Data Logger - what uses have people found?

[GTP_CargoRatt]

Ok, I have a question regarding wheel speed. I am comparing my lap with P1's lap in the Peugeot Seasonal TT. I have noticed a huge difference in wheel speeds. On average, his wheel speed is consistently around 35-40 mph higher than mine. The gap shortens to around 20-25 entering and exiting corners but really widens out in the straighter parts of the track. So, my question is, how to I relate this to my tune. Do I need to make gear adjustments or is it an LSD thing in regards to wheel spin. Tires are not turning red at all. He seems to be running a better gear set than I. I'm just having a bit of trouble deciphering the data here. If someone could help me out here, that would be great. I can provide pictures if that's whats needed to help analyze the data. Thanks for any and all help.

 

[Nish]

Could that be a tire size difference? Just a shot in the dark here.

Edit: Answer below.

 

[Gravitron]

Ok, I have a question regarding wheel speed. I am comparing my lap with P1's lap in the Peugeot Seasonal TT. I have noticed a huge difference in wheel speeds. On average, his wheel speed is consistently around 35-40 mph higher than mine. The gap shortens to around 20-25 entering and exiting corners but really widens out in the straighter parts of the track. So, my question is, how to I relate this to my tune. Do I need to make gear adjustments or is it an LSD thing in regards to wheel spin. Tires are not turning red at all. He seems to be running a better gear set than I. I'm just having a bit of trouble deciphering the data here. If someone could help me out here, that would be great. I can provide pictures if that's whats needed to help analyze the data. Thanks for any and all help.

You posted in this thread right after the answer was given, I think. Assuming P1's is in kph and yours is in mph, that is. Maybe?

 

[GTP_CargoRatt]

You posted in this thread right after the answer was given, I think. Assuming P1's is in kph and yours is in mph, that is. Maybe?

Ok, so what you are saying is that I have to switch to kilometers to get an accurate reading? Do I just switch it in the game options as I seen nowhere to switch it in the logger.

Sorry, didn't see the post you are referring to probably because I didn't refresh the page for awhile.

 

[Gravitron]

Yes, I think if you change it in the options and then run a new lap, you will be able to compare against others running in kph. But it might be easier to download one of the other top 10 who seem likely to have used mph?

 

[GTP_CargoRatt]

Yes, I think if you change it in the options and then run a new lap, you will be able to compare against others running in kph. But it might be easier to download one of the other top 10 who seem likely to have used mph?

Ok, thanks for the tips. 👍 Slowly getting this data logger thing figured out. And, just fyi, the ghost I downloaded is in mph so I am still kinda baffled as to the big wheel speed difference. Maybe rim size? I messaged him about it so I will wait to see. I think I am running 2" up rims so that could be it, yes?

 

[Motor City Hami]

Ok, thanks for the tips. 👍 Slowly getting this data logger thing figured out. And, just fyi, the ghost I downloaded is in mph so I am still kinda baffled as to the big wheel speed difference. Maybe rim size? I messaged him about it so I will wait to see. I think I am running 2" up rims so that could be it, yes?

Can you load speed as the fifth measure on the screen? If wheel speed and actual speed are all higher, he has either or both a better gearbox and or has found more corner speed or roll through.

 

[Gravitron]

Well there goes my theory. Personally I'm not paying too much attention to wheel speeds and just trusting the vehicle speeds.

 

[GTP_CargoRatt]

Can you load speed as the fifth measure on the screen? If wheel speed and actual speed are all higher, he has either or both a better gearbox and or has found more corner speed or roll through.

How do you mean? Not sure I follow you Keith as far 5th measure.

@Gravitron That's what I was doing too but then became interested when I heard it could help tune the LSD. Like I said, I just experimenting with the thing and trying out what other people say and their ideas.

 

[rams1de]

How do you mean? Not sure I follow you Keith as far 5th measure.

@Gravitron That's what I was doing too but then became interested when I heard it could help tune the LSD. Like I said, I just experimenting with the thing and trying out what other people say and their ideas.

You can have up to 5 options for each set you create, eg Speed, RPM, Gear, Wheel Speed Front Left etc.

From the little testing I've done, I'd agree with Graviton's explanation that the large difference in wheel speed you're seeing is down to units of measurement.

On flat, smooth surfaces wheel speed is very close if not exactly the same as your actual speed. Just imagine how much quicker the lap time would be if the other driver was going 30mph faster on the straight and 20mph faster in the corners.

You'll see variations in wheel speed with different LSD settings but the surface will cause a more dramatic difference, bumps, touching the grass or riding kerbs for instance. When that happens the graph will look 'peaky' for the brief period the car is affected.

 

[GTP_CargoRatt]

You can have up to 5 options for each set you create, eg Speed, RPM, Gear, Wheel Speed Front Left etc.

From the little testing I've done, I'd agree with Graviton's explanation that the large difference in wheel speed you're seeing is down to units of measurement.

On flat, smooth surfaces wheel speed is very close if not exactly the same as your actual speed. Just imagine how much quicker the lap time would be if the other driver was going 30mph faster on the straight and 20mph faster in the corners.

You'll see variations in wheel speed with different LSD settings but the surface will cause a more dramatic difference, bumps, touching the grass or riding kerbs for instance. When that happens the graph will look 'peaky' for the brief period the car is affected.

Ah, I see. I messaged the guy and he said he was using mph and not kilometers so it is still kinda baffling about the speed difference. I understand what you say though about the lap time though, that makes sense, especially with me only being like .800 off the P1 time. Thanks for the explanation and post. 👍

 

[Bobby Steel]

It's shows me higher G's in the corner. Something useful when testing cornering grip.

It shows when the dampers are too stiff making the ride height bounce. Or F/R are imbalanced.

It shows so much useful stuff for tuning the LSD.

It shows things different to many theories on the planet. Check those cornering G's

 

[SCClockDr]

In 2 separate lap saves in my LFA NUR. Had a 75mph difference in rear tires going through all gears on a straight. Any ideas ?

Im glad its back. It was the best way for me back in the day before online to learn about tuning my own cars, and it gives me something to do when internet is down for maintenance.

@CKVK There is a Bug in Data Logger if you use MPH, switch to Km/h then the speeds should match within reason.

 

[SCClockDr]

Ah, I see. I messaged the guy and he said he was using mph and not kilometers so it is still kinda baffling about the speed difference. I understand what you say though about the lap time though, that makes sense, especially with me only being like .800 off the P1 time. Thanks for the explanation and post. 👍

@GTP_CargoRatt There is a Bug in Data Logger if you use MPH, switch to Km/h then the speeds should match within reason.

 

[GTP_CargoRatt]

@GTP_CargoRatt There is a Bug in Data Logger if you use MPH, switch to Km/h then the speeds should match within reason.[/quote

Thank you, that was the answer to my problem. Everything looks on par now. 👍

 

[CKVK]

@GTP_CargoRatt There is a Bug in Data Logger if you use MPH, switch to Km/h then the speeds should match within reason.

Thank you SCClockDr

 

[Bobby Steel]

Confused, what are you talking about?? Did you test that Bug theory?????

I just did a test in data logger, I paused at the same spot once in mph then in klm/h and after converting from mph to klm/h and vise-versa both equal out to the same thing.

According to my test showing the same speed just displayed in different units, there is no difference using mph, no bug as you called it.

Not to overlook klm/m are not as long as miles so the gap is larger with klm/m vs mph.

Just checking 97klm/h = 60mph right?

So what are you talking about??

 

[SCClockDr]

Confused, what are you talking about??

I just did a test in data logger, I paused at the same spot once in mph then in klm/h and after converting from mph to klm/h and vise-versa both equal out to the same thing.

According to my test showing the same speed just displayed in different units, there is no difference using mph, no bug as you called it.

Just checking 97klm/h = 60mph right?

So what are you talking about??

@Bobby Steel look at the images posted in the OP of the thread. Not always does it occur but it is repeatable on occasion. Setting units to Km/h seems to eliminate the issue for me.

 

[Bobby Steel]

Same replay in the logger shows same results just different units.

Maybe post a pic where the reading is different in klm/h vs mph. All I see is the same thing every time, all the time, although you have to narrow in on the exact same spot.

 

[SCClockDr]

Same replay in the logger shows same results just different units.

Maybe post a pic where the reading is different in klm/h vs mph. All I see is the same thing every time, all the time, although you have to narrow in on the exact same spot.

Note the top graph, the speeds are closely matched. Then note both front wheels and the Left Rear where there is a difference in the blue/green graph line & the yellow line. Now look at the Right Rear wheel graph where the speeds are closely matched. I surrounded the most noticeable parts with boxes.

The same 2 files with the units set to Km/h result in all the graph lines closely matching.

 

[Bobby Steel]

Okay so you mean it glitches with 2 replays loaded. Buts when one is loaded it's correct. That's quite different, I though you were talking about the difference in wheel speed inside and outside.

I noticed it messing up with 2 replays loaded showing half speeds on one of the 2 but it goes normal with just one loaded. I just compare the results on wheel speed one replay file at a time.

I'll test if I get that same result.

I cannot recreate the problem. With 2 replays loaded, switching from mph to klm/h makes no difference. This on a FF car no assist and no ABS. Weird. I did see it happen, but can't get to happen again.

I did see half speeds when I first tested the logger so I know it happens. I was testing ABS vs no ABS so maybe the assist has something to do with it.

I'll test that tomorrow try to recreate the issue

 

[SCClockDr]

The 3 & 1 result is really odd, I used to design & code software and using differing functions/factors for the same calculation on differing inputs is not the way to create efficient & bug free code.

Looks like PD has a ways to go.

 

[donpost]

Done a little test on downforce.

R34 GTR Touring Car, max power, max gearing, max downforce, max ride height, softest suspension on all settings.

One lap of route X.

Test ride height at 0mph and crawling at 2mph shows all ride heights at 0mm.

At 220mph I had - 20mm front and - 60mm rear (full throttle, didn't think to test part and off throttle)


This was only a quick test, but it proves that downforce is acting on the body rather than the tyres.

Wow I'm amazed just how much the aero pushes down on the car Definitely need to think about using stiffer springs on the high aero cars then.


Tonight I discovered something you CAN'T use the data logger for. I tried using the longitudinal G data and the speed data to find the optimum gear shift points, but the lines are too "smooth" to tell.

 

[FussyFez]

Wow I'm amazed just how much the aero pushes down on the car Definitely need to think about using stiffer springs on the high aero cars then.


Tonight I discovered something you CAN'T use the data logger for. I tried using the longitudinal G data and the speed data to find the optimum gear shift points, but the lines are too "smooth" to tell.

Yeh, it would be good if you could choose one readout to fill the screen with a selectable scale, making any peaks /troughs stand out alot clearer.

 

[bread82]

Anyone know as of yet if different shaped wings have different effects on airflow or not?

I've only tested briefly but I've not seen any difference i.e. "20" rear aero gives the same top speed no matter what wing pattern (including custom wings).

@FuzzyFez, @donpost: Interesting stuff! This was on my "to-do list" but I'd not got around to it.

I tried using no wing and rake to see if the angled body gave downforce, but I only tried it on a 130 mph car and couldn't see any difference. I was hoping the low front would give more compression of the body overall. I need to try this on a LMP car or something which should show a clear difference at a very high speed (soft springs to give a big RH change). I think the description for downforce (or maybe ride height?) in the tuning menu says that rake affects aero, maybe it doesn't appear until you have added a wing to the car? Or maybe my test was just too slow.

It would be an interesting decision on whether to stiffen springs to take up the downforce from the aero vs. starting with a higher ride height - as well as stopping the car bottoming you'll obviously have "non aero" effects from the suspension tuning. I've read that sometimes (IRL) cars can be accidentally set up with the suspension tending towards oversteer, but the aero towards understeer meaning you get horrible transitions in behaviour in mid speed sections where the aero is just starting to come in

 

[Otaliema]

I'm going to have to take a look again at my Aero effects testing now that the data logger is out. From my first round of testing found here shows that any aero affects the top speed of the car. As for shape, size and design I saw no difference in speed and max/min on custom wings made only a minor difference in speed 1 or 2 km/h I think. front rear or flat floor. Granted I was travling at very high speeds 460+ km/h so that may have something to do with it but a blanket statement that wings don't affect the cars speed are incorrect. I also noticed during my testing in the FITT hot hatch challenge that wings reduced speed on Brands Hatch by a 5 km/h as well I could hit 212 km/h at the end of the back and I could only manage 207 km/h with a wing on the car everything else the same.

Edit see underlined text, I slightly miss read the previous post.

 

[Nish]

@bread82 I was also thinking about the end sections. I'd assume they affect lateral grip?