Corner Speed vs, GPS Speed vs Vehicle speed

[FoxSTI]

Looking at my logs I see I have the 3 different speeds above.
which one should I be using ?

I noticed both GPS and Corner speed always match, and they are faster then vehicle speed.
I guess the question I want to ask is what is corned speed and what it is useful for?

[adrian]

The difference between all of those channels will depend on how you have them setup in your dash.

If you open your Dash config and go to File>View Configuration Summary, find the 3 speed channels and it will tell you how they are calculated. GPS speed is obvious, vehicle speed will be calculated by whatever method you have setup and corner speed I am not sure. The only thing I can think of is Minimum Corner Speed but this shouldn't match GPS speed.

[FoxSTI]

Ill have to call Motec and ask what is its intended use (corner speed)

[David Ferguson]

Minimum Corner speed is usually a latched (remembered) speed that is the most recent minimum speed (which is nearly always during a corner when driving on a track). The idea is that lap time performance is often determined by how much mid-corner speed you can carry (especially in high-speed turns), and so that you don't have to look at the dash to determine this value in the corner, you can have the dash record the minimum corner speed and display that. It is not normally a channel that I would log.

When Minimum Corner Speed has been enabled, and is on the display, the driver will glance down at it following a corner and it will show the minimum speed for the previous corner. This allows them to do "self coaching" while driving on the track. Let me give you an example:

I was in the first year of running my Swift DB-5 Sports 2000. I had obtained a detailed track map of Laguna Seca, showing the radius and camber of each corner. Studying this, I decided that I was over-slowing for Turn 5, my minimum speed (from analysis) was usually about 65 - 67 mph, and I figured I could probably go 74-75 based on the G-forces of similar corners. I went out with minimum speed configured on the dash -- braked 20 feet later, the car moving a bit under braking, turned in, and got on the throttle as early as possible -- on the run up to T6, I looked down -- 67 mph. Next lap -- I carried the braking 40 feet beyond my normal braking point, the car danced around even more under braking, turned in, got to power and when I checked -- minimum speed -- 67 mph. I tried for 20 minutes as hard as I could and my best was only 68 mph.

I came back to the paddock, and thought about what was happening -- no matter where I started braking, my subconscious was able to get the minimum speed down to my "programmed" speed of 67 mph. That's when I realized -- it's not when you start braking, it's when you stop.

Next session I began braking at my usual mark, car completely in control, and mentally forced my self to use less pedal pressure and get off the brakes at a higher speed -- first time through -- 70 mph. I continued to work on this until I was in the low-70's and I could move the braking point closer to the corner. What was interesting was that despite my trying earlier I could not increase my minimum speed -- but I had the necessary info (minimum corner speed) available to work on it.

BTW -- that corner is now taken at the absolute limit in the mid-80's for me.

FoxSTI -- My guess is your Miniumum Corner speed is set up with a 0 mph hystersis -- this should be 3-5 mph -- the speed needs to go up by this amount before it updates the new Minimum Corner Speed.

[FoxSTI]

okay, so it the speed at which you take the corner, and should update after every corner from what I am understanding? (with proper settings)

[David Ferguson]

The data file had "GPS Speed", and "Corr Speed" (Corrected Speed) -- that is why they were the same. It also had Minimum Corner Speed.

[FoxSTI]

Ahhh.. no wonder, the eye of the experienced.
Thanks for pointing that out.

[the_bluester]

I have found corner minimum speeds a helpful metric in car development. A friend and I drive my car and we are pretty competitive, usually within a tenth or two of each other on any given day. Our corner speeds are also pretty much the same. Taken from that, when we made a change to the car we were able to see clear changes in mid corner speed allowing us to see if we were headed in the right direction with setup, most particularly in low speed corners (Our usual track is full of low speed stuff)