Valvetrain wear...what Rat DOESN'T do...
- Thread starter Shannow
- Start date
- Status
Im not familiar with those graphs or the test details and methodology, but I will comment anyway.
IMO the FMEP is just a guesstimated number made up from what an engine should make in calculated power and what it does actually make. But the difference between actual output and calculated output actually has to do with a lot more than friction, and more to do with compression ring pack loading and windage loads, both of which are present in powered and unpowered operation (the test engine was run unpowered?).
I would also be interested what pressure the crankcase was run under, as the apparent HP increases as the crankcase vacuum increases with RPM.
Every engine, even two examples of the same engine, would have significantly different friction values as well as actual output values. But I would guess the graphed information was derived and calculated from a particular test engine.
Anyway, pretty interesting, but shouldn't be relied on for across the board application.
IMO the FMEP is just a guesstimated number made up from what an engine should make in calculated power and what it does actually make. But the difference between actual output and calculated output actually has to do with a lot more than friction, and more to do with compression ring pack loading and windage loads, both of which are present in powered and unpowered operation (the test engine was run unpowered?).
I would also be interested what pressure the crankcase was run under, as the apparent HP increases as the crankcase vacuum increases with RPM.
Every engine, even two examples of the same engine, would have significantly different friction values as well as actual output values. But I would guess the graphed information was derived and calculated from a particular test engine.
Anyway, pretty interesting, but shouldn't be relied on for across the board application.
Originally Posted By: Jeff_in_VABch
Im not familiar with those graphs or the test details and methodology, but I will comment anyway.
IMO the FMEP is just a guesstimated number made up from what an engine should make in calculated power and what it does actually make. But the difference between actual output and calculated output actually has to do with a lot more than friction, and more to do with compression ring pack loading and windage loads, both of which are present in powered and unpowered operation (the test engine was run unpowered?).
I would also be interested what pressure the crankcase was run under, as the apparent HP increases as the crankcase vacuum increases with RPM.
Every engine, even two examples of the same engine, would have significantly different friction values as well as actual output values. But I would guess the graphed information was derived and calculated from a particular test engine.
Anyway, pretty interesting, but shouldn't be relied on for across the board application.
You omitted Volumetric Efficiency.
It's a crucial factor.
Im not familiar with those graphs or the test details and methodology, but I will comment anyway.
IMO the FMEP is just a guesstimated number made up from what an engine should make in calculated power and what it does actually make. But the difference between actual output and calculated output actually has to do with a lot more than friction, and more to do with compression ring pack loading and windage loads, both of which are present in powered and unpowered operation (the test engine was run unpowered?).
I would also be interested what pressure the crankcase was run under, as the apparent HP increases as the crankcase vacuum increases with RPM.
Every engine, even two examples of the same engine, would have significantly different friction values as well as actual output values. But I would guess the graphed information was derived and calculated from a particular test engine.
Anyway, pretty interesting, but shouldn't be relied on for across the board application.
You omitted Volumetric Efficiency.
It's a crucial factor.
Originally Posted By: Jeff_in_VABch
Steve:
Do you know of any place to get a 5.7 Hemi crate motor that is a value?
I have a truck that needs a new long block.
Jeff
Sorry I do not. My BIL runs a third generation high end machine shop, not known for bargains. If you know a dealer they can give you a hefty discount...
Steve:
Do you know of any place to get a 5.7 Hemi crate motor that is a value?
I have a truck that needs a new long block.
Jeff
Sorry I do not. My BIL runs a third generation high end machine shop, not known for bargains. If you know a dealer they can give you a hefty discount...
Start with a 48 degree block and go from there.
Which brings me to the exhaust lobe loading on a top fuel engine.....
Which brings me to the exhaust lobe loading on a top fuel engine.....
Naw, it don't take anything to open that valve against nitro
- Status
