Trs upper With a Bravo Lower
 

Anybody ever put a Bravo lower on a Trs upper?

http://i584.photobucket.com/albums/s...208_112941.jpg


I'll just leave this here then

did you do case mods/engineering yourself? Looks interesting.

Wow look at that weld

Yes I built it. It's a test unit I built specifically for my boat. The prop shat was 9 inches in the water now it's 4.250

Build pictures?

http://i584.photobucket.com/albums/s...201_170210.jpg
http://i584.photobucket.com/albums/s...201_182622.jpg
http://i584.photobucket.com/albums/s...203_192747.jpg
http://i584.photobucket.com/albums/s...204_173943.jpg

Awesome Job!!

Cool. A Bridgeport is on my tool list.

Nicely done!

hands down some of the best work right there.
will it still pump oil for cooling ?

Very cool.

Yes the oil passages are machined into the adapter plate

Slowryd. What is the dimmension from input shaft C/L to Prop shaft C/L?

I'll have to double check that. I wasn't really concerned with that when I built it I was mostly concerned with the prop shafts in relation to the bottom of the boat

Sure I understand, just wondering to compare with a TRS Piece I have, very interested in that distance.! Thanks

Very interesting. How has it held up? What did you do with the vertical shaft?

I can tell you it is 4.750 shorter than a stock trs

Haven't had a chance to run it yet. I machined a stock shaft to fit and spline it to fit the trs coupler

Curious what Gear ratio are you running?

Xr gears ? Prop shaft ? I had same idea.
You are a genius. Bravo hand grenades are easier to get parts . Try ceramic bearings ?

I am curious as to why? what is the advantage to a TRS upper? What is the advantage to a Bravo lower? Is it because the propshaft on the Bravo is a 1.25" XR shaft?

The trs has a strong upper the lower is the weak link,the trs uses angle cut gears in the lower and will break with some power the bravo lower uses straight cut net forged gears and are much stronger,i would think if there were more trs boats still around someone would build some straight cut gears ,billet carrier and 1.25 prop shaft,i don't think there is enough still around for this to happen,a konrad drive is pretty close to that idea

It's gonna be 1.68 for now. I'm using what I have from left over crashed drives to get this project started

Good idea, I think there are more than you realize.

Looks great and a great idea

How do you reverse the rotation?

Mark

That's the big issue right now for doing a twin conversion but I'm working at it. On my deal being a single and left steer I'm gonna switch to a left hand prop to make it drive forward in forward gear.
It's kinda screwed up that merc made the lowers different on the trs instead of the uppers as far as left and right goes.

Lock it in reverse. Make new gears ?
Great job buddy

My twin trs would need a reverse rotation motor. So if your lowers hold up it be worth it . New cam and dist. Gear firing order reversal.

I get 100 hours on a right lower and left never goes. Helical cut always pulls teeth. Trs needs straight gears like speedmasters.

EDIT...
Transmission can not be modified for rotation.
Thanks Marc

http://www.marinemechanic.com/fpdb/B...ers-Manual.pdf
http://www.baadteknik.dk/Manualer/Mo...elvetDrive.pdf

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.

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!

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

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.

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.

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.

have you thought about shortening bravo lowers for bravo uppers?

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?