Pulling g's

[billtebbutt]

As I start to delve into the murky world of understanding 2% of the data that my AIM system collects (I have had it for 3 years, so its about time to start!), I got stuck on something....

If we assume that between two corners, that each of them are say perfectly flat and the ONLY thing different between them is radius, should you be able to pull them same max g in each of them in theory? I understand that in posing the question, I am also assuming that the car behaves similarly in different types of bends.

Thoughts from the crowd?

cheers,
BT

[Garey Guzman]

As I start to delve into the murky world of understanding 2% of the data that my AIM system collects (I have had it for 3 years, so its about time to start!), I got stuck on something....

If we assume that between two corners, that each of them are say perfectly flat and the ONLY thing different between them is radius, should you be able to pull them same max g in each of them in theory? I understand that in posing the question, I am also assuming that the car behaves similarly in different types of bends.

Thoughts from the crowd?

cheers,
BT

It would be the same if the grip/friction coefficient is the same and the tires are able to stabilize fast enough and your braking is the same (off brakes at peak). The tighter turn will have a shorter peak G reading, i.e. steeper slopes to and away from peak.

[billtebbutt]

That makes sense to me Garey - thank you

bt

[lowside67]

I believe that's not the whole answer - it would be true of pure mechanical grip in a theoretical standpoint but the addition of aerodynamic forces (either lift or downforce) would skew that.

To me, the larger diameter corner allows a higher speed, which results in additional downforce, allowing for further speed yet and a higher lateral G force.

-Mark

[Garey Guzman]

I believe that's not the whole answer - it would be true of pure mechanical grip in a theoretical standpoint but the addition of aerodynamic forces (either lift or downforce) would skew that.

To me, the larger diameter corner allows a higher speed, which results in additional downforce, allowing for further speed yet and a higher lateral G force.

-Mark

Absolutely Mark, but I think Bill has an FF so I was replying based on that memory (which could be wrong). There are a bunch of smaller factors that will affect our cars but for our amateur events and our amateur analysis, we can get bogged down in the data if we are trying to read G to the thousandth. Crosswind and wind direction relative to the turns could be a smaller factor too, now that you mention it.

For me, the biggest help data gave me was macro level. For example, at California Speedway many years ago, I saw that I peaked at 1.7g and then noticed that the banking was at 1.3g. After seeing that, I was fearlessly flat through the banking, even going up or down to catch drafts because I then had confidence that I was within my car's capability through the banking, even though it was about 140mph and the walls were a little scary!

[Steve Davis]

I totally agree on the MACRO thinking. Trying to dig out midget diamonds is NOT really what data systems can/should do for us at our level. Look for your MAX G pull and compare it lap to lap and session to session. Don't think you should 'waste' time trying to figure out why you pulled 1.4 at one turn and 1.45 or 1.5 at another. The G info is just not THAT Accurate and there are a thousand reasons why there would be that much difference in the same turn in the same session but different laps.

I look at my max top speed on all straights - compared to the same during my last visit there .. if there was one. I want to move my AVERAGE numbers up and don't focus much on any single turn .. unless I'm having trouble there. I look at max top speed and max G pulled and what my best lap time was compared to my best rolling lap ... and the theoretical best laptime. Be careful with that theo time in AIM though. You need to make sure it doesn't consider OUT LAPS and IN LAPS .. my AIM system would report seriously bogus 'segment times' during pace laps (tire scrubbing) that would skew the theoretical time significantly. I had to manually go back and DISABLE those laps before the theo time started to look like something I could aspire to match.

I also look at all my engine data points that are important to general operation instead of speed - just to keep an eye on 'things'. I DO use my EGT (or WBO) to help make jet change decisions as well.

Steve, FV80

[mikey]

My fastest lap almost always correlates to the one with the highest average throttle position. So in my limited time to analyze data I tend to focus on how to keep my foot in it.