Undersquare vs. Oversquare Engines

360Z28 said

Moper,
the reference to F1 engines is that they go totally against todays thinking of what the ideal bore/stroke-rod ratios should be. i just thought it was interesting! 750+hp and only 250-300ft-lbs of torque will lay waste to most cars on the 1/4mile lol.
cheers

dgc333,
then they couldn't have used a long enought rod with a shorter piston..otherwise it woulda been significant. you wouldn't happen to have a link would you? or specs on what they did?
cheers

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The 454's were built with custom pistons, the difference between the two was the position of the wrist pin; lower in the piston for the short rod and higher in the piston for the long rod. Stroke was the same, bore was the same, compression was the same as was the head and cam.

I want to say it was Car Craft but it could have been Hot Rod that did the article, I get both magazines. In any case the article was to tray and prove or disprove the theory that a higher rod length to stroke ratio would make more power and in this case it didn't.

Regarding an F1 car you have to remember that Horsepower is nothing more than a mathematical expression of the rate at which torque is being generated or HP = Torque (in ft-lbs) x RPM / 5252. This is why every single HP/torque curve intersects at 5252 RPM. Drop that F1 motor into a 3000-3500 lb street car and it won't make enough torque to get the car moving and if it does a kid on a BMX bike could beat it in the 1/4 mile. Ever notice how those cars pull out of the pits (same for NASCAR Sprint Cup cars) they rev the snot out of the engine and drop the clutch to get the tires spinning. The torque at low rpm combined with the gearing needed for top speed just won't allow the vehicle to pull away from a stop any other way. You have to have a torque curve appropriate for the application.