True or false a 4stroke has better low end torque

[boater1234]

I was at the florida sportsman show this weekend and talked to a few merc dealers that told me that a 4stroke has better low end torque,also has better torque at the lower rpms,is this true?Also i was looking at the 20hp 4stroke mercs when he told me this.His response was the 4stroke will have better low end torque and the 2stroke will have better top end.Is there really any truth to this as this is not the first time i have heard this?He said when you hit the throttle for a 4stroke it has instant response as with a 2stroke it has to work a little harder if you floor it.I don't think he cared either way if anyone bought a motor or boat that is why it sounded so real to me.I asked him for a price way after we were done talking.Even a tohatsu dealer told me the same thing.So 3 different dealers told me the same thing without trying to push a sale on me.

Could it be possible they do but they are just so heavy it takes so much time for them to get on plane so it seems like the 2stroke has more power at the start,plus they are way lighter.Just asking a question here as it has peaked my interest.The reason for the queation is they had a nice fiberglass hull about 300lbs with a 20hp 4stroke merc and the guy said it gets on plane extremely fast and tops out at about 33mph.That is what got my attention to begin with.I like the 20hp merc/tohatsu it looks like a tuff motor with tons of power.Well i got thinking as i have a 2stroke i will spend a ton on oil for the next how ever many years as with this motor i change the oil once a yr and done so that equals like 8$ a yr for oil compared to like who knows 10 bottles of 2stroke oil a yr which is like $250.So in ten yrs it will be like $2500 in oil spend compared to $80,wow what a difference.This is got me thinking now as i may go with the 20hp 4stroke.Plus the guy offered me a deal on a 2011 merc 20hp for $2449+tax as i think thats awesome.Well i will see what the experts say about the low end power issue.

 

[F_R]

Re: True or false a 4stroke has better low end torque

Of course a 4-stroke needs more torque to handle the extra weight hanging on the transom. But generally speaking much of what you say is true. But a blanket statement like that can and does have exceptions. Besides, the propeller is the final connection with the water, and much can be done along that line.

It also is true that a two stroke is lighter, less complicated with fewer moving parts, runs cleaner (speaking of internal cleanliness), and less recriprocating weight. It is also true that they are almost a thing of the past due to environmental restrictions (ETEC being an exception).

 

[seahorse5]

Re: True or false a 4stroke has better low end torque

As F_R stated, you cannot make a blanket statement as everything depends on the design and purpose of an engine.

Here is a widely publicized torque chart comparing the 2-stroke Evinrude E-TEC V-6 to a 4-stroke Yamaha V-6. The 2 stroke is quite a bit more powerful in the midrange.

In the 20-25 hp range, the 2-stroke 25 E-TEC has instant starting and instant response compared to the carburetor equipped Mercury or Yamaha 4 stroke of similar hp.

Other makes and models may have different results.

that's not to say that 4-strokes are bad, but consider the source of your "information" - salesmen

 

[Bob_VT]

Re: True or false a 4stroke has better low end torque

Horsepower is horsepower. You are over thinking the situation.......... we are talking about a 20 HP outboard which will not be a primary water sport motor and will not be competing with a bass boat. Trust me the only time you will worry about low end power is in a severe storm or current. With everything being somewhat equal....... ANY new motor with a warranty is good.

I think all of the information is related to the use of the motor.

 

[metriccrescentwrench]

Re: True or false a 4stroke has better low end torque

Here is a widely publicized torque chart comparing the 2-stroke Evinrude E-TEC V-6 to a 4-stroke Yamaha V-6.

...... but consider the source of your "information" - salesmen......

Working from the numbers in that graph, the "225" HP E-Tec puts out a peak of 240 HP at 5500 rpms, while the Yamaha puts out a peak of only 217 HP at 6000 rpm - and that's IF the numbers on the graph are to be believed. The source of that graph - salesmen.

 

[lncoop]

Re: True or false a 4stroke has better low end torque

I think boater just loves small outboards and enjoys thinking about them a lot.

 

[Frank Acampora]

Re: True or false a 4stroke has better low end torque

Since a 2 cycle engine has one power stroke per cylinder per revolution and a 4 cycle engine has on for every two revolutions: A two cylcle engine OF THE SAME NUMBER OF CYLINDERS AND DISPLACEMENT as a 4 cycle will have MORE torque at both lower and upper RPMs! No mystery to it, just science.

And since the 4 cycle engines have less low end torque, they may have trouble getting a hull onto plane. To combat this very real problem, Mercury SUPERCHARGED the Verado engines to increase low speed torque.

 

[metriccrescentwrench]

Re: True or false a 4stroke has better low end torque

A two cylcle engine OF THE SAME NUMBER OF CYLINDERS AND DISPLACEMENT as a 4 cycle

But that's not the same as comparing two engines of similar HORSEPOWER. In THEORY, a 2 stroke engine of a given displacement should be able to make around twice as much power as a 4 stroke engine of the same displacement.

I believe what a lot of people are using as data points in this discussion are the really high revving 2 stroke racing engines. They get a lot of help from being able to use tuned exhausts (expansion chambers), and are set up to make a lot of power at really high rpm's. The go-cart engine I used to race revved to somewhere around 18,000 rpm, and it was a dog until it got up around 10,000 rpm. That was mostly because of how the exhaust was tuned.

 

[Silvertip]

Re: True or false a 4stroke has better low end torque

In just about all cases, the two stroke engines to this day have had WOT recommendations of somewhere between 4500 and about 5800 rpm while most of the four strokes these days have their WOT recommendations in the 6000+ range. So much for high rpm power comparisons. Not only that but many 4-strokes also have a higher ratio (lower gear) gear set than an equivalent two stroke to compensate for the lack of hole shot. Once up into the high horsepower ranges those differences are less dramatic. Getting performance from a four stroke involves cam, compression, carburetion (fuel injection) and timing. One can only massage camshafts so far and water reversion becomes an issue. Carburetion can dump as much fuel into the engine as the designers want but if the cam/valve size/duration won't allow its use there are power limitations. Four strokes can make top end power just like the go cart engine but also like them, they wouldn't be able to pull a sitting hen off her nest. Power tuning is possible on any engine but when dropping that engine into a boat, there are limitations as to what can be done. Land based vehicles have multi-gear transmissions to keep engines on their power band. Boats have one gear and needs to pull from a dead stop to wide open. try that in high gear with your stick shift car (or even second or third gear).

 

[TOHATSU GURU]

Re: True or false a 4stroke has better low end torque

Horsepower is horsepower. You are over thinking the situation.......... we are talking about a 20 HP outboard which will not be a primary water sport motor and will not be competing with a bass boat. Trust me the only time you will worry about low end power is in a severe storm or current. With everything being somewhat equal....... ANY new motor with a warranty is good.

I think all of the information is related to the use of the motor.

I coudn't agree more.

 

[boater1234]

Re: True or false a 4stroke has better low end torque

This is not about the motor,it's about what i was told and whether it's true or false.The only reason that the 20hp caught my eye is that is the biggest motor i could afford first of all so why would i look at anything bigger.Plus this dealer only had smaller boats there with all 15 and 20hp mercs on them.All i said I wanted to know if what they were telling me was true or not.Also i just don't understand the etec and the 4stroke comparison that is charted on here.

Seahorse5 that is not a fair comparison by evinrude when you put a heavier engine vs a lighter engine.Now i will almost bet if they went with yamaha v max sho the outcome would be much different or even lets do the HPDI direct injected 2stroke 175 vs a etec 175 thats a better comparison.Etec did that test because they new they were sure the yamaha 4stroke would fail.Put a fair test of 2 direct injected motors of the same size and displacement against eachother and see what happens.I don't think you will see the same outcome.

All i was saying also was i was thinking of the difference for me with the 2stroke oil to as i will save a ton of money on oil.The 2stroke merc eats oil and the 20hp 4stroke you change oil once every 100hrs as with any 4stroke.I never realized how much oil i will use through the lifetime of my 2stroke compared to only changing it once a yr in a 4stroke.

INCOOP you are right i have a passion for boats and motors like no other.I could go to a place and just observe all the boats and motors they have.I find these machines to be awesome and it just amazes me how far our technology has come.I love going to boat shows.It's not about whether i can afford one or not either,it's just i enjoy looking at boats and also cars and trucks.My passion was always for boats when i was very young.Even if i had a ton of money i have always liked small boats,big boats are to much work.My uncle told me a quote that i know everyone has heard a million times.The best day is when you buy a boat,the second best day is when you get rid of it because of how much money they usually end up costing you.With all these great new technologies and great warranties i belive alot of peoples outlook has changed a bit.It's just good down time for me.

 

[lncoop]

Re: True or false a 4stroke has better low end torque

Hear ya.

 

[JimS123]

Re: True or false a 4stroke has better low end torque

This is not about the motor,it's about what i was told and whether it's true or false.

There's your problem!

Back in the 1960's the marina people were experienced and when they told you something you could count on it. The owner and his son ran the business.

Today, the owner has retired and the grandson owns the business, but he's seldom there. The kid in the shop is a salesman and he don't know crap, but he thinks he does.

I realize its a generalization and a stereotype, but its all too often true.

 

[RRitt]

Re: True or false a 4stroke has better low end torque

Two strokes only get a complete burn cycle with no waste when the outboard is spinning at the perfect speed. At that speed, the burn is complete when the intake valve opens and the fresh intake gas does not get a chance to mix with exhaust fumes before the exhaust cycle is finished. In effect, each of the four cycles takes 1/2 of a stroke with no overlap. At that specific speed the 2 stroke will deliver better torque and power than a four stroke. At all other speeds the four stroke has an inherent efficiency advantage for a given displacement, compression, and fuel consumption.

 

[QC]

Re: True or false a 4stroke has better low end torque

I'll mess this all up, the most powerful (torque and horsepower) AND most efficient reciprocating engine in the world is a two cycle. What does this have to with this discussion? Nuttin'. Oh, and I never met my grandfather and my dad left when I was 6 and I'm a salesman . . .

 

[boater1234]

Re: True or false a 4stroke has better low end torque

Very interesting RRITT.So basically the 4stroke has more of the advantage like you said except when the 2stroke is spinning at the perfect speed.I guess we will never know what that speed is though right.So overall through out the rpm range the 4stroke will fare better.A car seems to have great get up and go when you floor them,so i guess this would be the same concept your saying.One thing i have noticed is almost all the 4stroke motors have way better gear ratios then 2strokes to make up for the power loss.Suzuki is one of those companys that is doing that with almost all their motors.One day they will have these 4strokes a ton lighter and more powerfull then ever.I think they are very close to getting that done.Look at the new 70hp yamaha at like 257lbs compared to their own 75hp 4stroke at 369lbs.The original 70hp 2stroke which i had a few yrs ago was at 238lbs so they are getting real close to weight.Makes you wonder though what are they taking out of these motors to make them over 100lbs lighter,or they are made way cheaper.Alot of plastic on these newer motors.

 

[foodfisher]

Re: True or false a 4stroke has better low end torque

See stupid human tricks "Don't buy this boat"

 

[jay_merrill]

Re: True or false a 4stroke has better low end torque

Evinrude has a very interesting DVD that touches on this subject. They pitted a pair of identical boats against one another, by putting a two-stroke ETEC 150 on one and a four-stroke Yamaha 150 on the other. They then tethered the boats stern to stern.

Upon a signal, both operators slammed the throttles into the wide open position. Within a few moments, the ETEC literally pulled the stern of the boat with the Yamaha under water and sank it.

 

[boater1234]

Re: True or false a 4stroke has better low end torque

Once again that is an unfair evinrude etec video.They knew before hand the 4stroke would fail or they would of never done the live tests.The main reason is probally it weighs much more then the etec.Like i said also in my last post lets do the yamaha 150 sho vs the 150 etec or the hpdi 150 vs the 150 etec and it will be a whole different outcome.Who knows the etec may still win but i bet it would be a closer battle then what is seen.Evinrude wouldn't put a dvd together if they knew there motor would fail against the 4stroke.This was all planned out from the start.I would bet the sho would pull the etec backwards.But we will never know as evinrude would never dare to go that route.Is the etec a good motor,100% but very misleading.I have seen both motors in action and they are both good motors but i would take the yamaha sho before the etec.Just my opinion.Also when i say low end torque i mean like in the lower rpm range not just hole shot.Probally the main reason the 4stroke won't plane as fast as the 2stroke is the weight it must carry.It is really a hit and miss on some motors as some 4strokes have really good low end torque because of they way they are gearing them now.I guess we can conclude the 2stroke will always be better at planing from a stand still i gather,the 4stroke will have better low and high end torque in the lower rpm range and the upper rpm range.So there is good and bad.

 

[bassman284]

Re: True or false a 4stroke has better low end torque

Yah, the old "hole shot' BS. I have a 60 hp Merc 4 stroke on my Lund and if I had any more hole shot I'd launch the boat clear out of the water.