Re: I'M DRUNK
I'm not sure what you mean about horsepower and the 4:11 thing. You may be referring to the axle gear ratio as 4.11. This means that the number of gear teeth in your differential makes 4.11 to 1 ratio. For every 4.11 turns of the driveshaft, the tire makes one revolution. If you change to a larger tire, you actually travel a further distance in each revolution but experience a change in the overall driveline ratio. Hence 4 cylinders that run larger than stock tires run higher RPM's to maintain speed and sometimes lose the use of 5th gear because a 4 cyl lacks the torque to override the loss of gearing. It feels like you are losing engine "power".
Engine horsepower and torque are calculated on an engine dyno. Net horsepower ratings are given by the manufacturer in the owner's manual or you can look them up online.
You can improve horsepower and torque by adding aftermarket intakes, better flowing exhaust, computer chip programs, throttle body spacers, etc...
Most manufacturers shoot for reasonable horsepower to vehicle weight ratios and are conservative in their computer programming to add longevity to the life of the engine and the emissions output.
You can compensate for the loss of power by regearing you axles to lower the engine RPM. Say for example that you went from stock tires up to some 32" tires. To get the back to the same feeling you had with the stock tires, you would want to regear the axles to either a 4.56 or maybe a 4.88 ratio. Regearing can get expensive, so most people just live with the loss of power.
Here's a horsepower and gearing example for you: I have the 360 mentioned above that has been slightly modified, so we'll say it puts out around 200hp. That's all fine and good but since I put the motor in, I changed from 35" tires to 39.5" tires without a gear change. I am still good on the road because a V-8 makes good torque to compensate for the change in tire size. However, in the woods it lacks the power that I want to spin the tires freely. The scenario is that I have an automatic with a 2.48 first gear, a transfer case with a 2.0 low range and 4.56 axle gears and 39.5" tires. That's a 22.6 drivetrain ratio. That's on the low end. My solution is to put a 4:1 transfer case in there which will double the 22.6. Then I'll be back in action.
I hope this information overload helps. I had nothing else to do at the time.
