Was watching Ship Shape TV....

[rodbolt17]

remember, when that Yamaha left Japan it had no prop. that was added at the builder/dealer level.
not all builders/dealers are worth dealing with.

[zenoahphobic]

Coriolis effect is greater on 4 strokes.

To that then follows LH props must therefore perform differently to RH ones. So which setup performs better on a four Stroke?

[BQUICK]

So how would a vented prop work on a 4 stroke? If their power band is higher up than a 2 stroke I feel it would be like putting a looser converter in my drag car.

Right, that's my point. Ship Shape was saying the 2 stroke needed the vents due to lack of torque...... I was thinking they got it backwards.

[rodbolt17]

depending on the application both engine designs can benefit from proper venting.
remember a two stroke has a powerstroke every time the piston comes up. a 4 stroke every other. both may have 6 cylinders. which one you think would have more bottom end grunt. until you toss in VCT.

[boscoe99]

remember, when that Yamaha left Japan it had no prop. that was added at the builder/dealer level.
not all builders/dealers are worth dealing with.

The manner in which maybe 90% of all new motors are over propped coming from the dealer or boat builder, I would suspect that most are not worth dealing with.

But then maybe it does not matter since maybe 90% of motor owners neither know or care what propeller is on the motor or how the motor performs.

Seems also that maybe 90% of all new motors are mounted lower than is optimum. To avoid a come back issue I suppose. So 90% of motor owners take a hit in less than optimum performance so the dealers don't have to deal with a few that might. A race to the bottom if you will.

[boscoe99]

Right, that's my point. Ship Shape was saying the 2 stroke needed the vents due to lack of torque...... I was thinking they got it backwards.

Nope, they had it correctly. But they might have been basing it on the two stroke performance from years gone by.

Today's two strokes are not the two strokes of old. You also can't go comparing a doggy four stroke of old with a high performance four stroke of today either.

[boscoe99]

depending on the application both engine designs can benefit from proper venting.
remember a two stroke has a powerstroke every time the piston comes up. a 4 stroke every other. both may have 6 cylinders. which one you think would have more bottom end grunt. until you toss in VCT.

Let's not leave out of the equation that the power pulse from the four stroke piston is about two times what the power pulse is from a two stroke piston. In theory, if the torque and thus the HP are the same at a given RPM then the perceived performance would be the same. Just two different ways of meeting the same objective.

I don't have a dog in the two stroke versus four stroke debate. I am a four stroke guy but don't mind if folks buy and use a two stroke. For some reason however, particularly on THT, it just chaps the ass of two stroke owners that four stroke motors dominate in today's market place. Why do they even care? Just buy and use what you want and don't be worrying about what the other man uses.

[oldmako69]

To that then follows LH props must therefore perform differently to RH ones. So which setup performs better on a four Stroke?

That depends upon which hemisphere the engine is being operated in.

[boscoe99]

That depends upon which hemisphere the engine is operating in.

It is hell crossing the equator from due north to due south in a single screw vessel. The whole ship shuddered violently as we crossed over. The swirl in the shit cans stopped turning in one direction and then started turning in the opposite direction.

It used a two stroke power plant.

[oldmako69]

Tne swirl can also be affected by P factor and angle of incidence. There are many variables.

[boscoe99]

AOA also.

What a bunch of BS'ers we be.

[panasonic]

depending on the application both engine designs can benefit from proper venting.
remember a two stroke has a powerstroke every time the piston comes up. a 4 stroke every other. both may have 6 cylinders. which one you think would have more bottom end grunt. until you toss in VCT.

Outboard VCT basically the same as a automobile/motorcycle system Rodbolt?

https://youtu.be/ry2nP7I315M

I honestly don't know what is the big deal about this Hole shot business is?


Your boat (same boat) can reach X mph 2 or 3 seconds before mine? Your engine is therefore a piece of sht!! So what. (let the rock throwing begin)

I have a 2 stroke and will keep it till it is done...noisy bugger.

Also have a FS and like it better because it is quiet, good on gas and don't pollute the environment as much.

[boscoe99]

I agree with comment about not understanding the hole shot business. I don't stomp on the gas pedal of my auto or truck and I very rarely go wide open throttle with my boat motors. If and when I am at WOT I did not get there from idle.

[zenoahphobic]

I think the prevalence of "high" performance in cars, lawn mowers, blowers, motorcycles to boats etc. says that the consumer wants power.

In my case I have lived through when things were "gutless" and boats requiring adequate thrust for waterskiing. So most of my life I have had to push pedals to the floor. Maybe that's why I tend to like to accelerate hard now and again - it gives me a freedom buzz. Now in America you have had no shortage of building everything big, so a complacency factor might be there in your attitudes., happy knowing you can floor it anytime.

A bit like the owner of an expensive ridiculously overpowered sports cars. Most places you simply cannot use the potential of these vehicles. What's stupid speed limiting, traction control and various vehicle controls about? We have motorcycles built in Japan that are large capacities and then really restricted for new drivers (LAMS system).

[rodbolt17]

I drove a 1970 w-30 442 for better than 22 yrs.
sometimes it was just a hoot to simply feel the back end try to pass the front end on rapid acceleration.
why the flats and bass boat dudes are so keen on hole shot???? dunno.
aint a bass on the lake can out run them.
my service managers ranger runs in the low 70's.