Datalogging helps improve launch

[SSSoon]

I've been playing around with my SCT tuner and discovered that it is a very useful device for analyzing my launch skills - far more useful than a timeslip from a drag strip or iPhone app or even a video of a particular launch, because the data is coming from the car itself. For those of you who have ever datalogged your car (and it can be a pain to get set up), you'll notice that the log is actually a csv file (a spreadsheet) where each row is a timestamped snapshot of engine parameters. I logged speed as well when i did my data logging, which is recorded in kilometers. (96.5 km/h = 60 miles/hour). I did a bunch of test runs and put them into the chart below.

Pretty cool, huh? You get EXTREMELY precise timing on how long it took you to hit any particular speed. In the runs below, I twice tried just flooring it - that's the red and blue lines. You can see that right at the 0.5 second mark the wheels started to slip and I had zero acceleration progress just about 1/2 a second. TC kicked in around 1.0 sec, the tires grab, and then the car accelerates again. Both red and blue lines show a 0-60mph run at about 4.85 seconds.

After that, I tried NOT mashing the gas but giving it gas in a more controlled fashion. That's the green line. No wheel spin but turns into about a 5.3 second 0-60 time. Yuck.

Clearly the best launch is in between - hit the gas hard but not all the way to the floor in the first 1/2 second. I guess this is what people talk about with "rolling on" the gas. To me it is really useful to be able to see it for actual runs I did so I can diagnose what I'm doing wrong and improve my launch. Takes practice, I guess.

Anyhow, just thought this was pretty cool. For any of you with tuners and laptops, you can self-diagnose your own launches better than other way. Sure beats scratching your head looking at a 60 foot time and and wondering why it sucks . No more guessing or futzing around with my iPhone app and wondering if it's accurate or not.

[ihaveacamaro]

looks really cool! Good job! Now you need to get that 0 to 60 time down

[SSSoon]

Originally Posted by ihaveacamaro

looks really cool! Good job! Now you need to get that 0 to 60 time down

Yup. I figure that if I could do a better job launching and eliminate the .5 second wheel spin, that would get me down to 4.3 or 4.4 seconds, which would be pretty healthy, no? (I have: 2SS, CAI, Ported TB, Solo high flow cats, Solo cat back. Conditions: 56 degrees, 40% humidity, 623 feet elevation)

Other than doing a better job launching, the chart seems to say to me there's not much else I could be doing as a driver...

[ihaveacamaro]

Originally Posted by SSSoon

Yup. I figure that if I could do a better job launching and eliminate the .5 second wheel spin, that would get me down to 4.3 or 4.4 seconds, which would be pretty healthy, no? (I have: 2SS, CAI, Ported TB, Solo high flow cats, Solo cat back. Conditions: 56 degrees, 40% humidity, 623 feet elevation)

Other than doing a better job launching, the chart seems to say to me there's not much else I could be doing as a driver...

I'd recommend two things to make your chart easier for readers to appreciate:

1) Some nice axis labels!

2) If there was a way to put rpms on the left side and show that concurrently on the graph, it could show where you shift and how long it took you to shift. Also, people much more knowledgeable than I could comment on where exactly to shift or help you out even more!

Even if the above two are not possible I still really like your chart and wish I had the time to install a datalogger on mine. The concept is very intriguing to me so that I could learn my 0 to 60 times and maybe help me get better at launching!

[SSSoon]

Originally Posted by ihaveacamaro

I'd recommend two things to make your chart easier for readers to appreciate:

1) Some nice axis labels!

2) If there was a way to put rpms on the left side and show that concurrently on the graph, it could show where you shift and how long it took you to shift. Also, people much more knowledgeable than I could comment on where exactly to shift or help you out even more!

Even if the above two are not possible I still really like your chart and wish I had the time to install a datalogger on mine. The concept is very intriguing to me so that I could learn my 0 to 60 times and maybe help me get better at launching!

Good point! Here's another shot with axes labeled.

I can do rpms alongside a single run - can't do multiple on the same chart of course. But nice suggestion. Let me cook something up...

[HufferSS]

So "datalogging" has taught you that in order to have a better launch you need to spin less......

That's genius.

[SSSoon]

Originally Posted by HufferSS

So "datalogging" has taught you that in order to have a better launch you need to spin less......

That's genius.

I guess you must be a pro and know exactly what to do to get an amazing 0-60. Good stuff. For me, being able to SEE where the problem is, and see the impact it is having vs. what is possible, is pretty useful.

[SSSoon]

Here's another plot with RPM and speed, just off one WOT run.

Boy, TC really kills the engine.

[GMteSSted]

Very good information...Is the T/C is killing your RPMs or the tires grabbing after spinning? Would be good to have a comparison of the RPM chart with and with out T/C.....

[daveagogo1]

I have not done anything like this but, it basically just confirms yet again what we have learned from the track over the years. Simply mashing the gas is never the best way to get your best 0-60 or overall time. For the best time on the track shut all the nannies off. Stall it at about 1200 or so. Varies by track condition and such. Let off brake, roll into throttle fluidly and continue to the floor as your moving. Mashing it equals tire spin and wheel hop.

[ihaveacamaro]

Originally Posted by SSSoon

Good point! Here's another shot with axes labeled.

I can do rpms alongside a single run - can't do multiple on the same chart of course. But nice suggestion. Let me cook something up...

Sure you can! If you make the same run the same color for both lines and just label the actual line rpm or speed, you would be able to compare multiple launches all in one concise graph


I do research at my university so we have to plot graphs that tell 20 different stories if you take the time to read them all. Never can have too clustered graph lmao jk jk


But your graph above does look very good! Just a quick question, why is there a lull in both lines from 0.75 to 1.2 seconds? Like the lines seem to be going straight across which would actually indicate no acceleration and thus no speed change... ??

[SSSoon]

Originally Posted by GMteSSted

Very good information...Is the T/C is killing your RPMs or the tires grabbing after spinning? Would be good to have a comparison of the RPM chart with and with out T/C.....

I'm not a pro at this but if T/C was off and I floored it, we would see RPMs go much higher and wheels just roasting for longer until I let off the gas. The fact that the engine RPMs hold steady at about 2600 for a bit there tells me that it's the computer sensing wheel spin and keeping the engine under control until the wheels stop spinning.

Having tried WOT with TC off a while back (did not log it) the back end breaks loose and you just roast the tires until you lift up. So at this point it does become a question of skill; using either TC or not, can you get the pedal in the right position to keep the tires turning but not spinning?

Based on what I see, I am going to try a full split second mash of the pedal and then lift off a bit and then mash again once clear of the 2600 rpm dead zone.

[SSSoon]

Originally Posted by ihaveacamaro

Just a quick question, why is there a lull in both lines from 0.75 to 1.2 seconds? Like the lines seem to be going straight across which would actually indicate no acceleration and thus no speed change... ??

You're right. Tire spin = no acceleration. That run was at WOT and TC seems to cut the engine pretty fast to restore traction.

[ihaveacamaro]

Originally Posted by SSSoon

You're right. Tire spin = no acceleration. That run was at WOT and TC seems to cut the engine pretty fast to restore traction.

That makes sense lol... dunno why I didn't think of that hahah