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Tor · 08-17-2016, 05:34 PM

Well, this car is turning into a science experiment.

I just came home from Nürburgring GP circuit. And I have so much data to look at that I might have to call in sick tomorrow. Work is really an annoying thing that gets in the way of all fun.

One stint on the GP circuit (about 15 mins):

Tires:
@Twinguin this thing is the sh!t.

Tire pressure before and after (actual cold pressure was 2.06 Bar, as it the tires cooled to ambient 26 deg C before going on the track) - snowflake is cold, sun is hot:

Not surprisingly the left-hand side tire pressures went up more.

Inside temperatures:

Middle temperatures:

Outside temperatures:

To be honest I didn't even look at it in details yet. 2.45 Bar (35 psi) hot is probably a bit too high. I didn't even look at the temperatures yet. Any opinion?

Edit (looked):
2.45 (35 psi) doesn't look too bad, I think. And is not completely out of line with what Yokohama recommends (32-34 psi).

Hot, taken less than a minute after coming off track:

Code:

Left front     Right front
2.45 Bar       2.40 Bar
O  M  I        I   M  O
67 63 64       63 60 60

Left rear      Right rear
2.45 Bar       2.40 Bar
O  M  I        I   M  O
60 58 62       60 58 57

I, inside. M middle. O, outside

Right-side looks like near perfect. Left-rear needs a bit more pressure to get rid of the middle 58 deg. Left front overheats on the outside - now what the hell do I do about that? @MaximeT , help please!

Maybe I need more camber up front (have -2.5 deg)? But what will happen to the right-front then? I could try to dial it up to -2.8 or -3 deg (max avaiable -3.5 deg). Probably it will make it less understeery too (more about that below).

Engine:

http://datazap.me/u/tor/track-0?log=...lo=16-27-34-37

My own interpretation, with explanations:

IAM (Long-term timing being pulled) = 1 or 100%, meaning no timing is being pulled
FBKC (instant timing being pulled due to knock) = Negligible. 10 events total with the highest being -1.4 deg as I get back on the throttle (tip-in, normal).
FLKC (what causes IAM to drop) = Generally less than -1 (which is good), in fact, mostly less than -0.5. Two or 3 times it goes below -1. I think this is normal when tracking too, and it doesn't cause IAM to drop (good).

I think the timing looks pretty robust for track usage, with the fuel I am using (Shell V power Euro 100 RON octane - 93 US I think?).

LTFT ("Long term fuel trims") are fuel the ECU is adding based on learning over time. At low throttle angles, the engine uses the Lambda probe to compare the fuel/air mixture to what is desired. It then stores the average fuel trims and applies them when aggressive input throttle is being used.

My long term fuel trims are a bit high above 5000 rpm causing the engine to run a bit richer than desired. And it means my "Mass Air Flow scale" (the calibration of the sensor that measures how much air is ingested) is slightly off (Still, it's a lot better than it was stock!!).

I calibrated it already. But I think 2 things were not optimum.
1) The logs used for the calibration was done at a low 13-15 deg C (German summer lol).
2) I think I smoothed them too much on the lean side. Which is now causing the ECU to add extra fuel.

So, I took the drive home as an opportunity to make 100 km of logging at a suitable 20-25 deg C ambient temperature, so I can try to get the calibration right. That's another set of data to look at and work on.

Driving!:
The important part. Of course, I took video too. I had a great free run all laps, which I did consistently around 2:40 (2:39,5 best, 2:41,77 worst). The times are not really great, but I am very satisfied anyway because I changed the way I attacked the corners a lot. I braked a lot deeper into the corners and went on low maintenance throttle and waited until after the apex before putting the foot down. It seemed to work wonders for my previously too throttle-aggressive self-induced oversteer. So I guess hitting the same lap times as before is a good beginning. When I have time, I will edit and upload the video.

Edit: Brakes:
The XP10 pads worked wonderfully. I did the pedal dance this time again and it really feels more predictable. It's a pain in the ass to do it. I have to start the car several times to get it to work after the engine has cooled down slightly when waiting to go out. I might have to get a PDNanny.
Of course, I took temperatures too

with a laser thermometer (after the tires). Both front and rear disc were around 170 deg C. The last 1 1/2 lap I didn't go full speed on the straights and didn't brake that hard. I kept the speed up in the corners though to keep the tire temperatures.

08-17-2016, 05:34 PM	#106
Tor Senior Member Join Date: Feb 2015 Drives: Toyota GT86 Location: Europe Posts: 919 Thanks: 369 Thanked 557 Times in 301 Posts Mentioned: 40 Post(s) Tagged: 2 Thread(s)	Well, this car is turning into a science experiment. I just came home from Nürburgring GP circuit. And I have so much data to look at that I might have to call in sick tomorrow. Work is really an annoying thing that gets in the way of all fun. One stint on the GP circuit (about 15 mins): Tires: @Twinguin this thing is the sh!t. Tire pressure before and after (actual cold pressure was 2.06 Bar, as it the tires cooled to ambient 26 deg C before going on the track) - snowflake is cold, sun is hot: Not surprisingly the left-hand side tire pressures went up more. Inside temperatures: Middle temperatures: Outside temperatures: To be honest I didn't even look at it in details yet. 2.45 Bar (35 psi) hot is probably a bit too high. I didn't even look at the temperatures yet. Any opinion? Edit (looked): 2.45 (35 psi) doesn't look too bad, I think. And is not completely out of line with what Yokohama recommends (32-34 psi). Hot, taken less than a minute after coming off track: Code: Left front Right front 2.45 Bar 2.40 Bar O M I I M O 67 63 64 63 60 60 Left rear Right rear 2.45 Bar 2.40 Bar O M I I M O 60 58 62 60 58 57 I, inside. M middle. O, outside Right-side looks like near perfect. Left-rear needs a bit more pressure to get rid of the middle 58 deg. Left front overheats on the outside - now what the hell do I do about that? @MaximeT , help please! Maybe I need more camber up front (have -2.5 deg)? But what will happen to the right-front then? I could try to dial it up to -2.8 or -3 deg (max avaiable -3.5 deg). Probably it will make it less understeery too (more about that below). Engine: http://datazap.me/u/tor/track-0?log=...lo=16-27-34-37 My own interpretation, with explanations: IAM (Long-term timing being pulled) = 1 or 100%, meaning no timing is being pulled FBKC (instant timing being pulled due to knock) = Negligible. 10 events total with the highest being -1.4 deg as I get back on the throttle (tip-in, normal). FLKC (what causes IAM to drop) = Generally less than -1 (which is good), in fact, mostly less than -0.5. Two or 3 times it goes below -1. I think this is normal when tracking too, and it doesn't cause IAM to drop (good). I think the timing looks pretty robust for track usage, with the fuel I am using (Shell V power Euro 100 RON octane - 93 US I think?). LTFT ("Long term fuel trims") are fuel the ECU is adding based on learning over time. At low throttle angles, the engine uses the Lambda probe to compare the fuel/air mixture to what is desired. It then stores the average fuel trims and applies them when aggressive input throttle is being used. My long term fuel trims are a bit high above 5000 rpm causing the engine to run a bit richer than desired. And it means my "Mass Air Flow scale" (the calibration of the sensor that measures how much air is ingested) is slightly off (Still, it's a lot better than it was stock!!). I calibrated it already. But I think 2 things were not optimum. 1) The logs used for the calibration was done at a low 13-15 deg C (German summer lol). 2) I think I smoothed them too much on the lean side. Which is now causing the ECU to add extra fuel. So, I took the drive home as an opportunity to make 100 km of logging at a suitable 20-25 deg C ambient temperature, so I can try to get the calibration right. That's another set of data to look at and work on. Driving!: The important part. Of course, I took video too. I had a great free run all laps, which I did consistently around 2:40 (2:39,5 best, 2:41,77 worst). The times are not really great, but I am very satisfied anyway because I changed the way I attacked the corners a lot. I braked a lot deeper into the corners and went on low maintenance throttle and waited until after the apex before putting the foot down. It seemed to work wonders for my previously too throttle-aggressive self-induced oversteer. So I guess hitting the same lap times as before is a good beginning. When I have time, I will edit and upload the video. Edit: Brakes: The XP10 pads worked wonderfully. I did the pedal dance this time again and it really feels more predictable. It's a pain in the ass to do it. I have to start the car several times to get it to work after the engine has cooled down slightly when waiting to go out. I might have to get a PDNanny. Of course, I took temperatures too with a laser thermometer (after the tires). Both front and rear disc were around 170 deg C. The last 1 1/2 lap I didn't go full speed on the straights and didn't brake that hard. I kept the speed up in the corners though to keep the tire temperatures. __________________ Build: T(h)or's GT86 hammer (Europe) - essential track setup Youtube: GT86 dude Last edited by Tor; 05-14-2018 at 04:47 PM.