Vmax f90 sho Yamaha

[Tige]

Gday all, does anyone have any idea of the hp the f90sho. I have heard there no real difference only stickers, others say there up to 10% better then the standard f90. I know they run a different gear ratio to give better hole shot but they also claim higher top speed. Cheers 

[kingie chaser]

Says it all here doesn't it?

https://www.yamaha-motor.com.au/products/marine/outboard/high-horsepower-four-stroke-115---425hp/high-performance-vmax-sho/vf90

 

Same HP, lighter weight, 1.8ltr displacement & reconfigured gears.

 

If you pull up the specs for each motor & compare side by side you could come up with some data to prove or disprove the claims either way.

Edited February 8, 2021 by kingie chaser

[Tige]

Looks the same specs to me, maybe it’s remapped for a bit more power. I read somewhere it’s a detuned 115. Can’t seem to find much facts.

[noelm]

This comes up all the time, the HO (or similar naming) do not have more HP, but they often have different gear boxes, and different torque range, most HO/VX/XS are better at take off (hole shot) mainly because of the gear ratio and the ECU mapping, thousands of internet myths abound about all the extra HP but it's been "myth busted" many times, even some salesmen still try to tell you about add HP.

[noelm]

Just to add, one example of a HO difference is the Evinrude, the "standard" was a 3 cylinder, the HO was a V4, still both 90HP but the V4 performed quite differently and suited a different application (and was much heavier)

[rickmarlin62]

Same hp  thsts why they are both 90 hp  ho suits lighter smaller hull for skiing type applications  not heavy loaded fishing boats  higher gear ratios wont give better holeshot on heavier hulls     horses for courses

[Tige]

thanks guys, I would love to see the exact same hulls with a vs comparison. Only a few hundred bucks more for the vmax interestingly.

[Tige]

10 hours ago, noelm said:

Just to add, one example of a HO difference is the Evinrude, the "standard" was a 3 cylinder, the HO was a V4, still both 90HP but the V4 performed quite differently and suited a different application (and was much heavier)

Funnily enough the Yamahas seem exactly the same motor on the web so may only come down to gear ratio and different mapping. Cheers 

[Davison]

On 2/9/2021 at 5:51 AM, noelm said:

This comes up all the time, the HO (or similar naming) do not have more HP, but they often have different gear boxes, and different torque range, most HO/VX/XS are better at take off (hole shot) mainly because of the gear ratio and the ECU mapping, thousands of internet myths abound about all the extra HP but it's been "myth busted" many times, even some salesmen still try to tell you about add HP.

I haven't seen it mythbusted before and I suppose it would vary between each manufacturer regardless. Evinrude actually used to state that besides the gear ratio, engines like the 115HO vs the standard 115 utilised the max 10% wiggle room they have in certified hp ratings, i.e. a 115 could technically legally produce 126hp, so most likened the 115HO as basically a 130.

Mercury's 115 and 150 Pro XS models also run more rpm than their standard counterparts. While this enables you to play with lower pitch props without necessarily losing top end, all things being equal, raising the rev limiter by 300rpm you'd expect slightly more peak power. Mercury's R&D VP stated as much-

“Horsepower is simply torque times rpm,” declares David Foulkes, Mercury vice president of product development. “As long as the torque curve is still climbing, if we add rpm, we get more power. And the 2.1-liter makes plenty of torque.”

Does 10% wiggle room in power really matter? I don't think so. It's more the gearcase and prop, although I wouldn't be so sure that the HO/Pro XS/SHO variants with their distinct tunes are running exactly the same peak power as standard, assuming the standard engines aren't underrated to start with.

[noelm]

HP is not exactly torque X RPM, but there is a formula to work it out, peak outputs are not the important number, it's the "curve" that matters, a nice flat curve is preferable to a sharp peak, but it all doesn't matter really, people and salesmen believe what they want.

[Davison]

Cowlings can be deceiving in that way. I'm looking for a 200hp at the moment, prefer my Yamaha dealer but the product planners have made it difficult, their only XL shaft 200hp is the 2.8L I4, sure it'll make 200hp but you won't see the bulk of it without a lot of revs on board. Mercury on the other hand, 3.4L V6 and 4.6L V8 200hp options, say no more.

[Tige]

I’ve ordered the vmax, it was bugger all more than the standard f90 so if all I get is fancy stickers on the cowl so be it. Yamaha claims it’s the best performing 90 on the market so I’m sure it will be good. How much better than the standard f90 will be interesting. Cheers for all the reply’s.