Drift Nirvana SC 3/26/17 lessons learned

*Disclaimer – This is mainly a brain dump for my own personal archive

Lesson of the day: Originally, my intent (as it has been the last few events) has to become accustomed to LFB and its proper usage. I did get plenty of Left Foot Braking in, but that was more from the Crown Vics we now use to teach newbies the basics. Basically, they get the steering wheel and I run the pedals on the skid pad.

I actually am playing with LFB in this video below

Regardless, the major point of the day were the 225 40psi Achilles ATR tires I was running. I’ve been told these tires have “less side bite” and I always assumed it was one of those subtle nuances that only good drivers could feel. But no. It was very apparent that the car wanted to float out whenever I was off throttle. If I was on throttle, the car gripped up and slid nicely. Unfortunately, by the time I was getting used to their grip level, they were already dead. After my 4th run, they were too loose to be of any use. By my 6th run, they were dead. So sadly, I barely got any seat time and had no time to practice LFB. They do smoke the most out of any tire I’ve ever used.

Next time, I’ll try to run some triangle tires as I hear they last a long time. I also hear they don’t grip too well and that they don’t smoke. At this point, longevity means the most to me.

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Yoshi’s Drift Box: Day 9

Ok well it’s almost been a month but a ton has been done. I managed to gather 4 beta testers and get a few of the newer arduinos. The screen is a higher resolution (I think 480×320 instead of 320×240) and shows much better in daylight than the old model. I think the aspect ratio of the screens are different so I’ll eventually need to redo the backgrounds. On top of that, there are now 4 plugs on the side (not that exciting), there is a reset button on the top, and the SD slot has been relocated to the top as well.

I had some issues with the touch screen and images showing up backwards but that’s fixed. I also had an issue with the touch screen sensitivity that the maker of this unit helped me fix.

The diagnostics screen now shows the list of logged PIDs dynamically with what’s in the config file within the SD card. Many bits of screen materials needed to be moved around for the new resolution. There is also new test code to properly read out DTCs that I’d like to test soon. I somehow broke the “Live Data” rpm code but I’d like to make that do more than just the time and RPMs.

For now, I’m working on documentation and polishing these units to be sent out for beta testing. I’m interested to see how people use this. If things go well, I hope to have enough feedback to do some firmware upgrades and logger upgrades. Finally, I have a drift event in just over a week so I’d love to finally test my outputs for video overlay.

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Yoshi’s Drift Box: Day 8

A bunch of miscellaneous things have gotten done but nothing super substantial. The logger viewer is basically in limbo for now. I had a bunch of feature requests and things that I thought would be useful. The GUI layout has changed drastically as I feel it’s very important to see everything at once. As a result, the application now opens in full screen mode.

The finished features include the following:

  • Play back functionality now working correctly
  • Integrated google maps into viewer
  • “Pin” location animated during playback
  • Accelerometer bubble
  • Torque log import/export features
  • Custom heat mapping for gps plotting (kml exportable)
  • General bug fixes/Gui updates

The important thing to note is that Torque logs are now accepted and exported. There is some video overlay software called DashWare I’d like to try out. Regardless, every video overlay software I found requires very rigid inputs and it seemed simpler to just export in a simple and known format.

Other than that, the main arduino unit itself now properly logs data fed in by the slave Arduino Uno. I’ve also tested input from a $4.27 GM clutch position switch (ACDelco part# D2203D). Eventually more inputs will be added but this is the simplest start to the process.

The main arduino mega unit now takes in config files for PIDs. I’m doing a limited release for some beta testers and I don’t want anyone to HAVE to compile and upload the arduino code. As a result, doing config files and images through the SD card is essential. Unfortunately, Freematics no longer sells the exact kit I originally ordered 2 years ago. On the bright side, the new unit has additional inputs and much better hardware options (better GPS module). I’m hoping to not have to recode much but some is to be expected.

So the near future to do list includes recoding for the new hardware, expanding configurations, and displaying your full PID list/etc on the diagnostics screen.

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Manual Brakes Postmortem

Warning: This will be heavily biased towards my specific setup. If you have had issues with boosterless brakes, this might work well for you though.

My brakes finally feel ok. I just finished a drift event 2 days ago and forgot that I even had issues with my brakes until half way through the day. They do take more effort than factory but not much. I feel like the firmness of the pedal is what spec E30 guys want in their cars.

The solution to my issue is still not completely clear. There was a spec E30 forum post I read where a driver hooked up pressure sensors to his brakes and depending on different inputs, the rear brakes would either work or not. He tracked it down to the rear proportioning valve. I debating on just deleting it but instead I replaced it with a factory unit for 12x the cost. At the same time, I swapped to a different (but used) factory cylinder, and deleted the ABS unit. The brake fluid from the old setup was pretty dark so I opted to replace the front brake lines as they were the most worn.

With all of those changes, my brakes felt great. In retrospect, I don’t think I know exactly what did it. My last master cylinder could have been internally fried from the heat from the headers. As a precaution, my new(er) master has a heat shield that attaches to the master cylinder mount. It should be attached to the engine but space doesn’t allow for it. Regardless, I could still grab the master after pulling off track from a run.

The other options are either the ABS delete or the rear proportioning valve. I kind of doubt the ABS unit because I couldn’t find it failing for anyone else. The online spec E30 forum post makes me think it was the rear proportioning valve more than anything.

I highly doubt swapping out the lines and bleeding the brakes did anything but you never know. In the end, this manual braking setup with the moved pivot point will work with the factory master. I went down the rabbit hole instead of simply investigating the rest of a system I didn’t know.

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Yoshi’s Drift Box: Day 7

It seems like every time I make a post on this project, I do completely different things than I set out to do in the post. I wound up cleaning up some code (but not much). I realized that the gauge animation code ate up a significant amount of time between PID polls so I managed to get a 4 PID from 600ms down to about 150. After that, I did some GUI improvements. The Subaru ECU still proves to be temperamental but things consistently work.

Originally, I wanted the log parser in a web application format but I don’t have time to learn everything I want to. So I started up a windows application. The application is still very fragile but it does load up logs and let you see data points as well as mix and match logged elements. It gives things like time stamps as well as parsing the GPS information.

I copied over the KML google earth code that I wrote and then wound up rewriting almost completely. I managed to get it to take in the GPS data but colorize the line based on any other logged data. The image below shows the line plot with speed information overlayed. Red is where the vehicle was stopped and green was my top speed for that log.

From here, I’d really like to output this data to something that can be imported by a video editor and overlayed on some in car footage. I also might go back to trying to get external input logging reliably. Or I might clean up code some more. I’m not entirely sure.

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E30 Brake System Overview

While troubleshooting my general brake issues, I found numerous gaps in my own knowledge. So here is my current understanding of the general E30 brake system (within reason). To start, late model E30s (not sure about before) have a 17mm rear and 22mm front sized Girling master cylinder. I’m surprised by the 17mm rear. To my knowledge, the ABS unit provides nothing other than ABS functionality. I think late model E36s and all E46s use the ABS unit to proportion as well as perform ABS functions.

E30s have 1 proportioning valve behind the driver’s shock tower on the rear line. I don’t know what its specifications are or why it’s there. Here’s the part number to delete it. (M10x1.0) though I havent tested this. But it’s there. My googling shows it as a common issue with the SpecE30 crowd. The ABS unit itself receives both inputs from the master and splits only the front lines out (see diagram below).

The rear line follows along the fuel lines to the back of the car where it wraps above the subframe and is T-ed out above the diff/subframe combo (T part number 34341111435).

The front passenger’s line run against the firewall under the heater core flap. The driver’s side simply exits on the shock tower and in front of the proportioning valve for the rear. The above diagram properly notes which port of the master cylinder goes front or rear (V front, H rear). I did not fully note down the ABS unit ports. Lower case “h” is for the rear but I don’t recall what “I” or “J” goes to (it’s left or right).

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Manual brakes – LS E30 problems

The LS swapped E30 inherently has to ditch the vacuum assisted brakes. Directly bolting the factory master cylinder to the firewall causes a large increase in pedal effort that isn’t acceptable. For this reason, the brakes cannot be left alone. Here are several options that I’ve researched and extremely generalized numbers to go with them.

Hydroboost Assist
Hydroboost is an assist method commonly used in diesels and trucks/vans. Diesels don’t make vacuums so the regular vacuum booster wouldn’t work. Hydroboost systems generate their assist based off of a fluid pump. Sikky makes a hydroboost kit based off of an E350 booster (IIRC) that is driven from the power steering pump.

Pros – No other modifications are necessary to your brakes. Plug in the kit and have factory feeling brakes back.

Cons – Some people don’t like the pedal feel and consider it “squishy”. If you drift and left foot brake, it completely changes how the pedal feels. There is added complexity to the engine bay but it’s not too bad. My only issue was that my track use overheated the unit and caused the brakes to stick.

Cost – The full kit from Sikky is ~$1200 with booster. But that’s it, plug in and go!

Wilwood Pedal box
He’s one I’m not super sure about. This should be another solution where you install it and go about your life. It replaced the clutch and brake pedal box with a proprietary pedal set. Garagistic makes a pedal box adapter so placing the pedal set in the car is simpler.

Pros – wilwood quality and adjustment. Allegedly still should keep the factory feel and function.

Cons – This looks like (again I haven’t done this) it would require a good amount of fabrication and work to fit into the car.

Price – The pedal adapter is currently $125, the pedal set is $200, and another ~$300 for 3 master cylinders. Plus miscellaneous fabrication and fittings. So I figure ~$800 all done.

Manual brakes and BBK
RX7 front brakes are a common cheap upgrade to the front of E30s. But they aren’t a complete solution. Massive makes an adapter bracket to physically remove the booster. But those two mods alone won’t give back the factory braking effort. I tried using a VW beetle (17mm) master cylinder. The car does stop better but now the pedal is squishy and still no where near factory levels of braking.

Pros – Cheaper of the solutions (but not by much). Fewer parts to worry about and requires little to no fabrication (just the pedal pivot relocation).

Cons – Doesn’t give great braking feel/force. But it works ok.

Price – ~$300-600 depending on what parts you pick up

Manual Brakes With Wilwood Calipers
This is the same as above but using wilwood brand calipers. The calipers are about $120 each for the front and $100 each for the rear so that and the welding needed to attach the calipers puts this around the $1,000 mark.

Pros – Better (possibly) factory feeling brakes. That cool wilwood logo.

Cons – Requires a GOOD welder as I haven’t found anyone making bolt on brackets for these. As I haven’t tried this, it’s possible braking still won’t be up to par with the factory.

Price – ~$1,000 depending on how much you can do yourself.

Manual Brake With 5 Lug swap
The biggest issue with the wilwood calipers is that the small factory rotors become the limiting factor. Larger diameter rotors give better braking (overly generalized). Swapping to full M3 E36 calipers (or E46 330 or any other swap option) will give better braking with the manual braking setup.

Pros – If you were already doing a 5 lug swap, this isn’t an issue. Retains factory parts. Very well documented swap.

Cons – Still might not give you factory braking (don’t quote me on that). Requires you to get 5 lug rims/tires/etc. And there’s 80 ways to go with the swap that might not give better braking performance. I think the E36 318 rear brakes aren’t as good as the Z3 rear brakes.

Price – $1200+

Brake Booster Relocation
Here’s a link to the basic setup. Essentially, you pull all the parts from an E32/E34 and fab it to fit an E30.

Pros – Mostly OEM parts. Retains the booster so it’s all factory.

Cons – Probably one of the most involved setups but not by much. You need to be able to weld and do brake fittings. This deletes the ABS unit and shoves all the bits in there. More parts in the engine bay and theoretically more parts for failure.

Price – ??? No one sells a kit and you’ll have to pay whatever the junkyard prices are. I honestly think this could be the cheapest of the “good” options.

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Yoshi’s Drift Box: Day 6

A lot has happened in 2 weeks. I found out that the I2C bus is easily susceptible to noise like in an automotive environment so the UART connection made a bit more sense. Even though it can only take in 1 input, I’m only going to connect 1 arduino. Which works out great because now I don’t have to split out the I2C connector.

Here’s what the current setup looks like. You push the button, the arduino uno reads it, sends it to the arduino mega, and the mega displays it on screen. With that, I’ve officially reached the end of the “proof of concept” stage. Now I know and have setup every major milestone in the system. The rest is code and finalizing IO.

Before that, I worked a bit on the gui. I went for that old NES look. The touch screen now displays 3 different setting screens. So far they don’t do much of anything, but you can swap between them. I’ve also been toying with some DTC reading/scanning/clearing code but that’s really far on the list of priorities.

The down side I realized is that the more PIDs you poll from the OBD2 port, the slower everything goes. Just reading the RPMs was a 60ms lead time. Reading in the final list of what I want (rpm/iat/clt/throttle %) bumps that time up to 600ms (over half a second). This is likely due to the kwp2000 “fast” protocol not being able to give me the data fast enough. But I think the LS2 uses the CAN protocol so this might be a non issue. I should test on the E30 soon.

From here, there’s still too much to list that needs to be done. For instance, I’d like to be able to read in a config file from the SD card. The main goal is to start cleaning things up. My code is pretty disjointed and messy. I’d mainly like to polish the GUI. Maybe look more into reading PIDs faster.

For my own archive, here’s the current list of external IO for the uno to eventually log:
Accelerometer for the uno (another MEMS to keep things consistent?)
Clutch switch
Brake switch
Ebrake switch
Steering wheel input? (I have no idea how I would do this)

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Yoshi’s Drift Box: Day 5

OK I lied. The urge to work on the expansion of inputs won over and I’ve done a bunch of research into that. The I2C connector the OBD2 plug uses is an expandable bus while the UART plug is only able to take in a single input. As a result, I made the decision to use another arduino (uno) on the I2C bus using the existing plug on the LCD TFT screen. This gives me another set of digital and analog inputs that can be farther away from the main unit (without tons of wires all over). This will also make a great way to mount a second accelerometer to calculate slip angles later.

Anyway, some sexy mods I did was to figure out how to make a basic dial gauge. I’m going to use it for RPMs since the tachometer doesn’t work on the LS E30. It’s also very noteworthy that the lag time between the car’s tach in the IG video and the arduino is minimal. This beats out most bluetooth solutions I’ve used in the past. This makes me very happy.

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Uh. Turn it sideways

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I’m still ordering parts here and there for the new arduino setup. But in the man time, I should be able to start to build out the UI. I’d like to get it broken into a few different useful screens. One will likely be checking and clearing DTCs and one will likely be just a main gauge readout. I figure I’ll have a third for reading out tons of other stuff but I haven’t fully filled out that thought process yet.

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Drift Box

Drift boxes are units for on track data acquisition. Many aftermarket units are well into the thousand dollar range. I’d like to create a cheap unit for data logging and drift telemetry.

Drift Box Day 0: Project overview

Drift Box Day 1: Basic setup

Drift Box Day 2: Images, touch screen, and accelerometer logging

Drift Box Day 3: GPS data parsing and KML export

Drift Box Day 4: OBD2 logging successful

Drift Box Day 5: I2C success and graphics

Drift Box Day 6: More external input and GUI updates

Drift Box Day 7: Data log viewer

Drift Box Day 8: Logger V1, new Freematics kit

Drift Box Day 9: Close to beta testing

Drift Box Day 10: Fruits of labor

Drift Box Day 11: Dashware and functionality additions

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