UZ torque in boat application

The 1UZFE EGR Delete Kit is available for sale here.

ozaristov300

New Member
Messages
7
Location
Hampton, Victoria Australia
From previous threads I note the standard torque of the 1UZ motor can be an issue in marine applications, leading some to go down the supercharger path.

For what it's worth, I was recently shown dyno graphs for a 1UZ-FE engine before and after the standard plenum chamber was replaced by throttle bodies and ram tubes (80mm). HP only increased 3% but peak torque increased by 47%. Is this therefore an option to supercharging?

Not being a boatie (other than a brief fling with a Bayliner 175 - useless ski boat), I'm confused by the claimed weight benefits of the all alloy V8 compared to the Chev engine, particularly when most ski boats I see on the Murray/Edwards seem to go to extraordinary lengths to add weight (ballast, wedge etc).

Hope this helps.
 

quadcam boat

New Member
Messages
358
Location
Emerald, Qld Australia
The weight thing is easy, if you are into wakeboarding, you need a massive wake so you have something to jump over. The guys that get off over wakeboarding load their boats up to the eyeballs with water sacks, or anything heavy to make a bigger wake. The Malibu boats have ann optional wedge that sucks the back of the boat down lower to do the same thing.

If you are into skiing, barefooting or most other types of skiing, you want the wake fairly flat, so weight savings are an advantage.
When it comes to performance, speed and racing, saving weight becomes even more important.
 

gr8dna

New Member
Messages
16
Location
SoCal
Well put. Two things I'd like to add about why drivetrain weight savings are cool to wakeboarders.

1) Towing. I appreciate the missing 300 pounds when hauling up a long grade. Then again, I've started to haul metallic weight around with me ;-)

2) Lighter engine allows you more control over where the weight/ballast is located.


For the most part, it's just cool to be able to say that our Epics have 300 HP and 315 Ft-Lbs out 600 pounds and 4 liters. Normally aspirated, no less.

When that little engine can get a 3500+ pound boat and three adults and 3000 pounds in ballast.....it's an effective little sucker.


Main thing about our engine in the boating application is not the weight savings so much as the fuel economy from MUCH improved efficiency as compared to 99% of towboat engines. Some of the other mfrs are putting Northstars in them, and that's really close to ours with a little more displacement. Not sure if it's VVT-i, but..

One last thing - from what I've seen on this site, the later generation 4.0s with VVT-i are much improved in terms of torque and power. Not a little bit, either. Of course, to get 300/315 out of an NA 4.0L, you've gotta pull out all the stops.

I love my engine, and although I'd REALLY like to build an aftercooled supercharged engine, I'm not sure I'd ever replace my stock Epic engine with it.
 

skiboat

New Member
Messages
5
Location
Torrumbarry Victoria Australia
I would like to enquire as to the props people are trying to run on their boats as you can prop any motor to get a desired out come. That is to say, if you put a prop on one type of motor say a 4 ltr motor you cannot use a prop that is suitable for a 5 to 6 ltr engine. I am yet to fit my motor in my boat but I have been fixing and setting up boats for 35 years. Austral in Sydney has a computor that they use, you put in the motor specs, boat hull weight & type and they will determine the right prop. Steve Morits has been making special variable pitch racing props to suit specific boats, to name but two. In my time in the boating industry the single biggest problem I deal with for private builders/fitters, is incorrect prop selection!!!!!!!!!!!!
Greg.
 

Peewee

New Member
Messages
2,637
Location
Perth, Western Australia
For what it's worth, I was recently shown dyno graphs for a 1UZ-FE engine before and after the standard plenum chamber was replaced by throttle bodies and ram tubes (80mm). HP only increased 3% but peak torque increased by 47%. Is this therefore an option to supercharging?
You have something WAY wrong there dude.

Factory Torque is about the 360Nm mark for the 89-94, 380Nm for the 95-97, and 400 Nm for the 98+ model.
The most Torque these motor will make NA is ~ 420Nm PEAK.
Which is about a 15% increase from 360Nm PEAK.


And the 3% power increase purely because the factory ecu sucks.
 

skiboat

New Member
Messages
5
Location
Torrumbarry Victoria Australia
jordys ski boat said:
Hi there skiboat
i am running a 13/16 prop behind my 1uz and it rev to 5500 rpm @ 98 Km/h(GPS)
What brand of prop?
That is a huge prop, I'm impressed with your motor. Not sure what you know about props but the following may help?
The first number is usualy the Diamiter and this determines how quickly the boat pushes out of the water on take off. The second figure is in effect the rev limter you usualy use it to set the top end. It is suppost to be the the amount of distance the boat is pushed foward each revelution (in Inches) there is an efficiency factor determined by the stiction of the hull your Stej would be about -25%. However, the most 3 blade props start to loose there abulity to work above 4,500 rpm (shaft speed) because of the size of the blades, there needs to be enough gap to let the water through in simple terms. I asume with the prop u use you mostly wake board?
To use the total range of your motor (will know more when I set mine up) you could try either of the following:a lay back style, this is a prop that has the blades leaning away from the motor, outboards use this to run higher rpm's. Or a prop with variable pitch, this design varies the pitch along the blade and can extend the efficiency range of the prop up high. The last thing is to source a smaller blade prop, most ski race boats "V" drives use the same direction of rotation and you can find many of these with smaller blades that have been cut or flaterned of the trailing edge.
Hope this helps or at least shares some knowledge.
Greg.
 

jordys ski boat

New Member
Messages
149
Location
frankston melbourne
hello Greg its an eagle prop made in SA it is a very high tuned prop
i tune and cup my own props
i have tryed 4 blades and a lot of three blades (eg) 12/15 3blade and the 1uz spins it
to easy
so i have found the 13/16 the best by far it did suprise me because a 350chev
would not spin the 13/16 over 3000 rpm
the supercharged 1uz has a lot of power it has plenty of speed for barefooting
i live in barooga on the river
 

craigzee

New Member
Messages
4
Location
aus
hey can anyone explain my prop to me
its a 3 blade prop only markings are LS14SC

cheers in advance
 

skiboat

New Member
Messages
5
Location
Torrumbarry Victoria Australia
Prop Info

Hi Craigzee, the prop you have is a LS14SC the "LS" is a code used by the prop manufacturer that tells you the diameter. The 14 is the pitch the amount the boat moves forward each rotation - hull stiction. The "SC" stands for "supper cup" a large blade with the back edge rolled up to stop the prop bogging down as the boat goes around turns.
Hope this helps, ring the manufacturer for the "LS" figure.
You can then use the info above to determine if your prop is the one you want.
Greg.
 

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craigzee

New Member
Messages
4
Location
aus
thanks skiboat, for the speedy reply, any ideas on how to work out the manufacturer? nothing is written on the prop, as for supper cup, in my application it doesnt seem to do anything bogs down pretty hard into corners, plan is to remove the thirsty 351c and replace it with a megasquirted 1u and some how run it with no o2
 

skiboat

New Member
Messages
5
Location
Torrumbarry Victoria Australia
If you place the prop back down on a piece of paper or card, mark the centre hole and the outer three points, you can the measure the diameter. That will give you the total dimensions. 13 x 14 etc. This is provided the prop is original. Best give me a call. 03 54877358 during business hours I can explain quicker that way.
Greg.
 


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