat McPherson;2619587]K, your suggestion that G holds the power back to the level he had before is a little strange to me.
QUOTE]

I never said go back to the power he had before

[QUOTE=Pure Energy;2621676]Nor did I say you did.

So K, are you going to be out east on the 26th?

http://www.offshoreonly.com/forums/s...d.php?t=187738

A little late for you G, but interesting...

[QUOTE=Pat McPherson;2623849]
Hold back, go back....same thing


The 26th, I hope so:ernaehrung004:

Pat, thanks I did see that thread, and they sent me a PM, looks like a nice way to bump the 600sci !!!!

Gary,know of any way to kidnap on of those NXT's (did I get it right?) from Merc. ?

Rick, I'm pretty sure the dealers are going to be breaking up the 700/NXT pkg. soon. So the NXT is perhaps another way to go. I believe merc does rate the drive at 800 hp !!!!

If so, I have a new drive I have just completed designed for single engine 30' and less boats. Well, it can be used for more than that but for this situation.

You won't have to worry about it breaking.

Rik, could you go into detail a bit ? ( Photos ), or should I give you a call ??

I'm dying to see a picture of this thing!

They are coming off the horizontal today.

I made a new rudder housing that accepts a "Bravo" style propeller.

This will give anywhere from 10-15 degrees more rake than I could get out of a Speedmaster propeller and we all know the cost obstacle when dealing with the speedmaster propellers.

The Maximus will fit also and this propeller has 30 degrees of rake.

This will allow a smaller boat that does not/can not handle a Cleaver propeller to run an Arneson without being burdened by a cleaver propeller.

The drive will have:

Less Stern Lift
Less Side Loading
Reduced Listing
Lower, FAR lower propeller cost and sourcing
Less "Man Handling" from the propeller

More Bow Lift
Less RPM to get on plane
Wider selection of propellers
Lighter propeller (if that matters)
Improved reversing, as the blade is not so blunt in the rear
Better tracking
More Propeller Rake. 25-30 degrees vs 15 for a Mercury Speedmaster.

For a small, or single engine application, this was an issue to some degree depending upon who's hull was being used. The propeller cost and selection was always an issue. Now with the high rake Maximus, the Bravo and others the advancement of technology has allowed us to take advantage of it.

hey superbabi...i think i saw you around the Seaside Bridge Friday...late afternoon

berns29, yes we were crusing around that time, just picked the boat from typhoon, what boat were you in ???:cool: