sometime

Interested if anyone has some ideas on this one. This is a trace from Sonoma Raceway CA showing turn 6 a.k.a The Carousel. It has two traces, brake pressure and accelerator pedal position. These are from an MX-5 ND via the CAN Bus on the OBDII port.



What's bugging me is there is no way my actual accelerator inputs should be this ragged on such a corner. It feels like there is some kind of sampling freq mismatch between what is available on the bus and what the logger is recording. The AiM ECU profile for the car has a default of 10Hz for this channel. What makes this annoying is the G-G graph with accelerator inputs becomes rather confusing with so much noise. Anyone have an idea why the trace looks like this, or is my driving really that bad

ProCoach

If it is 10 Hz, which it is, it’s measuring a change in position pretty frequently. The “noise” is the detail.

if you can look at other laps, other sessions, that might help determine if this is a one off or systemic.

Having looked at driver data in AIM every week for a dozen years, my money is on the AiM.

ProCoach

To do a proper analysis, need more information.

The fact that your part throttle fibrillates a small amount, then WHACK!, it goes to full after that extended period, is the most common opportunity for improvement I see for most drivers with throttle application...

Matt Romanowski

I doubt you have a digitally controlled foot!

What is the scale of the graph? Can you show feet at the bottom? Looking at the graph, it looks like you are zoomed into the point the detail looks like noise, but it's really what your foot was doing. I will try to post some similar data later. I believe it's Chris Brown's "Making Sense of Squiggly Lines" that covers throttle application speed vs horsepower. It's probably in Buddy Fey's book too.

I'd disagree with Peter's take on the throttle input and say that fibrillation is the wrong word. What you have is the irregular depression of the throttle. This is in near all data and seen in some of the data from the best drivers (I'm looking at 3 files from guys you watch on TV and it's there). That can be caused by a ton of reasons. What you AiM to do is get to full throttle. The way you do that is completely variable on the car, track, and corner. Some corners are a much faster application and almost a wack, some are smooth roll in. There is no one size fits all. What you did was a smooth, slow (I'm guessing without scale) squeeze to 60%, then went straight to full throttle.

If you want one of the best coaches, look up Thomas Merrill. He's local to you and one of the best coaches. He's not too shabby of a driver either.

ProCoach

Irregular depression of the throttle= throttle application fibrillation.

Not uncommon. Can be improved.

Throttle application speed is dependent at the highest level to platform acceptance.

But you have to bump up against resistance to that application to know.

Wheel speeds and the variance between ground speed and drive speed (or slip when applying throttle or brake, AT THE LIMIT) is the confirnation.

You don’t need a book or a coach to know and measure this. You have the tools already.

sometime

Thanks for all the feedback!

Little bit of context as it may be helpful. This is a 2017 MX-5 with stock motor, upgraded suspension and Yokohama A052 215/40/R17 TW200 tyres. This is from my fastest lap of the day (2:02.3) and from what I recall I carried quite a bit more speed into the corner than on previous sessions, and I was hesitant on the throttle trying to keep it balanced until I could get the car to the gripper inside lower down part of the corner (basically I was worried I had over cooked it). The car tightens it's line nicely under throttle thanks to the LSD, but as I was hesitant on the throttle it felt like the front was pushing. I have tried to construct how that felt in the measures graphs below.



Certainly I need to improve, I am just wondering how much I should trust the pedal position variation as a gauge of my accelerator application? You can also see from the screenshot, the steering angle has a good amount of noise as well. I should go check the video to see what I am doing with my hands.

ProCoach

Thanks for the additional info. The fact that you carried “much more speed than usual into this corner” would for sure not only inhibit the ability to complete application to wide open throttle sooner (which I think is a GOOD thing), but also add to your feeling slightly uncomfortable abs bumping up against that under steer that you say limited your progression further. Good work!

I think you can take that pedal position to the bank, as you can the steering angle input.

However, I would check the video FIRST, paying attention to the audio for throttle (may or many not confirm small changes) and steering input (would definitely confirm). Also, track position, when and where the salient inputs indicated in the data actually occur.

Matt Romanowski

I'm not sure that word means what you think it means https://www.merriam-webster.com/dictionary/fibrillation

Matt Romanowski

That all makes sense with the data you are showing. I would say to believe the PPS trace and steering. While I would say the video is a check for your hands, I don't see anything in the screen shots you posted to say that the data isn't right. It's not uncommon to be delayed picking up throttle when you carry too much (perceived or real) speed into a corner. That triggers changes in your brain patterns that make it tougher to add throttle. The key is to work on those entries, mid corners, and throttle response. You have to balance the big entry speed with getting back to throttle. It's a difficult blend and something that many drivers have trouble doing. You have to let the car settle enough through the cornering phase to where it will accept throttle, not transfer too much weight to the rear, and still get off the corner well. Pick up throttle too early and you get a soft push off. That is especially easy to do in lower horsepower cars. Wait to long to pickup throttle, and you're slow off.

sometime

So I put the video and data together:


Couple of things stand out. Firstly trust the data, it doesn't lie, I did wiggle the wheel. This was back in October, and now I watch the video, I remember trying to drag the car back to the apex curb with little nibbles of lock to see what it's reaction was. Secondly, getting data in your video automatically without messing around makes it a hell of a lot easier to work out what is going on at the time, not months later

Matt Romanowski

Integrated video is a key to being able to analyze your data quickly and efficiently. No one has enough time at the track to take separate video and data and put them together. If you want to go with a Smartycam HD, let me know. I'm sure we can work out some Black Friday / Cyber Monday / Rennlist deals.

ProCoach

Matt, so glad you’ve joined the rest of the world in this realization.

I have new and a few used SmartyCam HD cameras that I can set up to be plug and play available now.

Matt Romanowski

I've always been an advocate of data laden video done automatically. Its the beauty and ease.kf the Smartycam.

We disagree in using video for the analysis first. I don't go to video to try to see brake pressure application and release. I go to data.

ProCoach

Your quoted statement is what I have been promoting since I first saw this demonstrated in 2004.

This capability is present in nearly every other system (MoTeC, VBOX, Traqmate, Race-Keeper, Race Technology) I sell or have sold in the last fifteen years.

AiM has not offered this integrated capability until this year.

The required workaround using AiM video and data, until the July release of Race Studio 3 Analysis beta, has been to:

VIEW the SmartyCam video FIRST, adding depth, context and detail to what you are about to look at (and possibly form incorrect conclusions, if you don't) in the data file.

THEN, open the data file.

This process would have helped the OP.

Thankfully, users can now open a SmartyCam video file alone and get most of what they need.

If they desire more detailed and full-featured data integration with the video, they can download data from the current generation of loggers and see more.

Integrated, as it should be.

That is what I've been saying.

Sounds like you don't disagree.

Matt Romanowski

That wasn't what I was saying. The Smartycam puts the data on the video real time so it doesn't have to be done manually after (as you know). That is the critical part. Being able to do analysis with video is nice, but it's still not where I start. I prefer the quantitative measurements and analysis that the data gives, not the subjective watching of the video.

But, the OP is seeing the same thing in working with their video files.