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GT40 Engine torque and RPM |
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slmskrs 
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Joined: January-03-2012 Location: SF bay area, CA Status: Offline Points: 522 |
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 Topic: GT40 Engine torque and RPMPosted: January-06-2021 at 2:47am |
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Anyone know where the peak torque is (and associated RPM) on a GT40? I know the HP is 310@4800RPM. Just want to know where torque is (a torque curve would be great).
Thanks, Gordon
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Gordon '97 Ski Nautique, GT40
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DVskier
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Joined: September-04-2014 Location: Seneca SC Status: Offline Points: 449 |
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Posted: January-06-2021 at 9:21pm |
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I’m pretty sure the peak torque being 375 and the band is wide.
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slmskrs
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Joined: January-03-2012 Location: SF bay area, CA Status: Offline Points: 522 |
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Posted: January-07-2021 at 12:58am |
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Thanks. The lable on my GT40 (MPI) says 310hp and 4800RPM max. However, I've heard that the WOT range is between 4600 and 5000 (propeller guy). So I'm assuming that if max HP is 4800, it falls off quickly. Don't recall off hand but there is also a max continuous cruise RPM that I think is in the 4000-4200 range. Granted, I'm skiing in the course, so my speeds are 34.2 or 36mhp, and not much over 3800RPM. But it would be nice to know what the curve is and where the most torque is. I would like to think it is in the range where I'm skiing (3400-3800rpm).
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Gordon '97 Ski Nautique, GT40
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KENO
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Joined: June-06-2004 Location: United States Status: Offline Points: 10645 |
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Posted: January-07-2021 at 8:44am |
Here's a link to a 300 HP 351W engine. complete with a dyno graph. (click on alternative views) I'd call it a good representative graph showing just what Dave said above. It's got a higher performance cam and less efficient heads, but you should get the idea as far as the shape of the curve  |
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DVskier
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Posted: January-07-2021 at 1:43pm |
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The GT 40 engine is well known for having greater torque than the Excalibur 330 and 343 hp GM based 5.7 L engines. The Excalibur engines run a bit faster on top speed though 1-2 mph. The Excalibur does seem to running more smoothly. I’m happy to ski behind either one though.
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DVskier wrote: