Fast_Toys

Here is an interesting comparison between a Corvette and a Miata at a local autocross event. The Corvette finished .2 seconds ahead of the Miata.

Here is the line taken. Miata in red and corvette in blue:



Here is a graph showing speed of Miata vs. speed of Corvette



Lastly, here is a graph showing lateral g's of both cars. As always, Miata is in red.

0Randy@DRM

Very cool!!

Randy

ghoffman

Nice, what system did this?

Slalom4me

Nice work.

I would like to do something similar and place my system in other
cars that attend events I go to - especially in the GT3 that produces
times 9 sec faster than the next closest car (and 13 sec faster than
my '89).

BTW - I thought 'All Corvettes Are Red'

.

jlucas

IIRC, he's got a DriftBox.

Slalom4me

Interesting that the Miata's velocity between 2,700-3,100 ft
is decidely higher - perhaps the only area where this occurs.
Lateral loads over the same section are similar.

.

Fast_Toys

It's a driftbox. You can do exactly what you wanted and use the tool to compare to other drivers (faster ones!). I found it very enlightening and hope it will improve my driving!

Slalom4me

Looking at the map, it appears the Miata went off course, or at least took
a much more generous line going down from 650 to 300 toward the
finish.

.

gkmccready

How much? From where? How hard is it to use? I dug up info on the DriftBox earlier in the year but put it all aside during the big data acq discussion to see who picked what and how it worked. :-)

Fast_Toys

It's fairly easy to use. I figured it out in a day. The unit records all the data to a memory card and then you upload into software on your computer to analyze. You can move it from car to car easily too (just a suction cup mount).

jlucas

$750 driftbox.com or http://www.vboxusa.com/contact.php

My only advice would be to compare your needs and future wants. Other GPS based data aquistion systems (DL1, G2X) have sensor inputs and have more software analysis options for slightly more money. Try the software on all the products your interested in becuase that's where you get the benefit from the data that it collects. If Driftbox suits all your needs and you don't need any inputs, it's compact and highly accurate.

RAFTRACER

the lateral acceleration data in the above charts looks very "choppy" at sustained cornering loads......Driver induced, or is this normal from this system????

Axelrod

In this "speed" graph, it's somewhat evident that the Vette is absolutely crushing the brakes hard. Notice how much slower the Vette is going at full decel. There is a 5mph difference on the slow end of the tight turns!

On the other hand, it really shows that the Vette had all of the power. At the top end of acceleration, the Vette was obviously capable of higher speeds. Look at the 1500' mark in the G-graph as well. Where's there little G-load, the Vette is sailing.

The one thing that is a brutal reality, is that even though the Vette is making more peak speed more of the time... he's not using it smoothly. This is outlined in the G-graph. Both cars are running relatively the same G-forces, but the Miata is running smoother by maintaining higher speeds at the tighter turns. The data don't lie!

Without knowing the end result of the .2 second difference in favor of the Vette, I would've guessed a toss-up between the two, and would've slightly leaned towards the Miata after looking at all of the graphs.

jlucas

Danny, I think that just depends on what system you are used to looking at and what the default smoothing is set at. Raw accel data is quite "choppy", so whether you have realized it or not smoothing was probably applied. In some software packages, the smoothing value can be set to match your preference. For example....

The images are large so click on them to see the detail differences on the lat accel graph.
0.01sec smoothing:


0.3 sec smoothing:


0.5 sec smoothing: