This isnt a Pure Stock nor a FAST Car, but supposin' I had a 3300 lbs car with (stock looking exterior, suspension and stock 14" 225/r75 tires) with Option 1) 400HP/410TQ (Flywheel) and the ET calculators says 12.40, what range would it likely really run at best? Option 2) 425HP/440TQ (Flywheel) and ET calculator says 12.15 what range would it likely really run at best? Option 3) Option 2 plus a 150 shot and ET calculator say 11.00 what range would it likely really run at best? (Im trying to figure the flywheel HP required to turn 12.0-12.5 in stock appearing trim in a 3300 lb car.) How far off are the ET Calculators? Thanks tim
sounds like the times you want to run will need much wider/stickier tires than those 225/75/14's. no matter what hp, you will have major traction issues below 14 sec, if you can even get that low with those tires. Et calculators may not take into account you spinning all the way.
ET calculators Tim - I think most of the programs assume that the car can use the power the engine is putting out. The main place that stock tire cars have trouble will be right at the starting line and through the 60' lights. Typically, 2.0 seconds is a pretty darn good short time (60') for a street tired car. The calculator probably assumes more ideal traction and a short time of say 1.60 seconds. That's a difference of .40 seconds. The rule of thumb is that reductions in short time are good for twice the reduction in the quarter mile. That means real quarter mile times might be 0.8 seconds slower than the calculated ET (based on my assumptions above). This probably does not apply well to the nitrous calculation - nitrous comes on hard on the top end. It might be a good compromise for under-tired cars, as long as you don't get into traction issues at the fast end of the track. :eek2:
Like the others said, those ET calculators assume good traction. They are all based on curve fitting real-world data from the track. I've seen different curves published for race cars vs. street cars. But even the latter will not be too accurate, since they can't predict how much YOUR car will spin the tires (or how much YOU will have to back off the throttle to keep that from happening). What should be much more accurate is a HP vs. MPH calculator, since trap speed is not influenced much by what happens in the first 60 feet. So maybe what you can do is plug some numbers into an ET predictor which also gives you MPH, then find out how much horsepower it takes to give you a couple more MPH (since that's what you need, extra MPH to make up for the slow start).
calculator Here is a link to a number of different calculators on the same link. http://www.ajdesigner.com/phphorsepower/horsepower_equation_rotating_horsepower.php Pretty accurate for my turbo car. Of course I had my drag radials on. But the trap speed calculator was pretty accurate for horsepower. Mikey
