Put that same motor in a 4000 lb car and the high horsepower low torque motor would,nt get out of its own way... :confused: :D
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Put that same motor in a 4000 lb car and the high horsepower low torque motor would,nt get out of its own way... :confused: :D
Guys...horsepower is simply the result of the calculation of torque at a particular RPM. Horsepower is a measure of work done based upon, in this case, rotary motion. Torque and horsepower can be equal at 5252 RPM ONLY if the motor can spin to that rpm. In the case of diesel engines that are high torque at low RPM's they may not be able to get up to 5252 RPM.
Small motors like F1 build peak torque at very high RPM and have transmissions that keep the RPM in the desired range.
Here is my .02:
HP is just the measure of how much work the engine is capable of doing. The rpm does not enter the equation of HP except that you have to pick at what rpm you measure it. When assembling and selecting components for the engine you have to choose where you want to make that horsepower. If you make good power on the bottom end you will produce more torque from, make the power on the top end less torque. Once you have assembled the engine you can then change the props, gears, impellers etc to make changes which will alter where on the curve the boat actually sees the torque.
Seems to me that if you build for decent torque all the way through the rpm with max torque at max rpm you get the most flexibility with making changes with the props, etc.
The 5252 number means absolutely nothing. It is a coincidence which happens on a large number of boats. I saw a thread a while back which made an absolutely true statement, Covert to metric units and the 5252 number doesn't work anymore.
You guys think too much about it... :D
So where are the photos of the DCB Jrocket?
Hey, happy fathers day to you.
You Te
You guys think too much about it... I agree, but for us outboard folks, like the Honda commercial: if you don't have to worry about your motor, what will you think about...
BTW- The 5252 # maybe trivial but not meaningless. Often power numbers are given without an " at #### rpm" or not given with a torque number. Knowing that at 5252 rpm they are the same, give you a point to approximate from to fill in blank.
I'm sure there is also a similiar point in metric terms where the same is true.
bump for first page of archive
STV Keith is right. I will add that it depends on the boat though. For O/B applications where the boat is real light (Mirage, STV, etc.) you really don't need that much torque, thus a 2.5L motor is just fine. However, if you run a 21' Daytona or similar (heavier boat), you need a 300X or so to get that sucka out of the hole and up to speed.
On the same 21' boat, I'd put my money on a 2.5 280 over a 300X anyday!!!
It's going to be a terrible loss when we loose access to this thread.
Wow, this shit is old...