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kerrdawg40 
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Joined: 18 Apr 2010
Location: Kentucky
Points: 22
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 Topic: 226 max rpm
Posted: 27 Aug 2011 at 6:52pm |
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On a D-17 stock 226 engine ---how many rpm's can it turn before the peak horsepower is met . I know you can pull the gov. open and turn it on up to 3000 rpms, but are you making any more horsepower or just putting a strain on the motor parts .
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Longmeadow Farm
Silver Level
Joined: 30 Jul 2011
Location: Eastern NY
Points: 321
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Posted: 27 Aug 2011 at 7:37pm |
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Not sure why you're asking this question, but HP can increase with RPMs up until the engine destructs in a gas engine. What is more important is the amount of torque an engine produces and at what rpm. A D-17 gas looks like it has max torque at 1655 RPM according to the Nebraska test data.. The HP rating is a somewhat useless measurement without knowing the rpms of max torque.. as this is the effeciency point of field class farm tractors.. and an indication of what rpm you should run your tractor. Higher RPMs might produce a better "sound" but it doesn't produce more work output.. gear up and throttle back to the max torque throttle position. Easier on your ears and pocketbook...
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kerrdawg40
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Joined: 18 Apr 2010
Location: Kentucky
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Posted: 27 Aug 2011 at 9:06pm |
Sorry I didnt state I am using this in pulling events (4500,5000,5500 lb. classes ). Basically I am asking if max torque is around 1700 then wouldnt turning it very much higher be mundane ?.Also at what point would stock valve springs lose effectiveness . What rpm ?
Edited by kerrdawg40 - 27 Aug 2011 at 9:07pm
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mlpankey
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Joined: 13 Sep 2009
Location: Vols country
Points: 4580
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Posted: 28 Aug 2011 at 12:55pm |
no peak torque always occurs below the rpm peak horsepower does. You can also gain ground speed by rpms . This is the biggest help in pulling a sled . Object in motion stay in motion untill a force equall to stops the motion. Ideally you rpm past peak and let the sled pull you into peak .
The valve spring depends on there spring rate in lbs. i had a set of old springs that had 20 lbs of seat pressure once and valve float occured at 1800 rpms . Have springs with 110 lbs on seat and havent found the rpm that they float at but valve train weight was also greatly reduced as well. One has to be carefull with seat pressure though they can get out off solid lifter range and into roller lifter spring rates and cause a solid cam and lifter failure quickly. Lighter valve train weight same valve spring rate always equalls a higher obtainable rpm if the gov. and carb will let it.
Edited by mlpankey - 28 Aug 2011 at 1:07pm
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DrAllis
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Joined: 12 Sep 2009
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Posted: 28 Aug 2011 at 1:12pm |
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Peak torque is clear down around 900 to 1000 RPM's.
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LouSWPA
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Joined: 11 Sep 2009
Location: Clinton, Pa
Points: 25182
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Posted: 28 Aug 2011 at 1:34pm |
 Longmeadow Farm wrote:
Not sure why you're asking this question, but HP can increase with RPMs up until the engine destructs in a gas engine. What is more important is the amount of torque an engine produces and at what rpm. A D-17 gas looks like it has max torque at 1655 RPM according to the Nebraska test data.. The HP rating is a somewhat useless measurement without knowing the rpms of max torque.. as this is the effeciency point of field class farm tractors.. and an indication of what rpm you should run your tractor. Higher RPMs might produce a better "sound" but it doesn't produce more work output.. gear up and throttle back to the max torque throttle position. Easier on your ears and pocketbook... |
Perhaps I am misunderstanding your point, but HP curves are never linear with RPM.....at some point in RPM. HP starts to fall off, yet RPM can still be increased.
Torque is work potential, and HP is how fast that work can be done, so, as you say, both are important
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mlpankey
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Joined: 13 Sep 2009
Location: Vols country
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Posted: 28 Aug 2011 at 2:52pm |
Torque is what we convert to get horsepower .Torque and horsepower are equal at 5250 rpm. Any modifications can and will move torque and horsepower up the rpm range . My last puller idled at 1000 rpm. Yes Lou every engine will rpm past peak horsepower and torque . I find this useful in pulling but others have different opinions and limit their cubic inches to achieve a higher rpm that produces power instead of taking a larger cubic inch motor past the rpm where it produces power and letting it pull into peak power . The engine that produce the highest rpm will always have a higher horsepower to cubic inch than a larger engine but one will be limited by cubic inches and demand rpm for breathing adequately . The bigger cubic inch engine will be limited in horsepower by breathing but if rotating mass is the same as the small one it will rpm right on up .hope this makes since . a naturally aspirated 226 making 100 horsepower will have to do it above 5500 rpm . A naturally aspirated 390 cubic inch make 100 horsepower at 1650
Edited by mlpankey - 28 Aug 2011 at 2:56pm
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