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HP vs Torque

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Old 12-17-2002, 02:50 PM
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Quote:
Originally posted by audacity
"(Assuming torque peek is lower than HP peek, which 99% of the time it is)" IT IS?...better change that.
Not the number itself, but the rpm which they peek. Sorry.
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Old 12-17-2002, 02:55 PM
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Volvo duo on an HTM?
 
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Old 12-17-2002, 02:57 PM
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rpm and tq will always cross at 5252!
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Old 12-17-2002, 03:02 PM
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Quote:
Originally posted by audacity
rpm and tq will always cross at 5252!
The actual value of the respective units will, but I was comparing rpms. The torque peak will typically occurr at a lower rpm than the HP peak rpm.
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Old 12-17-2002, 03:04 PM
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if your engine's peak tq is at 6500...and tq is < the amount your hull requires to obtain that speed??...then you engine builder should (or should have)....change cam timing and or cams...a cam good for 6500 rpm should not be in a application of 5800rpms....why have all that lift and increased ramp times if your not using it....it just takes from a durability prospective....
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Old 12-17-2002, 03:09 PM
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from your numers...it sounds like you NEED to go up in rpms!...your get's close to peak hp and are way past the 5800 mark....I WOULD TRY that first! try to dial in the props for 6500
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Old 12-17-2002, 04:12 PM
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Brad,
I have a batboat B24 and replaced the stock 350 with a HTM 565 engine. The boat runs much more stable with a duoprop according to those who tried the Bravo, but not as fast.

Audacity,
It sounds like you really know your stuff. My peak torque is at 5800 and I don't remember what the value is. The peak HP is 6500 RPM and is 650 HP according to HTM.

My engine builder died in the HTM crash so not much I can do about wrong cam, etc. I already blew up one duoprop drive with a stock 502 and replaced it with the HP version of Duoprop along with the new engine. I am concerned with durability and drive very hard. (I guess that means I'm not that concerned ) I spend a lot of time in the air and sometimes miss with the throttles, but not that often. I love the acceleration from 75 - 90 and just want to break 100 all the time. It sounds like going for less pitch and higher RPM might actually get both the best speed and durability.

Thanks to all of you for the input.
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Old 12-17-2002, 04:38 PM
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Tom,
sorry to hear about the engine builder.

here are a few other key pints to keep in mind:...........

1. be sure you are not exceeding the drive specs with rpm...i would think you are currently in the hp department.

2. you have a dual prop so some rules and limitations have changed. you may be able to get away with adding diameter to one and take away from the other allowing only one to make contact at (your #) a given hi speed...Again, i have never done dial in work for a dual prop application...

3. you may want to investigate the limitations hydrodynamicly of your drive...you may be at its limits??...again, i have no idea. you may want to start a thread or call the manufacture to see what data is out there about others using this drive on applications above 100+ mph.

4. remember throttle input is required log before the prop(s) leave the water... it's not how fast you go,,,it's how well you go fast that wins everytime!!! you know someone said that in a magazine once.

Last edited by audacity; 12-18-2002 at 07:46 AM.
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Old 12-17-2002, 05:11 PM
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Is that really you Joey ??? You sound so humble

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Old 12-18-2002, 07:45 AM
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shhhhh,,,over on that side of the country!
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