One against two

[bonneville]

I don't think its just the fuel usages that the single had over the twin, what about hole shot !
quite suprising on how over all equall the test results were.
interesting as well, was the supposed rev drop with twins to cruise at the same speed !
this was "clinically" as close as you could get to all thing equall, of course, repowering or thinking of the option would be much harder to predict.
great post Honda cheers
bonneville

[gofishin]

Interesting Honda!

Seems like a Yamaha sanctioned test too, so one would assume both have been propped with similar style props to get the most out of the donks.

Bit hard to read the tables on an iPhone though, hoping I can on a bigger screen.

Wow thats suprising, I would have thought the single would have been a bit quicker top end. Looks like the twins beat the single in every way except for fuel consumption.

Don't forget that the 150's are more than their sticker, and the 300 is less.

US EPA data have the 150 developing 160HP at a rated speed of 5500rpm, while the 300 puts out 288 at a rated speed of 6000rpm.

2 x 160 = 320HP vs 288HP

However... from what I can see, it looks like both wound out to 6000rpm, where the 150's would be punching out even more than 160HP too.

What this does clearly show is the additional drag that twins create and therefore have to 'overcome ' in comparison to a single.

In this case it takes an additional 32 'plus' HP to generate only an additional 1.4 mph.

Interesting hey?

Cheers
Brendon


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[Noelm]

Where does all this business about certain motors putting out more or less HP than stated? The old Suzuki 140 being only 128HP, now the 150 Yamaha is 160HP and the 300 is a nice neat 288 HP.

[caravellerob]

I agree Noelm, unless the motors are all put on on a test bench you would never really know what they make. Who knows the 140 suzi might make its claimed 128 hp at 4000 rpm. I wish the manufacturers would put out dyno figures / graphs showing the rpms / HP through the rev range. This would give a real idea of the usefulleness of a motor as oppossed to the 200 hp at 6000RPM which really means stuff all other then verifying the sticker on the side!!

[gofishin]

Where does all this business about certain motors putting out more or less HP than stated? ...

Do you mean "where is..." Noelm? See below good quote incl. link which I stole from Honda's reply on a previous thread. (Saves typing )

...The old Suzuki 140 being only 128HP, now the 150 Yamaha is 160HP and the 300 is a nice neat 288 HP.

The Suzy being 128 has long since been proven as utter BS. It has 138 HP as I assume you know/recall.

All data for power and torque figures for outboards are as below US EPA link.

What I have posted for the Yams was obtained the last time I downloaded the file, title incl 2007-2011data etc. And most likely still is relevant, except they will have added 'recent models' too. They do not retest outboards unless there is a model change, i.e. F300A... (V8) to F300B... (V6).

When I'm on my PC later tonight I will attach summary data from a spreadsheet I made.

So below is fact.

You can find the output of most outboards if you look hard enough, the 128hp suzi info is a myth. the actual tested figure is 138Hp.

the following link contains the american certification data for engines, so you should be able to find what you are looking for.

http://www.epa.gov/OMS/certdata.htm#marinesi


Note the heading on the columns - ALL the numbers are in metric form. HP on the spreadsheet is in KW, torque is in NM - you need to convert it for HP and ft-lbs!
....
Regards
Honda.

Edit: Attached spread sheet of summary data for selected Yammy's. This is the raw data extracted by me a few years ago from the 2007-2011 US EPA Database. The columns in green are what I converted (to HP) and calculated from their 'Max Torque' at that particular RPM.

This data 'is real'. Anyone can check for themselves!

Cheers
Brendon

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[gofishin]

I agree Noelm, unless the motors are all put on on a test bench ....

They are, by the relevant dept. of the US EPA. See above link.

...you would never really know what they make....

And that's why they are all tested by a totally independent body!

Cheers
Brendon


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[tjotter]

re
http://www.australianboatmags.com.au...VEY31_prev.pdf
Not your setup or problems your end, only the first page is available as a free download. Members can view whole file...

I think anybody can buy, probably $5.
http://www.australianboatmags.com.au..._downloads.php

[wayno60]

http://www.yamaha-motor.com.au/sites...C_F100_x_2.pdf

http://www.yamaha-motor.com.au/sites..._640C_F200.pdf

[gofishin]

Further from my previous post...

...Getting back to reality, the best technical comparison of twins vs a single, that I can remember reading, was by F&B back in Aug/Sept 2008.

They did a detailed performance comparison on two identical 685 Explorers, one with an F250 and the other with 2 x F115's. A summary can be found here:

http://www.australianboatmags.com.au...VEY31_prev.pdf

I have the mag somewhere, but it has been that long since I have read it the details are a bit vague.

From memory:

• at cruise - similar performance, near identical fuel consumption
• WOT - single of course had more top end (less drag & slightly more HP)
• grip & 'zap' of the twins was understandably fantastic

At the time I was considering both options on my 685, but I went the single, and am very glad I did...

For anyone that is interested, here is the summary page of the single vs twins comparo mentioned above...

PS. US EPA Data for both engines;
Model, Disp, HP, @ rated speed, Max Torque [N.m], @ rated speed, HP at max torque (calc)...

F115A, 1741cc, 118HP, 5500rpm, 151N.m, 4500rpm, 95HP
F250A/B, 3352cc, 240HP, 5500rpm, 303N.m, 4000rpm, 170HP

[chooky]

My hypothetical question involved 1 single or two of the same single ie say 250hp or 500hp.

[stevemid]

My hypothetical question involved 1 single or two of the same single ie say 250hp or 500hp.

This is why politicians never answer hypothetical questions.

[fisho64]

Politicians rule #1-never ask a question unless you already know the answer