So I stumbled upon the speed, rpm, dist-travelled pids on the sct x2. Went to my trusty airport road and attempted some 1/4 mile runs. Funny thing was both times I tried I didnt actually run the full 1/4 mile haha. My 60 foot 's were around 2 to 2.1 which suck. One thing I noticed though after a little run on the way to work is that at the 1/4 mile mark im running about 104-105. Wouldnt that equate to a nice 1/4 mile time? On a run yesterday when I didnt actually stay into it all the way to the mark I still passed the 1/4 mark in 13.39s near 102... mind you that was with my speed declining just before the mark..

Dont flame me for doing this on a road since I have been through this explanation before with everyone. As far as accuracy goes this logging technique must at least be as accurate as a g-tech meter if not better.

 

You can do that on an XCal II ? I must have missed that, any doc links you can share ?

-Bryan

 

<div class='quotetop'>QUOTE(2005RedGT @ February 28, 2006, 11:46 AM) Quoted post</div><div class='quotemain'>
You can do that on an XCal II ? I must have missed that, any doc links you can share ?

-Bryan
[/b][/quote]

I dont have any links to share. But I can explain a bit more. When you open LiveLink with the sct connected to the car and to the laptop just click the icon on the top left (has a little graph on it). This will bring up the PIDs screen to choose what you want to monitor. Select the "Misc" and expand it. There should be one (of each of the following) "RPM" or something w/RPM, "Dist_Travelled", and Vehicle Speed Sensor (There is two on mine I just chose the first one from the top. Then you can choose to graph those 3 sensors. Start datalogging. Take off and I just run mine up to about 105. Once you feel like you have run the 1/4 mile you can then stop datalogging and save your run. It will be a .csv file that you can open later in Excel. It logs very frequently so its going to be a lot to scroll through but once you figure out your starting point and time you are set to calculate anything you want. IE: 60 foot, 1/8, 1/4 0-60 , 0-whatever. The dist_travelled is really your tripmeter but its logging out like 6 decimals of precision. Like 40.456832. Then you just add .2500000 or .1250000 to your start distance to figure out how far you needed to travel for the 1/4 or 1/8. Look the distance up and get the time. The time is automatically inserted in the file as well and is out 6 decimals.

Note: Just running to 105 may not be enough at least it wasnt in my case. Once you get your numbers you can see if you were "into it" long enough. I ended up on two runs letting off just before i reached the 1/4 mile mark which made my numbers off just a bit ... I was still going 102 nonetheless.

Let me know if you have more questions about this.

 

Just for comparisons sake, here is a slip from one of my trips to the track. 13.7 @ 104

 

Thanks pittperson. Now I can do some comparo's on my speeds and times vs yours. On my best run I ran a 2.00288 60' and crossed the 1/8 mile marker at 84.9 mph in 8.70261 seconds. On that same run though I ended up with a 13.39927 @ 104.1. My 1000 foot on that run was 11.22615. This is awesome.

I think Im going to write a piece of software to accept time entries from the datalogging and turn those values into 0-30, 1/4, 330' values. It will be a quick way to figure out a whole bunch of info without having to build an excel file w/ lots of formulas. It could archive them as well for future reference. Sort based on fastest in a category you select. This sct is even more incredible then I first thought.

 

Where does the car's computer measure speed and distance? Rear wheels?

If you have any wheel spin then that is counting towards your quarter mile distance.

At the track your end speed isn't your top speed for the run, but the average for the last 60 ft, right? It's trap speed, whatever that is, I don't recall exactly and too lazy too look it up.

 

<div class='quotetop'>QUOTE(pittperson @ February 28, 2006, 2:46 PM) Quoted post</div><div class='quotemain'>
Just for comparisons sake, here is a slip from one of my trips to the track. 13.7 @ 104

[/b][/quote]


What mods did you have when your ran that time? I trap around 103 at 13.6

 

<div class='quotetop'>QUOTE(ren274u @ February 28, 2006, 3:37 PM) Quoted post</div><div class='quotemain'>
What mods did you have when your ran that time? I trap around 103 at 13.6
[/b][/quote]

I just had the c&l intake and 93 octane diablo tune. stock tires.

 

<div class='quotetop'>QUOTE(My Blue Heaven @ February 28, 2006, 3:18 PM) Quoted post</div><div class='quotemain'>
Where does the car's computer measure speed and distance? Rear wheels?

If you have any wheel spin then that is counting towards your quarter mile distance.

At the track your end speed isn't your top speed for the run, but the average for the last 60 ft, right? It's trap speed, whatever that is, I don't recall exactly and too lazy too look it up.
[/b][/quote]

You are correct. So in order for it to be 100% accurate you would have to not have wheelspin at launch (bog it) The times however are accurate for 0-100 that sort of thing where distance isnt used assuming you pick the correct time from the log instead of picking a speed that may have been when it was spinning. Thats easy though with the number of data points. Thanks for pointing out the distance thing.. I kind of overlooked that [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img].