Marine Design Corp

Bravo Anti-Cavitation Cap

A revolutionary solution to a long-standing issue facing many performance boaters with Bravo style drives. In our never-ending search for top speeds, we install shorty drives with high X dimensions trying to chase a big number. While these upgrades frequently increase top speeds, they commonly lead to frustrating challenges just trying to get the boat on plane. Top speed numbers are great, but struggling to get on plane without your family and friends having to huddle in the front cabin is just not fun.

Identifying the Issue

MDC’s Bravo Anti-Cavitation cap is a simple solution to a complicated problem. After researching the issue, with the help of one of our dedicated customers, we discovered that the propeller is cavitating because it is also drawing in air through its hub, and not just from the surface, as most would believe. When you hit the throttles to get on plane, a low-pressure area is generated by the propeller as it tries to push the boat forward. Being that water is about 800x denser than air it is easier to just pull air through the hub and from the surface than move the water. The direct result is cavitation. Having a high X dimension / shorty lower just exacerbates the issue by making it even easier for the propeller to pull air from the surface and increasing the air that was already being pulled in through the propeller hub.

The Solution

MDC’s Bravo Anti-Cavitation Cap blocks the source of the air that is being pulled through the propeller hub. Cleverly designed, and easily installed, the Cap fits over the thru-hull exhaust input for the drive. Obviously, this system will not work unless you have performance thru-transom exhaust, and no captain’s choice or thru prop. Installation is easy and does not require removal of the drive. The system has been tested on numerous boats that had issues coming on plane, and every one of them not only saw significant improvement, they no longer require any special efforts to get on plane. So, instead of swapping out your shorty and losing speed just to be able to get on plane with your family and friends onboard, just install the MDC Bravo Anti-Cavitation Cap and go boating.

This is a direct replacement for the flanged shaft (Mercury OEM's #939064, 93906A2, 8M0192274) inside the bell housing for a driveline setup with a Bravo drive. They are made from 4340 chromoly and actually weigh 0.2lbs heavier than the stock ones even though they are exactly the same dimensions. Made in the USA. 

The Marine Design Corporation IAC Survival Kit is designed specifically for Mercury Racing 600SCi, 662SCi and 700SCi engines but will work with many other applications. See the full list of compatible engines in the additional info section. Our kit eliminates costly PCM damage that can occur when an IAC fails, which can be a common occurrence. The kit was developed for twin engine applications and includes two plug-and-play IAC harnesses that are fused to prevent a direct short to the PCM. Also included are two USA made IAC units with gaskets, hardware, (just in case you drop one in the bilge) spare fuses and a canvas storage pouch. Replacement IACs and fuses are also available.

The advantage of the harness is to prevent a failed IAC from damaging the PCM, which is $2,000+ to replace. The harness contains a replaceable fuse that will blow and prevent the shorted IAC from damaging the PCM (ECU-Computer). This is a common failure point blamed on the IAC but the root problem isn't the IACs, it's the fact that Mercury is exceeding the duty cycle on many of the engines that causes them to overheat and short out.

Replacement pair of harnesses to use with 221-1090.

The advantage of the harness is to prevent a failed IAC from damaging the PCM, which is $2,000+ to replace. The harness contains a replaceable fuse that will blow and prevent the shorted IAC from damaging the PCM (ECU-Computer). This is a common failure point blamed on the IAC but the root problem isn't the IACs, it's the fact that Mercury is exceeding the duty cycle on many of the engines that causes them to overheat and short out. Used on 496MAG, 496MAG HO, 525EFI, 600SCi, 662SCi, 700SCi, 850SCi, 1075/1200SCi and other applications.

Single Replacement harness to use with 221-1090.

The advantage of the harness is to prevent a failed IAC from damaging the PCM, which is $2,000+ to replace. The harness contains a replaceable fuse that will blow and prevent the shorted IAC from damaging the PCM (ECU-Computer). This is a common failure point blamed on the IAC but the root problem isn't the IACs, it's the fact that Mercury is exceeding the duty cycle on many of the engines that causes them to overheat and short out. Used on 496MAG, 496MAG HO, 525EFI, 600SCi, 662SCi, 700SCi, 850SCi, 1075/1200SCi, and other applications.

This Marine Design Corporation Replacement IAC is designed specifically for for 850SCi, 1075SCi or 1200SCi engines. Made in the USA. Direct replacement for Mercury Racing #8M0050118.

NOTE: SOLD EACH. Two are required per engine. Image Shows top and bottom view.

TrimSync Race Edition+ includes all of the standard TrimSync features AND allows the user to program up to four preset positions that can be recalled with the push of a button. Typically, one preset would be the highest you would ever want to safely trim at speed. Another might be 2°-3° below neutral for when you encounter a wave. Race Edition+ allows you to quickly and safely trim to your “sweet spot” without having to watch the trim indicators or worry about over-trimming at high speeds.

TrimSync Race Edition is also available for trim tab / tunnel tab combinations, which greatly reduces the complexity of coordinating the position of each separately. With up to four presets the user can move the drives and tabs in unison to their individual pre-programmed positions, with a single push of a button. Of course, all presets can be easily overridden by simply pressing any other trim button, just as you would normally do.

NOTE: Please specify when ordering if using Mercury Racing Engines.

Operating a multi-engine offshore powerboat can be a little overwhelming at times.  That’s probably why offshore racing is the only motorsport that requires two drivers. Most offshore boats have an engine trim button built into the throttle lever handle.  We all know that the drives rarely stay perfectly even using just the BOTH button on the throttles.  Having them offset can impact handling, and can be dangerous at high speeds.  So that after a couple of moves we are all reaching to the dash to try and even them out.  Over and over again.

TrimSync is a patent pending device that monitors the trim for twin and triple engine boats, so when the operator presses the BOTH/ALL button, it will automatically adjust the drives to be in perfect alignment, every time.  You will never have to worry about how accurate your mechanical trim indicators are because TrimSync will always move the slowest drive to match the others.  There are no extra buttons or complicated operating instructions, just push the BOTH button and TrimSync does the rest.

If, for some reason, you want one drive to be at a different trim then push that drive’s trim button and it will move just as it always has. TrimSync will re-align the drive trim the next time you push the BOTH button. Just drive!

NOTE: Please specify when ordering if using Mercury Racing Engines.

NMEA 2000 Software Upgrade For TrimSync

We will upgrade your TrimSync system to NMEA 2000 compatible specifications. Enjoy advanced NMEA 2000 devices and interconnectivity. 

Not Required on Smartcraft equpped boats. 

TrimSync - Diagnostics Kit Add On

MDC Diagnostic Kit for DriveSync and TrimSync systems consists of a USB cable and software to access onboard diagnostics, calibration process and fault codes. Step-by-step instructions and a built-in help command reduce the time and effort in diagnosing trim-related issues. Using a Windows 7 or later laptop you can run diagnostic tests to determine if there is an issue with the senders, wiring, or trim pump, before they become a problem on the water.

While running the boat, DriveSync and TrimSync log multiple types of errors and retain them even if the power is turned off. The Diagnostic kit allows you to access the error logs to assist in troubleshooting trim issues. For example, air in the hydraulic lines, a trim cylinder that is failing, or trim sender issue will be logged as an error letting you know which engine had the issue, and how many times it has occurred.

The Diagnostic Kit also provides a remote support capability (requires Wi-Fi) to assist with setup or troubleshooting.

Note: Must Be Purchased With A TrimSync Product Or Kit

Shift Controller

DriveGuardian Kit, NXT Damper Plate/DriveGuard

Direct replacement for the factory NXT damper plate with a 1.375” shaft that has 26 splines. Heavy duty design with 8 springs and a solid backing plate that can withstand more torque than the OEM units.

DriveGuardian NXT is a patented device that improves the reliability of your NXT transmissions and drives. DriveGuardian reduces the torque spikes that are created each time the propeller becomes aerated or exits, and then re-enters the water after hitting a wave. These spikes are generated by the inertia of the rotating engine components and have been measured to be 2X-4X the actual torque output of the engine. These torque spikes far exceed the manufacturer’s torque rating for the NXT transmission and drive, which can lead to broken gears and twisted shafts. DriveGuardian is a torque-limiting clutch that absorbs the damaging torque spikes and protects your entire drivetrain. DriveGuardian has been proven on the racecourse with numerous National and World Championships in offshore powerboat racing.

This is a Packaged Price Deal

Make sure to fill out this calibration questionnaire when ordering.

DriveGuardian NXT

DriveGuardian NXT is a patented device that improves the reliability of your NXT transmissions and drives. DriveGuardian reduces the torque spikes that are created each time the propeller becomes aerated or exits, and then re-enters the water after hitting a wave. These spikes are generated by the inertia of the rotating engine components and have been measured to be 2X-4X the actual torque output of the engine. These torque spikes far exceed the manufacturer’s torque rating for the NXT transmission and drive, which can lead to broken gears and twisted shafts. DriveGuardian is a torque-limiting clutch that absorbs the damaging torque spikes and protects your entire drivetrain. DriveGuardian has been proven on the racecourse with numerous National and World Championships in offshore powerboat racing.

Prior to shipment, each DriveGuardian is mounted to a specially built dyno and load tested to ensure they meet strict manufacturing standards. Your DriveGuardian is then calibrated for your specific engine and drive combination.

DriveGuardian is manufactured using billet aluminum housings and Kevlar clutch plates. The clutch plates are replaceable and the typical rebuild interval for an offshore performance application is 500-600 hours. DriveGuardian NXT retains the OEM damper plate and is a direct bolt-on with no additional modifications required. Includes a 1-year Manufacturer Warranty.

Make sure to fill out this calibration questionnaire when ordering.

DriveGuardian SCS Crashbox, Top Mount Starter

DriveGuardian SCS is a patented device that improves the reliability of your drives. DriveGuardian reduces the torque spikes that are created each time the propeller becomes aerated or exits, and then re-enters the water after hitting a wave. These spikes are generated by the inertia of the rotating engine components and have been measured to be 2X-4X the actual torque output of the engine. While the SCS Crashbox has been proven to be nearly indestructible but these torque spikes can easily exceed the ratings of your drive and lead to broken gears and twisted shafts. DriveGuardian is a torque-limiting clutch that absorbs the damaging torque spikes and protects your entire drivetrain. DriveGuardian has been proven on the racecourse with numerous National and World offshore powerboat racing Championships.

Prior to shipment, each DriveGuardian is mounted to a specially built dyno and load tested to ensure they meet strict manufacturing standards. Your DriveGuardian is then calibrated for your specific engine and drive combination.

DriveGuardian is manufactured using billet aluminum housings, Kevlar clutch plates and include a heavy duty 8-spring damper plate. DriveGuardian replaces the factory flywheel and damper plate assembly and is available for either top or bottom mount starters. Standard units are neutral balance for crankshafts with two-piece rear main seals. Other combinations are available upon request. Installation is a direct bolt-on with no additional modifications required. Includes a 1-year Manufacturer Warranty.

Make sure to fill out this calibration questionnaire when ordering.

SSM Borg Warner 1.375 x 26

DriveGuardian SSM is a patented device that improves the reliability of your transmissions and drives. DriveGuardian reduces the torque spikes that are created each time the propeller becomes aerated or exits, and then re-enters the water after hitting a wave. These spikes are generated by the inertia of the rotating engine components and have been measured to be 2X-4X the actual torque output of the engine. These torque spikes can easily exceed the ratings of your drivetrain components and lead to overheated transmissions, broken gears and twisted shafts. DriveGuardian is a torque-limiting clutch that absorbs the damaging torque spikes and protects your entire drivetrain. DriveGuardian has been proven on the racecourse with numerous National and World Championships in offshore powerboat racing.

Prior to shipment, each DriveGuardian is mounted to a specially built dyno and load tested to ensure they meet strict manufacturing standards. Your DriveGuardian is then calibrated for your specific engine and drive combination.

DriveGuardian is manufactured using billet aluminum housings, Kevlar clutch plates and include a heavy duty 8-spring damper plate. DriveGuardian replaces the factory flywheel and damper plate assembly and is available for either top or bottom mount starters. Standard units are neutral balance for crankshafts with two-piece rear main seals. Other combinations are available upon request. Installation is a direct bolt-on with no additional modifications required. Includes a 1-year Manufacturer Warranty.

Top or Bottom Mount Available

Make sure to fill out this calibration questionnaire when ordering.

Replaces Stock Coupler

DriveGuardian is a patented device that reduces the leading cause of pitted/broken gears and twisted shafts in Bravo sterndrives. DriveGuardian replaces the factory Bravo rubber coupler with a multi-plate torque-limiting clutch that is calibrated to your specific application. The cause of many gear and shaft failures is the enormous torque spike that is generated each time the propeller either partially or fully leaves the water, and then is re-submerged. These spikes are generated by the inertia of the rotating engine components and can be 2X-4X the actual torque output of the engine. Each spike lasts only a fraction of a second and throttling alone cannot eliminate them. Every spike causes stress to the gears and shafts which greatly reduces their usable life.

DriveGuardian has been proven on the racecourse with numerous National and World Championships in offshore powerboat racing.

Prior to shipment, each DriveGuardian is mounted to a specially built dyno and load tested to ensure they meet strict manufacturing standards. Your DriveGuardian is then calibrated for your specific engine and drive combination.

DriveGuardian is manufactured with billet aluminum housings and Kevlar clutch plates. DriveGuardian replaces the stock rubber coupler and installation is a direct bolt-on with no additional modifications required. Includes a 1-year Manufacturer Warranty.

Make sure to fill out this calibration questionnaire when ordering.

Heavy Duty Crashbox Damper Plate

• 13-1/2 outside diameter mounting plate.
• plate is .100 thick.
• smaller bolt pattern: (8) 3/8 holes on 9" bolt circle
• larger bolt pattern: (12) 3/8 holes on 12-5/8 bolt circle
• part is 1-1/2 overall thickness
• 2" x 10 Spline

Heavy Duty damper plate with eight cryo-treated springs and chrome moly backing plate. Built to withstand the extreme HP and torque of today’s high performance engines.

Heavy Duty NXT Damper Plate

NXT direct replacement Hi-Performance drive plate rated for 2,000 ft-lbs Chromoly hubs and Cryo treated springs. 1.375" 26 spline. HRS-A36 Plate.

• Made in the USA, patent pending
  
• Anodized billet aluminum for maximum corrosion resistance, even in saltwater environments.
• 100% rebuildable
• Direct replacement for the OEM coupler, zero modifications required.
  
• Chromoly splines that are stronger than the OEM coupler and can be replaced (for less $$ than purchasing a replacement OEM coupler) when required. 
  
• Replaceable Polyurethane dampeners with external wear indicator
• Rated for 1,000+HP
  
• Perfect for diesel engines and applications that see extended idling (which is a common issue for the OEM coupler).
• Unlike the OEM coupler, will not break loose and spin if the dampening material fails (Get Home Mode)
• Two year warranty
• Replaces Mercruiser # 8M0098795, 861523A18, and 861523A9

• Includes 2 Polyurethane dampeners and 1 spline hub.
• Used on 221-1022 Drive Couplers ONLY!