4 strokes outboards IS THIS A MYTH?

[Manos]

I was going through the IL GOMMONE magazine last night and I found these calculations in various issues.


Giovanni Bracco
Raid 2003 GOLFO DI BARATTO/PARIS

Total Miles 2696,00
Total hours of navigation 152,00
Consumption 4680,00 ltrs
Consumption/hour 30,80 ltrs
Average Speed 17.80 knots

YAMAHA 225 4-Storkes
RIB MAR.CO 25 CABINATO

4680 LTRS / 2696 Miles = 1.735 LTRS/MILE

Giovanni Bracco
OLYMPIC RAID 2004
Italy to Greece

RIB Nova Jolly King 990
Suzuki DF 250 4-strokes

Second part Mediterannean Sea

Total hours of Navigation 102
Average Speed 22,65 Knots
Consumptiopn for this leg 4450 ltrs
Consumption/hour 43.5 ltrs
Total Miles for this leg 2310

4450 / 2310 = 1.926 ltrs/mile


Odessea Raid 2004 Italy to Turkey via Greece

RIB 6-6.5 mtrs
Mariner 150 4-strokes

Total Miles 2420
Total hours 143
Total Consumption 5120
Average speed 23 miles

5120 / 2420 = 2.115 ltrs/mile!!

I don't know if I'm wrong or not but these figures don't impress me that much. In fact these engines possibly have worst consumption than the 2-strokes equivalent. If you add high service costs of the 4-strokes compared toa 2-strokes, one question comes to mind

Do the 4-strokes that are staffed down our throats every single day worth buying or not? Or the 4-stroke myth is something more sinister that we think (I have my own theory on this :naughty: :naughty: :naughty: )

Am I worng? and if Yes... appreciate to know the why! :chapeau:



Ich ging durch die IL GOMMONE Zeitschrift gestern Abend und ich habe diese Berechnungen in verschiedenen Ausgaben gefunden.

Giovanni Bracco
RAid der GOLFO DI BARATTO/PARIS von 2003

Gesamte Meilen 2696.00
Gesamte Stunden der Navigation 152.00
Verbrauch 4680.00 ltrs Verbrauch/Stunde der 30.80 ltrs
Durchschnitt Rast 17,80 Knoten

YAMAHA 225 4-Stroke
RIB MAR. CO 25 CABINATO

[B]4680 LTRS / die Meilen = 1,735 LTRS/MEILE von 2696 [/ B]

Giovanni Bracco
OLYMPISCHES RAID 2004 Italien Griechenland

RIB Nova Jolly King 990
Suzuki DF 250 4-stroke

Zweit trennt Mediterannean See

Gesamte Stunden von Navigation 102
Durchschnittlich Rast 22.65 Knoten
Consumptiopn für dieses Bein der ltrs von 4450 der
43,5 ltrs von Verbrauch/Stunde
Gesamte Meilen für dieses Bein 2310

4450 / 2310 = 1,926 ltrs/mile[/ COLOR]

Odessea Raid 2004 das Italien von der Türkei über Griechenland

RIB 6-6.5 mtrs
Mariner 150 4-stroke
Der Gesamt Stunden von gesamten Meilen 2420 143 Gesamtverbräuche 5120 Durchschnittlich rast 23 Meilen

[COLOR=Red]5120 / 2420 = 2,115 ltrs/mile!!

Ich weiß nicht, wenn ich bin falsch oder nicht aber diese Figuren mich nicht beeindrucken, der viel. Eigentlich haben diese Maschinen vielleicht den schlimmsten Verbrauch als das 2-wird gestrichen Gegenwert. Wenn Sie hohe Dienstekosten von den 4-Schlägen hinzufügen, hat toa 2-Schläge verglichen, kommt eine Frage, zu bedenken

Macht die 4-Schläge, die mit Personal unseren Kehle jeden einzelnen Tag Wert hinunter versorgen, kaufend oder nicht? Oder der 4-Schlag Mythos ist etwas finsterer, dass wir denken (habe ich meine eigene Theorie auf dies: ungezogen: : ungezogen: : ungezogen:)

Bin ich falsch?, und wenn Ja... schätzt, das warum zu kennen! : chapeau:

[Manos]

May be this is motor is a 2-strokes. Is not clear what it is and my Italian is not that great. But I just think that Mariner do not make 4-strokes engines.

Odessea Raid 2004 Italy to Turkey via Greece

RIB 6-6.5 mtrs
Mariner 150 4-strokes

Total Miles 2420
Total hours 143
Total Consumption 5120
Average speed 23 miles

5120 / 2420 = 2.115 ltrs/mile!!

[Matt_CDN]

Wenn man representative motoren (also nicht extreme) vergleicht dann verbraucht ein 4 takter im schnitt weniger als ein konventioneller 2 takter. Bei vollgas verbrauchen sie in etwa gleich.

Ein DFI 2 takter verbraucht praktisch genau gleich wenig wie ein 4 takter.

Matt

[Manos]

Close to my thoughts Matt :chapeau:

[Matt_CDN]

Close to my thoughts Matt :chapeau:

No surprise because:

a. Great minds think alike :biere:

b. These thoughts are the correct ones :chapeau:


Matt


P.S.

Mercury even claims their Optimax DFI 2 strokes use LESS gas as the average 4 stroke and may be right. If compared to state of the art 4 strokes they pretty much come out even ... give or take a little depending on which set up favours which powerplant.

[Manos]

:lachen78: :lachen78: :lachen78: :biere: :biere: MAtt you make me laugh :lachen78: :lachen78: :lachen78:

Seriously though, the reason I started this thread is becuase of this observation:

YAMAHA 225 4-Storkes
RIB MAR.CO 25 CABINATO

4680 LTRS / 2696 Miles = 1.735 LTRS/MILE
according to the chap who saild the boat Giovanni Bracco.

My 200VMax 2-strokes (not the HPDI) with 17" pitch Yamaha Salt Water prop (changed the 21" Yamaha Pro prop I had on it for this one and I may go up to 19") on the same boat gives on the FLOSCAN and between 3500-4000 revs about 1.3-1.6 ltrs/mile in moderate seas, trim -3 and jack plate up 2 notches. I think the speed is between 24-26 knots and the boat is a little heavier (I estimate between 200-300kgs, due to added bulk heads in the cabin, a cooker and a frige, and some added decoration for comfort etc) than when it did that raid when everything was bare for obvious reasons.

The logical thing would have been for the boat to go slower and have higher consumption but it does not.

I thought is very starnge and either the guy who sailed the boat is wrong or I have a great little 2-strokes motor :naughty: :naughty:

[Matt_CDN]

The 200 V MAX is no fuel miser... so you are getting good fuel use there ..

Generally I dont think you can compare all these numbers as the conditions were different ..

It makes sense that the 150 uses more gas to go as fast or faster as the bigger motors ..

Matt

[Manos]

Yes Mat I agree with what you say.

I think the VMax is doing well as you say it drinks petrol like a bottomless well :lachen78:

However, the numbers showing the cnsumption of the 4-strokes are an indication that it may be a falacy that the 4-strokes have better consumption than the 2-strokes.

By the way the 150 Mariner is a 4-stroke

[Matt_CDN]

Here is a chart that I created a while ago ... all motors are Yamaha, 2 stroke, HPDI and 4 stroke compared to a optimax soprtjet ...

Your motor is the purple dotted line ...

You can see that the HPDI and 4 stroke are very simlar and differences probably come mostly from the boat rather the motor.

The 200 VMax is on a very light boat with high pitch prop thus very fast and very hungry (more as it would be otherweise)

http://img109.exs.cx/img109/1826/ALLMPGMPHj.jpg

Matt

[DschungisKahn]

question: yes - 90 hp - the 4-stroke outborder is much better

200 hp - take a diesel inboard machine

[Matt_CDN]

Thanks but no thanks :zunge:

[Manos]

Matt this is E X C E L L E N T!! :chapeau: :chapeau: :chapeau: Thanks for that! :biere: :biere: :biere:

I wonder what would it show if we had a chart for a boayt weight 1800kgs and different motors such as:

Yamaha 250 HPDI
Yamaha 225 HPDI
Yamaha 200 VMax

It will be interesting to see as we all now think that although the 200VMax is thursty on my MAR.CO is not more thursty than the 225 HPDI or even the 250 HPDI that they had on it before.

In any case is a very good dat. Many Thanks

[nordy]

Giovanni Bracco
Giovanni Bracco
Raid 2003 GOLFO DI BARATTO/PARIS

Total Miles 2696,00
Total hours of navigation 152,00
Consumption 4680,00 ltrs
Consumption/hour 30,80 ltrs
Average Speed 17.80 knots

YAMAHA 225 4-Storkes
RIB MAR.CO 25 CABINATO

4680 LTRS / 2696 Miles = 1.735 LTRS/MILE



The reason for the low average consumption of this boat is the low average speed of 17.8 knots.
The other boats have speeds around 23 knots.

That makes a difference of 23 % !

The higher the speed the higher engine load and revolution and therefore a higher fuel consumption will be the result under normal cruising conditions.

Greetings Nordy

Note:
There is no discrepancy to your interesting chart because that shows consumption defined in miles per gallon, it's the reciproke of our common European definition in l/km.

[Manos]

Nordy do you think that the 225 4-strokes has low consumption?
I think that is quite a lot.
My VMax (and is a very thirsty engine) does better than that and at higher speed on the same boat with a 17" Yamaha Salt Water prop. As I have see now that the boat can take even a 19" I will be changing the prop so I will be getting higher speeds and better consumption still.
When I make the journey in the summer from Cape Sounion to Lefkada, I will measure the consumption more accurately and over a longer distance and varied sea conditions to be 100% correst

[nordy]

Nordy do you think that the 225 4-strokes has low consumption?

Is 1,74 less or more 2,12 l/miles ?!

Greetings Nordy

[Manos]

OOO Sorry Nordy :cognemur: :cognemur: :cognemur:

I see what you mean. :chapeau: :chapeau:

The 4-stroke 225 Yamaha has lower consumption than the 150 Mariner. The Mariner however is a smaller engine (not in cc but out put).

From what i know (and please correct me if I'm wrong) the 225 produces actually less than 200bhp due to high gear reduction ratio. If you compare this motor with any 2-strokes 200 series you see that the consumption is higher (I think?)

[Matt_CDN]

OOO Sorry Nordy :cognemur: :cognemur: :cognemur:

I see what you mean. :chapeau: :chapeau:

The 4-stroke 225 Yamaha has lower consumption than the 150 Mariner. The Mariner however is a smaller engine (not in cc but out put).

From what i know (and please correct me if I'm wrong) the 225 produces actually less than 200bhp due to high gear reduction ratio. If you compare this motor with any 2-strokes 200 series you see that the consumption is higher (I think?)

Not to worry here. The 225 produces 225 HP at the shaft ... the different gear ratio will mean different torque thus larger prop .. in the end there shouldnt be a fuel use difference based on that ...

The US are adopting a law that motors can not be underrrated as much anymore. This was done to look good in tests .. so pretty soon motors sold in the US will actually have the HP they are rated for .. IMO 2006 or 2007...

Matt

P.S. They make a 300 HDPI now .. maybe thats the motor to get :)

[Matt_CDN]

If you need more fuel data for Yamaha motors then you may want to look here:

http://www.yamaha-motor.com/products/otb/perfbull/

where yamaha hides their excelent performance bulletins ...

Matt

[Manos]

Cheers Matt. Great link!! :chapeau: :chapeau: :chapeau: :chapeau:

PS MAtt I don't suppose you can shed some light to the fact that my Yamaha engineer and many others insist that the 2-strokes VMaxes the 200 and the 150TRP (not HPDI) produce the 200VMax, 230bhp and the 150VMax, 170bhp. Something to do with this VMax technology which kicks in after 4000rpm.

Is this correct?

[Matt_CDN]

Cheers Matt. Great link!! :chapeau: :chapeau: :chapeau: :chapeau:

PS MAtt I don't suppose you can shed some light to the fact that my Yamaha engineer and many others insist that the 2-strokes VMaxes the 200 and the 150TRP (not HPDI) produce the 200VMax, 230bhp and the 150VMax, 170bhp. Something to do with this VMax technology which kicks in after 4000rpm.

Is this correct?

Most motors are underrated ... I think bombardier even admits the ETEC 150 actually has 168 HP. Thats a little over 10% more. Not that we complain here :).

The reason for this is simply that in tests the "150" will shitkick other not underrated 150 HP motors... Also people will say brand such and such motors are stronger. Its just marekting....

If the VMax 200 is 11 % underreated then we are already at 222 HP so I beleive the claim, although 230 HP seems a little high.

I doubt this has anything to do with the VMax technology... I am not sure what it is they call VMax but I assume it is a tweak to the induction system...

2 strokes will work best at certain rpm where the air resonates properly through intake and exhaust ... At what RPM this happens is purely how the engineers laid it out. VMax seems to have this happen at 4000 RPM and more which makes sense for a "go fast" motor...

To make things short ... nothing extraordinaire here ... Peak HP is still peak HP (VMax or not) and the motors are still underrated like most other motors ....

Matt

[Manos]

Cheers Thanks for that Matt :chapeau: