Horrific 2zz Black MR-S bodge work "track car"

Started by threepot, May 30, 2022, 15:05

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JB21

Quote from: threepot on September 14, 2022, 09:42Been messing about with datalogging apps on the Android phones, all very impressive stuff for incredibly small money spent. It was watching the DannyDC2 MR2 race videos that really caught my eye.

Then came the stumbling block, the 2zz-ge MR2 uses an early Japanese ECU which doesn't comply with normal ODB2 KWP2000 communication, it uses some weird JOBD platform.

I was originally using TrackAddict but there was no way of getting it working on the JDM 2zz-ge ECU, but it turns out that RaceChrono does allow all weird and wonderful custom commands and stuff! Tinker time indeed.

After some googling, it turns out that someone has figured out the correct ELM327 commands for the JOBD ecus (on some Torque Pro gauge app forum), which is:-

ATIB 96 \n ATIIA 13 \n ATSH8213F0 \n ATSP4 \n 0100

So you put that in "Initialisation Commands" settings box, and pick protocol 4



And then we are datalogging throttle position, revs, vehicle wheel speed sensor, coolant temp.. all sorts. The down side is the refresh rate isn't amazing, and the more channels you pick the slower it gets.




Keep it sensible, just Revs, VSS and TPS and we are getting 2hz which is fair for a budget!

Then I really wanted brake pedal datalogging... it is good to see the braking points consistency etc. Thing is the 2zz doesn't have a brake pedal switch input (the 1zz Mr2 does though).

Using my scanner I noticed there is a channel for "power steering oil pressure switch" from when this is used in a Toyota Celica or Corolla which has a mechanical hydraulic steering pump with a pressure switch.



So I made a custom PID input in racechrono with an algorithm like this.. it uses PID 0x01E8 and it extracts bit 6 which goes from 0 to 1 if the oil pressure switch is high/low. Then x100 so the brake goes from 0% to 100%.




Then I wired up a feed from the green brake light wire, which energises a relay, creating a ground on the PSOilPressure input pin D28 - because the oil pressure is a ground switch basically. So now we get a nice datalog with brake pedal input too.

This is all just using a super cheap £5 ELM327 bluetooth OBD2 device (beware some are very poor and some are semi functional, find a good one in the chinese lottery!). I also tried to use a Carista interface but I found the datalogging speeds were about 20% slower.

Coupled with a solid mount for a phone so the G force sensors are as accurate as possible and an external GPS receiver - I'm trying a Garmin GLO which claims 10hz, this should be a pretty nifty datalogging setup for an imbecile like me.

I've tried this previously with my JDM 2zz ecu and it just wouldn't connect. Guess you're using the Celica JDM ECU? Mine is the Corolla JDM ECU. Had to purchase a handheld JOBD scanner for faults.

threepot

If you want a known working ELM327, PM me your address and I'll send you one in a jiffy bag.

Did you mess with the initialisation stuff etc?

I bet if you use the initialisation string etc you'll be up and running as the JDM corolla will be on the same protocol as the celica one.

JB21

Quote from: threepot on September 14, 2022, 11:17If you want a known working ELM327, PM me your address and I'll send you one in a jiffy bag.

Did you mess with the initialisation stuff etc?

I bet if you use the initialisation string etc you'll be up and running as the JDM corolla will be on the same protocol as the celica one.

Thank you for the kind offer. I've got 2 ELM37 dongles, let me try again and if they dont work I'll take you up on the offer.

threepot

#103
I have a good hoard of this chinese crap! I helped develop a code reader for some weird thing that wasn't obd complaint. The product was based on ELM327, but as we found out genuine ELM327 chips are non existent, and only varying degrees of semi functional chinese clones flood/saturate the market.

This is only a small handful of what I kept. (the back plug with the black taped up thing was the prototype test product) Some of the little blue ones are really good clones and are fully functional with the full ELM327 command set, and thus work properly with all the Android/Apple apps. So to send you one up is really nothing, especially if it helps your cause.

I'd say 90% of "elm327" clones are not really functional. So it is a bit of a mine field.

I feel a sorry for Elm Electronics in Canada who actually designed/programmed this interface on PIC chips. Their name and product has truly been hijacked by the pirates.


threepot

Just for reference, the initialisation string "ATIB 96 \n ATIIA 13 \n ATSH8213F0 \n ATSP4 \n 0100" does this:-

ATIB 96       Set baudrate to 9600
ATIIA 13      Set ISO (slow) initialisation address to 13
ATSH8213F0    Set Header to  82 13 F0
ATSP4         Set Protocol 4 = ISO14230-4 KWP (5 baud init, 10.4 kbaud)
0100          Send 0100

threepot

#105
Been playing with this datalogging stuff tonight again. The Garmin GLO bluetooth GPS unit is ballistic for the money. I'm getting 0.6m to 0.7m location accuracy continually at 7 to 8 locations a second.

That blows my head off that you can track something so closely in the big big world we live in, for beer money.

I have found the OBD2 data logging is running with a delay of 526 milliseconds.

The VSS speed value from the ECU is lower than reality by 4%.

So here is graph with those two factors corrected....


But it goes to prove that GPS cannot measure very quick velocity changes, you can see the gear changes more realistic on the OBD red line.

AJRFulton

#106
Quote from: threepot on September 15, 2022, 22:44Been playing with this datalogging stuff tonight again. The Garmin GLO bluetooth GPS unit is ballistic for the money. I'm getting 0.6m to 0.7m location accuracy continually at 7 to 8 locations a second.

That blows my head off that you can track something so closely in the big big world we live in, for beer money.

I have found the OBD2 data logging is running with a delay of 526 milliseconds.

The VSS speed value from the ECU is lower than reality by 4%.

So here is graph with those two factors corrected....



But it goes to prove that GPS cannot measure very quick velocity changes, you can see the gear changes more realistic on the OBD red line.


The GLO is usually accurate to 0.1 seconds on track - I use one, but have a transponder as well for competition - so both run concurrently. The transponder measures to 1/1000th of a second, and be more or less spot on.

Just looking on Speedhive, and on Harrys Laptime at the last time I did competitive laps

Last 10 laps GLO + Harrys (to 1/100th of a second) vs the Transponder (to 1/1000th)

+ 0.15
- 0.08
- 0.01
+ 0.05
- 0.11
+ 0.06
- 0.06
+ 0.06
- 0.11
+ 0.14

That is the first time I've written them down to compare actually - usually just glance over and happy they are similar enough. I'd be quite happy to say it makes a phone based GPS lap timer accurate to about 0.1 of a second

It is great for an £80 bit of kit, and accurate enough to be useful for both competition and track days. I find the cornering speeds to be accurate enough as well using the GLO, so definitely useful for some secondary analysis.

A big improvement on the built in GPS on a phone (which I found to maybe as much as +/-0.75s). But that is a 1-2Hz refresh rate vs 8-10Hz.

threepot

#107
It really is quite amazing all this is possible with such cost effective and accessible equipment. Timing to within 0.1 seconds reliably is outstanding really. The analytics and comparison tools in RaceChrono are quite close to what professional race teams have.

The phone/tablet that you run the app on make a difference too - I was using an old Samsung Xcover 3, but then tried my new Xcover Pro Enterprise edition, and the logs have way more frequency/sample rate.

Thus getting a pretty modern android phone, and wiping it clean, take out the sim card, turn off the wifi etc. Just use it as a dedicated race computer will give you the best accuracy possible. Along with a super rock steady mount so the G-force sensors work better.

Stepping up to a 20hz or 25hz GPS receiver I would assume will over double the accuracy, but they are a fair few quid to buy.... and for a mere tinker like me I would see no benefit.

I've just plugged the Garmin GLO into a windows PC, downloaded the update software and updated the GLO. It is now showing update rates of 8.5hz to 9.5hz... but I will go out tonight and try it out in the real world.

I also bought this Vgate iCan Pro interface, and that is no faster or slower on the OBD2 logging. It seems to be a limitation of the ECU - you can only pull about 4 values a second via the diagnostic port on this JOBD protocol.

threepot

Just a non eventful status update on project horrific....

Done a couple of track day over the last month, first was a dry one, everything stayed good, really got to grips with the car. It was a mostly dry day, rained for a little bit... managed to swap ends on the car in a blink on the way into Lodge, perfectly clipping the apex backwards  ;D That one day plus a 3 sisters day saw the rear yellow pads turn into this, too much chicken braking...





Thus bought some carbotechs to see how they fair XP8 on the rear, xp10 on the back... hoping to shift a bit of brake bias forwards.

Only other thing to report was I found 3 out of 4 of the MeisterR coiler overs had come loose on the ride height adjuster lock nuts. Front right was physically rattling about.

Then did another Oulton day on Tuesday, but it was a wet one, very wet indeed. Like an idiot tried going out on the AR1 tyres, 2 laps and came back in! AR1's do not work on standing water, scariest drive ever. It rained less, moved over to a set of NS2R's I had, then enjoyed the rest of the day as a dryish line came along the track though out the afternoon. But the NS2R's have got nothing on the AR1's by along way. Spent quite along time chasing this little Ignis turbo that belongs to a friend. But shock horror... nothing fell off, nothing broke, no rattles!  :)



Two more track days booked for between now and Christmas, hopefully the weather will be kinder to me next time. MR2 on a wet track day requires a few pairs of spare underwear. I might get a set of proper race wet tyres just so those days are not a right off.

Alex Knight

Great update.

I've personally melted a set of YellowStuff pads on the rear of mine (literally).

Switched out to XP10s and haven't looked back.

Interesting comment regarding the Meister Rs. That's unacceptable, and further justifies my decision to fit high quality (TEIN) coilovers.

JB21

What days you doing? I've just missed an Oulton day due to Flu, so looking to book again. Potentially Saturday 3rd December.

threepot

Quote from: JB21 on November 18, 2022, 12:56What days you doing? I've just missed an Oulton day due to Flu, so looking to book again. Potentially Saturday 3rd December.

I'm booked in for Wednesday 30th November and Friday 9th Dec. But maybe I could do another one, last jaunts before Christmas..... but you will be way faster than me  ;)

I have a hanging chest infection too at the moment, wife has been ill with it for about 3 weeks on and off. I went out on an emergency Calpol run for the kids last night - I went to 5 shops that were all sold out. That says something.

Quote from: Alex Knight on November 18, 2022, 10:52Interesting comment regarding the Meister Rs. That's unacceptable


I suspect the folk that owned this never bothered to tighten the coil overs properly in the first place, those silly half moon spanners are not a great fit. I doubt this car has seen any real track action in its life on these dampers. On Tuesday I did one hour and twenty straight non stop lapping, came in for 20 minutes, then went back out for another hour and a bit till it went dark and closed. Getting in the zone, some serious non stop kerb/apex hunting action  >:D

I did put it on the grass again too in the afternoon on Tuesday. I was stuck behind a beemer for about 10 laps, he wouldn't let me past as I was slower on the straights... I got all fed up, then followed his really scabby line though cascades and ran wide onto the grass on the exit on the right. I felt like an idiot. I was an idiot.

AJRFulton

#112
Quote from: threepot on November 18, 2022, 10:28Thus bought some carbotechs to see how they fair XP8 on the rear, xp10 on the back... hoping to shift a bit of brake bias forwards.

Only other thing to report was I found 3 out of 4 of the MeisterR coiler overs had come loose on the ride height adjuster lock nuts. Front right was physically rattling about.

Then did another Oulton day on Tuesday, but it was a wet one, very wet indeed. Like an idiot tried going out on the AR1 tyres, 2 laps and came back in! AR1's do not work on standing water, scariest drive ever. It rained less, moved over to a set of NS2R's I had, then enjoyed the rest of the day as a dryish line came along the track though out the afternoon. But the NS2R's have got nothing on the AR1's by along way. Spent quite along time chasing this little Ignis turbo that belongs to a friend. But shock horror... nothing fell off, nothing broke, no rattles!  :)

AR1's behave very like slicks despite being E rated. Any rain that's significant enough to cool the tyre (ie anything above a bit damp) and they are pretty useless. Still find them the fastest dry E Rated track tyre though.

Don't rate the NS2R on track at all, but will be a lot better in damp/wet than the AR1.

threepot

#113
To hedge my bets, I've had a new set of Uniroyal Rainsports fitted to a spare set of 15" PFL wheels. At least I have 1 set of tyres that will make a very wet track day worth doing a few laps. Those AR1's were deadly, and the NS2R's were better but not great.
I just need to remember that if it drys out, I need to get these Rainsports off the car ASAP as I will melt them in no time.


thetyrant

Quote from: threepot on November 18, 2022, 14:18I'm booked in for Wednesday 30th November and Friday 9th Dec. But maybe I could do another one, last jaunts before Christmas..... but you will be way faster than me  ;)


Might try and get booked on for 9th in my mini if places still available after the weekend, mini is currently my daily due to warranty issues with the usual daily so dont want to risk mini on track until im happy i have other transport, which i should know after weekend hopefully :)
Ex-2005 roadster  owner, i will be back :D

threepot

I can promise you the weather will be dry... because I've bought a set of wets  :))

JB21

Quote from: threepot on November 29, 2022, 13:03I can promise you the weather will be dry... because I've bought a set of wets  :))

I bought my full wets last year for this year's TD's and everyone has been dry, 9 in a row. Can't complain though really.

RS5's are unbelievable in heavy rain, good in light rain, poor in the damp and surprisingly half decent in the dry.