Whats harder on a engine boosted or natural asp
- Thread starter ZZ71s
- Start date
too answer that you'll want to look at the most common sources of engine failures and deduce how each modification increased the stress levels.
It may be surprising, but at any given horsepower level on the same basic engine displacement a supercharged engine that's been properly built should be under less stress, while its true the cylinder pressures increase significantly with a supercharger, if you stay out of detonation, the extra cylinder pressure, is within limits usually not a big problem for a properly built engine.
a well build N/A engine rarely exceeds 1.25 ft lbs of torque per cubic inch of displacement, a supercharged engine can easily make 1.6 ft lbs per cubic inch, while its true that the increased cylinder pressure that produces the higher torque that a super charger equipped combo, will produce,it will increase the strain on the block and main caps, and rods, etc. by the time your run up into the rpm levels required to duplicate the same horsepower levels with a N/A combo you've also significantly increased stress on the valve train, main caps and rod bolts so its effectively a wash,
the formula for hp is torque times rpm divided by 5252=hp
lets assume your building a 383, and youve got 475 ft lbs at 5000rpm. that equals 455hp
reduce compression and add a supercharger and you can get that 1.6 ft lbs per cubic inch or about 610 ft lbs at that same 5000rpm or 583hp, with about the same stress, in some areas and only slightly more in others, PROVIDED the correct components are used.
the problem is that youll rarely see a properly built engine as most guys try to skate by using as many O.E.M. components as they can to save money and still try to maximize the engines hp, stressing the components to and past the stress limits they were designed for.
but keep in mind that stock engine blocks are generally factory rated at 350-450hp,stock rods and cranks at 400-500hp/6000rpm,, once you exceed those power/rpm ranges your block strength becomes a limiting factor
yet youll want to remember
getting into detonation,
poor lubrication,
in-effective cooling
and high rpm stress
main caps moving under stress
are the most common problems,
in PROPERLY BUILT AND ASSEMBLED ENGINES.
you can control high rpm stress levels by simply limiting your engine rpms to piston speeds below 4000feet per minute, and valve train rpms to below about 6500rpm, with quality roller rockers and a rocker stud girdle ,use a properly thought thru lubrication and cooling system, that are more than adequate for the application are not all that difficult to build and use.
use of the far stronger forged components like cranks and pistons and connecting rods with 7/16" ARP rod bolts can easily double or triple the strength of the standard O.E.M. cast components
youll want to read thru these threads
viewtopic.php?f=53&t=204
viewtopic.php?f=53&t=253
viewtopic.php?f=53&t=247
viewtopic.php?f=53&t=2726
viewtopic.php?f=53&t=510
viewtopic.php?f=53&t=341
viewtopic.php?f=52&t=181
viewtopic.php?f=57&t=149
viewtopic.php?f=57&t=853
viewtopic.php?f=57&t=1540
viewtopic.php?f=50&t=2883&p=7484&hilit=detonation#p7484
viewtopic.php?f=55&t=2718&p=7057&hilit=+detonation#p7057
viewtopic.php?f=53&t=2610&hilit=+detonation
viewtopic.php?f=44&t=937&p=6449&hilit=+detonation#p6449
It may be surprising, but at any given horsepower level on the same basic engine displacement a supercharged engine that's been properly built should be under less stress, while its true the cylinder pressures increase significantly with a supercharger, if you stay out of detonation, the extra cylinder pressure, is within limits usually not a big problem for a properly built engine.
a well build N/A engine rarely exceeds 1.25 ft lbs of torque per cubic inch of displacement, a supercharged engine can easily make 1.6 ft lbs per cubic inch, while its true that the increased cylinder pressure that produces the higher torque that a super charger equipped combo, will produce,it will increase the strain on the block and main caps, and rods, etc. by the time your run up into the rpm levels required to duplicate the same horsepower levels with a N/A combo you've also significantly increased stress on the valve train, main caps and rod bolts so its effectively a wash,
the formula for hp is torque times rpm divided by 5252=hp
lets assume your building a 383, and youve got 475 ft lbs at 5000rpm. that equals 455hp
reduce compression and add a supercharger and you can get that 1.6 ft lbs per cubic inch or about 610 ft lbs at that same 5000rpm or 583hp, with about the same stress, in some areas and only slightly more in others, PROVIDED the correct components are used.
the problem is that youll rarely see a properly built engine as most guys try to skate by using as many O.E.M. components as they can to save money and still try to maximize the engines hp, stressing the components to and past the stress limits they were designed for.
but keep in mind that stock engine blocks are generally factory rated at 350-450hp,stock rods and cranks at 400-500hp/6000rpm,, once you exceed those power/rpm ranges your block strength becomes a limiting factor
yet youll want to remember
getting into detonation,
poor lubrication,
in-effective cooling
and high rpm stress
main caps moving under stress
are the most common problems,
in PROPERLY BUILT AND ASSEMBLED ENGINES.
you can control high rpm stress levels by simply limiting your engine rpms to piston speeds below 4000feet per minute, and valve train rpms to below about 6500rpm, with quality roller rockers and a rocker stud girdle ,use a properly thought thru lubrication and cooling system, that are more than adequate for the application are not all that difficult to build and use.
use of the far stronger forged components like cranks and pistons and connecting rods with 7/16" ARP rod bolts can easily double or triple the strength of the standard O.E.M. cast components
youll want to read thru these threads
viewtopic.php?f=53&t=204
viewtopic.php?f=53&t=253
viewtopic.php?f=53&t=247
viewtopic.php?f=53&t=2726
viewtopic.php?f=53&t=510
viewtopic.php?f=53&t=341
viewtopic.php?f=52&t=181
viewtopic.php?f=57&t=149
viewtopic.php?f=57&t=853
viewtopic.php?f=57&t=1540
viewtopic.php?f=50&t=2883&p=7484&hilit=detonation#p7484
viewtopic.php?f=55&t=2718&p=7057&hilit=+detonation#p7057
viewtopic.php?f=53&t=2610&hilit=+detonation
viewtopic.php?f=44&t=937&p=6449&hilit=+detonation#p6449