Limiting factor for RPMs?

[OldMachinist]

I just re-read all my posts and I never asked why you liked RPM. The only thing keeping me from high RPM is like several posts from others said COST! I love it but can't afford it.
My constant theme has been MAXIMUM CUBIC INCHES the block will allow.
If you want people to have a discussion I suggest you quit lying about what they say and trying to change the subject when you know you are wrong. This is the constant theme with you when you finally realize you are wrong but won't admit it. Change the subject and never directly answer questions that are posed to you.

[dieselgeek]

Notice how TC keeps posting links and articles that don't agree with his original premise whatsoever? He always does this crap because he's still looking for an actual logical reason for the first fifteen pages of bullshit he's caused.


Face it, Alex. You don't really know what you are arguing about as usual, and this thread won't result in you having a running HotRod, as usual. Giant waste of everyone's time... As usual.

[TheSilverBuick]

That rollingthunderz quote he was using was taking the quote completely out context too. The author was using the same piston speed for the short and long stroke engines to make it so some people can understand why there is more vertical friction of the piston rings to cylinder wall on a longer stroke, by basically showing it has more vertical travel to "drag" against. Of course it completely leaves out the increased drag of extra surface area a wider piston has on the cylinder wall has. I don't claim to know A) what the difference is in contact area (don't care enough to calculate) or B) that it even makes a difference. But my guesses are that on A there will be a break over point where the frictional area of one will start to out pace the other as bore is decrease and stroke increased (I don't know which) and B it's not really going to matter as OEM's or others would be making engines in only that way for peak power and efficiency, which they don't. Bore's and strokes of engines are all over the place, under and over squared.

[squirrel]

And we seem to be neglecting the fact that ring drag is mostly a product of how much pressure is in the cylinder at that specific time, and it changes constantly. It's highest at the beginning of the power stroke.

[TC]

I just re-read all my posts and I never asked why you liked RPM. The only thing keeping me from high RPM is like several posts from others said COST! I love it but can't afford it.
My constant theme has been MAXIMUM CUBIC INCHES the block will allow.
If you want people to have a discussion I suggest you quit lying about what they say and trying to change the subject when you know you are wrong. This is the constant theme with you when you finally realize you are wrong but won't admit it. Change the subject and never directly answer questions that are posed to you.

You ask this....

The whole reason I questioned you TC and got this started is your use of that short stroke NASCAR crank in your benchrace turbo engine. Why limit yourself to smaller c.i. than the block will support?

I think I'm getting the RPM stuff from other posts, probably getting you confused with someone else...... But what I posted still represents why I'm going with a smaller stroke and why I plan on spinning this motor 8000rpm......

As for Benchrace, this motor is a camshaft, bearings, pushrods, shaft rockers and pistons away from being a reality..... Those are the only things I still need to buy before taking this motor to my buddy Rick for machining and final assembly, hell I even got the turbo headers and turbos already...........Oh and I guess we should add a carb on that list to.......

[TC]

Notice how TC keeps posting links and articles that don't agree with his original premise whatsoever? He always does this crap because he's still looking for an actual logical reason for the first fifteen pages of bullshit he's caused.


Face it, Alex. You don't really know what you are arguing about as usual, and this thread won't result in you having a running HotRod, as usual. Giant waste of everyone's time... As usual.

Actually one of the links does agree with what I'm saying, you should read a bit more carefully next time............

And let me ask you this, when you decrease parasitic losses on a crankshaft what does that allow the crankshaft to do..........

[Bob Holmes]

Damn it Randal, there you go getting all scientific on us. I hate it when you derail a good TC driven "Theory" fest with facts. I was looking forward to at least another couple of pages of cut and paste of articles that don't substantiate his theories and which, I'm convinced, he doesn't comprehend or understand.

At least it's fun to read the articles.

[Bob Holmes]

We're talking about worrying about parasitic lose on a dual turbo, 8,000 rpm, 1,200hp engine...

[TC]

That rollingthunderz quote he was using was taking the quote completely out context too.

It was?? or is that you can't comprehend??......

The size of the crankshaft stroke also affects engine acceleration as a longer stroke makes the piston travel more distance to complete a full revolution.

The difference in piston speed can be measured in feet per minute between different size stroke crankshafts. For example, a 3.75 inch stroke crankshaft has a piston speed of 4,375 feet per minute and a 4.25 inch stroke crankshaft has piston speed of 4,958 feet per minute. This means the piston for the longer stroke crank travels more distance, specifically 583 feet more per minute or 9.72 feet more per second. Another method for a comparative analyzes is to consider the 1/2 inch longer stroke of the 4.25 inch crankshaft requires the piston to travel 1 full inch more per revolution by traveling 1/2 inch lower and another 1/2 inch higher to complete a full revolution of the crankshaft. The longer stroke crank travels 7000 inches more distance at 7000 rpm or 9.72 feet more distance per second. (7000 inches /12 = 583 ft per minute & 583 ft / 60 = 9.72 per sec)

This also means a 4.25 stroke crankshaft, with the same piston speed as the 3.75 stroke crank, rotates at a slower speed. The slower crankshaft rotation results in a slower rate of engine acceleration, which results in a slower rate of vehicle acceleration.

These are some of the factors that make crankshaft stroke an important component for engine acceleration. These examples can also help to explain why some big stroke engines make more power on a dyno and run slower at the track than a less powerful engine that can accelerate faster.

[TC]

We're talking about worrying about parasitic lose on a dual turbo, 8,000 rpm, 1,200hp engine...

I'm not, that is what I'm trying to get across to OldMachist, who cares about stroke when you got turbos and are making 1200hp.........

[TC]

Hell might as well add to the bashing.......

This has always been my thinking.......

8000rpm will produce 8000 more power cycles in the same minute than 6000rpm will do.....

A 5.88 gear will deliver the power to the rear wheels twice as fast as a 2.73 gear.......

And a 31" tall tire has a bigger contact patch and delivers more power to the ground during one rotation of the tire than a 28" tall tire..........

But then I'm sure you'll disagree with me on this to........

[jcharliem]

^^^^ Blah, blah, blah. How many future threads will be laced with this type of script? TC, I hope you continue to post... as you're terrific fodder for the BS entertainment meter.

[TC]

^^^^ Blah, blah, blah. How many future threads will be laced with this type of script? TC, I hope you continue to post... as you're terrific fodder for the BS entertainment meter.

As long as I'm putting joy into your life, my job is has been done....... If you knew me in person you'd know I like to make people laugh......

Though it is nice to know that my views about big bores and short strokes are shared with one the best engine builders in the country, Reher-Morrison, I read through his whole blog and I was surprised at how much we think alike......

[squirrel]

A 5.88 gear will deliver the power to the rear wheels twice as fast as a 2.73 gear.......

That makes no sense at all.

And a 31" tall tire has a bigger contact patch and delivers more power to the ground during one rotation of the tire than a 28" tall tire..........

That makes no sense at all.

[jcharliem]

...it is nice to know that my views about big bores and short strokes are shared with one the best engine builders in the country, Reher-Morrison...

Really? Seems like your changing your viewpoint now. The article references larger bore allows for monster valves and unshrouding (which is what I stated on page 6 to your question as to why Pro Stockers use large bore / short stroke combos). I thought your original premise was shorter strokes can "rpm faster" (whatever that means). Now you're singing the tune of Dave Reher. The entertainment meter is on tilt again.