Formulas for 1/4 Mile Performance

General Chat Suggestions
1

stealth316.com/2-calc-hp-et-mph.htm

A quick reference guide for calculating acceleration performance.

My quickest actual time in my green car: 14.397 @ 95.92 (not adjusted for density altitude otherwise it’d be quicker/faster). With a race weight of 3,950 lbs, standard all-season street tires, and using the factory rated 280hp (my car has no power adders - yet!!) the calculator gave the following numbers:

The LRT Formulas: 14.540 @ 96.90 mph. LRT claims 271hp based on my trap speed, and 291hp based on my ET…
The Patrick Hale Formulas: 14.075 @ 96.843… that ET would only be possible on drag radials with my car or with all-wheel drive. Hale claims 272hp based on trap speed, 262hp based on ET…
The Fox Formulas: 15.148 @ 95.188… that ET would makes sense either with really tall gearing or front-wheel drive. Fox claims 287hp based on trap speed, 326hp based on ET…

I figured these formulas might help backed up with at least some real-world data. :mrgreen:

2

Oh nice! :slight_smile:

3

The problem I see with the formulas is, that they only take weight and power into account, so they are just rough estimations. In the car designer, we have more parameters which should have an impact on top speed, acceleration (and 1/4 mile stats) such as gear ratios, tire parameters, drag and center of mass just to name a few.
I’ve already tried out models based on differential equations (so the real deal :wink:), but tire slip is messing things up and I have not found a numerical solver yet who can do the job properly. Without tire slip, it’s not a big problem to simulate straight line performance of a car with all the parameters.

4

Oh we can certainly do better ingame, but those might be useful for folks who want to estimate in the meantime :slight_smile:

5

Wow, that’s really impressive! Can’t wait to see how it all comes together. I figured the formulas could be used as a starting point, not necessarily a solution… but if you’re working on models and are making progress that’s good news!