Mag 27 X-Dim
 

Anyone know what the best x-dim is for a 27 starfire? I thought I remember seeing 16 1/2" but cant find the thread. Switching from TRS's to Bravos do you know how much shorter the bravo is from propshaft to driveshaft?

Thanks - Marshall

Marshall,

Can't help you on the X question, but would like to know more about how your approaching the conversion (patching in) of the TRS to smaller Bravo cutouts. I'm in the process now of doing the same thing (weather liminted though) I removed the whole transom (found alittle rot @ the drain hole) so my repair will be from the inside - filling the TRS cutouts first before installing the new transom.

scippy,
My transom appears to be fairly dry according to the moisture meter but you never know till you get in there. I am only assisting in the fiberglass work but my understanding is, depending on the condition of the transom coring, you cut a rectangle 1/2 the thickness of the transom around the existing cutout from the eng compartment side just overlapping the old trs bolt holes by 2" or so. After that is glassed in with new coring you cutout 1/2 thickness from the outside a larger rectangle by 2-3" all around, resin and thru bolt to sandwich the 2 cores. Reglass the outside and prep for paint. Recut for the bravo template and seal the edge.
I'm still finishing all the deck hardware etc. removal and then there is a lot of small repairwork to do to prep the hull for repainting, but when the transom repair stage comes I'll prob do a thread on the donzi site with pics etc.

Marshall,

I'll make sure to look for that when you post it up!........Tomorrow is the first day of winter and it seems I've had enough already. I visualized myself doing a whole bunch of work (transom & fiberglassing) in my portable structure, so far there dashed even with the help of a propane heater.....just hoping for a string of 40 degree weather to make a start of it again.

scippy,
I will post some pics for sure. I was lucky and found some nicely heated space but I feel for ya, weather forcast does not look to be in your favor for a while.

i repowered my Mag 27 sport 10 years ago .
I put a set of Bravos on , and put the X at 16.5" which worked well. Back then i was running 3 blades on the boat , which worked well. I am sure 4 blades would have been much better though .
She had twin 500 HP engines and ran in the low 80s .

Good luck with your project -

What is your reason for switching drives?

How much do you think it will cost to do this job?

Sorry, I don't check this site as often as donzi.net. I was already repainting and doing fiberglass repair to the boat so the transom patch and recut was incremental. TRS drives were mounted up to the rubrail but probably deep compared to todays setups. I had problems getting the merc trans serviced, one was leaking badly and am going up from 425 to 550hp per side. Switch to bravos and the x-dim can come up 2-3", no trannys. The job is mostly labor which is not cheap in my neck of the woods, the transom work is around 3k I'm guessing by itself. Pics on the donzi site under talk about other boats.

Thanks for the info, we spoke a couple weeks ago I think. I'm thinking about 17" and running 4blades, I heard of a recent bravo convert that supposedly went to 18.5" but I'm trying to get a confirmation. A guy in the midwest did an XR conversion and went to 5 blade hydro's and said they did 80mph with only 425hp per side. Should talk to him soon to check what X they went with.

-Marshall

Marshall just wondering how many inch centers [drive to drive] are you going to use ? 29" to 32" or ??????? A non stepped bottom Mag running 80+, now that's a beautiful thing. :drink: Mark