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View Full Version : how fast is fast for a sweet 16



rockindaboat
08-20-2003, 09:47 AM
just trying to figure out how fast i can get my DONZI 16 to go? and what it will take to go FAST ?

mattyboy
08-20-2003, 10:28 AM
Rockin,
you need to post up your specs on the boat then the boys can give you your answers
list your
drive
engine
prop
drive ratio
also do a search on the 16, and read the model list that might give you some info as well

we have some pretty fast 16 around so it can be done wink


Matty

Matt

oldLenny
08-20-2003, 10:39 AM
78 is the "current record" I believe. That being Jamie Root, and there are a few around 70-72 flat. Forrest Collie, Randy etc...

Rootsy
08-20-2003, 11:03 AM
76 lenny... don't give me THAT much credit... we are headed for 80 sooooooooon :D

for most... 60 - 65 is PLENTY fast in a 16... it likes to get a little squirrly and tempermental... unless taken to the next level

you can make a 16 as fast as you dare to push it... but it takes a few certain things...

1. The size of your wallet
2. The size of your balls
3. Determination and thought
4. Test, Test, Test

the whole deal with the 16 is not how fast it is, i can toss 700 hp in and let her rip, yee haw... donno how long i'd live though... IT IS MORE about how well it handles at high speeds... what good is 70 or more if you are scared to death cause it is just totally out of control, on the edge or just plainly unsafe... noooo thanks...

put the hp in, 300 - 320 pshp will get you to 70... raise the X dim (either cut a new hole or look for an alpha SS, arneson, or bravo / imco) and play with props... add hydraulic steering... trims tabs if you wish... those are the basics... you have to keep the hull in check...

my boat was a handful to hold onto at 68 with an alpha GEN II and a cleaver... the SS transformed it along with the right prop, some weight transfer and there is more to come. Hydraulic steering to keep the drive tight and straight plus a bit more hp to push us further... as well as some bottom work just for experimentation sake.

mattyboy
08-20-2003, 11:15 AM
don't forget the plain crazy 16 with the700 hp blower motor on Winnie,
Rockin listen to Rootsy or Forrest they know their stuff.

I had mine up to 85 mph before I had to stop for a toll :p

Matty

rockindaboat
08-21-2003, 10:28 AM
thanks for the feed back!i am running a mopar 318 board 30 over with a mild cam.and just picked up a set of ported and polished heads for it.it also has what i think is a volvo 270 drive turning a 14 3/8 x21 LH short hub prop. I just blow the motor, had a detination problem,i would like to put a 360 mopar in it but a marine engine supplier told me that my oil pan,fly wheel,and pullys wont work,and after doing that he says i would have a vibration be cause of the 360 is internaly balanced.we have been swapping 360 for 318 in car and trucks and it is a bolt in opperation.maybe someone can give me more info on this swap?i realize the key to speed is cubic inches and deep pockets.thanks for your feed back look forword to more!

Rootsy
08-21-2003, 11:18 AM
i have a roughly 1970 Invader, model unknown, with a 360 "superbee III" motor in it.. uses a paragon V-Drive and has a new SS propshaft... it is doing nothing but rotting away... has an aluminum intake on it also.. the motor is complete less carb... if she spins i have no idea... but the flywheel is there...

TORQUE is what it takes to get speed... takes a certain amount of TORQUE to spin a given prop a given rpm pushing a given load... so you want to make as much torque as you can as far into the power band as you can... that way you can spin more pitch faster... which means more speed.

and i have roughly 5000 bucks (and god only knows how many hours) into a 23 mph gain...

MOP
08-21-2003, 11:20 AM
Like you said 360 from 318 swap is a natural, but you can't mix the parts like your suppier says. You have to marinize or find a marinized 360. I am not sure if there are any performance cams for the 360 but all else is on someones parts shelf. The swap is can be done but in my opion I would buy a Chevy bell housing and do a 350. Parts availability is great for Chevy, I think you would be a lot happier in the long run and have a little lighter engine package. My 2 cents!

Cuda
08-21-2003, 12:08 PM
Swap to a chevy. Lot's more parts available and cheaper too. You can shake a tree and parts for a SBC will fall out of it.

JimG
08-21-2003, 01:02 PM
That 318 is a great motor! Is it original? Post a pic... :D

I have over 1200 hours on a 318 in my cruiser, and know of several with over 3000 hours on them! I'm suprised you blew one... they are almost bulletproof!

Cuda's right about parts though! Regular parts, (intake manifolds/heads/cams/water pumps, etc) are readily available anywhere, but high performance exhaust manifolds are scarce.


JimG :D

BUIZILLA
08-21-2003, 01:34 PM
The 273-318-340 family is internally balanced.

The 360 family is external balanced...

mucho problemo if you mix rotating parts...

J

Budman
08-21-2003, 02:51 PM
I had a 340 Plymouth Duster a while back which was slightly modified. The modifications included a Mopar Purple Camshaft, blueprinted heads with race hemi outer valve springs, 750 holley, and headers. It was a great street car and was really fast. SummitRacing.com has a great selection of performance parts.

rockindaboat
08-21-2003, 06:42 PM
thanks again for the feed back.the motor is at the rebuilder hopefully i,ll get it back next week.i wished i talked to you guys sooner before i spent the money on new parts for the mopar,i just happen to have a 350 sb all rollard out for my criscraft that i havent touched since i found my donzi.this swap maybe the way to go but it will have to be next sping. boat buget is depleted.i still have hopes to get in water this year so i will try the mopar againe.i have had many mopars in the past and never seen one melt a piston like this,only one melted one the rest are fine.so i guess i can say I AM A MELTER OF STEEL.

MOP
08-22-2003, 07:04 AM
Scot the Harbor Master had the same thing happen to him just before his 18 was to be sold, one piston shot the rest fine. Corbon deposits can light off, also spark plugs. Another thing that I believe can also be a cause is cheap spark plug wires bundled together allowing the wire to cross fire. Even good high quality wires should be routed with looms. Many of the guys use high energy systems that makes wire routing and the use of the plastic seperators all the more important.

rockindaboat
08-22-2003, 08:05 AM
I think you hit the nail on the head with the wires.had problems with coil wire so i used a older one.when checking the motor out i noticed it was arking on the manifold so i rapped it with a tee-shirt so it woudnt ground out to get it off the lake.

MOP
08-22-2003, 08:46 AM
Even on stock engines good wires are a must for marine applications. I have never understood why some people cheap out on wires, the new wire wound ones seem to be one of the best. $40-50 bucks is cheap insurance for any multi thousand dollar engine.

Forrest
08-22-2003, 09:46 AM
From my experience, in addition is more power, I found that weight reduction goes a long way in the 16. I'm running a 302 Ford motor (about 150 lb. lighter than a SBC) and aluminum exhausts. Also, just about all 16s have their outdrives buried too low in the water causing the operator to trim to the sky in an effort to get more speed. Trim too high on a 16 and you don't go faster, it just turns into a hairy ride! For that reason, a higher than stock X-dimension works wonders for the handling and stability as well as top speed on the 16. With a higher X, you can run the 16 pretty much flat to the water with using very little positive little trim. The only real way to cure the X-dimension problem is with an Alpha SS.

If I had more money to throw at it, I would consider building an aluminum-head stroker-motor based on the 302 Ford block rather than going to the heavier Chevrolet small block, but now I got hitched, bought a fixer upper house, and a pair of DPX drives for the Magnum, that aint' going to happen anytime soon! eek! :D

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Forrest

Trying to figure out what happened . . .