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It has become obvious that DE,Jr has a plate motor advantage; it has to be something unconventional and I'm wondering if they have maybe discovered that contrary to popular belief "shorter" con rods can make more power. Assuming the conventional engine has a stroke of 3.5" and a rod length of 6.125" so that the length to stroke ratio is 1.75. Compare this to the BMW M3 that has a ratio of 1.48 and that engine makes 1.7 hp/cu in. And likewise these litle newer 4 banger auto engines have ratios at about 1.5.
Now consider the worlds largest, most powerful and most efficient engine has a ratio of about 1.16. Look in the link, find the "to scale" cross section and do a little measuring. And my guess none of these engines were built like this just to save height.
Ok now

I have a ME handbook that has about 6-7 pages of charts etc. on crank operated reciprocating elements and with different rod to stroke ratios. The charts show piston position and velocity relationship to the crankpin at 5 degree intervals, angles for different fractions of the stroke, inertia factors and piston accelerations at 5 degree intervals. There is also a section about offset cranks and the really strange part is with an offset crank or wrist pin the stroke will be longer than normal.
Main thing to remember is the ratio of piston velocity to crankpin velocity is referred to as the tangential factor or crank turning ability. It is very easy to look at these charts and see that a shorter rod provides a higher T factor AND it come sooner in terms of crank degrees AND time. Time is very important with respect to blowby leakage and BTU leakage to the water jackets and nearly all of this occurs near TDC. To me this is total evidence that theorietically the short rod should makes more power. Most all say the extra angularity and friction loss is more than any gain of the short rod; I always felt the drag of the rings was the bigger part and angularity would not matter that much. On TV years ago I saw a dragster make several runs blowing oil smoke like fogging mosquitoes and he was the fastest in his class; I'd bet he had intentionally left the oil rings off to save friction.
Another strange thing is that at 90 deg. ATDC the T factors are all 1 regardless of the rod length.
Now to the intake stroke and of course the piston behaves the same way. I look at it this way; if it were possible the best thing that could happen is on the intake the piston moves INSTANTLY from TDC to BDC and simply resides there until time to start on the comp. stroke, but of course that's impossible so I'll go for the next best and that is get it away from TDC as quickly and with as much velocity as possible. You know about RAM effect and by the way have you ever wondered why Dodge chose to refer to their first V8s as RAMS; no it wasn't because they looked liked goats.
One of the funniest things that you could read about is the same folks that say long makes more power will also say that offsetting the wrist pin in the direction opposite crank rotation will give more power and an OS pin and a shorter rod do about the same thing; in that they give the piston more velocity earlier.
If one sets out to outengineer the M3 he's got one heck of a job on his hands and no way would they make the con rod 1/2" or so shorter just to save engine height.
And you know, I think this short rod deal would be more at home on a plate motor than anywhere else, relativly low rpm and the restriction should like the extra piston velocity.
 

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Long rod motors trade off volumetric efficiency for combusion efficiency due to the longer piston dwell times. Short rod motors seem to make more peak power with a peakier torque curve. Fine for a race engine, but not as great on the street.
Since the number of forward gears in transmissions has increased, combustion chamber design has increased combustion efficiency, and variable valve and intake runner length have become available. Short rod motors can be made more liveable on the street.

What you've said seems right, though I'm sure it's not a new discovery to NASCAR engine builders.
 

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if you ask me, I think dale jr has the right idea with the restrictor plate races. They draw the biggest crowds, and can you think of a better way to start off the season than winning at daytona? The big reason has to be the size of the purse. Jr has raked in over 2 million but matt kenseth has only brougt in alittle over one million, and matt kenseth is the points leader. if your in the buisness of racing, winning is good, but money is better. The more money you can make, the better you can make your car. if you look at DEI a few years ago, they wern't as dominant as they are now. this is because DEI has focused on winning the big races(restrictor plate races like daytona) and its paying off for them now. they can stick more money into their cars, and they can test more too. now were starting to see DEI up there in the standings because of this, and a new race philosophy that Jr and Matt Kenseth seem to be sharing. They're not worring so much about having a great car at the start of the race, but they're concentrating on making their cars better as the race goes on. If you look at the standings, all this seems to be paying off.
 

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DEI spends more money of its budge on plate racing than any other team. It was an idea Dale Sr had for his team. To be good everywhere, and to be the best at the plate tracks.

4 plate tracks a year with the unknown accidents that you could get swept up in can kill your championship chances. Leading those races and being at the front helps ya win points, money, and reduce the chance of becoming a hapless victim of the plate monster known as the "Big One"

Last year I recall Michael Waltrip reporting that DEI spends a full quarter of their budget on plate stuff. Thats more than any other team. And its not all motor research, its on aerodynamics and other things too.

RCR was dominant like this in 90's with Dale Sr at the wheel, plus I think Jr learned a few tricks from his old man that he never told anyone. Anyone can draft, but not everyone can make the draft work for them.
 
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