4 stroke power! We will have a 500hp outboard

[sho305]

DI certainly has a future. Did you see the new Audi V8 DI that redlines at what, 8200rpm? And BMW is using it too. Maybe in another decade we will see it in normal cars...none of them seem to be interested yet. Everyone knows us Americans like the lowest tech in our cars... Must be why the American cars outsell everyone. Dah.

Hey, lets strap that Yami 4 stroke to an Allison and see what kind of numbers it gets...

I've had various oil injected machines, but not an OB. Everything I had that ran on land or ice took very little oil for the injection. Most took a couple tanks of gas or more to the oil tank.

[jhwh]

The 1 thing 4 strokes have going for them is not having to add oil to a boat mounted tank. The saltwater market is where the money is at and people are just getting tired of adding oil every time they gas up. Some of the big triple eng boats have to add oil before they even get back to gas up. Also the 4 strokes just dont break as often as the 2 strokes. I think eventually we will see a direct injected 2 stroke with an oil pan and pump system. Might be an Evinrude though. I also think eventually all the 4 strokes, cars and boats will be direct injected due to the low CO2 ex. Another engine to consider is the 150 Yamaha 4 stroke, 2.7 liters and 468 lbs. The Hondas do have all that aftermarket support though.

everybody drive 4-stroke cars... don't see them complaining now do you?
on my boat with the 4-stroke engine I monitor oil a couple times a year but never had the need to refill during the season.

on my boat 2-stroke outboard you get really really tired of filling oil on the engine yes, I removed the VRO and just mix in the gas, less hassle.

[jhwh]

DI certainly has a future. Did you see the new Audi V8 DI that redlines at what, 8200rpm? And BMW is using it too..

all decent cars has sequential injection directly into the cyl intake. (DI)

TBI and all other messy forms if FI is icky.

don't mix DI with HPDI

[jimmyb]

everybody drive 4-stroke cars... don't see them complaining now do you?

how many straight drive ratios (no gearbox) cars do you see? comparing a car motor to an outboard motor is not a good comparison!

something to think about: take a 250XS powerhead and drop it in a car... tons of torque, screaming top end, but great fuel economy at partial throttle (cruise mode in the car) because of the stratified combustion that is happening... and 1/2 the weight of a comparable power 4-stroke and it is non-aspirated (as the 4-stroke would have be to match the torque, or it would have to be a BIG displacement)

[stan merck]

all decent cars has sequential injection directly into the cyl intake. (DI)

TBI and all other messy forms if FI is icky.

don't mix DI with HPDI

We are talking about injecting right into the combustion chamber after the valves are closed, not from behind a valve. Then there is no contamination of the fuel mix during valve overlap. Eventually the laws will be so strict that 4 strokes will have to use this style of injection.

[BarryStrawn]

something to think about: take a 250XS powerhead and drop it in a car... tons of torque, screaming top end, but great fuel economy at partial throttle (cruise mode in the car) because of the stratified combustion that is happening... and 1/2 the weight of a comparable power 4-stroke and it is non-aspirated (as the 4-stroke would have be to match the torque, or it would have to be a BIG displacement)

On the other hand, how many Orbital technology car engines do you see? Heck of a lot of car and truck companies bought licenses and spent piles of time and money and couldn't make an engine to compete with four strokes. They tried for all the reasons you mention, it just doesn't work well enough. I expect the 250XS powerhead would have lousy emissions compared to a car engine. The EPA specs for outboards are primitive compared to what the autos are doing.

[1BadAction]

how many straight drive ratios (no gearbox) cars do you see? comparing a car motor to an outboard motor is not a good comparison!

something to think about: take a 250XS powerhead and drop it in a car... tons of torque, screaming top end, but great fuel economy at partial throttle (cruise mode in the car) because of the stratified combustion that is happening... and 1/2 the weight of a comparable power 4-stroke and it is non-aspirated (as the 4-stroke would have be to match the torque, or it would have to be a BIG displacement)

cool, there is at least 1 person other than me that understands that snowmobiles and cars are poor comparisons to outboards.

[blkmtrfan]

cool, there is at least 1 person other than me that understands that snowmobiles and cars are poor comparisons to outboards.

I think jimmyb knows quite a bit about outboards

[1BadAction]

im just sick of hearing "my ricer car/suzuki motorcycle/snowmobile has a 1.6L NA 4 stroke and makes 250hp" that might work if outboard powered boats weighed 800lbs ready to run and had 6 gears!

[halveb]

It has been 30 years since I have run a sled, they have transmissions now?

[pyro]

Nope, not really, just two clutches (the "pulleys") and a belt. The engine-side clutch has a centrifugal mechanism that pulls the two halves together and drives the belt toward the top of its diameter as engine speed increases, and the other one pulls apart to decrease its driven diameter. Thus, a variable-ratio "transmission" of sorts.

[blkmtrfan]

Thus, a variable-ratio "transmission" of sorts.

Not really of sorts, they really are a CVT, and vary gear ratios

[sho305]

http://www.theautochannel.com/news/2...11/010071.html


"...Audi's FSI direct gasoline injection technology. As in a diesel, a precise amount of fuel is injected directly into each combustion chamber at precisely the right moment, under extremely high pressure, to ensure maximum vaporization for complete combustion. This improves both fuel economy and emissions - both engines are rated ULEV - and allows a higher compression ratio to be used without pinging, knocking, or other damage, thereby further improving efficiency."
------------------

Yeah, I just read a great thread on the honda I4 making 500hp or more and being the best OB ever....hmmm. I wonder how many of them hold those motors WOT for even 10 minutes, heck even a minute alone.

Sure a sled will hold a max rpm you have it set up for, lets say 7,000 to 10,000 rpm (its max power rpm), from a stop about a 1/2 second after you hammer it, to top speed. Unless you tune it differently of course, or run out of gear...and they can be changed too. You can set just about any engagement rpm. The new CVT trans in some new cars works like that with a metal belt in oil. The rubber one on a sled wears as you can imagine, and that in very cold temps and relatively brief WOT conditions. Most gas golfcarts use the sled type belt as well as Polaris ATVs. Look up Comet Clutches on the net. Most stock type sleds will let the motor run under max rpms up to 20mph or so for less power and less spinning...then let the rpms go up to max the rest of the way up. They also drop the rpms down at less throttle, sensing engine output/torque changes. Wonderfully simple and very tunable, but not so durable under big power and not as efficient as gears...efficientcy not so bad when it pulls less weight around and then has less slip.

My golfcart has about 11hp they tell me, and it gets around pretty good. It does run out of gear and revs up at top speed (about 28gps with the 22" tires). The clutch it has is cheaper and does not have as much gearing range as a sled, but same design. It will peel the big fat atv tire in sand some, but at ~600lbs and 11hp you mostly get low parts breakage and your can hauled around whenever you want for hardly any gas. It slows to nothing on steep hills, but still chugs up them nicely. The next one will have more hp... and a better clutch I can tune more. I drilled this one out but can't change the weights/springs/etc. Likely just as well with the stock motor. Once it revs the power goes away with this 4 stroke. I had a 2 stroke that would rev way out, did 40+ with the little stock tires.

You have to remember a 4 stroke or diesel in a car is really no big deal. You have a 500lb engine block in a 3,000 car so who cares about +/-200lbs? In a OB boat the motor is as much as the hull, and in a boat weight is the enemy of performance. In a car you can just put the next wider size tire on and 200lbs is nothing. Same with a sled, weight kills performance and makes it hard to use a hefty motor over a light one. If it was not illegal (or banned/etc) for a car or road bike to have a 2 stroke, they certainly might. The 2 stroke road bikes were very fast....still are by today's standards with little or no changes. If I remember right the 350 twin in a yamaha banshee is out of their european road race bike.

[jhwh]

honda bf150 has a 2.4l vtec 16v, how much different is that from the 2.4 found in their cars?

mercruiser SBC, how much different are they?

cams needs to be different, cooling etc but it seems that car engines work.

[sho305]

Other than the cams and ignition and safety items I don't think the auto motors are much different than marine versions when in stock form. Most of the hipo ones go to blowers or more cubes. They just can't get a flat powerband at higher levels of output without. In a car it does not matter.