Its time to start again. We finally managed to rig up a reliable data logger. We have several logs of the car going around an autox track.

link to files...

[directory with zipped log files] It looks like the repairs we did to fix the fueling worked. Now we probably have waay to much fuel.


Let's try to organize the details in subsections, and simple format (not lengthy sentences)





Pictures can be found at MembersPage/GrmRacer/GrmProgress



[More normal shape of Alpha-N VE table]

Thank-you Jorgen!

I suggest connecting the MAP hose before the throttle blades instead of after, it makes the air pressure correction simple. Not only for barometric correction but also for any RAM air effect or any filter restriction. I'll try to find a spot all the vac pickups are on the after throttle position. I might be able to fab something.


[cutout on 1.0.53]

This is a snapshot showing an odd log event where Injectors get zero'd. I thought this was a fuel pump relay problem, but the logs show that the injectors PW goes to zero.

Is this with the very old 1.0.53 ? -- Yes

Maybe tps or kpa threshold reached (if ECU config does not match the config posted on the page) ? Hard to tell, but you'll likely need to upgrade to 1.1.81 anyway. -- I have upgraded and I am very happy. I'll find the old config and post it with it. I would have done it earlier,but I could only get tables&config as the VemsTune would crash trying to talk to it.

1.0.53 Currently running car

This is the configation we had when we left the track at the end of 2009. We just got the car to do a pass at 14.7 with a bad clutch. So the weekend was spent replacing the clutch. Also got the Knock sensor wiring in place. I need to get the correct pinouts. Nitrous wiring now also in place.



Air leak fixed

System is supposed to be full Alpha-N, but at 2500 RPM constant throttle, PW for injector is zeroized. I'll post megatune log in am when I can start the car.

1.1.70 Newest version That ran the car

[1.1.70 vemscfg] for Alpha-N with TPS calibration

Suggested improvements

  • One thing that would be fantastic for upgrading and starting cars would be a setting in the gui that allowed for a start & time mode. Something like the standard warmup/crank mode with a fixed timing. (I did find that the old command Manmda00 for 0d and Manmda28 for 10d and Manmda50 for 20d advance)
  • implemented, try Tools / "ign lock" in VemsTune. Similar to "iac lock"
  • another thing that would be fantastic is a software switch that allows on the very basic controls to be used for very rough tuning. But that is not well enough defined.
  • implemented: req_fuel, ign lock and iac lock are such rough controls. But it's still needed to get the basic settings right (and wiring details are needed to verify those).

[Idle] Blipping the throttle during warmup

[Long idle]

[idle] Closed throttles

[stuck throttle?]

[running config]

[another version]


Had the car running on 1.0.53 -- we had a few issues, so I figured I'd update to the current Release. The website indicates 1.1.81 is the current release.

I don't seem to be triggering on 1.1.81. So I'm downgrading to 1.1.78 (after I check the changes page).

Basic trigger setup is

simple Hall trigger (4 window on distributor total 720d) Could this be the problem.

I have time arranged for a dyno in the next two weeks. So it would be fabulous to have it running on the newer firmware.

Still have a few mechanical bits to do like change the Clutch back to a real clutch. the stock 8v one that is in it now doesn't do its job.


Getting car ready a month in advance this time.

Getting New ITB manifold installed issues before were with major air leaks in the old ones..

I'll have updates this weekend as install happens.

BTW the new software looks fantastic!!!


$2006 Challenge:

Were off and going. Running a 3.3 with Release 1.0.53

our msq file is

[Rushi's] old configs

Question regarding PulseWidthCalculation? for full AlphaN.

The PulseWidth? is calculated by the following equation

PW(ms) = req_fuel(ms) * load/100 * VE/100 * gammae/100

A little matlab snippet to figure out how the VE table entries correlated with time.

My value for the bin was 22-23

function output = VEtable(dummy)
%values taken from my log file
req_fuel = 12.5
rpm = 4621
rps = rpm./60
effrps = rps./2
effperiodms = 1./effrps.*1e3
gamma = .98
pw = 2.8
VEelementraw = pw./ ((req_fuel).*(gamma))
output = VEelementraw.*100

If the VEtable is configured (at WOT) well with what a dyno HP plot would look like, the VE table relates the of TPS% to air flow. For example if 1% throttle is 10% flow the VE table would reflect that.

I'll be posting some matlab code soon that takes RPM,HP, displacement, airtemp, and outputs various VE tables:

with some modifications we can also do the same for AirDensityControl? maps as MAP is supposed to determine % throttle open with some non-linear effects already included.


The config has full AlphaN

$2005 Challenge

Car not going this year. A multituide of last minute problems has conspired to prevent the two planned cars from attending.

Not really bad ignition switch, bad grounding of ignition module

Anyway plans are already underway for next year. And the cars/engines are partially built.

Physical Setups

VEMS needs/checklist




  • *Knock setup for using stock VW sensor for a 2.0L [PL] block

Software/ configuration

Assuming that all my needs are already implemented in firmware setups Please correct if not done..

Current firmware version you want me to run

Turbo VEMS v3.1

Naturally Asprirated car -- VEMS v3.2

For $2004 challenge

So we placed 29th overall in the $2004 challenge

our 1/4mi time was 14.6 after 1/2 hour of tuning on a turbo Yugo MEgasquirt fuel map, a bad coolant sensor, and no nitrous..

oh well.

Yes that PVC works.


Lots of pics and snippets..

GRM = Grassroots motorsports (

Documentation and History

This is to document any changes or addons that are made to MS-AVR (GenBoard or AfreshBoard) during the building of the 1988 scirocco
Starting point BasicInstallation?

The plans
2.0L ABA 16v Turbo

Triggered via the hall sender built into the block

nitrous injection
water injection
ignition control
traction control

Whats happening this year no time for turbo.

2.0L 9A

1.8L 16v head P&P

nitrous direct port injection

water injection via cold start in custom intake manifold

MS-AVR for ignition and fuel

<insert stuff for car setup>


EGT's on the cheap using raw thermocouple and Dupont LTCC tape.

Stuff Im going to document

MembersPage/GrmRacer/GrmWiring This one is hard to read, but pretty complete
MembersPage/GrmRacer/GrmCircuits This one is easier to read and follow, but not complete yet
MembersPage/GrmRacer/Grm?2005RaceQuestions -- Need help here.
InputTrigger/MultitoothTriggerWheel -- Page describing how to implement this
NitrousController -- Page describing adding nitrous to control stuff
TractionControl? -- Used specifically to cut off fuel and air to reduce HP output to stop the tires from spinning
GearSelect? -- Circuit to show what gear you are in for an early A1 VW transmission with the big reverse gear connector and the upshift light
IgnitionVW -- information on adapting the stock VW ignition circuit to the MS-AVR system with minimal changes to the system. It should be a fully mappable ignition, by replacing the Typical Hall sender output from the Hall sender on the distributor to the Ignition controller. Ideas abound for a cheap and easy replacement.
WaterInjectionController? - This page will describe adding water injection to the racecar.. Please dont try this at home you can seriously damage your car.

MembersPage/GrmRacer/GrmInjectorSetup -- what I have to do to get the car running..

Disclaimer: I'm trying all this stuff at once. None, some, or all of it may work to some degree or other. This STUFF is developed for off-road use, and the car only has to last about 5 drag runs and 2 autocrosses. So think about that before you do any of this.

to the stock ignition box from the distributor or

The 2.5 bar MAP sensor that you asked: MPX4250AP (MembersPage/MarcellGal)


Im working on the lpc2119 library for the possible ARM processor use. Take a look at the library and see if I got it right.

a possible source for connectors

[Genboard pics]

Notes for assembly