SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Sicaz66 on April 09, 2013, 10:55:42 PM
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Just bought a 21' bahner open bow, has a stock fresh 454 with stock jg pump with jetovator. How fast should it be? Old owner said only 55mph? What should I do to get 65-70 out of it?
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Sounds like the owner was being honest. I'd say 55-58 mph.
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My 21' Ultra open bow runs healthy as can be and it's an honest 58 on gps with gear, cooler, ez up and one passenger with 3/4 tanks.
You can easily do 70 with it if you pull the jet out, patch the hole in the floor and transom, spin the motor around and throw some v drive hardware at it.
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Sounds about normal to me. As far as what would it take to make it go 70?
Double the horsepower and put it on a diet to remove over 400 pounds, sounds like I'm kidding right?
I'm not. :sly:
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Any recommendation to get it to do 65?( within a reasonable budget).
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Sounds about normal to me. As far as what would it take to make it go 70?
Double the horsepower and put it on a diet to remove over 400 pounds, sounds like I'm kidding right?
I'm not. :sly:
Oh..... :-[
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I say enjoy the boat. Mine runs mid 50's and I haven't had a horrible day yet. You'll find that most of your driving time will be pulling skiers or tubes or just cruising around 3400 rpm and having a good time. Put the money into making it comfortable and the stereo sound good. After all, you didn't buy a CP or Daytona, you have a fun, useful boat.
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Any recommendation to get it to do 65?( within a reasonable budget).
Not knowing exactly what's in it now, hard to say.
You almost can't miss with a little more camshaft duration, better top end (heads, valve train, carburetor etc...), hotter ignition and higher flowing exhaust.
Unfortunately, the side effects are, more noise, more maintenance, more gas and I have noticed fast boats make you more nervous as far as who you let drive it... :-\
As for the hull, less hook in the bottom, rough up the shiny gel coat on the wetted surface, move as much "necessary" weight aft and lose the rest.
Most of all, make sure the tune is DOBA... (Bead On Balls Accurate).
Also too, you can go faster down river. ;)
GT
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I say enjoy the boat. Mine runs mid 50's and I haven't had a horrible day yet. You'll find that most of your driving time will be pulling skiers or tubes or just cruising around 3400 rpm and having a good time. Put the money into making it comfortable and the stereo sound good. After all, you didn't buy a CP or Daytona, you have a fun, useful boat.
Winner winner chicken dinner... 8)
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I'd be with GT on this. 21', open bow, great pleasure craft, that does 55 MPH....I'd leave the focker alone and maintain it!!!!!
First, maintain it and keep it working, you see the threads on here how many of us are rebuilding or blowing $hit up???
A 21' heavy ass, open bow, boat to your target MPH is a VERY big order. And you're gonna burn through equipment to do it like I burn through a bottle of "Cabo".
Can't get half nekkid, bikini-clad women in a non-running boat in the driveway...............
Ray
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Problem is I can't leave stuff alone... :screwy:.. Can get some free procomp heads?( I know crappy out of the box,reason why free is my buddy dropped a valve,heard the castings are ok with work?) have an msd ign set up, pump is super sloppy and getting rebuilt, aed 750 dp carb, mild cam, with roller rockers, dual plane or high rise intake? most of these parts are free or cheap. ( pillaging friends garages ;D) what is the census?
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Don't touch the pro comp heads. For what it cost me to have mine taken care of I could of bought a set from any other manufacture
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I can get them redone pretty cheap.with all new name brand parts for under 500.
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Currently have a choice of 2 carbs. AED 650 double pumper ( milled choke etc.)or 750 Holley vac 2nds.(elect choke )?
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I've heard too many negative things about pro comps. Check over your fuel system. Start with how much fuel pressure it's giving to your carb, don't just start buying parts.
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Agreed on the procomps.mainly I've heard castings are o.k. But the parts used to put them together are garbage. Hence the dropped valve. I'm trying to make use of parts at hand.
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Not knowing exactly what's in it now, hard to say.
You almost can't miss with a little more camshaft duration, better top end (heads, valve train, carburetor etc...), hotter ignition and higher flowing exhaust.
Unfortunately, the side effects are, more noise, more maintenance, more gas and I have noticed fast boats make you more nervous as far as who you let drive it... :-
As for the hull, less hook in the bottom, rough up the shiny gel coat on the wetted surface, move as much "necessary" weight aft and lose the rest.
Most of all, make sure the tune is DOBA... (Bead On Balls Accurate).
Also too, you can go faster down river. ;)
GT
Defiantly agree. I was around 55 ish in the 20' Nordic. I built the motor to a 468 in the high 500hp range, Holley 850 w/ jetting at 80 squared, high flow 4" exhaust, full MSD ignition, droop, diverter, and less weight. I am now at an honest GPS 67mph, with just me, no coolers, and half tank of gas All that work, and that's all I'm getting. You can do some tinkering, and in tease ho numbers, but your not going to get too much more with out a BIG motor, race pump etc...
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Just bought a 21' bahner open bow, has a stock fresh 454 with stock jg pump with jetovator. How fast should it be? Old owner said only 55mph? What should I do to get 65-70 out of it?
I agree with everyone, not worth the amount of money for what you will gain. Leave it the hell alone and enjoy a mechanically reliable cruiser. Drop some coin on a longer bimi( open bows look awesome with a larger bimi and the people up front enjoy it) get 2 good batteries and a nice sound system. Buy some towables ( the 2 person sport inflatable ones are awesome, Own 2 myself) keep up on the maintenance, and enjoy it. Want something fast gonna have to buy something lighter and smaller and normally you don't go blasting around the lake wot.
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I will say make the equipment you've got efficient and the best it can be for what it is. I can say I'm happy with mine, until it breaks.
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Currently getting pump rebuilt adding an inducer while I'm at it. Back to my original question.
Unfortunatly im not going to leave it be.55mph is way too slow.
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The inducer is great for low end but wont' add any top end. I had the same issue with my 19 ft miller and to get from 55 to 70 (with one 220 lb person and 10 gal of gas) was about $8000 not including the lighting headers (water injected) and needed if you have a engine cover thats another $2300. You'll need the correct headers to avoid reversion from the increased cam you'll need for the hp. So If its worth about $10000 to do it than go for it. If your a gear head and can do the engine rebuild yourself costs come way down. Every 50 lbs is 1MPH so if you can loose 750lbs your there (just kidding)If I had it to do over I'd settle for the 55 just my opinion
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How about a 755hp blower motor. Think this will make my float scoot? :screwy:
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Just my .02. There are many reasons you do not see cadillac sedans running the NHRA or NASCAR circuit. They are built for a different purpose. You have a nice family boat. Everything you do will be a compromise. For what it will cost to build a RELIABLE 550-600 Hp engine, you could buy a hot rod boat that will run more than 70.