4 strokes outboards IS THIS A MYTH?

[Manos]

OOO Sorry Nordy

I see what you mean.

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]

Zitat von Manos

OOO Sorry Nordy

I see what you mean.

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:

Um Links zu sehen, bitte registrieren

where yamaha hides their excelent performance bulletins ...

Matt

[Manos]

Cheers Matt. Great link!!

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]

Zitat von Manos

Cheers Matt. Great link!!

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