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roadking
08-25-2003, 02:56 PM
'99 22zx 350mpi,300hp,alpha1 - all stock

With a 24p bravo1, I'am only hitting 56mph and with a mirage plus 23p, I am only hitting 59mph.
Boat runs great, but from what I read on this web site it should be faster. Anyway, I'm thinking about getting new exhaust and air filter. Any ideas on brands or other things I could do without spending too much $$$$?

Thanks for the help.

tmdog
08-25-2003, 03:33 PM
ROADKING, IF YOU WANT SPEED, SPEND THE BUCKS AND PULL THE ENGINE AND CAM IT. OTHERWISE YOU ARE WASTING GOOD MONEY FOR POOR RESULTS. ACCORDING TO DENIS MOORE, THE SMALL BLOCK GURU, HE STATED UPGRADING THE EXHAUST ON A STOCK SMALL BLOCK IS A WASTE.IT MAY ENHANCE A BIG BLOCK TO SOME DEGREE. INTERNALLY MODIFY THE ENGINE TO GULP MORE AIR THERFORE BUILDING MORE PONIES, THAN A BETTER EXHAUST WOLD BE BENEFICIAL.

Scubado
08-25-2003, 05:40 PM
Road King,

I have a 2000 22ZX with the same set up as you. I've also been told (by the good folks at Stainless Marine) that an exhaust system will produce no HP gains with that engine.

My boat runs in the mid 60's with the bravo 24P, non labbed prop. I'm hitting the rev. lim. @ 5000 rpms.

The Alpha drive is rated @ 300hp max... It might get real expensive to produce any apreciable speed gains. Buy Dennis Moore's book small block book, it's a good one.

Most everyone I've talked to with our set up easily runs in the low 60's. I do it all the time even with a full boat (fuel and people) and high altitude. You might check your timing.

If you find any cheep bolt on HP, I'd love to know about it. Labbed props are about the best investment I can think of at this point.

jeepfan99
08-26-2003, 07:19 AM
I am also running the exact same set-up. 2000ZX full loaded with gas and guests and she easily gets in the low 60's. I have ridden by myself and reached approx 65-66 @ 5400rpm (on the speedo not gps). I just posted a question regarding a K&N filter (my next purchase) and it may improve rpm but not HP. I run K&N in everything I own from cars to 4 wheelers. Some people like them, some don't.

olredalert
08-26-2003, 08:45 AM
Roadking,

------Is your boats bottom painted?......Bill S

roadking
08-26-2003, 04:51 PM
Thanks for all the input, no the bottom is not painted. I'm still pretty confused about all this. My bravo 1 24p was new last month. I'm still a rookie, do I need to send it away to have it "labbed"? I purchased it because Donzi told me it was the correct prop for my set up. The Mirage plus 23P was faster, but didn't handle as well.

Greg K
08-26-2003, 05:17 PM
We need more info, engine rpm's and if it's GPS speed you're getting?
Might not be getting full throttle or full open position as well.

roadking
08-26-2003, 06:04 PM
RPM's 5200 - Magellan GPS...speedo stoped working!

roadking
08-26-2003, 06:08 PM
also had motor checked before purchased. the hull has a couple of chips from bad fork lift operator, but the hull is out of the water when going near 60, so I wouldn't think that would matter.

Bryan Tuvell 33ZX
08-26-2003, 08:03 PM
My first Donzi was a 1999 22ZX, (came with MP23)
a 4 blade Bravo I lab prop, 350 motor ran mid to high 60's, more so 63 to 66 (did I mention I was hard on outdrives with this simple set up?). Right at WOT, rev limiter on ocassion trimmed to the stops.

I would have the boat looked at by a Merc Mechanic and not do anything else until then.
Bryan

Shanghied Again
08-26-2003, 08:18 PM
RoadKing, Look at your prop and see if its a left hand or right hand, The Manufacture sometimes can make a mistake a set the drive the wrong way, We have had this happen on a 38ZX Rotation was in and props were out. This is an easy cituation to fix, You should be right hand rotation.
If it is take Bryans advise and take the boat to a good mechanic; Your boat should be running 63-65mph factory.

Greg K
08-27-2003, 08:17 AM
Using a prop calcultor, with a 1.5 gear ratio, you're looking at 25% plus slip on the prop. Pretty high percentage if you have that gear ratio.
I wonder if you might have a higher gear ratio in the drive which puts the speed and revs closer to typical slip percentages and the speed you're attaining.

Scubado
08-27-2003, 04:45 PM
I think you have the right props for that boat, the four blades have always worked best for me. My prop is not labbed... What is the gear ratio on that Alpha? I think mine is 1.62 or something close to that :)

The speeds I run are gps documented, although the speedo is fairly accurate (within a couple mph at most speeds)

There has to be something else going on there, are you loaded down with a bunch of fat chicks? It's a known fact that too many ramp tramps are harmfull to your top end speeds eek! :)

roadking
08-27-2003, 05:15 PM
the Merc web site says the alpha is 1.47 - 1.62, so I guess mine is 1.47 if the 1.62 is an option.

these speeds are just me w/"no fat chicks"

roadking
08-27-2003, 05:26 PM
the prop is right hand. I'll have to get a mechanic to look at it. I keep it in the Baltimore Inner Harbor at Lighthouse Point, anyone know of a good mechanic that I should call. Thanks agaign for the help.

Scubado
08-27-2003, 05:43 PM
The drive is most likely the 1.62. That's what every other one I've run across has had anyway. There is a sticker on mine, could be a serial # that could clue you in too if you know how to interpret them.

Greg K
08-28-2003, 06:16 AM
Now that we've established you probably have a 1.62 drive ratio, the slip numbers improve, but still somewhat high.
How's the boat trimmed when going for speed?? Tab position and drive position and anything else that may be dragging it down.

roadking
08-28-2003, 07:15 AM
thanks for the input. I'll take it out Friday or Saturday and make sure it's not driver error! It's possible that my trim tabs aren't going all the way up.

roadking
08-28-2003, 02:35 PM
just got back from a joy ride. w/Bravo1 prop I was able to hit 59.5MPH (GPS). trim tabs were up and played aroud w/the trim to reach that speed. I guess I'll be able to break 60 w/the Mirage+. From everyone's input it still seems a little slow.

Greg K
08-28-2003, 04:17 PM
OK..you got 3 mph more out of the Bravo. The actual pitch could be less than 24 actually, even though it's stamped a 24. I'd try another prop and see what you can get out of it, possibly another Bravo in a 25 or mirage+. Good luck.