10000 RPM yamaha

[soggybear]

I was recently told by a reputable source that Yamaha is soon to release a 10000 rpm 4 stroke that is designed to compete with the go fast Merc's. The design is suppose to be a major leap forward in the evolution of the outboard engine and is reported be as light as a 2 stoke 280 hp engine. Not sure of the HP range yet. Anybody heard about this new Yamaha?

[T-REX]

is reported be as light as a 2 stoke 280 hp engine.

This iz tha part dat iz gunna be hard ta believe....

10K ain't dat hard to believe when ya lissen to them jap road race engines...If Honda and Suzuki had more intrest in OB race'in, I bet U could bet 10K + 4 strokes would be ther!!..........JMO:thumbsup:

[jimmybrie]

As light is not that hard to beleive when you look at a zx-10 or R-1 it wheigh 375 lbs complete (the whole bike). So the engine (with transmission) must be at most 200 lbs. It turns 12000 RPM and puts out 180 hp to the wheel which is 200+ to the crank:eek:.

So remove the tranny (remove almost half the weight) and make it 2.0 L I guess they can come out with something around 150-200 lbs.
HP figures surely wont be around 180 x 2 because they will have to setup it to get some torque. But I think 300 HP would be possible.

And when you need more, just put a turbo on it and go 400- 450 HP:D

Once thought of putting 2 ZX-14 motors in the back of my tunnel (inboard direct drive) but guess I don't have enough time and money to spend:D

Just my opinion:thumbsup:

[soggybear]

[QUOTE=T-REX;1718296]This iz tha part dat iz gunna be hard ta believe....


Hey T,

Suppose we shall soon find out... I have been told by the same individual who is a Merc dealer as well as a Yamaha dealer that is is slated to be released in 4 months or so ... that was a month ago... he actually talked himself out of an immediate sell by divulging this info so I am taking his advice and waiting to see what really happens. Apparently the whole thing has been real hush hush with yamaha ... guess they don't want any premature ejack ... I mean evaluation... spoiling their booty...


Yet to be seen... I wouldn't be too surprised though ,,, I'm sure they've been working on things for awhile. It would be nice to see some head to head competition with the big boys. Just think of the rivals it would create. ESPN loves that stuff... The bigger the rivals waged the greater the money earned...

:reddevil:

[Instigator]

As light is not that hard to beleive when you look at a zx-10 or R-1 it wheigh 375 lbs complete (the whole bike). So the engine (with transmission) must be at most 200 lbs. It turns 12000 RPM and puts out 180 hp to the wheel which is 200+ to the crank:eek:.

So remove the tranny (remove almost half the weight) and make it 2.0 L I guess they can come out with something around 150-200 lbs.
HP figures surely wont be around 180 x 2 because they will have to setup it to get some torque. But I think 300 HP would be possible.

And when you need more, just put a turbo on it and go 400- 450 HP:D

Once thought of putting 2 ZX-14 motors in the back of my tunnel (inboard direct drive) but guess I don't have enough time and money to spend:D

Just my opinion:thumbsup:
So take that 12,000 RPM motor, stand it on a mid section and fire it up.
Now put it in gear on your 1300 lb boat w/a 28" pitch propeller and see how much torque you have at 1000 RPM :p
Look at a dyno chart of one of those motors. They don't start making power until 9K +.
Similar to stopping your crotch rocket at a light and then jamb it in 6th gear when the light turns gree:pn and see what happens :p

On weight, it kills me that the Japanese are going to revolutionize the O/B market in weight reduction. Let's see, when the O/B's first started getting popular back in the '30's........they were being hand carried from their trunk to the water. Think they may have already been looking at weight ;)

As to the 10K Yammi aimed at a 2.5............very cool. Let's see it.
We know a 300 drag makes what.......340 HP's out of the box???
At I think 350ish lbs???
Pretty tall order to do that w/a 4 stroke.
They'd probably have to do it w/a 4 banger but don't see 300 HP's possible naturally aspirated and turbo's or anything else ad's weight.
A current 225 4 stroke (which may be able to be modded to 300 HP's) p.head is probably 350lbs-ish dressed.
On top of this the 2 stroke has the inherint torque advantage (cu.in. to cu.in.) compared to a 4 from the start.
Be cool if it's true though. Love to see the technoligy and if anyone could do it.......

[jimmybrie]

So take that 12,000 RPM motor, stand it on a mid section and fire it up.
Now put it in gear on your 1300 lb boat w/a 28" pitch propeller and see how much torque you have at 1000 RPM :p
Look at a dyno chart of one of those motors. They don't start making power until 9K +.
Similar to stopping your crotch rocket at a light and then jamb it in 6th gear when the light turns gree:pn and see what happens :p



That's why I said they may go up to 2.0L and cam it for torque. Did you ever tried a ZX-14? Starts to pull at 4000 RPM's:eek:

I fully agree it would need torque for water application but I think it's possible. As the 2.5 Hi-po it's not designed to go on a heavy hull.

Again JMO:thumbsup:

[mackeral5]

I just want to see an average weight outboard motor that 1) will live at 10k pushing a boat all day and 2) have flat enough of a torque curve to be useful.

hard to believe, regardless of manufacturer.

[JR IN JAX]

The little 1.2 litre in my Honda turbocharged PWC turns out 165 HP at 6K and has good bottom end torque/fuel economy. I just rode a Friends 1.5 litre Honda and it was a rocket turning out 200 HP at 7K thats just as good on fuel . With just an extra psi or two of boost a 250 HP would be easy. The motors probably weigh 200 # and then you would need a mid/gearcase/intercooler so about 350# would be possible. With a two litre, 300 plus would be easy at close to the same weight.

[Mark75H]

I'll believe it when I see it ... I'd say its not the time to release such a motor ... November as a 2010 model ... I guess we will see ... I'll be checking back

[mackeral5]

perhaps some sort of hydrostatic drive could make it work, kindof like a high-stall torque convertor.

I'm sure it will happen someday, just not in 2010.....if it was going to happen that soon,(mass production of such a powerplant) somebody would have already done it in a small shop/backyard/etc.

what happened to all the rotary outboard ideas/discussions??????? they dropped off the radar, just like my home-grown yammie v4 efi project that never saw completion

Apparently the time/$$$$$ didn't work out so it will be a good while before an outboard of this type is in PRODUCTION.

[Forkin' Crazy]

RPM range is too high. I think longevity is the problem. They have come a long way in the past few years in alloys and coatings, etc but not enough yet. If you run the guts out of one, like you can a two stroke, day in and day out, and it won’t live. Just like the super cross bikes now that are all four stroke. They need a lot of maintenance.

No thanks!

[Thewayweroll]

Its probably to compete with the 400hp Suzuki which is on the way as well.:rolleyes:

[E-tec1]

beleive me....comin out the door with somethin new and different isnt easy and the expectations can only climb.....but for the mere fact, that someones bean counter department actually acknowleges that there is an arena for racing to still exist is more important to this entire rumor than the motor and what it does itself....we have one american company that has given up that game, the rest are hesitant to even begin,, so just for the HOPE of high performance outboarding to even continue to exist i say....... bring it on......................

[soggybear]

beleive me....comin out the door with somethin new and different isnt easy and the expectations can only climb.....but for the mere fact, that someones bean counter department actually acknowleges that there is an arena for racing to still exist is more important to this entire rumor than the motor and what it does itself....we have one american company that has given up that game, the rest are hesitant to even begin,, so just for the HOPE of high performance outboarding to even continue to exist i say....... bring it on......................


Hadn't really thought of it that way ... well put ... as you've stated one company has pretty much dropped from the performance arena ... it will be nice to see one step up to the plate with something viable ... personally I hope it is as revolutionary as what has been indicated to me. We could use a new and/or improved spin on things besides building a bigger boat for bigger motors.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

[whipper]

beleive me....comin out the door with somethin new and different isnt easy and the expectations can only climb.....but for the mere fact, that someones bean counter department actually acknowleges that there is an arena for racing to still exist is more important to this entire rumor than the motor and what it does itself....we have one american company that has given up that game, the rest are hesitant to even begin,, so just for the HOPE of high performance outboarding to even continue to exist i say....... bring it on......................
I have no idea what the numbers are but isnt outboard Raceing fairly big in Europe and Downunder right now? I just see races on sites when im googling and always seems to be over seas some were. Personaly i believe with the econamy the way it is the popularity of the out boad will only get better again. As an example in my town out boards at the dealer out wieght inboards by 90% this year. They used to bring in the Bayliners and Campions with the 3.0Lt v6 inboards and this year the majority have Verodos or 3.0lts hanging of them. I pass this dealer every day for 18 years. They had a hudge invantory in Spring but all sold now prety much I noticed. The trades seem to all be inboard big heavy older boats judgeing by the used invantory. Just an observation.

[whipper]

Hears a tug of war between a yamaha and an Evinrude.:D http://www.youtube.com/watch?v=_-7I00cZUE0

[Mark75H]

I have no idea what the numbers are but isnt outboard Raceing fairly big in Europe and Downunder right now? I just see races on sites when im googling and always seems to be over seas some were.

No, there are only 3 or 4 fairly small series running in Europe, and the down under racing is small, too. Count the number of boats you see in each YouTube vid from Europe, that is almost all there is, though it is much more popular with spectators there. There are only a few dozen boats in each of those classes you are seeing.

This week 150 APBA Mod racers converged on Zanesville OH for their Nationals, bigger than anything in Europe or down under, but you didn't hear about it. After a week off, about 350-400 APBA Stock racers will be at Grass Lake Michigan for a week of racing that overlaps with a long weekend of alky hydro racing at Depue IL with about 250-300 racers expected.

[Bryan1257]

After reading here about all the kool engines, I ve wondered why the japs havent built an outboard like they have crotch rockets. a turbo outboard would be cool! The inline 4s are awesome powerplants on a bike. even the pwc`s have turbos. also the technology for all outboard makers is to me 20 yrs behind or they have reach a plateau for the time being! where are the super and turbo charged mercs and omc`s I have often wondered??? It is time for a really cool motor to be released, I hope yamaha or somebody does it!

[Rigaud]

Theirs a lot of active racing programs all over europe, Arab countries and so on but depends what you all consider outboard racing. As well Rib (rigid hull inflatable boats) are extremely popular in europe and the African continent just that most people here don't know about it. Just some examples below from a quick search. Racing with outboards is simply very popular in so many different types and categories through out the world. The U.S. is a small fraction of whats out there.

http://www.ioc-tr.net/en/teams.asp?team=88
http://www.f1h2o.com/
http://www.youtube.com/watch?v=lgnX3zDzzXo
http://www.youtube.com/watch?v=ZLfXLFBIS_0&feature=related

[Mark75H]

How many boats race F1 world wide? only a handful ... more people have read this thread than race F1 all over the world

"Super Light" inflateable tunnel racing does have a world wide following, but not as much as drag racing or PWC in the US


The reason you don't see stuff like turbo'ed and supercharged motors like PWC's have is because a PWC maker makes the whole vehicle ... an outboard maker can't control what boat & prop his motor goes on so a huge safety factor has to be built in, severely limiting power output.

All-out-racing outboards are making close to 200 hp from 30 cubic inches ... running about 110 mph ... outboard technology is not behind PWC or anyone else

[Bryan1257]

All-out-racing outboards are making close to 200 hp from 30 cubic inches ... running about 110 mph ... outboard technology is not behind PWC or anyone else[/QUOTE]


I agree on the all-out- racing-motors, but disagree on whats available to the general public.:D but you do know more about the industry than I do:cheers:. I didnt know anything about 2.5 existence until 5 years ago. only brochure motors.:nonod:

[87gtNOS]

Torque?

On my Yamaha 1000cc 4 stroke snowmobile, it revs 11000rpm...but the PTO is gear reduced and spins 8500rpm. Gear Reduction = Torque!!
160+ hp / 108 ftlbs SAE on the dyno.

Thousands of people run the **** out of these snowmobile engines (a variant of the R1 bike engine). By that I mean EXTENDED rpm use of 9000+ rpm for an EXTENDED period of time!!
These engines are durable!

[jimmybrie]

Torque?

Thousands of people run the **** out of these snowmobile engines (a variant of the R1 bike engine). By that I mean EXTENDED rpm use of 9000+ rpm for an EXTENDED period of time!!
These engines are durable!


:iagree:

They even put bender racing turbo kits and the engines are able to survive. That means there's a good safety factor on the 160 hp 1000cc.

The question is 108 ft-lb of torque at what RPM? Like it has been said before, snowmobile have the benefit of a clutch/pulley system to keep the engine in the powerband.

But major improvements in various fields have been made through trial and errors. If you don't try anything for sure you won't make errors but you also won't make any improvements...

We'll see...

Again JMO

[Mr.Rude]

If you look at crotch rocket engines, yes they turn ungoddly RPM (upward of 17000 on some 600cc models) but the final gear ratio on any of them is not even 1.0:1 Sixth gear on mine is 1.160:1
I would think that the common gear reduction that all 4 stroke outboard engines currently use to offset the powerhead would allow for this type of setup. 10K with a 1.75 or 1.5 gear readuction sounds far more likely.

[skydog]

I bet they will!! Yamaha took over the sled world with there 4 strokes! I just love them i have had 3 of them blowen!! 1 liter over 300 hp!! :) :)

Skydog

[Mr.Rude]

No, there are only 3 or 4 fairly small series running in Europe, and the down under racing is small, too. Count the number of boats you see in each YouTube vid from Europe, that is almost all there is, though it is much more popular with spectators there. There are only a few dozen boats in each of those classes you are seeing.

This week 150 APBA Mod racers converged on Zanesville OH for their Nationals, bigger than anything in Europe or down under, but you didn't hear about it. After a week off, about 350-400 APBA Stock racers will be at Grass Lake Michigan for a week of racing that overlaps with a long weekend of alky hydro racing at Depue IL with about 250-300 racers expected.

Not hijacking here... but, this is a sad case of affairs when there are more racers than spectators. I have attended many boat racing events and the crowds arent there. NASCAR has 40+ drivers and MILLIONS of fans. I personally do not like NASCAR, but we lack the general publics approval or interest for some reason unknown to me. Sorry, Just adding my $.02

[Ted Stryker]

I'll cut through examples and and state My opinion to say if the Japs want to get serious with lightweight 4-stroke outboards they will give the 2.5 Merc all the competition that they can handle... Introduce a state of the art turbo system and it's all over for a Hi-Po 2.5 Merc... It may weight a bit more but the HP will be aplenty...

[Instigator]

Sleds = infinitely variable transmission ratios w/a centrifugal clutch. Thats how it can push the load w/its low amount of low end power. Put a 1 speed (you pick the speed) gear drive on it and let the clutch out.

PWC's = jet drive. Acts like a torque converter in a car. They can get it to flash where ever they want.
Ditch the pump and put a surface drive through the transom w/o changing anything else and see what happens.
There is a video on youtube where they did it w/a Bussa motor. To say it was a disappointment/joke would be an understatement.

For a turbo O/B where do you install the innercooler?

Like the guy (Robby) that used to be on here from New Zealand. He raced a 2.5 liter indboard. They all ran in-line car motors.
Robby ran a V-6 OMC cross flow and set/held every record they had for that class. Last I heard he was replacing the dinosaur w/a 2.5 Merc ;)

Heck, lets just screw on a 200 HP bike motor to any 200 HP, 2 stroke O/B mid and see how it compares to what came off it :D Lets put it on a 18' Checkmate w/a 24" wheel.
Think it'll plane :p

[87gtNOS]

If you look at crotch rocket engines, yes they turn ungoddly RPM (upward of 17000 on some 600cc models) but the final gear ratio on any of them is not even 1.0:1 Sixth gear on mine is 1.160:1
I would think that the common gear reduction that all 4 stroke outboard engines currently use to offset the powerhead would allow for this type of setup. 10K with a 1.75 or 1.5 gear readuction sounds far more likely.

MrRude, do keep in mind that gear reduction or multiplication has zero affect on HP, only TORQUE.
:thumbsup:

[Mark75H]

NOS, that is exactly what Rude is saying ... these other vehicles have torque amplification, boats don't ... requiring them to have monster torque curves that limit max power.

Give the 10k Yammer the same real torque curve without amplification and the top hp will likely be in the same range as existing outboards

[87gtNOS]

:iagree:

They even put bender racing turbo kits and the engines are able to survive. That means there's a good safety factor on the 160 hp 1000cc.

The question is 108 ft-lb of torque at what RPM? Like it has been said before, snowmobile have the benefit of a clutch/pulley system to keep the engine in the powerband.


Again JMO

Yup, guys run turbos making 300+ hp reliably!:cheers:

My sled made over 100 ftlbs from 8000 ENGINE rpm (6500 at the pto) through to 10600 engine rpm (8600 at the pto).:thumbsup:
Gear reduction is 1.2333 . So without it, the motor makes the typical 80 ftlbs of torque all the 1000cc bikes make....

With nitrous oxide, 160 ftlbs/220hp with nitrous!!:reddevil: at 9 to 1 A/F!!

I think with such an outboard application, the gear reduction would have to be a little greater. Thus MORE torque would be produced and the powerband would be flatter.

It sure would be interesting!!

[6Killer]

About every 4-6 months these threads come along. They are seriously funny. First of all, what some of you you describe would never perform like you think, second, there is NO market for it. Even if by some miracle ( a really big one), how many of you would lay down $25-30K for one? Think they will sell for $5000? Yamaha makes a 350 (or so) outboard, what does a 350 Yamaha cost, what does it weigh? There you have it.

[T-REX]

About every 4-6 months these threads come along. They are seriously funny. First of all, what some of you you describe would never perform like you think, second, there is NO market for it. Even if by some miracle ( a really big one), how many of you would lay down $25-30K for one? Think they will sell for $5000? Yamaha makes a 350 (or so) outboard, what does a 350 Yamaha cost, what does it weigh? There you have it.


DAMM PARTY POOP'R:eek::D:p

[E-tec1]

what Rex said.........damn party pooper:D go pick on laker or somethin......we be talkin serious **** here :eek:

[87gtNOS]

what Rex said.........damn party pooper:D go pick on laker or somethin......we be talkin serious **** here :eek:

LOL:thumbsup:

[jimmybrie]

About every 4-6 months these threads come along. They are seriously funny. First of all, what some of you you describe would never perform like you think, second, there is NO market for it. Even if by some miracle ( a really big one), how many of you would lay down $25-30K for one? Think they will sell for $5000? Yamaha makes a 350 (or so) outboard, what does a 350 Yamaha cost, what does it weigh? There you have it.

:iagree:

Good point:thumbsup:

[Mr.Rude]

MrRude, do keep in mind that gear reduction or multiplication has zero affect on HP, only TORQUE.
:thumbsup:

:thumbsup: My thoughts exactly!


NOS, that is exactly what Rude is saying ... these other vehicles have torque amplification, boats don't ... requiring them to have monster torque curves that limit max power.

Give the 10k Yammer the same real torque curve without amplification and the top hp will likely be in the same range as existing outboards

:iagree:Mark75H has my back!


Yup, guys run turbos making 300+ hp reliably!:cheers:

My sled made over 100 ftlbs from 8000 ENGINE rpm (6500 at the pto) through to 10600 engine rpm (8600 at the pto).:thumbsup:
Gear reduction is 1.2333 . So without it, the motor makes the typical 80 ftlbs of torque all the 1000cc bikes make....

With nitrous oxide, 160 ftlbs/220hp with nitrous!!:reddevil: at 9 to 1 A/F!!

I think with such an outboard application, the gear reduction would have to be a little greater. Thus MORE torque would be produced and the powerband would be flatter.

It sure would be interesting!!

Sure your sled makes 100+ tq from 8000 RPM to 10600, Thats great... FOR THAT APPLICATION! A flat torque curve that starts where? The curve is going to be the same relative to RPM. Just because you go from a 1.0:1 to a 3.0:1 doesnt meant that it starts earlier. It is still proportional to the engine RPM. Even with a 3.0:1 reduction, what are you going to do from idle to 2700 (0-8000 engine speed) until you start makin that torque? It better be on a surfboard CAUSE IT AINT PUSHING NOTHING ELSE on plane! 1000 ftlbs at a given RPM is no good if it only has 25 ftlbs from 0-3000 which is way further up the powerband than a 2 stroke. With a steep prop, your a sittin duck!

[Laker]

what rex said.........damn party pooper:d go pick on laker or somethin......we be talkin serious **** here :eek:


bite me!

[DoktorC]

NOS, that is exactly what Rude is saying ... these other vehicles have torque amplification, boats don't ... requiring them to have monster torque curves that limit max power.



Boats do have torque amplification...it's called a lower. The Yamaha 87gt is refering to has a gear reduction built into the crankcase (just like the Yamaha PWC engines) this allows the engine not to over rev the clutch/impellar that they are attached to. It also gives the benefit of added torque. Is it a reality for a production outboard..I doubt it...but I have also heard of some "cool" stuff coming down the pipe from them. A supercharger would deal with the lack of low end torque.....;)

What kind of torque does a V6 make? I've always wondered...you don't see many dyno curves.

[Laker]

It would be totally doable as Yamaha, Kawasaki, and Honda all know what power curve needs to be employed for watercraft. A jet drive isn’t much different at all than a prop drive. We do it now with jet pumps on the bottom of outboards and the HP Rating is lowered to reflect the pumping losses. Do the reverse.. Take the 250hp Supercharged big bore Inline 4 cylinders currently inside the top shelf PWC… Stand the motors up/repackage to look good and attach a gearcase and you have the start of something. 2.0L Supercharged I4 could easily be 300hp and 8000+rpms would be realistic..

[Mark75H]

Boats do have torque amplification...it's called a lower.

You are right; I meant to say variable/changeable torque amplification

[jimmybrie]

What kind of torque does a V6 make? I've always wondered...you don't see many dyno curves.

Yeah I'm also curious about that:confused:

Once asked the question in another thread and didn't get any answer?

Maybe a dyno guy will chime in:)

[STV_Keith]

For a turbo O/B where do you install the innercooler?


In the front. ;)

[STV_Keith]

What kind of torque does a V6 make? I've always wondered...you don't see many dyno curves.

Around 240ft-lbs for a 260hp 2.5. See this thread... http://forums.screamandfly.com/forums/showthread.php?t=176866

[87gtNOS]

Sure your sled makes 100+tq from 8000 RPM to 10600, Thats great... FOR THAT APPLICATION! A flat torque curve that starts where? The curve is going to be the same relative to RPM. Just because you go from a 1.0:1 to a 3.0:1 doesnt meant that it starts earlier. It is still proportional to the engine RPM. Even with a 3.0:1 reduction, what are you going to do from idle to 2700 (0-8000 engine speed) until you start makin that torque? It better be on a surfboard CAUSE IT AINT PUSHING NOTHING ELSE on plane! 1000 ftlbs at a given RPM is no good if it only has 25 ftlbs from 0-3000 which is way further up the powerband than a 2 stroke. With a steep prop, your a sittin duck!

Remember, I have 1000cc, 1 liter. How about that 2.5L merc, making 96ftlbs per LITER!!!
I just checked on one of my dyno sheets....77+ftlbs at 5000 PTO rpms. 2.5L merc makes about 180 ftlbs at 5000 rpm. 77x2.5 = 192 ftlbs.

It's all relative, and I am sure the power (from the gear reduction making the PTO even lower rpm) would be very similar.

BTW, would this also mean that 260hp divide into 2.5L = 104 hp per LITER vs. my 160??:reddevil:

[Mark75H]

So, if I'm not confused, the Yammer would require twice the gear reduction to deliver the same torque to the prop .... ?

[Mr.Rude]

I am saying even if you have a 2:1 foot you will still need additional gear reduction at the powerhead to make it applicable for moderately loaded hulls on an engine that can turn 10k RPM. There is no way to have a 0-10k powerband. The key to the engines on motorcycles is piston speed and velocity. A supercharger/turbocharged engine is a different mindset than a 12000 RPM screamer. The best practical setup would be a supercharged slighty oversquare engine with a moderate RPM range. The trick is more on the weight than the output. The Verado is a great example, A supercharged 4 valve/cyl engine makine great power, but to heavy to get out of it own way on most hulls. The supercharger/intercooler alone weighs too much. A turbo gives little to no bottom end grunt and is extra weight as well.

[DoktorC]

So, if I'm not confused, the Yammer would require twice the gear reduction to deliver the same torque to the prop .... ?

Or make a 2litre version of the yammer. I think that while the chances of it actually coming to market is slim to say the least there could be some potential in this style of engine for a fast boat application. These motors produce similar PEAK numbers (per cc) as a 260 on regular gas and with a warranty. I know the torque curve isn't there but the idea wouldn't be to use this exact sled engine but a variation of it...instead of basing the 350 on the tundra engine and having a 807lb monster.

It's fun to dream. Especially when there are NO new 260's "our" performance stuff will come from somewhere....all those 2.5's where new at one point.

[Mark75H]

Doubling the motor doesn't usually double the torque. Maybe close, but usually 10% 15% less, sometimes even less.

BUT ... the first speculation mentioned in this thread is a 1 liter Yammer. A 2 liter would be a lot bigger and heavier than a 1.

[DoktorC]

Doubling the motor doesn't usually double the torque. Maybe close, but usually 10% 15% less, sometimes even less.

BUT ... the first speculation mentioned in this thread is a 1 liter Yammer. A 2 liter would be a lot bigger and heavier than a 1.

ok...if we stick with the 1liter then we're at 160hp. How much torque does a 150 v6 make? This may actually be an interesting comparison. Since most 150's rev in the 6k area it means the Yammer could be geared down at the crank almost 2:1 to have the same driveshaft speed. Area under the curve is still an issue, I agree, but it's WAY lighter.

So we would have 160hp with 162lb/ft of torque...from a 1L 4stroke that weighs 30-40lbs less. Like I said, it's not quite there but it's A LOT closer then a car motor stood on end.

220hp and 120+lb/ft of torque (which translates into 240 with the crank reduction) are available with the addition of a supercharger but you'd have to run premium lol.

[Lockjaw]

My Seadoo RTX has a supercharged 1.3 liter 3 cylinder motor, and makes 225hp or something like that. I makes plenty of power down low.

A turbo would also be do-able, and since you have an abundant supply of water, all that is needed is a liquid intercooler. With advancement in turbo technology, getting one to spool up down low, especially with the load a planing boat would put on it, I think it would be easy to do.

The Suzuki 4 cylinder 4 strokes have a 2.5 gear reduction, if you use variable valve timing to help with the low end, have some sort of forced induction, and gear reduction, then I think its possible.

And I got news for you, once the boost comes up, its gonna be fun. :thumbsup:

[jimmybrie]

So we would have 160hp with 162lb/ft of torque...

If I'm correct, it would be 80 hp and 162 lb/ft... 160 hp is for twice the RPM remember.

Too bad life is always that way... with the same base you gain somewhere and you loose elsewhere.;)

[jimmybrie]

A turbo would also be do-able, and since you have an abundant supply of water, all that is needed is a liquid intercooler. With advancement in turbo technology, getting one to spool up down low, especially with the load a planing boat would put on it, I think it would be easy to do.

The Suzuki 4 cylinder 4 strokes have a 2.5 gear reduction, if you use variable valve timing to help with the low end, have some sort of forced induction, and gear reduction, then I think its possible.

And I got news for you, once the boost comes up, its gonna be fun. :thumbsup:

:iagree:

Have done a turbo kit for my roadstar warrior... boost comes up at 1300-1500 rpm, 2000 rpm = full boost:reddevil:

O.k it's a V-twin that only revs 5800 rpm but it kind of lines up with what you're saying.

And yes water/air intercooler and variable valve timing is some interesting technology that could be used.

I really think the biggest point is the money issue we where talking about earlier.

[87gtNOS]

I am saying even if you have a 2:1 foot you will still need additional gear reduction at the powerhead to make it applicable for moderately loaded hulls on an engine that can turn 10k RPM.....

We aren't talking about moving a houseboat here!! Again, it's all relative, and perhaps a 2.5 merc may have better uses in some circumstances than a 10000 rpm Yammy, but that yammy is gear reduced to 7500rpm!! The hole torque band just moved down 2500rpm!:thumbsup:

[JR IN JAX]

Ya'll are missing the promise of the Honda Turbo's engines; The 1.2L is 165 HP at 6000 RPM/12 PSI and the 1.5L is 200HP at 7000 RPM/10 PSI. The 1.5L with a different ECM/13PSI is turning out over 250 HP at 7200 RPM. The 1.5 has tremendous bottom end torque.

Their torque does not need any gear reduction and Bill Acosta in Hawaii has a Honda rental fleet that has 1500+ hour original motors. His prevoius fleet was the Yamahas with the gear reduction and they began burning oil at less than 600 hours.

[DoktorC]

If I'm correct, it would be 80 hp and 162 lb/ft... 160 hp is for twice the RPM remember.

Too bad life is always that way... with the same base you gain somewhere and you loose elsewhere.;)

Gear reduction does NOT effect horsepower...only torque. The engine is still spinning the RPM.

[jimmybrie]

Gear reduction does NOT effect horsepower...only torque. The engine is still spinning the RPM.

Sorry you're right, RPM is cut in half not HP (hp=rpm x torque)

Sometimes I get little air bubbles to the brain, might install a bleeder or something:D

Thanks for the remind:cheers:

[jimmybrie]

Ya'll are missing the promise of the Honda Turbo's engines; The 1.2L is 165 HP at 6000 RPM/12 PSI and the 1.5L is 200HP at 7000 RPM/10 PSI. The 1.5L with a different ECM/13PSI is turning out over 250 HP at 7200 RPM. The 1.5 has tremendous bottom end torque.

Their torque does not need any gear reduction and Bill Acosta in Hawaii has a Honda rental fleet that has 1500+ hour original motors. His prevoius fleet was the Yamahas with the gear reduction and they began burning oil at less than 600 hours.

What weight? 1.5L outboard?

[Mark75H]

ok...if we stick with the 1liter then we're at 160hp. How much torque does a 150 v6 make? This may actually be an interesting comparison.

You keep mentioning peak torque ... the important torque numbers on boats to compare one useable motor with another are not going to be peak numbers where they can be compensated with gears, but the torque at 1,800 to 2,800 rpm where the motor is doing one of its hardest jobs, getting the boat over hump onto plane

At the 1,800-2,800 rpm range, reed valve 2 strokes are pushing monster torque

[Markus]

I know the torque curve isn't there but the idea wouldn't be to use this exact sled engine but a variation of it...instead of basing the 350 on the tundra engine and having a 807lb monster.


The Yamaha V8 can deliver more than 600 hp when turbo charged. Now that is a monster.

http://www.autoblog.com/2008/10/21/spy-shots-noble-m600-caught-testing-in-the-u-s/