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View Full Version : how far should your bullet be under your boat



dallas
04-30-2002, 06:39 PM
i hear every one talk about x dimesion i measured it under the center pod it was 6 inches under on my 26 daytona is this right or to low im not running as fast as i should thanks how many inches should it be? thanks

Charley
04-30-2002, 09:26 PM
sounds WAY low to me

Craig
05-01-2002, 03:55 AM
Was that from the bottom of the center pod to the centerline of the prop shaft?
Craig

dallas
05-01-2002, 06:14 AM
it was from the point its what i call the bullet of the lower unit from the center pod. i took a straight edge thanks

HavasuDreamin'
05-01-2002, 06:37 AM
Although I don't know the larger cats too well, I do know the smaller ones run the propshaft even with the bottom of the center pod give or take a 1/2 inch. It sounds to me like your X is too low, I mean way toooooooooo low! I bet you pick up at least 5 mph by rasing it 3" to 4". Good Luck

DogHouse
05-01-2002, 08:01 AM
Yeah sounds like your drive is too low for ultimate top end. It may be about right for all around performance if you care about getting on plane quickly, skiing, and low speed cruising. My drive is even lower, makes for great holeshots compared to some of the cats with really high X, but then my top end is definitely limited. My 23' tunnel with ~750hp only runs low 90s, but man does it get there in a hurry. I'm running 1.5 gears and a 26 prop, just bump the throttle and the boat jumps on plane. Then it will cruise at 2000 rpm with very little slip. The "perfect" drive height just depends on what you want to do with the boat. Somebody needs to come up with a jack plate for i/o drives!

mikey
05-01-2002, 09:28 AM
Originally posted by dallas:
i hear every one talk about x dimesion i measured it under the center pod it was 6 inches under on my 26 daytona is this right or to low im not running as fast as i should thanks how many inches should it be? thanks
The 'X' dimension in the location of the motor crankshaft centerline. The lower horizontal (propeller shaft) of a standard Bravo 1 drive is 21-13/16" below the 'X' dimension. We install the standard Bravo 1 packages at a 15-3/4" 'X' dimension. This is measured from the flat of the center pod and not from the forward 'V' section. If you subtract 15-3/4" from 21-13/16" you have the propeller shaft about 6" bellow the bottom of the flat part of the center pod. The center pod on the 26 Daytona is about 4-1/2" higher then the outside sponsons. This puts the propeller shaft 1.5" bellow the outside running surface. We rigged the very first 26 Daytona with a 16-3/4" 'X' dimension. It did not work and the drive had to be lowered.
Mike Peterson
Eliminator Boats

HavasuDreamin'
05-01-2002, 09:59 AM
There you have it!
I told you I was no expert on the big cats. My 19' has the center pod even with the outside sponsons. Good Luck!

DogHouse
05-01-2002, 12:18 PM
Mike, when you say "did not work", what exactly do you mean? Did the boat fail to get on plane or was it just slipping too much at low speeds to be usable?
It looks like twin installations can get away with much higher X dimensions, because I've seen some of them with the propshafts a couple inches above the outer running surfaces. Of course they weren't exactly what I'd call "ski boats" either!
Thanks,
-brian

mikey
05-02-2002, 09:38 AM
Originally posted by DogHouse:
Mike, when you say "did not work", what exactly do you mean? Did the boat fail to get on plane or was it just slipping too much at low speeds to be usable?
It looks like twin installations can get away with much higher X dimensions, because I've seen some of them with the propshafts a couple inches above the outer running surfaces. Of course they weren't exactly what I'd call "ski boats" either!
Thanks,
-brian
Way to much prop slip. The twins do run much higher, prop shafts even or above the bottom. You can run a higher 'X' with a stand-off box, maybe 2" more with a 12" set back.
Mike

MIKEHTMSR24
05-02-2002, 06:29 PM
[ Somebody needs to come up with a jack plate for i/o drives![/B][/QUOTE]
They do but only the rich and famous could afford one. I saw a pic and it looked like it had about a 4" throw