10 best reasons to rev to redline under no load:

10. I'm not old enough to drive, but my mommy gave me an '03 S2000.
9. I want to commit suicide by polluting the air and taking everybody with me.
8. My doctor just told me I only have a hundred hours to live, and I want to use up my F20C before I go.
7. I'm hypnotized by the Castrol Synthetic (sp?) commercial and I want to try it for myself.
6. I sold my stock wheels but can't afford new wheels so my car's up on blocks.
5. I blew my differential so I have no way to apply load.
4. I blew my clutch so I have no way to apply load.
3. I've been launched into orbit so I have no way to apply load.
2. I'm deaf already but I love the feel of the engine vibrating itself to death.
1. I read this thread and just had to try it.

Thank you xviper for a nice response.
Now I understand what grumpy old Rick Hesel was talking about.

 

[QUOTE]Originally posted by Barry WY Silver/Black '01
[B]Thank you xviper for a nice response.

 

It seems lately there all days like that. I have given up on the explanations because it seems most people over read into it or come back and tell you that your full of crap. I liked the bicycle definition but after reading posts after it I wonder why you put yourself into all that. It seems you have to define your definition and I don't have the patience for that.

 

San Marino & xviper: please don't stop posting detailed explanations just b/c some people disagree or are too immature to rebutt you politely. Not everyone on the board is a complete moron. Some are only semi-moronic folks, like me!

 

Question for xviper: Since only 1 of the 4 strokes of a piston is a power stroke aren't the other 3 (intake, compression, exhaust) virtually under no (or very little) load?

 

Ummm hello... gas prices gas prices...

 

<JOKE MODE ON>

You know, after reading this thread it occurred to me there's a very simple solution.

If revving the engine w/no load is bad--simply introduce load.

For all of you who wish to do this, before revving, let out the clutch pedal to the friction point. For safety sake, put on the parking brake while you're at it (don't want to peel out after all).

Now rev away!! With your clutch partially engaged, you'll introduce load/resistance into the system and prevent premature engine wear!

(Don't mind the aweful smell...)

BTW: Don't try this at home, please be sure to be at least 10 miles away from your house and the nearest Honda dealer.

</JOKE MODE OFF>

{evil grin}

Randy

 

You are right ----- sorta. "Load", in this discussion, is the "resistance" the engine (each piston, if you will) pushes against (like the weight of the car, the friction in the tranny, diff, etc.). Where a lack of load is most noteworthy here is near, at and just after each piston's power stroke. Where in the power stroke the piston "drives" the crank, in all the other strokes, the crank drives the piston. The difference is that during the power stroke, all that force is pushing against something. It's better to be pushing against a good resistence than none or hardly none at all.
Imagine yourself bench pressing near your maximal, but comfortable weight (let's give it 100 lbs just for fun). You are told to do as many reps as possible in a given time. Let's say you can do 10 reps in 15 seconds. Now, make the weight "0". Use the same amount of force to do the same "rate" of reps. Without the 100 lbs of wt. at the top of each rep to "resist" your strength, what happens at the top now? The momentum of your arm muscles will cause some over-extension of your joints, right? Where you are correct is that the other 3 strokes would be the same regardless of the presence of load. When I said "each and every stroke, I should have specified each and every power stroke". This would be like you pressing 100 lbs. and at the top, someone holds the weight up so it doesn't come back down, you keeping your hands on the bars and someone else is moving the bar for you for 3 more strokes. As opposed to you driving the first push with NO wt. at full strength. In having a load on that push, you are reducing the stress on your joints by 25%. Since it's only 25% of the time, this is why I tried to stress to NOT WORRY ABOUT IT SO MUCH! It was an explanation, NOT a warning. Sorry, but that's the best analogy I can come up with right now. Goofy, huh?
I think to give more detailed analysis on this subject, one would have to be a mechanical engineer and those listening need to be almost as well versed, so I think I will stop at this stage. I don't want to have to bring out the row boats, teeter totters and sex toys!

 

I know this is just supposed to be an analogy, but I think it's confusing because the difference here is that the speed is going to increase with "0" weight. In your engine, we're comparing a fixed speed, load vs. no load; here, it's the force that changes, not the speed, so I can't see why there'd be any more momentum.

I'm a mechanical engineer and I guess what I can't figure out is, what are the clearances that you mentioned were closed under load but open at low load? And how does a load close them? Are we talking wristpins, crank journals, or ??? Those things are going to experience a load reversal many times a second either way, and I'm trying to figure out what it is about a load that would decrease bearing clearances.

 

If I get xviper's new sex-toy mod, how many strokes will my engine need to make the awful smell that Randy referred to?