The Road to ChumpcarThe home of "Apex of Failure" a crap-can racing team.

Those of you who read this blog carefully might already know that I’ve been working on a data logger for the race car.  It was originally conceived during the 24hours of Spokane last summer.  We had some overheating problems during the race and the drivers needed to constantly monitor and radio in oil and water temperatures.  To add to that the gauges aren’t terribly easy to read so it was somewhat distracting.  Since I like building cool stuff I thought, “hey why not make a data logger!”.  Its taken some time to get this off the ground, but I finally have something to show off so I thought I’d write about it.

My goals are to log and transmit the following information:

• temperature data (oil, water)
• throttle position and brake
• rpm
• 20Hz GPS
• speed
• G forcess
• lap times and split times

Because I don’t have access to the race car every day, (Seattle to Eugene is a long drive)  I’ve decided to start with the last four bullets.

Blow is the custom data acquisition unit I made.  Features include:

• 20Hz GPS module with high gain antenna
• Bluetooth interface
• micro SD card slot
• 8 +/- 15v tolerant analog to digital input  ports (16 bit!)
• 8 3.3v tolerant digital IO or analog input ports
• 1 i2c port for expansion (eg accelerometer, gyro, compass, etc)
• 1 counter input for RPM

Since I didn’t want to build a car computer (the logger board does have an 8bit microcontroller but that doesn’t really qualify by today’s standards) with display, I figured the easiest way to collect, process, display, and re-transmit the logged data is an android phone, specifically Leo’s old Droid X.  It already has bluetooth, accelerometer, a nice display, battery (for when the kill switch is off), 3g data, a decent processor, and LOTS of storage space; it should provide plenty of power to process the data we collect.   Since the ‘phone’ has to be mounted in the race car I also 3D printed a two degree of freedom mount.

There’s a lot of parts talking to other parts in this project, so let me draw a diagram of whats going on so everyone is one the same page.

 

At this point most of the hardware is complete and its more a matter of software.  I’ve spent the last two evenings prototyping the software in Python and MATLAB (the embedded code is of course in C).  This is mostly because I’m most comfortable parsing text and drawing the track map in python and I’m most comfortable processing data and plotting in MATLAB.  Once everything is done the python code will be ported to java and run on the phone, while the MATLAB code will most likely be replaced by html5/javascript, since its the easiest way to make a GUI and because its (mostly platform independent.

Starting with the Python code, I’ve written a small API deal with noisy GPS data a compute the most likely on track location.  This is actually the most important piece of code because visualization won’t work without it.  You can plot data vs time instead of position but, for example, turn 1 at PIR may be 10 seconds away from the start finish line one lap and 12 seconds away another lap but it’s always going to 300m away (the Python code also helped me compute that distance).   The Python code also helps me validate track maps stored as GPX files, which any trip planner software/webservice will generate.

In MATLAB I’ve built a data visualization graphical user interface (GUI).  You can click the lap number and it plots, in this case speed vs track position or you can select multiple laps for comparison.  My hope is to be able to compare fastest laps from each driver to see where we can each improve our laptimes.  For example, at Laguna Seca I know from Micah’s video that we can do at least a second better if we stitch together each drivers best sectors!

As a side note, I didn’t have any real data to work with (the data I took at Laguna Seca in December was missing some critical information, so I couldn’t use it here), so I had to create my own track by driving around the block a few times, which is why you see my stopping so much and driving so slow.

I think that’s all I have for now.  If you have any questions or comments please leave them below!  Also, I reserve the right to edit this post for clarity or to add more information.  You’ve been warned.

May this be a warning to you all you chump “hopefuls”,  crap-can’s self replicate.  Unchecked all your garage space may soon look like this.

That’s a bit better now.  Should last a week or two before the chaos creeps in again.

My primary goal was to sort out the parts we would be bringing to Spokane and what we would be leaving.  We won’t be short of alternator belts.

I replaced the warning light panel and found out that I hooked up the oil pressure sender wrong.

Last time I tested the headlights and night, I noticed that removing the stock headlight switch also prevented the gauge cluster lighting and the running lights from coming on.  So I reinstalled the stock switch (and figured out I messed up some of the plugs).

I also found the missing 4th bolt for the seat brace and got it installed.

I got started making a new “dash as well”.  As you can see the glare is pretty bad.

Well color me flat black.

I added a little tape for the gauges.  It’s still a bit shiny but better than before.  Maybe I can get some spray adhesive and some cloth to put on top?

My oil pressure gauge fix was unsuccessful .

Figured the oil drain plug was on pretty loose too.

Under tray is back on now.  I also taped up all the space around the radiator to help duct the air through the radiator.  Spokane last year was pretty near 100F.  The forecast so far is a bit cooler, but it could be a real issue during the race.

 

I replaced the speedo cable.  It works great now (not that it does any good for us).

I added a second strap to the coolshirt box.   At least two straps have to fail now.

Tanner hooked us up with a 4th spare wheel (to replace the one we damaged in portland).  So now we have a lucky white wheel!  I’ll get a tire on order and that means we should have a full set of tires to spare.

Next week, were going to work on the spare motor.  It doesn’t need too much work (hopefully).

The todo list is getting really small.  We’re actually ready to race now, all of this is just extra prep at this point.  The car runs great.  Pulls pretty good, drives straight.  Feels solid.  Shifts smoothly and cleanly.  Starts really easily.  It think we might have even gotten it to idle right now.  Brakes feel amazing like the first car.  I really enjoy the “making the car better” thing.  It seems like its been ages since we have been able to do that.

I have a couple leads on a 5th driver.  Maybe big news next week!

Stepan came over today and we took some time to wrech on the race car. The biggest priority was to deal with the brakes. If read our last Portland write up, you will remember that we were have all sorts of issues with the brakes. Eventually we got them working, but never feeling quite right. The pedal was very light until it engaged and then it was very stiff. It stopped the car fine but the feeling wasn’t there. It was difficult to judge. We tried multiple master cylinders and fluid changes. Nothing would change the feel. Now that we have this new parts car, we have a new brake booster to try. Off came the old part (this is the one that was in the wreck in late 2010).

The unit out of the parts car (which was just rebuilt recently!) came out without a hitch.

Then went into our car.

During the bleeding, we accidentally let it suck air.  That made the job 3x longer.  Eventually it was finished and felt great.  Feels like it the first car did!  Job done.

Stepan replaced the cracked rear view mirror as well.  While he did that I fixed the shifter bushings.  We keep loosing the lower white bushing.  I found another one and installed it.  I also stole the boot and shift nob off the parts car as they are in better condition than ours ever were.

The “todo” list is getting pretty small.  Only two of these absolutely has to be done before we race, and that’s the fuel filter mount (which we can probably steal off the parts car!) and plugging in the stock headlight switch.

I’ll leave you with some parting beauty shots.

Sorry I haven’t been better about keeping this here web log up to date.  It’s been a very busy summer so far.  Last weekend I found some time in between things to get some projects finished.  I have continued driving the car.  It’s been driven around the block a dozen times or so as well as getting a full heat cycle each time.  So far no more leaks and starts great every time.

First off, I got the coolshirt cooler and pump remounted and wired.  Works great once you get the air out of the system.  I wish it flowed a little faster, but It worked great last time we race at spokane.  Most of the driver’s will have shirts this time around.  I think the only person without a shirt is going to try to make their own.  I might try to get another strap on it somehow for redundancy’s sake.

I also ordered our new headlights.  I broke down and got some name brand stuff, Hella 500′s.  The mounting is well designed and the install was pretty simple with the provided harnesses and relays.

I ran the wiring through the hood so it should be pretty well protected.  It’s just a single 13mm-ish nut to reaim them as well.  They came with nice covers for day driving and transportation.  They work ok.  It’s definitely a spot light.  I would have liked more lateral spread from it.  The original plan was to put hids in these housings but I would have had to manufacture a mount for the bulb.   They are also very very annoying to other drivers with hids in them.  Here is a little video of me driving it around the loop. Eyes have been night vision than my camera. So its a bit better than this video makes it seem.

It needs more testing.  They need to be aimed better and try some more long distance stuff.  I also need to reinstall the stock headlight switch so we can get the dash lights and tail lights on.  I’ll probably just turn it off and tuck it back under the dash or something and leave that stuff on all the time.

 

Last we met, our intrepid band of scamps had finished getting their newly rebuild motor back in the car.  We join the team as they finish hooking the new heart up.

We finished the wiring, there wasn’t much left.  Under the car, spark plugs, hook up the ecu, that kind of stuff.  We also started putting fluid in too.

Water too.

Ohh hay, we got another parts car!  Poor rx7s.  They find their way here and just get destroyed.

First thing we cut from its ferrous flesh is some shifter bushings that were lost during the swap.

Installed, it will need to get fixed before the race, but its good enough for now.

Time for the big molment!

Were missing the studs on the exhaust manifold so… its just the exhaust manifold right now.  We primed the fuel pump and didn’t find any leaks.  Turned the kill switch and cranked the motor.  We were rewarded with some deep hollow sounding thump thump thump then faster and it fired.  Only needed like 3 seconds of cranking.  AND IT WAS LOUD lol.  A little smokey but it died down right away.  The best part?  Oil pressure rose to the top of the gauge.  Booyah.  The aftermarket gauge didn’t read anything though.  I wonder if its broken?  Probably not.  I wonder if there is a clog in the oil system somewhere?  I hope not.  If there was, it would probably be in the oil lines or the oil cooler.  Both are relatively straight forward to replace.  We will have to run some more tests to be sure.

It even idled great and solid at 1k rpm!  There is a little water leak coming from one of the hoses on the radiator.  It should be straight forward to deal with that as well.  All in all very good.

Next week we should be driving it.

Were a little short on pictures today, I was working too hard!  We moved our regular weekly work sessions to thursday to better match the new groups schedules.  Earlier this week I nearly finished up the “long block”.  Today, we aim to put it in!

I just had a couple of little things to take care of before getting the tranny on.  The throw out bearing was making a ton of noise in its previous life.  So we swapped that out with a much better unit we had.

That means we are ready for the clutch.

Easy peasy.

We managed to get the tranny on without too much drama as well.  During install, we noticed that the clutch slave boot had torn pretty good.  We managed to find a serviceable boot on a spare.

It’s always a bit tricky to get the engine in.  In the grand scheme of things it wasn’t so bad.  It’s sitting nicely in there now.

With the engine in now, we met our goal but still had some steam left.  We got the radiator in, intake hooked up, most of the engine wiring done, fuel lines on, most of the water lines, clutch hooked up.  There is only a hand full of little things left to do top side.

The starter, speed sensor, tranny sensors, and all that junk still need to be hooked up.  It still has no fluids.  Were some how missing one of the shifter bushings too .  Next week, we should be able to fire it!

Awesome progress for a weekday.  Feeling good.

I have been taking some rest time from the race car, I think it has shown in the frequency of updates.  I apologize, and promise that it will be picking up again.  We have a tentative team ready to go for Spokane at the end of july.  Lots of new faces and new energy, it feels good.  To help get this next push off, I have a treat!  Another engine build .  After our motor failure (due to oiling issues that were my fault, mistakes made during the build) in Portland, we needed yet another rebuild.  This time I had several very expensive lessons to leverage.

This time around, I went with all mazda stuff.  With the mazda racer sponsorship program it actually ended up being the cheapest too.  As usual during the last failure we ruined a bunch of stuff.  We got new(to us)/used center iron, front iron, rotors, front counter weight.  We also got new side seals, and oil control rings, gaskets, rotor bearings, misc.  Were going to reuse our apex seals, corner seals, and everything else not mentioned.

This time around, I spending a lot more time measuring parts and checking tolerances.  This is the e-shaft getting checked to make sure its straight.

Cleaning is almost half the work of the whole build.  Here is one of the new (to us) rotors cleaned up some.

The irons were pretty rough.  Lots of oil and gunk.  The coolant seal grooves needed some love too.

More clean up.

Clean up all done, its time to start fitting everything.  First off, the side seals come too long from the factory.  They have to be individually fit per groove with hand grinding.

… and then disaster.  While fitting one of the new rotors, I discovered an issue.  It looks like this rotor was dropped.  This corner here is bent in.  The apex seals and corner seals don’t fit anymore.  This rotor is junk now.

So I grabbed one of the rotors from the last build.  The front rotor didn’t loose compression and looks ok.  It’s within tolerance for weight too.  At the end of the clean up day this is where we stood.  A couple side seals fit in one rotor and most of the cleaning done.

I continued putting in time after work getting side seals fitted.  On the last side of the last rotor (the reused one from our last build), I hit a major problem.  The side seals didn’t have enough clearance and were sticking in the grooves.  I gave up finding another after a week of searching and said f’it.  Time to chump.  I have been told by at least two people you can just sand it to get your clearance… (the shop manual says not to do this, lol).

It worked well I think.  Its still nice and sharp.  I checked the clearance and its spot on now.  Side seals done.

I finished marking them up and got the petroleum jelly out to get the final fitment done.

Time to start stacking the motor.  I finally broke down and got a pineapple engine stand adapter.  It has been well worth the money.  Doing work on the engine stand is so nice.  Screw the bucket.

Lots more clearance checking.

Were switching out the oil jets on the e-shaft as well.  These are race parts that help oil flow.  These should help keep things lubed and cooled at high rpms.

New jet on the left, old one with the ball and spring on the right.

Now we are ready to stack.  Hylomar is put in the groves.  The coolant seals are fit.

The first housing is slid down.

The first rotor is inserted (this time, the right side up ).  The e-shaft also makes an appearance here.

Apex seals carefully fit.

The center iron is prepped…

… and then fit to the stack.

While prepping the second rotor I discovered a big issue… I had too many outer coolant seals.  That means that I missed one in this stack here.  Looking back through the pictures, the mistake was clearly found .  It was missed on the front side of the center iron, so a lot of it had to come apart again.  SOP for my builds, sigh.

Rear iron is prep’d.

Second rotor is installed.

With the last iron fit, it was time to get the through bolts in.  Too bad they got stored with water in the bag and are now nasty.  Time for a second prep/clean up.

Torqued.

Flywheel on.

Front needle bearings fit.

The rest of the front e-shaft parts are fit to test the play.

Within tolerances.  On the outer edge, but my other spacer would have made it work.  Good enough for chumpcar.

Oil pump fit…

… and the gears and chain.

I need a stop for the flywheel, engine stand makes things easy again.

Front cover oil passage fit properly this time.

The missing oil control plunger was also replaced and installed.

RTV applied and ready to go with the front cover.

Here is that oil passage that was missing the o-ring last time.  Looks good this time.

Pulley and bolt installed.

Time for the oil pain.  The pickup fitted.

This oil level dealy sensor was leaking before.  There will never be a better time to fix it.  RTV to the rescue.

RTV ready for the oil pan…

… and fit.

Time to start with the little things.  CAS installed as well as the oil dip stick and cap.

EGR block off reinstalled.

5/6th port sleeves reinstalled.

Oil pressure sender installed.

Water pump and it’s housing are cleaned up…

… and installed.

Lower intake manifold (LIM) ready to go on.

Along with it, I also installed the rats nest and wiring harness.

The lower fuel rail and injectors go on.

The UIM (upper intake manifold) goes on and its hooked up.

Throttle body installed.

The last exhaust manifold had an issue last while we took this engine out.  One of the studs to the cat back snapped off.  These are huge and a giant pain in the butt to drill out.  Luckily I have a couple spares.  All the spares had some kind of issues though.  I picked this one out, since the only issue was this M8 bolt that had snapped its head off.  This hardware is used to hold the heat shield on the manifold.  I drilled out the hole and retapped it.

Not the best, but it will do.  Generous amounts of anti-seize was applied to all hardware touching this manifold this time around.

As the motor sits now.  Nearly ready to fit the tranny.

The garage did get a bit blown out.

Ahh that better.

Until thursday old friend!

Stepan came over and we got to work again.  The goal was to pull the motor, and if we were lucky, pull it apart and see what failed.  We’re getting much better at this.

I didn’t take many pictures during the engine pulling process.  I think we have enough of this on the blog already.  The only notable things were a broken fuel filter mount (that I just pulled and installed 2 weeks ago!) and this seized exhaust manifold to catback stud.

Weak.  Ohh well, we have other manifolds.  The motor is stripped now and ready to be taken apart.

Oil pan off.

I might have overdone it on the hylomar.  You can see it stuck to the oil pickup here.

Front cover off.

Where did my little rubber oil ring go .  All that work.  I think maybe RTV was the only thing helping me .

Back on the bucket!

Flywheel off and a couple gentle taps to help the rear iron off the stack.

The rear rotor is exposed.

Everything looks pretty much as we put it together.  Seals look ok.  This rotor did have lowish compression though.  Hmmm.  Stationary gear bearing looks about like before.

The corners were labeled and all the fiddly bits individually bagged.

Rotor out.  Fiddly bits skittered.  We found and were able to identify almost everything.  The apex seal springs from “3″ fell into the center iron.  One of them was retrieved.  One is still missing.

The underside of the rotor.  Seems to be in order.   Bearings look ok.

Rear housings look ok too.

When that housing was lifted, I found an odd looking situation on one of the water seals.  I’m pretty sure they aren’t supposed to split like this.

Center iron removed to reveal the failed rotor.  First off, notice all the crusty bits around the oil seals in the center there.  Thats not right.  Also notice the discoloration in the center of the sides of the rotors.  The seals are firmly stuck in there with no spring back at all.  That explains our compression issues.

Bearings have some wear.  I didn’t’ see any copper though.  I suspect this rotr is shot anyway.

With the rotor out, we can see some new discoloration on the front iron.  It still seems fairly smooth.  We might be able to reuse it.

The other side of the rotor has the same discoloration and stuck side seals.  More pronounced here.

The housing front he front looks ok too!  That’s a big win.  That’s the hardest to get and most easily damaged part of the motor.

Another shot of the damage on the front iron.

Nothing notable here, but I thought it was interesting.  This is what a spark plug looks like mounted in the housing.

So in the end, it was the reused side seals that did us in.  In the grand scheme of things, this is probably one of the better issues that we could have found with out symptoms.  It’s still going to need another “rebuild”.  I’m going to spend a lot more time measuring things to specs this time around.  I’ll probably try to do a compression test before it goes back in the car too.

An expensive lesson, but were at least we are getting better at this.  It only took us 4 hours to pull and fully strip the motor.  That’s significant improvement.

I’m going to invest in better tools, and an engine stand this time.  I’ll also be doing things more right.  At least this time we have a lot more schedule to work with.

Since our oil issues should be behind us, I got to work on something fun today.  Paint!  Here are some before shots.

Good ol’ rustolium.  Just a foam roller to get it done.

Like magic, the car is all black now.

I’m going to leave the door like that.  It’s a good battle scar.  Gives the car character and is probably good luck.  I gave it a couple hours to dry before laying out the tape for the hood star.

As it sits now.

I cleaned up the wiring a little.  It’s still a mess, but at least its secure.

While doing that, I messed up the fire extinguisher mount a little.  I went to town with rivets….. its stable now.

I also finished off the roll cage padding.  Secure and complete now.

I also discovered a serious brake leak.  This sensor thing was leaking.  I got another good half of a turn on it.  I hope that was it.  I also adjusted out the rod on the brake booster a little longer to make contact with the master cylinder sooner in the pedal travel.  The system still doesn’t feel right though.  More investigation tomorrow.

Here is how the cockpit sits now.

I took it for a little drive.  It’s way better on/off throttle now with lugging after the timing has been adjusted better.  The brakes certainly do work, but the feel still isn’t there.  It’s hard to describe.  It feels like nothing is happening, then its solid.  Maybe there is still some air in there?  Might as well try another bleed.  The idle is pretty touchy while its cold, rock solid once its warmed up though.  The oil pressure seems ok.  It’s not super high , but its not as low as it was before.  I’m going to be all paranoid about it now.

Just a couple things left for tomorrow (including an alignment).  I haven’t even started packing for the track yet.  Here we go!

I started today off with a quick wash. The car is going to get a fresh coat of paint and I wanted to get most of the moss off before it took the new coat. Just a scotch bright pad and some dish soap.

This is when I discovered why the new oil pressure gauge wasn’t working.  I had the sensor wires mixed .  Once they were straightened out, I was hit with the reality that we really do have an oil pressure issue.  It was reading even less pressure than the stock gauge.  I did a little research and made some calls (thanks again marc!).  My symptoms matched a somewhat common newbie engine builder mistake.  This FAQ does a decent job explaining it http://mazdatrix.com/faq/oring.htm.  TL;DR I think I forgot a little rubber o-ring.  I also think I messed up this by-pass oil pressure system and forgot a part.  Unfortunately, this means I need to take the front cover off.  Since I let it warm up, now I had a hot engine to work with .

After a quick lunch and parts run I got started with taking the alternator, CAS, and fan off.

Water pump housing off.

Fan shroud and main pulley out.  Now I can start working on the cover.

It took some work to get it off.  That RTV I’m using is working really well.

So where does that put me?  Lots of nasty well set RTV to clean up.  Ohh yeah, and to do this all without contaminating the oil pan with garbage that could clog the system.  Sure enough, the rubber o-ring is missing.  That is definitely a problem, and it will affect oil pressure.

The second issue I thought I had, was this oil bypass spring system.  I remember only installing the nut and the spring.  There is also supposed to be a cap in there too.

I have no idea what the “cap” looks like though.  The parts catalog didn’t have a good picture.  The FSM didn’t either.  I found a bag from one of the motors that had washers with this stuff.  Maybe that’s the cap?  Another call confirmed that yes, this is what we needed.

I “mummified” the front cover bits to try to protect it while I cleaned up the gasket surfaces.

Now it’s time to tackle the main issue.  It looks like the nylon got crushed a little.  The bigger issue is that none of the rubber o rings that came with the gasket set fit.

I filled down the washer a little, and went to the parts store to find an oil ring that would fit better.  I also put a little RTV on it this time.  Time to get the front cover back on.

Water pump and main pulley back on.

Belts and alternator on.

Oil lines and fan cover on.

Everything done now, just waiting to burp the water.  Even though the package for the RTV said it was ready for service right away, I wanted to give it a couple of hours extra to set.  About this time, the rest of the team showed up.

Nick got to work finishing the window net.

I built a fortress (ducting) to keep the haters (air) out (in).

Nick also got a cover made for the gas cap area.  It’s not strictly necessary but I want as much separation as possible between the fuel and the driver’s cabin.

Ryan found a way to effectively hide our roof thunder.  This is a piece of all thread welded to the cage and attached to the roof with a giant washer.

Rob fixed up a couple holes in the firewall.  Minor safety stuff but safety is key.  I’m glad we had time to do this.

We also rocked some new and improved windshield braces.  Hopefully these will kinder to the glass.

Nick also reinforced the gauge cluster mount.  This thing isn’t going anywhere.  I was worried that we might get some vibration on track.  This is no longer a concern.

Bam look at this race car here.

OHH YEAH forgot to mention, the oil pressure is fixed!  That o-ring did the trick.  Were up to like 45 psi at IDLE.  Heck yeah!  I’m so glad we stayed on this abnormality and tracked it down to the root cause.  I’m sure we would have tanked the motor on the track if this hadn’t been fixed.

Tomorrow there are lots of little adjustments still left.  Were close, real close.