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Correct, the SSM version will fit virtually any transmission / drive combination. We would need to check the input shaft specifications of the MG502 to see if they are the same as a Borg Warner 72C. If not, then we would need a custom damper plate. We also have a shaft mounted version that might be an option for you as well depending on your power levels.
Mike |
Originally Posted by Philm
(Post 4219926)
Gotcha, so each one is custom "tuned" for the engine package it is going on. The peak shock load will always be greater than the peak engine torque anyway, probably many times greater in some cases.
. Its not always the engine's power output at the flywheel that breaks drives, shafts, etc. For many years we've all associated that XXX HP is too much for XXX drive, or we've said things like, "an XR is fine behind a 525EFI", Each boat setup is different. Speed factors in, water conditions factor in, prop blade count, diameter, slip factor, weight of the boat, all factor in. If flywheel HP was the only definitive of breaking drives, we would never have the scenerios like, Guy #1 "Well I got 100 hours out of my XR drive behind my 525 before it broke", Guy #2 "well I got 300 hours from my XR behind my 525 before it broke" The flywheel output is the same, but that doesnt mean that the drivetrain is seeing the same torque levels. I think its been proven, that say a stock XR drive, can take 525 merc flywheel output. What the XR can't take, is the output from the water twisting the prop backwards. Think of the water as an engine, and the propeller as a the flywheel. At any moment you allow the water (engine) to grab and twist that prop, your actual engine's output becomes irrelevant. That scenerio, can easily supercede your engines flywheel output many times over, which Mike has validated during his development. If we all had the same hull combo, the same props, the same engines, the same water conditions, maybe, you can get remotely close to what actual flywheel torque level XXX drive can handle. But with so many variables, its simply not possible to establish that number in my opinion. The ONLY constant we have, is the power the engines make. Anything else, we have no control over, as far as what loads the drivetrain will see while in operation. Hull weight, prop style, blade count, slip, speed, and so on. Until now that is. With the Drive Guardian, you now are able to control the maximum torque the drivetrain will see, which will be very relative to the engines flywheel output. |
Inertia!
Engine spins up when leaving the water and then the prop catches again and has to "pull" the engine rpm back down. Result, higher torque than engine rated output. Another scenario is a simple shift directly between reverse & forward or forward and reverse. Two issues: 1) prop may not have stopped turning in one direction before it is reversing direction, 2) the engine unloads briefly between gears and the engine rpm raises above idle. Combine the two and the torque can easily be higher than rated engine torque. |
Originally Posted by MILD THUNDER
(Post 4220096)
The way I look at it, and Mike please correct me if I am wrong on any of this, is that
Its not always the engine's power output at the flywheel that breaks drives, shafts, etc. For many years we've all associated that XXX HP is too much for XXX drive, or we've said things like, "an XR is fine behind a 525EFI", Each boat setup is different. Speed factors in, water conditions factor in, prop blade count, diameter, slip factor, weight of the boat, all factor in. If flywheel HP was the only definitive of breaking drives, we would never have the scenerios like, Guy #1 "Well I got 100 hours out of my XR drive behind my 525 before it broke", Guy #2 "well I got 300 hours from my XR behind my 525 before it broke" The flywheel output is the same, but that doesnt mean that the drivetrain is seeing the same torque levels. I think its been proven, that say a stock XR drive, can take 525 merc flywheel output. What the XR can't take, is the output from the water twisting the prop backwards. Think of the water as an engine, and the propeller as a the flywheel. At any moment you allow the water (engine) to grab and twist that prop, your actual engine's output becomes irrelevant. That scenerio, can easily supercede your engines flywheel output many times over, which Mike has validated during his development. If we all had the same hull combo, the same props, the same engines, the same water conditions, maybe, you can get remotely close to what actual flywheel torque level XXX drive can handle. But with so many variables, its simply not possible to establish that number in my opinion. The ONLY constant we have, is the power the engines make. Anything else, we have no control over, as far as what loads the drivetrain will see while in operation. Hull weight, prop style, blade count, slip, speed, and so on. Until now that is. With the Drive Guardian, you now are able to control the maximum torque the drivetrain will see, which will be very relative to the engines flywheel output. |
We installed a Drive Guardian in a 30 foot Sutphen with a 950 HP blower engine. Max torque was 1100 ft. lbs. We completed two races,two poker runs and several trips to Marthas Vineyard. The drive is max machine upper with an IMCO lower. Saris pulled his drives apart last week . We are checking ours this week.
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Originally Posted by Got Freedom?
(Post 4220071)
Correct, the SSM version will fit virtually any transmission / drive combination. We would need to check the input shaft specifications of the MG502 to see if they are the same as a Borg Warner 72C. If not, then we would need a custom damper plate. We also have a shaft mounted version that might be an option for you as well depending on your power levels.
Mike Freedom - I believe the spline on the BW and MG are the same! Can someone please PM me a price? Thanks Jim |
Why is the price top secret?
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Calm down sparky.
The bravo version is $ 2495 |
Which is a LOT cheaper than a gear coming out the side of a gearcase... :)
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Really thrilled with all the emails and phone calls I've got over the past weekend, a lot of guys are going to have a great, trouble-free 2015 season!
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Originally Posted by 502ss
(Post 4220314)
Thanks ICDEDPPL!
Freedom - I believe the spline on the BW and MG are the same! Can someone please PM me a price? Thanks Jim Email me at [email protected] |
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Originally Posted by MILD THUNDER
(Post 4219523)
and the enormous torque spikes that occur when the prop aerates for a millisecond and grabs again.
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Originally Posted by onesickpantera
(Post 4221061)
I think this is the part many don't realize. It's not always getting "big air". Running WFO and getting air under the prop for a split second, or even partially getting air, also cause huge torque spikes.
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Does it rob anymore h.p. in comparison to a rubber coupler????
Does it have a max h.p. rating? ??? Pretty cool idea. Sounds like it's doing a good job so far! Congrats! |
Originally Posted by scarab63
(Post 4221140)
Does it rob anymore h.p. in comparison to a rubber coupler????
Does it have a max h.p. rating? ??? Pretty cool idea. Sounds like it's doing a good job so far! Congrats! They are on the Qatar boat so I think a horsepower rating may not be an issue for you but I could be wrong :drool1: |
Originally Posted by ICDEDPPL
(Post 4221361)
Yes, it robs the transmission and drive of horsepower during spikes that exceed the DriveGuardian rating :D Otherwise there is no loss.
They are on the Qatar boat so I think a horsepower rating may not be an issue for you but I could be wrong :drool1: |
MDC has designed and fabricated components that are being used by Spirit of Qatar but the team is not running DriveGuardians at this time. The Bravo version is nearly the exact same physical size as the stock coupler but does weigh a little more. Even so, the Moment of Inertia is relatively low since the mass is close to the center of rotation, which is the opposite of a flywheel. The NXT and SSM version have a lower Moment of Inertial than the stock setup. There is no added friction and no loss of HP.
Mike |
My bad, thanx for the correction Mike.
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If there is a loss it's extremely small. We didn't lose any MPH. Not at all.
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Planning to install this winter and fix my broken NXT transmission problem. I hope this is the answer.
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..
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Originally Posted by Boxer
(Post 4220289)
We installed a Drive Guardian in a 30 foot Sutphen with a 950 HP blower engine. Max torque was 1100 ft. lbs. We completed two races,two poker runs and several trips to Marthas Vineyard. The drive is max machine upper with an IMCO lower. Saris pulled his drives apart last week . We are checking ours this week.
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Originally Posted by turnerrd
(Post 4221536)
Planning to install this winter and fix my broken NXT transmission problem. I hope this is the answer.
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Great thread...!
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Originally Posted by turnerrd
(Post 4221630)
Curious how yours looked?
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Originally Posted by turnerrd
(Post 4221630)
Curious how yours looked?
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Can we work out an OSO volume discount?
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The Drive Guardian seems like an innovative idea, just a little pricey!
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How much is a typical rebuild on a XR Due to broken gears or snapped vertical shaft?
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I think the last lower I did was $2200. It was worn from hours not broken from a shock load.
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Just the upper gear set is $1600.
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Seems like the thing to do would be to put a sacrificial bravo behind 550 to 600 hp go wave hopping and see if you can break it, or at least how long does it take. That would answer a lot of questions for the average throttle jockey whose timing is not always what it should be.
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Originally Posted by buck35
(Post 4238459)
Seems like the thing to do would be to put a sacrificial bravo behind 550 to 600 hp go wave hopping and see if you can break it, or at least how long does it take. That would answer a lot of questions for the average throttle jockey whose timing is not always what it should be.
For the pricing on breaking an XR, it depends on how much carnage. If you put a pinion through the side of the case, it's going to hurt $$$ |
We have had great success including the Drive Saver in-line with Bravo XR's and extension boxes. https://www.gcsmarine.com/content/dr...rs/drivesavers
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Originally Posted by TeamSaris
(Post 4238513)
It would help immensely.
For the pricing on breaking an XR, it depends on how much carnage. If you put a pinion through the side of the case, it's going to hurt $$$ |
Originally Posted by buck35
(Post 4238597)
I'm sure it does, that comment was directed at the good folks building and selling the drive guardian. A utube video showing a boat getting aired out with poor throttle control would be a nice way to show off the product to those maybe on the fence about justifying the cost.
Here is a few excerpts: On Water Test results The following data was collected in a 42’ Fountain Lightning with HP700SCi engines, SSMVI drives with 6-blade Hering propellers and without a DriveGuardian installed. A video of the run can be found at http://youtu.be/7s2NbrbGc6E The boat was fitted with a number of sensors and a Data Logger to collect and store the information. Once back on shore the data was downloaded to a laptop for analysis. The parameters collected during the test run included: Throttle Position – This information was used to measure the reaction time of the operator and determine the exact amount of throttle applied during each Synchronization Event. Vertical Acceleration - An accelerometer was used to determine exactly when the boat began to leave the water after hitting a wave and the force experienced re-entering the water. RPM – The crankshaft speed was captured to determine the peak RPMs when the propeller was out of the water and how far they dropped when it was re-submerged. Boat Speed – A GPS sensor was used to determine the exact speed the boat was traveling during the run. Torque & HP - A Strain Gauge was fitted to the port engine’s driveshaft that accurately measures the output of the engine and the torque spikes generated by the propeller. This technology is extremely accurate and similar to what is being used in Formula 1, NASCAR, & NHRA. Once downloaded to a laptop, the engine’s horsepower can be calculated using SAE J1349 JUN90 to correct for atmospheric conditions. Essentially this device functions as an onboard dynamometer with a data logger to collect the information for analysis. Test Data – (no DriveGuardian) This test was conducted in 1’-3’ waves (per the NOAA near shore forecast) on Lake Michigan, with Northwest winds at 10-15 knots. The purpose was to confirm the existence of torque spikes and to measure the peaks and durations of the Synchronization Events. Figure 3: Three Second Snapshot Shaft Dyno Data At a test boat speed of approximately 65MPH, two torque peaks (yellow plot line) are visible in the Shaft Dyno output in Figure 3. Both of the spikes in Figure 3 are 60% more than the engine’s peak output and beyond the stern drives maximum input rating of 1,160 ft-lbs. it is interesting that the throttle position (blue plot line) at the peak of the torque-spike had very little effect on the severity of the spike. This makes sense if you recognize that the torque-spikes are a direct result of having a large mass (engine, flywheel, coupler, drive shaft, U-joints, gear sets, etc.) rotating at high RPM (red plot line) and then being suddenly slowed down by the propeller. In the highlighted area of Figure 4, a drop of 193 RPM, (red plot line) resulted in the torque jumping from 263 ftlbs (propeller nearly out of the water) to a spike of 1,278 ft-lbs (yellow plot line) in 0.08 seconds. In this example the event duration is so short that the operator was unable to compensate and the throttle position remained essentially constant at 55% open (blue plot line). Table 1 is the results of a mathematical model of the 1,278 ft-lb torque spike that is highlighted in Figure 4. Based on the1.52:1 gear ratio for the drive, you can see that the propeller shaft sustained an even greater torque spike of 1,918 ft-lbs. In the highlighted area in Figure 5, a drop of 863 RPM (red plot line) resulted in the torque (yellow plot line) jumping from 103 ft-lbs (propeller out of the water) to a spike of 1,262 ft-lbs in 0.129 seconds. Operator reaction time was relatively good with the throttle position (blue plot line) dropping just before the propeller left the water and then increasing to 44% less than a 1/10th of a second before torque spike. As a great example of rotational inertia, please notice that immediately following the highlighted torque spike in Figure 5, the throttle position was held at 10% for more than 2/10ths of a second. At this point the propeller is in the water and the torque spike is gradually dissipating, but the RPMs barely change for a full the full 2/10ths of a second, even with the throttle practically closed. Test Data – With DriveGuardian DriveGuardian was installed in the same boat as in the previous test (42’ Fountain) and run on Lake Michigan in a NOAA recorded wave height of 1’ with a southeast wind of 5-10 knots. In the highlighted area of Figure 6, a drop of 621 RPM (red plot line) resulted in the torque jumping from 155 ftlbs (propeller nearly out of the water) to a DriveGuardian regulated spike of 1,130 ft-lbs (yellow plot line) in 0.095 seconds. Boat speed was 85MPH and the throttle remained approximately 85% open (blue plot line). So, with an RPM drop of more than 3X the highlighted area of Figure 4 and over roughly the same period of time, the torque spike was still 12% lower. This plot clearly indicates how effective DriveGuardian is at regulating torque spikes Using the same mathematical model as the previous test and based on the data from the DriveGuardian test, Table 3 shows that it would require an Inertia-Induced Torque of 3,316 ft-lbs to decelerate the rotating mass of the engine from 5,408 RPM to 4,787RPM in .095 seconds. While some of this energy would have been dissipated by the propeller, clearly the data proves that DriveGuardian regulated the torque spike to a preset value of 1,130 ft-lbs and protected the stern drive from a damaging torque spike. Drive it like you stole and the Drive Guardian will do the rest :D |
I'm not a doubter by any means as I work with and on equipment daily, also seen many 3pt implements with a similar setup as I live on an orchard.
Just saying a moving picture says more than any chart can :cool-smiley-027: beat of luck to all of you, I think its a great idea, but you got to get em out there, then voila! |
The first set of pictures is our pinion gear from 2013, it has 3 races on it. No Drive Guardian.
The second set of pics is the pinion from this year, same side, same drive. 5 races with the Drive Guardian. I assure you we ran just as hard, coming second in points and winning another World Championship. Same props, same engines. It does have some wear, hence the sheen to it, but no big dents or dings from impact like the first one. Fantastic results. http://i116.photobucket.com/albums/o...psa52be8fe.jpg http://i116.photobucket.com/albums/o...psd152d448.jpg http://i116.photobucket.com/albums/o...ps28d08862.jpg http://i116.photobucket.com/albums/o...ps02172db1.jpg Second set http://i116.photobucket.com/albums/o...ps98604e6a.jpg http://i116.photobucket.com/albums/o...psa6ed8822.jpg http://i116.photobucket.com/albums/o...psc53506a2.jpg Happy to snap some more if needed. |
Wow the second set looks like new parts compared to the first!
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