raising x dimension -increase rpms
 

hey guys, will raising my x dimension increase my rpm up top? i've got a 24 CONDOR OFFSHORE (SAME HULL AS A 24 PANTERA) and i'm running an hp500 (carb) with a bravo 1.50 .With a labbed bravo 1 26p,68.5mph (gps) at 4800 rpm wot, and a stock mirage 27, 68mph at 4600 rpm wot. I've been following PANTERA 650+ threads on OSO to sort of help me with my set up because like him i was discouraged with my top end #s. Also i recently measured a 24 pantera where the the drive was 2 inches higher than mine.(7.25 pad to gimble base) mine (5.25). The boat has no problem getting on plane and is a rocket midrange,but i would like to see 5000 rpm wot and 70's on gps. future plans are to buy one of Maxx's cut down bravos,am i heading in the right direction?

X dim
 

from my experience with a Baja sport 240, i can say that running a 2" shortie helped increase my RPMs and top speed.

Baja sets their X dim rather conservatively, but raising my X 2 " gave me 3.5 mph . As far as the Panteras go, Jo sets them pretty aggresively as it is so bringing them higher probably would hurt your performance.

With my 28 Pantera, i found that running the propshaft between 4 and 4 3/4" below the bottom of the boats works the best.

Are you sure your motor is making it's rated HP? How much does your boat weigh? Does that boat have a 7' beam? If your hull is the same as a 24 Pantera I would think you should be going much faster. I run 70+ gps any day in my 24 Superboat with 385 HP.

hey dave,boat is a 7' beam, 4500? lbs. ,brand new 502/502hp with 20 hrs,nickerson holley carb,lightning headers,motor sounds real healthy- no black transom. This boat originally had a 350 /alpha, i converted to the bravo, lost 5 mph, upgraded to the 502,gained back 15mph. I know the drive is mounted deep,i was just uncertain how much thats affecting overall performance. my options are to bolt on a shortened drive or have the transom redone this winter? I figured this boat to run mid 70 s .

Re: X dim
 

Same here. I just dropped my drive an inch and am at about 4 1/4" now. Props bites better and get better bow lift.

If you are at 7.25 below the bottom, then its too low.

Griff...
I think Condor24 meant that his drive is 7.25 to the gimble base. which means his X is somewhere around 16 inches (give or take) so a 2" shorter lower might do it. Condor, you would want to confirm what your prop shaft is from the very bottom of boat. If your prop is more than 5 inches below the boat, try a 2" shorter lower. Otherwise, you may want to re-do the drive height as you stated. But its alot of work. I may do mine this winter too. to lower my drive.

$$$$$$ The only good solution is a imco ext.box with 3" of rise and 380 k planes with hydrolic steering. this is the only safe way.

I have the imco box 3 " raised. I may replace it with a nuetral box. Or I may even go without it. before you buy the box let me know, I ll save you some money. The box alone from Imco is about 800.
Youll still need all the hardware from imco. But this will be a winter project for me so we have plenty of time to talk.

talk soon

Bruce

you'll need k planes also that hull wants to lay to the starboard under full throttle climb from 65 to 80+ then chine walk wildly, I know! and anbody runnng 70 plus witout hydrolic steering I would not ride with.

Thanks for all the advice, i'm going to verify my prop shaft to pad height and see how far away from 4-4.75 i am. Do you pantera guys prefer the 3 or 4 blade props?

I prefer four blade or five blade to reduce slip. but hey ...try em all if you can

I'm running labbed a Bravo 1 4 blade on my 28. I might try a Mirage plus now that I've lowered the drive, but getting on plane in any reasonable amount of time could be tricky.

X dimensions,,, is this my prob ???
 

Ive added about 60 hp to my already 490 hp 502. I think Ive have picked up maybe 2 mph , its a lot quicker getting there but the top speed isnt increasing like i hoped. I measured the distance from the bottom of the boat to the prop shaft , it appears to be about 7.5 inches. This is on a 21 foot baja. Should i be thinking about a shorty or the cut down bravo Maxx is testing. Best MPH to date , 74 at 5500rpm. thx guys...sj