Like the title says... my manual says the recommended operating range is 4500-5500rpms. I've seen several setup / numbers posts stating that they could / should be run to 5800 or so.
Is this a typical practice?
Safe for the engine?
Like the title says... my manual says the recommended operating range is 4500-5500rpms. I've seen several setup / numbers posts stating that they could / should be run to 5800 or so.
Is this a typical practice?
Safe for the engine?
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I reject your reality and substitute my own!
absolutely
The good question is "why"?
If you look at most horsepower curves, increasing rpm may not increase hp and in some instances decrease hp. You also risk a mechanical failure.
The gains are not worth the risk unless of course you are racing which is another issue.
that's a good question... that goes along with my thinking, but i've seen so many posts stating "that engine needs to run 5800rpm for best performance" etc. etc. sounds like some guys push the max range, not sure how good an idea it is.
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I reject your reality and substitute my own!
If you want confirmation that it's ok just contact any of the guys at Hydro-tec. They are the Yamaha go fast gurus. Personally I've run my 2004 HPDI 300, 6000 rpms or more (limiter is just under 6200) w/no problem. The motor has a built in rev limiter that won't allow you to over rev. As most all motors do these days. There are (4) guys in our club that all run Yamaha, EFI and HPDI's turning them w/no problem. Again contact any of the guys at Hydro-Tec, Wayne or Jon for starters.
Its better to set up your motor to turn the max or a little more rether then setting it up to hit the minimum rpms at wot. Lugging an HPDI is certain death.
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by falcooon »</td></tr><tr><td class="quote">The good question is "why"?
If you look at most horsepower curves, increasing rpm may not increase hp and in some instances decrease hp. You also risk a mechanical failure.
The gains are not worth the risk unless of course you are racing which is another issue.</td></tr></table>
This is and isn't true. Horsepower doesn't make your boat faster rpms do. A 300hp and a 200hp outboard will do the same mph at 5800rpm if the gear ratio is the same as well as the prop. The 300 will obviously allow you a bigger prop though. What I'm saying is if power drops past 5500rpm's but you're still gaining rpm's you will go faster.
Fwiw I was told by Mat at HT that 5800 was fine.
GUNNA SAY IT AGAIN, ABSOULUTELY
I have always proped my boats to run 5700-5900. Have been doing it this way for 30 plus years with three different bands never had a failure caused by high rpm. Here are a couple things to think about my 250 SHO says that rpm range is 5000 to 6000 but max hp is at 6000 so it says to me if you want to use all the hp that you paid for you need to run it at the top of the rpm range or slightly over. When I was thinking about a hydro tec phase 3 kit for my efi I ask them about turning this motor over 6000 rpms. They told me they run the same bottom end as that engine has and turn it 9500 rpm with all stock Yamaha parts on their race engines.
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by hooken203 »</td></tr><tr><td class="quote">They told me they run the same bottom end as that engine has and turn it 9500 rpm with all stock Yamaha parts on their race engines.</td></tr></table>
For what duration and how many hrs in between teardowns?
I think the new secret color is "A-Rig"..........
Call them and ask. Til the checkered flag drops I would guess.
Doesnt matter the point is that they do it and you have no reason to worry about spinning yours to 6500. If the factory sets the limit at say 6150 they know the parts will live at that rpm.
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by hooken203 »</td></tr><tr><td class="quote">I have always proped my boats to run 5700-5900. Have been doing it this way for 30 plus years with three different bands never had a failure caused by high rpm. Here are a couple things to think about my 250 SHO says that rpm range is 5000 to 6000 but max hp is at 6000 so it says to me if you want to use all the hp that you paid for you need to run it at the top of the rpm range or slightly over. When I was thinking about a hydro tec phase 3 kit for my efi I ask them about turning this motor over 6000 rpms. They told me they run the same bottom end as that engine has and turn it 9500 rpm with all stock Yamaha parts on their race engines.</td></tr></table>
I had a reputable race motor builder tell me to keep my motor at or below 6800 rpms. All the bearings he used in the motor were the same as his race applications that turn 11,500, but those use forged pistons. Aluminum pistons will start to loose their wrist pins going much above 6800. Just FYI to be careful and double check the information before hitting those upper Rs.
Run as close to the rev limiter as possible. I turn 5,900-6,000 rpm with my F60.
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