Monday, July 16, 2012

Initial Tuning Experiences - Part 1

Its been a long time with no updates.  Unfortunately, my project was put on hold shortly after it began because I moved into a new house.  After a few months, I've finally got back on track with this project and have a ton of updates to share.  The first half of these updates will cover my experiences getting the MS2 running and drive-able on my MSM.  The second half will cover fine tuning and little things I'm still playing with.

VE Analyze Live! or VEAL is an optional feature included in the registered version of TunerStudio.  In case you are wondering if its really worth the $50, it is... just go buy it.  This tool has saved me so much time.  Traditionally, you'd be doing some driving/logging.  Reveiwing the logs, making your best guesses as to what to change and by how much and then doing all of the driving/logging over again to see just how good of a guesser you really are.  VEAL takes all of that and turns it into an automatic process.  All you do is tell it what you'd like to tune, how you'd like to tune it, and then drive around and let the magic happen.  Its an amazing program that saves you a ton of time, but there are some specific things to be aware of while using it.  I'll try to outline what I've found that has worked for me.

1.  If you have a MSM, you may need to unplug the VTCS solenoid near the back of the intake manifold.  When I started my MSM on the MS2, I didn't notice anything strange, but after driving it a few miles I could tell something was wrong.  It felt choked and sounded like a WRX.  At the time, I attributed this to me not tuning the fuel map.  I figured once I got it dialed it better it would be fine.  It wasn't until I was finally at the point where I started tuning above 5500 RPM that I really knew something was wrong.  My car would run 11.5 AFRs up to 5500 and be pretty much dead slow/disappointing.  After 5500 all hell broke loose and the car went insanely lean.  I contacted the person I sourced my MS2 form to find out what I was doing wrong, still convinced that there must be something I wasn't tuning right.  He asked if I would try unplugging my VTCS solenoid.  After I did that, the car was completely different and ran the way it should.  I had to start from scratch with my fuel table however, as everything I had done was way way too lean now that the VTCS butterflies weren't choking all of the airflow.  If you run into the same behavior, unplug your VTCS solenoid.  In fact, I can't think of a good reason to have it plugged in honestly, just unplug it now and start tuning from there.

2.  You must have a good AFR Target table before attempting to use VEAL.  VEAL only knows what you want in a specific area of the map if you tell it.  If you've got a horrible AFR table, VEAL will give you a correspondingly horrible fuel map.  Fortunately, my basemap came with a reasonable AFR target table that I used straight away.  After I got more savvy, I did end up modifying it a bit, but its definitely good enough/safe enough to use as is.  Eventually I'll post up my entire MSQ and split out all of these tables in the blog, but for now, if you are just starting out, the basemap table you have is likely fine.

3.  You don't want VEAL to touch anything below 30kpa or 1500 RPM.  VEAL can do strange things to your fuel table when entering over-run fuel cut, or in very high vac.  The software gives you an easy way to filter what specific conditions you want to be met for autotune to be active.  I set a filter that says Min Fuel load must be 30 and min RPM must be 1500.  This way it won't touch your idle or very bottom of your fuel table.  You'll want to change those manually later.  As a side note, you do not need to turn of accel enrichment or over-run fuel cut to use VEAL.  I always did turn EGO off, but I'm not sure that was required either.

4.  Don't do anything by hand until you know what you are doing.  As long as you have a reasonable AFR target table, VEAL will do a pretty damn good job of getting your tune very close to optimal.  I know it may be tempting to be an idiot-know-it-all (like me) and shortcut the process by just saying "Hell, if the basemap is 20% rich between 2000 and 4000, I'll just select everything above that and cut 20% out of there also, that should save me some time."  It won't save you time.  You'll end up creating horrible handmade tables that you'll end up scrapping and letting VEAL do its thing anyway.  Once you DO really get a feel for how much VEAL is changing cells and where you'll appreciate how incredibly small changes have a very measurable effect.  Just take it slow, assume that you really don't know better than VEAL (until much later when you eventually do).

5.  Do lots of driving.  Don't just do full throttle pulls.  Cruising will autotune pretty quick because you spend so much time doing that, but also pay close attention to areas of the map that you may not visit as often.  For me, this was the 4-5 psi high rpm portions of the map.  I know, typically if you are at 6500-7000 rpm you are probably also at 10-11 PSI.  Several full throttle pulls (eventually, remember to work up to this slowly) will get that higher boost high RPM area sorted out pretty quickly.  What I found was that my map was pretty crappy everywhere that wasn't cruise or full boost.  So spend some time tooling around with VEAL on at various RPMs at every boost/vac level you can hit.  I found it best to set VEAL's cell change resistance  to Easy when just starting out and then eventually to Normal once you start getting close.

After you've done all this, you should have a pretty drive-able car that is in most ways better than it came from the factory.  The next blog post will outline a few little things that I had to change on my tune to get from pretty darn good to completely great.


Saturday, March 31, 2012

First Start

Today was a really exciting day.  I was able to spend some time in the garage getting my Megasquirt (MS2) connected to the MSM.  My goal for today was to just get all of the pieces connected and to start the car and get it to idle.  I didn't spend any time actually mounting things, so the MS2 unit is currently just sitting on my drivers side floor mat.


I currently have my MAF relocated to the throttle body side of my intake plumbing.  I'm not going to be using that with Megasquirt, so that will need to be removed and my length of aluminum pipe with the GM IAT bung will be taking its place.  The GM IAT sensor uses a different plug than the stock MSM IAT sensor.  I purchased the GM IAT with a plug and pigtail so that I could wire the new plug in tandem with the existing IAT plug.  I just stripped a bit of each stock IAT wire and soldered the new plug onto the existing wiring.  Now both plugs are split off of the stock IAT wiring and I can swap back and forth if needed.


Again, since I didn't have as much time to devote to this today as I would have liked, to save time I just screwed the new IAT into the IAT bung pipe and left the pipe hang out in the open air.  I figured since I wasn't going to be actually driving the car today, ambient air temps would be close enough to idle off of.  I'll need to remove the stock MAF and the IAT bung pipe I purchased from BEGI will be installed there instead.  I went ahead and unplugged the MAF and the other air temp sensor usually located in the factory airbox.


After plugging the newly wired IAT plug in, I ran the required vacuum line to the MS2.  The MSM has lots of those little green and white check valves on almost every vacuum line.  Make sure to avoid those, or at least T off a source before it gets to a check valve.  


I then pulled the 3 plugs from the factory ECU and plugged them into the MS2 harness.  There are several additional wires that can be connected to the MS2 unit to allow you to switch between ignition tables, boost tables, activate launch control, etc.  The only one I was interested in today was the 0-5v wideband input.  I ran the output wire from my PLX wideband to the correct input on the MS2.


At this point, the instructions say to turn the key on and make sure you hear the fuel pump priming.  So I crossed my fingers and turned the key on.  It sounded normal, primed for about 2 seconds.  Good, at least I know something is working :)


Next I needed to setup my project in Tunerstudio and connect my laptop to the MS2.  More info on exactly how to do this is available here:  http://www.miataturbo.net/showthread.php?t=40159  If you purchase from Reverant, he also includes detailed instructions on how to setup the project in TunerStudio, and the ini file you'll need for the ECU.   I've got an el-cheapo USB to serial converter that always seemed to work fine for connecting to routers and switches, so I didn't buy a new one and just prayed this would work for me.  I finished setting up the project, connected the cable and turned the key on again.  Tunerstudio said it was connected, YAY!


Next I need to calibrate the TPS sensor.  Reverent calibrates almost everything in the basemap.  My TPS signal was reading .2 instead of 0 with the throttle closed.  I opened the appropriate menu, clicked "get current" on the closed throttle box, floored it, clicked "get current" on the open throttle box.  Now its correct, time to move on.


Usually at this point in my projects something goes wrong.  I usually need to make 4 trips to the auto parts store and bleed all over something before its made right. Things had been going too well, so I was expecting something horrible any time now.  What can I say, I'm not much of an optimist.  


After stalling as long as I could, and rechecking everything 4 more times, I went ahead and pushed the clutch in and attempted to start the car for the first time.  It cranked only slightly longer than normal, and immediately fired up.  o_0


It was fairly rich, but I attributed that to the warm up enrichment.  It came right up to around 1900 RPM and as it warmed up, eventually settled to around 900 RPM.  It was running very rich however, 11.5 on my wideband gauge.  So I opened the Fuel table, highlighted the 4 cells around where it was idling and clicked the decrease value button once.  Now I'm up to 11.7.  Ok, good... the car is listening to me.  Clicked it 5 more times.  Car sits at 14.5 and idles great.  Click Burn to save the changes, sit in awe of how little time it took me to get this far.


I reved the engine just to see how it would respond.  Everything seemed really normal.  Its a bit rich everywhere, but I expect that.  After all, I've only tuned 4 cells of the fuel map at this point ;)


My wife comes out into the garage, and looks at my laptop displaying all kinds of data about the car.  She says, "that's really cool, now take me out and lets eat some mexican food".  Ok, time is up for today.  So I shut down.


Total time spent in garage, 45 min.  The car starts and idles like stock.  It responds to the changes I make to the fuel table and is ready to be tuned.  I couldn't be more pleased with the progress I made.  I'm very excited to clean up the install and to get out on the road and start tuning.

Tuesday, March 27, 2012

What do I need, how do I get it?

So you've decided to go Megasquirt.  Like my shop teacher always said "you need things to do stuff".  Profound words....


Here are the main components you'll need along with some suggestions on where to find them:


Megasquirt unit - There are a few different ways to go about this.  You can just go directly to http://www.diyautotune.com/ and order up the kit and pieces required to build this unit yourself.  This will save you a few hundred dollars and if you are successful, officially make you far more skilled with a soldering iron than I am.  This approach is beyond the scope of the blog.


I purchased my unit pre-assembled from an individual on http://www.miataturbo.net/.  His user ID is Reverant.  Send him a private message and let him know what you are looking for.  You may also want to wait for a group buy on these, as it will save you a few dollars.  www.miataturbo.net is an amazing resource, but you have to be able to accept the small number of trolls that will try to drag you into arguments.  You need to have message board common sense skills, including how to ignore trolls to get answers there.  


If you order from Reverent, the unit itself will most likely take 3-4 months from the time you order it until it is in your hands.  Plan accordingly.  You'll have plenty of time to read up on megasquirt.  He will ship the unit with a base map for your car.  This will be setup as a rough starting point based on the information you provide to him during the build process.  He tunes a good number of Miatas and most likely, he'll have one that's close enough to your car to at least get you started.  


Wideband - You must have a wideband AFR gauge that is capable of outputting a 0-5v signal to an external source. Almost all of them have this.  I'd say pick your favorite brand.  The innovate mtx-l is very popular.  I went with the PLX AFR2 because I liked the DM-6 touch screen multi-gauge it came with.  I've read too many LC-1 horror stories, don't buy that one.


IAT sensor and bung - If you have a MSM, then you have a factory IAT sensor.  In theory you could use this with megasquirt.  You don't really want to however.  The GM open element IAT offers far better response, is very well supported by megasquirt, and is fairly cheap.  Go to http://www.diyautotune.com/  and order a GM Open Element IAT sensor with pigtail for ~$22.  You can order the steel or aluminum bung you'll need from them at the same time.  If you don't have a welder, and don't feel like finding a local guy who will enjoy laughing at you when you respond to the inevitable "what car is this goin' in" question, you can pay BEGI $25 for a short pipe that has the correct bung welded in: http://www.bellengineering.net/product_info.php?cPath=6_41_297&products_id=674


A laptop - If you have an old one with a serial port, that's great.  If not, http://www.diyautotune.com/ has the USB adapter and tuning cable available.  If you are buying the serial cable at an electronics store, you'll want a DB9 Male to Female straight through cable.  They are most commonly labeled as "serial extension cable".


TunerStudio MS & Megalog Viewer - Both are available for free from http://tunerstudio.com/index.php/tuner-studio  You'll want to pay the $50 for the full version of tunerstudio so you can get the VE Analyze live feature (autotune).  Lots more about VE Analyze live to read about here: http://www.miataturbo.net/showthread.php?t=42925


Misc stuff - 


  • 5/32 (4mm) vacuum line and a vacuum T - Needs to reach from engine bay to MS unit.
  • Digital Multi-Meter - Needed for troubleshooting.



Friday, March 23, 2012

How did we get here!!?

The Miata is a fantastic car.  Its relatively light weight, has a near perfect 50/50 weight distribution, is rear wheel drive, is nearly bulletproof, is cheap to fix, has huge aftermarket support, and is probably one of the best cars to learn to drive on a track or auto-x course.


My first Miata was a white 99 base model.  I loved that car, but starting a family meant that the 2 seat Miata wasn't going to work for much longer.  Many years later, I was able to afford another Miata, and I purchased my 2004 Mazaspeed Miata from a private seller with only 14,900 miles on the clock.  I liked the updated interior, and the improved chassis feel.  I also liked the factory turbo, and the improved suspension.


After modifying the MSM by replacing the intake/downpipe/exhaust.  I started to really dislike my MSM.  It felt like it was strangled from 3-5.5k rpms.  It wasn't fun to drive at all.  At the time, the Hydra EMS from FM was the only option I knew about that would correct the horrible factory ECU tuning this car was cursed with.  I didn't really want to spend the $2,000 that would be required to fix it.   I ended up seriously considering selling the car.


Just before I listed the car for sale, I went out to the garage to try one last desperate measure.  Faulty TPS signal interpretation has received the majority of the blame for the MSMs trainwreck of a ECU.  The generally accepted method to fix this is to either install a series of resistors that modify the TPS signal, or just unplug it.  I didn't feel like driving to radio shack, so I unplugged the TPS sensor for the first time and went for a drive.


Long story short, I fell in love with my car again.  I realized that I didn't hate my MSM, I just hated the ECU.  This cheap workaround wasn't going to be a long term fix for me however.  The car idled strange, and the overrun fuel cut was completely missing now that the ECU had no idea when you took your foot off the gas.  I could have probably lived with the strange idle, but not having the overrun fuel cut working meant the car got worse gas mileage.   It was also tricky to drive quickly, since many other cars have trained me to become accustomed to the now missing engine braking effect while entering corners.  So I set out to find a way to fix this without spending $2000.  I researched the following options and formed the following opinions:


Hydra: Expensive ($2,000), would probably do everything I will ever need, but I just don't want to spend $2,000 to fix my problem.  Still has issues controlling the voltage on the alternator.  I wasn't willing to pay $2k and have to deal with voltage issues.


Adaptronic & Xede: Cheaper (~$1,450), but quite a lot of money to spend on a piggy back.  Xede can't raise the revlimitter.  The fact that the factory ECU is still in the mix scares me.  From what I know of it, Its pure evil and I'd like to exorcise it completely.


BEGI Reflash:  Not cheap ($895 with changes for larger injectors).  Would require me to send the chip back and forth for re-tuning after any changes.  This was never really an option for me, I don't think spending almost $900 on a tuning solution you have no control over is a good idea.  Also, evil ECU is still evil.  Reports of other people experiencing "the bog" even after a reflash didn't make me feel good about it.


AEM FIC:  Cheap (~$300), can control larger injectors.  Almost cheap enough to make me live with the evil factory ECU.  It can't raise my revlimitter however, and by the time I was ready to pick an option, I was getting sick of the factory crippled redline of 6,500.


Megasquirt:  Cheap for a full standalone (~$800 all in).  Can do everything the Hydra can do.  Will require more tinkering than a Hydra, but it is a LOT cheaper.  This is the direction I decided to go.  In my next post, I'll outline how I ordered it, how long it took to be built, and what it looked like when it arrived.