[Z06] Is it harmful to rev your z06 engine?
thats funny
11-11-2008, 01:46 PM
#42
Burning Brakes
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I'm 50 and still a virgin because I'm too damn ugly to get a hot girlfriend so I need to drive a c6 and that still doesn't pull chicks so I'll never get married, what do I do.com
Last edited by ^ROCKSTAR^; 11-11-2008 at 02:50 PM.
11-11-2008, 02:50 PM
#43
Burning Brakes
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I just want to thank everybody that came in this thread and provided helpful and substantial information pertaining to my topic..
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
11-11-2008, 04:53 PM
#44
Pro
Quote:
Originally Posted by bob53
My simple minded understanding is this -
Under no load, at high revs, there are tremendous stresses on the connection point between the connecting rod and piston at the piston due to the huge changes in acceleration with no opposing force (no load) at the top and bottom of travel when it changes direction.
So yes, revving the motor at high RPM a lot while not moving forward is not good for the motor.
You guys are kiddin' right? A motor under load is just what it means...LOAD. Revving to 7000 rpm under LOAD is much more stressful on your engine than revving it to 7000 rpm under NO LOAD. You guys are just spreading an old wives tale.
And BTW, piston acceleration is at maxmium at mid stroke, not at TDC or BDC where it is in fact at zero acceleration. On the compression stroke, the piston begins to decelerate once it reaches mid stroke until it is fully decelerated to 0 at TDC. And acceleration is a function of piston velocity and rpm...it does not vary with load.
Just an example...
On the compression sroke, the rod is trying to force the piston upwards against compression. Therefore, the more the compression (load) the greater the stresses on the rod and journal beaings. And of course this is also true on the power stroke.
So let's stop telling people revving under no load is worse than under load. That is jibber jabber.
Originally Posted by bob53
My simple minded understanding is this -
Under no load, at high revs, there are tremendous stresses on the connection point between the connecting rod and piston at the piston due to the huge changes in acceleration with no opposing force (no load) at the top and bottom of travel when it changes direction.
So yes, revving the motor at high RPM a lot while not moving forward is not good for the motor.
You guys are kiddin' right? A motor under load is just what it means...LOAD. Revving to 7000 rpm under LOAD is much more stressful on your engine than revving it to 7000 rpm under NO LOAD. You guys are just spreading an old wives tale.
And BTW, piston acceleration is at maxmium at mid stroke, not at TDC or BDC where it is in fact at zero acceleration. On the compression stroke, the piston begins to decelerate once it reaches mid stroke until it is fully decelerated to 0 at TDC. And acceleration is a function of piston velocity and rpm...it does not vary with load.
Just an example...
On the compression sroke, the rod is trying to force the piston upwards against compression. Therefore, the more the compression (load) the greater the stresses on the rod and journal beaings. And of course this is also true on the power stroke.
So let's stop telling people revving under no load is worse than under load. That is jibber jabber.
11-11-2008, 09:43 PM
#46
4th Gear
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http://www.epi-eng.com/piston_engine...celeration.htm
Velocity is zero at TDC and BDC. Acceleration is maximum.
Velocity is zero at TDC and BDC. Acceleration is maximum.
11-11-2008, 09:57 PM
#47
Burning Brakes
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and btw, piston acceleration is at maxmium at mid stroke, not at tdc or bdc where it is in fact at zero acceleration. On the compression stroke, the piston begins to decelerate once it reaches mid stroke until it is fully decelerated to 0 at tdc. And acceleration is a function of piston velocity and rpm...it does not vary with load.
so let's stop telling people revving under no load is worse than under load. That is jibber jabber.
http://www.epi-eng.com/piston_engine...celeration.htm
velocity is zero at tdc and bdc. Acceleration is maximum.
velocity is zero at tdc and bdc. Acceleration is maximum.
Free-revving your engine under zero load is MUCH LESS stressful. It never ceases to amaze me at the old-skool (spelled wrong purposely) mentality so abundantly strong across the internet.
Last edited by RWTD; 11-11-2008 at 10:03 PM.
11-11-2008, 10:09 PM
#48
Race Director
http://www.epi-eng.com/piston_engine...celeration.htm
Velocity is zero at TDC and BDC. Acceleration is maximum.
Velocity is zero at TDC and BDC. Acceleration is maximum.
Acceleration is the change of velocity of an object over time
Even though a piston is momentarily not moving at tdc, the rate of change of velocity is at it's highest.
11-11-2008, 11:49 PM
#49
Burning Brakes
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Quote:
Originally Posted by bob53
My simple minded understanding is this -
Under no load, at high revs, there are tremendous stresses on the connection point between the connecting rod and piston at the piston due to the huge changes in acceleration with no opposing force (no load) at the top and bottom of travel when it changes direction.
So yes, revving the motor at high RPM a lot while not moving forward is not good for the motor.
You guys are kiddin' right? A motor under load is just what it means...LOAD. Revving to 7000 rpm under LOAD is much more stressful on your engine than revving it to 7000 rpm under NO LOAD. You guys are just spreading an old wives tale.
And BTW, piston acceleration is at maxmium at mid stroke, not at TDC or BDC where it is in fact at zero acceleration. On the compression stroke, the piston begins to decelerate once it reaches mid stroke until it is fully decelerated to 0 at TDC. And acceleration is a function of piston velocity and rpm...it does not vary with load.
Just an example...
On the compression sroke, the rod is trying to force the piston upwards against compression. Therefore, the more the compression (load) the greater the stresses on the rod and journal beaings. And of course this is also true on the power stroke.
So let's stop telling people revving under no load is worse than under load. That is jibber jabber.
Originally Posted by bob53
My simple minded understanding is this -
Under no load, at high revs, there are tremendous stresses on the connection point between the connecting rod and piston at the piston due to the huge changes in acceleration with no opposing force (no load) at the top and bottom of travel when it changes direction.
So yes, revving the motor at high RPM a lot while not moving forward is not good for the motor.
You guys are kiddin' right? A motor under load is just what it means...LOAD. Revving to 7000 rpm under LOAD is much more stressful on your engine than revving it to 7000 rpm under NO LOAD. You guys are just spreading an old wives tale.
And BTW, piston acceleration is at maxmium at mid stroke, not at TDC or BDC where it is in fact at zero acceleration. On the compression stroke, the piston begins to decelerate once it reaches mid stroke until it is fully decelerated to 0 at TDC. And acceleration is a function of piston velocity and rpm...it does not vary with load.
Just an example...
On the compression sroke, the rod is trying to force the piston upwards against compression. Therefore, the more the compression (load) the greater the stresses on the rod and journal beaings. And of course this is also true on the power stroke.
So let's stop telling people revving under no load is worse than under load. That is jibber jabber.
11-12-2008, 08:11 AM
#51
Le Mans Master
I wouldn't make it a habit to free rev the car at idle, regardless of oil/coolant temp. I see these idiots at these saturday night car meets that free rev like near the limiter (some bouncing off), and I'm just cringing 
maybe rev it to 4000 or something, but save the 5K+ for actual in gear situations
maybe rev it to 4000 or something, but save the 5K+ for actual in gear situations
11-12-2008, 10:03 AM
#52
Pro
http://www.epi-eng.com/piston_engine...celeration.htm
Velocity is zero at TDC and BDC. Acceleration is maximum.
Velocity is zero at TDC and BDC. Acceleration is maximum.
Velocity is zero at TDC and BDC and therefore acceleration is also zero. If acceleration is delta V over delta T, since delta V is zero, acceleration is zero.
The largest change in piston velocity per unit time occurs at mid-stroke, therefore acceleration is at maximum.
11-12-2008, 11:52 AM
#53
Pro
Velocity is zero at TDC and BDC and therefore acceleration is also zero. If acceleration is delta V over delta T, since delta V is zero, acceleration is zero.
The largest change in piston velocity per unit time occurs at mid-stroke, therefore acceleration is at maximum.
I had to plot the values myself to see it.
Nevertheless, I stand by the position that running at max rpm under load is more stressful than running at the same rpm under no (or little) load. To suggest otherwise is nonsensical.
11-13-2008, 03:01 AM
#54
Instructor
I just want to thank everybody that came in this thread and provided helpful and substantial information pertaining to my topic..
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
11-13-2008, 02:05 PM
#55
4th Gear
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As can be
seen in this figure, the maximum of total load magnitude,
which is equal to the maximum of bending load
decreases as the engine speed increases. The reason
for this situation refers to the load sources that exist in
the engine at 355 degree crank angle. At this crank
angle these two forces act in opposite directions. The
force caused by combustion which is greater than the
inertia load does not change at different engine speeds
since the same pressure versus crankshaft angle is
used for all engine speeds. The load caused by inertia
increases in magnitude as the engine speed increases.
Therefore, as the engine speed increases, a larger
magnitude of inertia force is deducted from the
combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
seen in this figure, the maximum of total load magnitude,
which is equal to the maximum of bending load
decreases as the engine speed increases. The reason
for this situation refers to the load sources that exist in
the engine at 355 degree crank angle. At this crank
angle these two forces act in opposite directions. The
force caused by combustion which is greater than the
inertia load does not change at different engine speeds
since the same pressure versus crankshaft angle is
used for all engine speeds. The load caused by inertia
increases in magnitude as the engine speed increases.
Therefore, as the engine speed increases, a larger
magnitude of inertia force is deducted from the
combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
11-13-2008, 02:33 PM
#56
Melting Slicks
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St. Jude Donor '09
As can be
seen in this figure, the maximum of total load magnitude,
which is equal to the maximum of bending load
decreases as the engine speed increases. The reason
for this situation refers to the load sources that exist in
the engine at 355 degree crank angle. At this crank
angle these two forces act in opposite directions. The
force caused by combustion which is greater than the
inertia load does not change at different engine speeds
since the same pressure versus crankshaft angle is
used for all engine speeds. The load caused by inertia
increases in magnitude as the engine speed increases.
Therefore, as the engine speed increases, a larger
magnitude of inertia force is deducted from the
combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
seen in this figure, the maximum of total load magnitude,
which is equal to the maximum of bending load
decreases as the engine speed increases. The reason
for this situation refers to the load sources that exist in
the engine at 355 degree crank angle. At this crank
angle these two forces act in opposite directions. The
force caused by combustion which is greater than the
inertia load does not change at different engine speeds
since the same pressure versus crankshaft angle is
used for all engine speeds. The load caused by inertia
increases in magnitude as the engine speed increases.
Therefore, as the engine speed increases, a larger
magnitude of inertia force is deducted from the
combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
11-13-2008, 02:52 PM
#57
Pro
The force caused by combustion which is greater than the inertia load does not change at different engine speeds since the same pressure versus crankshaft angle is used for all engine speeds. The load caused by inertia increases in magnitude as the engine speed increases.
Therefore, as the engine speed increases, a larger magnitude of inertia force is deducted from the combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
Therefore, as the engine speed increases, a larger magnitude of inertia force is deducted from the combustion load, resulting in a DECREASE of the total load magnitude.
http://www.eng.utoledo.edu/mime/peop...07-01-0258.pdf
And BTW, running the engine faster (for a given combustion load) reduces the total load on the engine according to the article cited above. Of course, the article doesn't indicate what happens as combustion load is varied for a given speed. They used WOT for the analysis and concluded that the resulting load was greater than the inertia load. Therefore, as the throttle is closed, the combustion load is likewise reduced and since it is a larger component of total load than is inertia, the total load will decrease as engine loading is reduced.
Ergo, reving an engine under no load is less stressful than running at the same speed under load.
11-13-2008, 05:01 PM
#58
Drifting
I just want to thank everybody that came in this thread and provided helpful and substantial information pertaining to my topic..
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
I figured the few occasional A** clowns would drop in and add their 2 cents but that's to be expected on these forums..
To all the people that were helpful though I just want to say thank you.
Moderators..you can close this thread.
11-13-2008, 05:26 PM
#59
Melting Slicks
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St. Jude Donor '09
Right -- but the biggest A** clown in this thread being you...maybe think about your actions before denigrating others here. You so remind me of those HD riders constantly blipping the throttle to impress others with the "bada**" sound of a bike that has nothing under the hood, but just sounds like a lot of noise. Only difference here, is that under the Vette's hood lies a monster, just waiting to be wrecked by someone like you revving the **** out of it in neutral.
11-13-2008, 05:32 PM
#60
Melting Slicks
The most important thing is if the motor is cold you can spin a bearing in a heart beat. Same thing goes even when under a load let the car get up to running temp coolant (180) and oil temp (160). Is pretty simple to know how long it takes, just pull up your temps on the DIC and see how long it takes. Don't watch the analog gauge. This is an easy way to due severe damage. This is engine 101 stuff.
Last edited by LPE385; 11-13-2008 at 05:37 PM.