Speed secret # 5

[jim_howard_pdx]

SPEED SECRET # 5

I first heard about this secret from my friend's dad that campaigned a Dodge Dart with a 426 Hemi. He taught me three things. One: Be in racing for the trophies cause it is the same amount of money and work if you lose, and you have nothing to show for the trouble. Two: Know the rule book better than your competitors, and use every factory racing part to your benefit. Three: The car with the longer rod WINS.

So this is not my speed secret, it has been around since I was in puberty. But I want to discuss it so you can understand its effects on the engine, the cam, the torque, and your et's.

Lets talk about rod length.

Lets look at a small block chevy as an example. 3.5 stroke with a 5.4 inch rod. This nets a 1.54 rod to stroke ratio. Look at my stock 428 engine. It had a 1.78 rod to stroke ratio. This is why my engine can produce 540 hp with a cam similar to the small block chevy's pink cam that made only 375 horsepower. Subtract 540 from 375 and you get 165 horsepower difference. Subtract 428 from 350 and you get 78 cubic inches. So it is not just the cubic inches that made this huge horsepower difference. The chevy has about 390 ft pounds of torque. My 540 hp engine made 616 ft pounds of torque.

See what I am pointing at!!! If you want a boost in torque, increase the rod ratio. On a Bonneville type engine you are after 2.1 or 2.2 rod to stroke ratio.

The engine I worked on for my Buddies Pantara was gunning to be a 200 mph world record car. We ran a 351 W block to take advantage of its .995 higher deck height. Using a 302 crank ground to small block chevy rod journal size, we got the longest rod possible for the engine with custom domed pistons. We hit 224 mph on the first run, and 219 mph on the return run.

Why does a long rod build power and speed?

If you look at the crank shaft as it turns, the piston moves up and down the bore. The length of time it dwells at top dead center is affected by only one thing....ROD LENGTH. The longer the rod, the longer that piston sits there as the flame front burns the fuel, exerting pressure against the piston and combustion chamber giving us our ultra high torque.

The biggest benefit of long rods, is that with tight quench, detonation is dramatically curtailed. So we could run an additional point of compression. This is a win / win situation.

Most important in my mind, is that this extra torque exists at EVERY ignition event. So you get more torque at every rpm range of the engine. Better down low, better in the midrange, and awesome on top. It gives you this without the need for a special camshaft.

So on my next engine, I plan to build a small cubic inch, long rod engine with a Vortec Super charger and water injection. I am going to run high boost, high quench, and high dynamic compression just like I did on that Bonneville engine.

So for all you racers out there in the 11's, 10's, 9's, and faster. Comment on this thread and let everyone know what long rods has meant to your ET's because you cannot get from here to there without torque and the guy with the longest rod WINS.