4 stroke vs DFI

[swist]

So given the data we are seeing in some other threads and in the literature, what are the reasons for prefering a DFI two stroke over a 4-stroke, given similar fuel efficiency and compliance to 2006 EPA?<br /><br />As I see it the 4 strokes are heavier, sometimes by a lot - they have a lot more moving parts but they are based on car technology which is pretty well proven. Most 4-strokes have a pretty good reliability record. DFI engines have not been around long enough to give a true picture of their long-term reliability. Though they have fewer moving parts, the are still technically very complex. Changing oil vs adding oil to the gas seems to me to be a wash - not something you'd base a major purchase decision on. Nor does it seem like there's going to be a huge difference in price once all the mfgrs are going full bore with production of both types and competition sets in.<br /><br />And this is just IMHO... the DFI, being an evolution of the 2 stroke technology used for years, seems somehow to be a better "fit" to the marine enviroment. I can't give quantitative data for this, but the 4-stroke strikes me as a bit of a square peg in a round hole - not quite as blatant as the stern-drive, but you get the idea. <br /><br />Any thoughts?

 

[WillyBWright]

Re: 4 stroke vs DFI

I like the DFI concept. Different manufacturers go about it in different ways, and who's proves to be the most durable will prevail. The rest will cop out and go 4-stroke. The weight issue is huge. Imagine that technology working it's way into sport aviation. Maybe even Indy cars, atlhough I don't think they'll ever make it as a conventional motor replacement. Powering a hybrid? Or adapting it to a Rotary, now that'd be exciting. A DFI Rotary Hybrid car. I Like It!<br /><br />As a sport outboard for going fast, 2-strokes all the way!

 

[Forktail]

Re: 4 stroke vs DFI

Any thoughts?

4-stroke = pressurized, filtered lubrication system = better longevity, durability, and dependability.<br /><br />As for the weight...check out Suzuki's Fuel Injected DF140 4-stroke at 410 lbs vs. Evinrude's 135 DFI at 419 lbs. Check out Yamaha's Fuel Injected F150 at 466 lbs vs. their DFI 150 at 468 lbs. It looks like some of the DFI's know how to pork it on too. <br /><br />The point about aviation brought up a good reminder....you don't see 2-strokes in certifed aircraft.

 

[seahorse5]

Re: 4 stroke vs DFI

Those are weight comparisons between V6 DFI motors and inline 4 cylinder 4-strokes.<br /><br />In the popular 200-225 hp category, what are the different weights between each manufacture's V-6 4-stroke compared to their V-6 DFI offerings? That would be closer to comparing apples with apples, and not oranges.<br /><br />If you don't have the info yet, the 2005 Evinrude 200-225-250 hp E-TEC weighs 524# with a 20" shaft and 532# with a 25" shaft.

 

[Forktail]

Re: 4 stroke vs DFI

Seahorse, whether you want to except it or not, when it comes to weight there are some 4-stroke EFI's that are lighter than similar horsepower 2-stroke DFI's. My examples were comparisons between similar horsepower, not engine block design. <br /><br />It's not my problem, or a detriment, that an EFI 4-stroke can use a different style block to accomplish the same HP as a heavier DFI.<br /><br />

If you don't have the info yet, the 2005 Evinrude 200-225-250 hp E-TEC weighs 524# with a 20" shaft and 532# with a 25" shaft.

You make it sound like that's big news or something??<br /><br />Those are the exact same weights that those DFI Ficht Ram Evinrude's have been for the past several years. <br /><br />And if you want to try to compare a Ficht to a 4-stroke in that HP range, then you'll really be comparing apples to oranges. As the Ficht is a POS and the 4-strokes are Cadillac's. <br /><br />BTW, any little bit of extra weight on a boat that can handle 200-250 HP is moot, IMO. And don't forget you'll have to add in the weight of your remote oil reservior and rigging, plus a tub full of spare spark plugs and some extra tow rope.

 

[quantumleap]

Re: 4 stroke vs DFI

Why do people always point out that the midsize 4-stroke are 4cyl. as opposed to v-6. The inline design offers lots of benefits, including less weight and lack of vibration. <br />Forktail is comparing equal hp rated motors. If they achieved them with an updated inline 4cyl design as opposed to a v-6, so be it. <br /><br />Inlines are the wave of the future as V-6 have the same inherent design flaws as v-6 auto motors. It is common knowledge that the inline 6 is a smoother design that can generate more hp and torque than a similar sized v-6. It's just when the gas crunch hit in the seventies, the auto makers knew that buyers would balk at going backward in time by switching form a v-8 to a inline six, so they lopped two cyls off the v-8 to have a more hi-tech sounding "v-6". Problem was, most of the american v-6 auto motors were/are junk and ran and idled like crap. The move back to the inline design was inevitable and is here to stay.

 

[JB]

Re: 4 stroke vs DFI

I'm a FORD man myself.<br /><br />You will get many opinions presented as though they were facts. Evaluate them accordingly.<br /><br />I love my 4 stroke, lots of guys love their DFI 2 strokes. Nothing can convince either of us that we made the wrong choice. In my opinion, we probably both made excellent choices.

 

[DJ]

Re: 4 stroke vs DFI

In line 6 versus V-6.<br /><br />Actually, the V-6 was adopted due to "packaging" and crash worthiness.<br /><br />An in line six is difficult to "package" in a smaller vehicle. It is also harde to deal with as far as crash preictability. The more compact V-6 package behaves diferently in a front end collision.

 

[quantumleap]

Re: 4 stroke vs DFI

During the gas crisis, the underhood area was as big as it has ever been and there was plenty of room for inlines. The manufacturers wanted a motor that was more fuel efficient, meeting new EPA requirements, than a v-8 but that they could still market as hi-performance, thus the "v-6" was born. Chevrolet's early v-6's were the same bore and pistons as the old small block v-8's, just with two cylinders missing. This was also cheaper from a design standpoint than redesigning and updating the inline 6.

 

[seahorse5]

Re: 4 stroke vs DFI

Just to keep things in perspective and to compare weights of 4-stroke and DFI outboards of the same engine style (6 cyl.) and power range (200-225), the following is a list of motors and what they weigh. This way you are comparing apples to apples using engines with the same cylinder configuration and same power rating.<br /><br />Mercury 225 Verado 4-stroke 649#<br />Mercury 225 OptiMax 497#<br /><br />Johnson/Suzuki 225 4-stroke 580#<br />Evinrude 225 E-TEC 532#<br /><br />Yamaha 225 4-stroke 583#<br />Yamaha 200 HPDI 466#<br />(no 225 25” HPDI for ‘05)<br /><br />Honda 225 4-stroke 599#<br /><br /><br />The four 4-strokes average just over 602#<br />The three DFI motors average slightly above 498#<br /><br />The 4-strokes average about 21% heavier than the DFI's. This is not a condemnation of any type of motor, just a comparison.

 

[Forktail]

Re: 4 stroke vs DFI

Seahorse, the Verado has a supercharger, integrated hydraulic steering, and a larger alternator for Pete's sake. Apples to apples? Not.<br /><br />Plus you've figured in the 25" shaft weight for the Honda and Yamaha 225's, yet used the 20" shaft weight for the Optimax. Tricky.<br /><br />Not to mention you figured in a smaller 200 hp DFI with the larger 225 hp 4-strokes. No Apples to apples there buddy.<br /><br />Don't forget to add in the weight of the 2-stroke oil tank reservoir and it's rigging. You missed that.<br /><br />So lets look at some more....<br /><br />If in-line blocks are your hang up, then check out the in-line Optimax 75 at 375 lbs. Even the in-line, 4-stroke Honda 75 and the larger Yamaha in-line 80 weigh less (373 lbs and 356 lbs respectively).<br /><br />Lets take the E-Tec's smallest model, their in-line 40 hp at 235 lbs. Again, the 4-stroke, in-line Honda comes in almost 40 lbs lighter at 198 lbs. The Yamaha inline 40 is lighter too at 198 lbs. That's a big difference for such a small outboard! <br /><br />Oh, yea...same with the 50 hp too.<br /><br />Now lets look at the most popular segment of outboards...those under 40 hp. Oooops....I guess they haven't figured out how to get DFI to work on those smaller outboards yet, while you find 4-strokes in even the smallest of outboards.<br /><br />I won't go on. But you get my point. If you're going to use weight as a reason to justify a DFI over a 4-stroke, you're only going to be able to do it in a few limited applications. And even then, IMO a few extra pounds on the big HP models are well worth the benefits you will receive in longevity, durability, and reliability. If weight is that big of a concern, get a 2-stroke outboard with carbs, and cut out the prime rib and beer.<br /><br />The DFI's aren't light. And no matter how light they might get, they'll still be unreliable DFI's. When they prove themselves over thousands of hours on a commercially operated fishing boat, and I start seeing them in aircraft, then I might give one a try again.

 

[seahorse5]

Re: 4 stroke vs DFI

Forktail wrote:<br />...you've figured in the 25" shaft weight for the Honda and Yamaha 225's, yet used the 20" shaft weight for the Optimax. <br /><br />Oops, you're right, I missed that, so you have to add about 9# to the total. Thanks for pointing that out.<br /><br /><br />Forktail wrote:<br />Not to mention you figured in a smaller 200 hp DFI with the larger 225 hp 4-strokes.<br /> <br /><br />Yammy doesn't make a 225 HPDI and that was noted in the figures. <br /><br /><br />Forktail wrote:<br />Now lets look at the most popular segment of outboards...those under 40 hp. Oooops....I guess they haven't figured out how to get DFI to work on those smaller outboards yet, while you find 4-strokes in even the smallest of outboards.<br /><br /><br />2 years ago I watched Bombardier demonstrate a 3.3hp E-TEC motor showing things to come. The design has been around since 1999 when OMC developed it as FICHT II. They also adapted it to a chain saw for R&D. Since it's magneto and doesn't need a battery, belts, air compressors, or 1000 psi fuel pumps, the system can be scaled up or down depending on the motor size.

 

[tym42ply]

Re: 4 stroke vs DFI

Since this thread started out as a compairison of the 2 technologies we should also power, fuel economy and enviromental impact. <br /><br />Power: No contest 2-stroke DI wins hands down.<br /><br />Fuel Economy: The new E-Tecs are actually much better at low speeds and equal mid range and WOT<br /><br />Emmissions: Almost the same when we are talking HC and Nox, but the new DI's are much much better on CO. Not to mention the emission level for 2-strokes account for all the oil used, 4-s do not account for the oil once it is removed, it still has to be disposed of.<br /><br />I just don't see any advantage for a 4-S.<br /><br />Oh and as for dependability, Forktail, you are be compairing today's 4-S to the old OMC Fichts. If you knew anything about today's direct injection engines you would know that they are very reliable and even better in the case of the E-Tecs.

 

[jegervais]

Re: 4 stroke vs DFI

Let the fun begin...<br /><br />Hey gang, direct from the Mercury Verado sight, they have this note at the bottom of the specification page for 225 Verado:<br /><br />"* Comparative weight refers to base engine with out oil, propeller or integral steering cylinder. This figure will provide apples to apples comparison to the competition."<br /><br />Apparently the manufacturer thinks it's an apples to apple comparison.<br /><br />Wonder how much it weighs when you add 2 gallons of oil, a prop & the steering system?<br /><br />Also, since the inline blocks are mentioned, don't forget the E-TEC 75/90 (20") tip the scales at 320 lbs.<br /><br />Regarding the "little DI's", I too have seen the 3.3 sea horse mentioned, as well as a 25 horse one. They're coming. <br /><br />BTW, there is a resort outfit out on Lake Mead (I think it's called Forever Resorts??) that rents out house boats to tourists/vacationers. Most of their fleet is being upgraded now, but they've been running 1999 Evinrude 90/115 Fichts since 1999. Almost all of the engines have between 3000 to 5000 hours on them.

 

[ivar]

Re: 4 stroke vs DFI

I'd think its a bit early yet to say much about the reliability of the E-tec engines , but I'm sure they have undergone some of the most extensive and rigorous testing in the boating industry. <br />I have both 2- and 4-strokes (Yamaha) and I like'em both. <br /><br />As for the 2 vs 4 reliability , it seems to me that a lot of peoples problems are fuel related, a 4-stroke is less likely to fry a piston , but it will run like crap too if it don't get the fuel it wants. <br /><br />As I see it , both have their places, for fishing and cruising I'd pick a 4 , for skiing and more performance-oriented boating, 2-stroke all the way for me.

 

[red10]

Re: 4 stroke vs DFI

Ivar, I can't agree with you more, bass boats have dfi and pontoons have 4 stroke

 

[NOSLEEP]

Re: 4 stroke vs DFI

Even some of us fish'n and cruising guys prefer<br />a 2 stroke.

 

[Forktail]

Re: 4 stroke vs DFI

Seahorse, if we add in the weight error you made on the Optimax, remove the 200 HP outboard from the 225 hp comparison, and remove the odd ball Verado from the comparison, we end up with 11.5% more weight in that particular HP class. Not 21%. I think you we're being a little deceptive.<br /><br />Adding the Verado to your comparison would be like adding carbureted models to your DFI examples. Different outboard technology. New outboard technology. The Verado is certainly in a class by itself. The Verado is supercharged and inter-cooled. Integrated digital throttle controls. Electro-hydraulic steering. And lets not forget the 225 Verado you used in your comparison is the same basic outboard, with the same weight, as the 275 Verado.<br /><br />As for DFI in the smaller outboards.....We could talk all day long about R&D, what's to come, and the future of the Universe. But back on Earth, I'm talking about an outboard I can buy and use. So ask yourself if there's already DFI technology in small outboards, why we can't buy it? Hmm. <br /><br /><br />tym42ply,<br /><br />

Power: No contest 2-stroke DI wins hands down.

There are examples (on identical boats) showing where 4-strokes can plane faster and have better top end. The 4-strokes (especially the in-line's) have a reputation of great low-end and midrange torque.<br /><br /><br />

Fuel Economy: The new E-Tecs are actually much better at low speeds and equal mid range and WOT

Again, there are many examples where 4-strokes outperform DFI's in fuel consumption.<br /><br /><br />

Emmissions:

Who cares...they all meet the EPA requirements.<br /><br /><br />

Not to mention the emission level for 2-strokes account for all the oil used, 4-s do not account for the oil once it is removed, it still has to be disposed of.

4-strokes don't burn the oil and expel it into the water and atmosphere like a 2-stroke, never to be seen again. 4-stroke oil can be recycled or used for other energy purposes.<br /><br /><br />

I just don't see any advantage for a 4-S.

Pressurized, filtered lubrication system. Proven, reliable fuel injection. Instant, smokeless starts. Quiet, clean, and smooth running. Better longevity, dependability, and reliability. Better resale. <br /><br />And...from JD Power:<br /><br />"Consumers who purchased a new boat equipped with a two-stroke outboard engine report twice as many problems as those who purchased a boat equipped with a four-stroke outboard engine.....Owners of new boats with four-stroke electronic fuel injection (EFI) outboard engines report the fewest number of engine problems, while owners of boats with two-stroke carbureted outboard engines report the most problems, according to the study."<br /><br /><br />

Forktail, you are be comparing today's 4-S to the old OMC Fichts. If you knew anything about today's direct injection engines you would know that they are very reliable and even better in the case of the E-Tecs.

You are mistaken. I'm a commercial fleet operator. I run the best I can find. I have to

 

[Forktail]

Re: 4 stroke vs DFI

John from Illinois,<br /><br />

Hey gang, direct from the Mercury Verado sight, they have this note at the bottom of the specification page for 225 Verado:<br /><br />"* Comparative weight refers to base engine with out oil, propeller or integral steering cylinder. This figure will provide apples to apples comparison to the competition."<br /><br />Apparently the manufacturer thinks it's an apples to apple comparison.

You might as well compare carbureted 2-strokes to DFI 2-strokes. Or maybe you don't understand the unique induction system of a supercharger.<br /><br />There's no other outboard to compare to the Verado. That is, unless you can find another supercharged outboard with the new technology and features of the Verado? So of course Merc considers it an apples to apples comparison...they're the only apple.<br /><br /><br />

Wonder how much it weighs when you add 2 gallons of oil, a prop & the steering system?

No outboard that size will come with steering, a prop, and oil.<br /><br />The point is that it won't need a remote oil reservoir and the rigging like a DFI. And whether the Verado comes with the electro-hydraulic steering installed or not, it's design is integrated into the outboard itself, along with the digital throttle and controls. That's weight, and a totally different technology that your DFI's won't have. Hardly apples to apples.<br /><br /><br />

Also, since the inline blocks are mentioned, don't forget the E-TEC 75/90 (20") tip the scales at 320 lbs.

Well, it looks like you're willing to sacrafice weight for technology where 2-strokes are concerned, yet ignore the fact 4-stroke technology is getting lighter.<br /><br />The E-Tec 75/90 is heavier than traditional 2-strokes, like the Yamaha 90 at 261 lbs or the Merc 90 at 303 lbs. Even Yamaha's 4-stroke F80 comes in only 36 lbs heavier...and it's got 4 cylinders compared to the E-Tec's 3-cylinders! More poof that the DFI's aren't light-weights at all.<br /><br /><br />

Regarding the "little DI's", I too have seen the 3.3 sea horse mentioned, as well as a 25 horse one. They're coming.

So why isn't it available for us to buy? What good does it do us? Hmm. In the mean time the little 4-strokes are chugging away. <br /><br />

...they've been running 1999 Evinrude 90/115 Fichts since 1999. Almost all of the engines have between 3000 to 5000 hours on them.

3000-5000 hours...on fleet outboards...operated by tourists...on house boats....and they're Ficht's....<br /><br />That might just deserve a phone call. Or maybe as a Johny/Evinrude dealer, you're just exaggerating a tad much.

 

[quantumleap]

Re: 4 stroke vs DFI

The way I see it, the increase in performance of 2 strokes over four strokes is rapidly diminishing while the reliablity of 4 strokes over 2 stokes is growing except for the reported service EXPECTATIONS of the e-tech motors. Time will tell on these. If they can really run 3 years with no problems or service, they will be a viable alternative to the idea that 4 strokes would have be the motors of the future, based on EPA requirements. For up to this point, Ficht, Optimax etc. have not been synonymous with reliability.