Help me debug my performance calculator!

The title should really be "Help me test...". Debug implies there are problems. I'm sure there are, but I don't know of any at the moment :)

Link here

I made this as my second attempt at a html/javascript project.

I'd like you guys to try it out and tell me what you think. Especially those of you with dynosheets, weights & timeslips for the same car. I already know of a few things I can do to improve accuracy, but I want to see if I'm even in the ballpark.

Instructions: Follow steps 1-??

For step 6: Launch Acceleration will be maintained from launch until Launch RPM is hit. This is to simulate slipping out the clutch, TC lockup, wheelspin, etc. You may have to fiddle with these until you get a 60ft. that's about right.

The calc will shift at redline in every gear, unless there is a situation where a higher gear makes more power @ the same speed. This will be apparent in the graphs. You can inspect the peak for each to see optimal shift RPM.

would you please explain step 2? I can't deselect any of them once selected

Step 2: Best Fit Curve (Pick what fits best) 3rd order 4th order 5th order 6th order

Once the dyno data is in, just cycle through the best fit curve options and leave it on the one that best matches your data points.

I just put in the specs for the aero-Locost I'm building, using somebody else's dyno.

A minor issue, but as I click through the best fit curve options, the button doesn't switch from one to the next, but rather leaves any one I have tried showing 'selected'.

The much bigger issue is that the expected results are WAY off. I'm not even sure how to describe it. Maximum G doesn't seem to affect anything. Launch G of 1-4 results in 5+ second 60 ft, 70+ second 1/4 mile, and 13+ mph trap. Launch G of 5-6 results in surprisingly reasonable numbers. Then, oddly enough, launch G of 7-9 returns to the same results as 1-4 G. And finally, launch G of 10+ results again in strangely reasonable numbers. During the periods of 'reasonable' results, the launch RPM seems to be reasonably effective, but it's hard to tell with such skewed results.

Here are my inputs:

Dyno - 5, 10, 20, 30, 50, 70, 80, 90, 100, 110, 130, 150, 160, 165, 6th order

Ad = 1.5, Cd = .35, Mass w/ Driver = 775

Tire = 225/50-16, Diff = 3.55, Trans = 3.72, 2.20, 1.50, 1.00, .79

Good luck!

I fixed the radio buttons.

Well, I got closer on performance.

I had a messed up conditional... it was short shifting during some ridiculously low RPM (that's never actually used) during the launch period.

Now with a 0.9G /2500rpm launch and a 1g max accel, I'm seeing a 14.9 @ 96mph.

A 4000rpm launch gets me a 14.5 @ 96mph.

A 1.2G/4500 gts me a 14.1 @ 97mph.

Maximum G still doesn't appear to do anything.

Driven5 wrote: Maximum G still doesn't appear to do anything.

It does if your car has the power to exceed that acceleration. I.E. if your Locost had 600hp, it would greatly exceed 1G (or whatever the tire traction limit is) if left unchecked.

Got it, I think...It's really only useful for cars that are traction limited beyond the launch?

In that case, even though this is only a theoretical example still, I'm thinking your formulas might be able to use some refinement. Every purely power to weight based performance predictor I have used puts this in the 12.7-12.8 @ 105+ range...Which does seem to correlate reasonably well with the actual times from other known cars of similar power to weight ratio.

Driven5 wrote: Got it, I think...It's really only useful for cars that are traction limited beyond the launch? In that case, even though this is only a theoretical example still, I'm thinking your formulas might be able to use some refinement. Every performance predictor I have used puts this in the 12.7-12.8 @ 105+ range...Which correlates well with other known cars of similar power to weight ratio.

Yes, just for those traction limited beyond launch.

I just realized I had some efficiency modifiers in there that should be removed as the dyno data is at the wheels already. I'll pull them out and give it another shot.

Closer. Took out those efficiency modifiers that I overlooked before. 1.2G/4500rpm launch gets me a 12.9 @ 100mph