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-   -   Trs upper With a Bravo Lower (https://www.offshoreonly.com/forums/drives-lower-units/333032-trs-upper-bravo-lower.html)

Mbam 12-26-2015 07:08 AM

Pump indexing allows the trans to work with either engine rotation, however you cannot change the engine rotation with the trans. Input rotation = output rotation regardless. Running it in reverse to go forward is a big no-no.

Rookie 12-26-2015 11:14 AM


Originally Posted by Mbam (Post 4388226)
Pump indexing allows the trans to work with either engine rotation, however you cannot change the engine rotation with the trans. Input rotation = output rotation regardless. Running it in reverse to go forward is a big no-no.

Perfect, Thank you.
I will edit the above post.

goin70 12-27-2015 02:18 AM

Awesome project! It is exactly what I could use on my Cigarette 20 TRS, left rotation. I understand you are testing and please keep the results flowing. What would it approximately cost to make this type conversion? It would be interesting to hear the performance improvements. Thanks for posting!


502ss 12-27-2015 08:38 AM

Some awesome engineering! Very cool project! Keep the info coming!

goin70 12-27-2015 12:48 PM

After taking a look at the setup, I noticed a different trim ram than I am running. What model ram is on this setup and are you running a special trim pump? I still have the slow prestolite trim pump. How do you like the trim operation?

SlowRyd 12-27-2015 01:24 PM


Originally Posted by goin70 (Post 4388498)
After taking a look at the setup, I noticed a different trim ram than I am running. What model ram is on this setup and are you running a special trim pump? I still have the slow prestolite trim pump. How do you like the trim operation?

i have the later model Trs trim rams with the Prestolite pump. I run 0w-20 motor oil in mine to speed it up a tad. it seem to work fine. The boat was real touchy on trim which is one of the reason I built the shorty.

goin70 12-27-2015 03:49 PM

Thanks! I need a apply a great deal of trim to get the TRS's deep drive, to any respectable speed. I have another friend with a Donzi X18 TRS that got excited about your project and interested if you ever plan to produce any lowers. I will be interested in your reliability and performance. What amount of power are you putting through the setup? We both are running Merctrans transmissions. I have a left rotation and he has a right rotations. I appreciate the infor on the trim rams.

SlowRyd 12-27-2015 04:12 PM

Yes I am planning on building units for sale. Here in Texas the weather allows us to test year round so ill be testing it extensively and hoping to be able to have units ready by mid summer. Im running a n/a 468 that made 594 hp and 540 ft/lbs of tq. With a custom borg warner 1018 velvet drive that i built. Ive been 82 in the boat before it starts to porpoise witht the trs lower with nose cone.

phragle 12-27-2015 04:17 PM

have you thought about shortening bravo lowers for bravo uppers?

goin70 12-27-2015 05:37 PM

Please keep me posted on the testing and production plans. Is it possible to change the depth from the current 4.750 without substantial cost? My engine is almost exactly the same output as you are running, but I go through a built Merctrans. I believe if I do not abuse the setup the trans should give me some service life. It is not practical to move the motor forward and install a Borge Warner transmission. Does the setup have any limitation to propeller diameter and pitch. It looks to be a close fit. What propeller are you running? Great stuff and thanks for the additional information?


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