Assembling a Megasquirt from scratch for 3B

[amd is the best]

Hello all!

This is my first post on here and I wanted to just say that this looks like a very informative and useful site! This isn't exactly the place to introduce myself but I'll keep it short, haha. My names Nick and am from Albany, NY. I have an APR stage 3 B5 S4 and a 91 200 20v.

Anyway, back on topic. I am interested in assembling a MegaSquirt unit for my 200 because I plan to put an Garrett GT3076 (and supporting mods) on it and want to be able to run it properly with standalone EMS. I am not new to MegaSquirt at all and have assembled quite a few of them for previous cars that I have owned. I see lots of people running the VEMS kit's and from what I understand they are pretty much a modified MS unit designed to be plug and play which makes it a lot easier for the end user for a very fair price. I'd want to keep my costs down as much as possible and assemble one myself.

I am looking for someone who would be willing to share with me the actual modifications that need to be made for MS to understand Audi's I5 triggering. If anyone can point me in the right direction that would be awesome!

Thank you all in advance,
Nick

[ShadowofBob]

I tired this using Jean Belinger's trigger board(changes the 2 VR and 1 hall sensor signals to a understandable form for megasquirt) and never had any real success. The best I got was a good idle and revs to 3000 rpm. At that point the signal would start dropping out. I ended up just switching to VEMS due to this and I wanted to other features as well. I got a deal on it and ended up about spend the same amount since MS has no WB02 built in.

If you are going to use megasquirt I would install a 60-2 wheel in some form combined with the hall sensor in the distributor. There's 3 options to get 60-2. The easiest is probably use a modified crank pulley/balancer(034 sells this and a bracket), a 60-2 flywheel(034 sells a custom steel one and supposedly one from a later Audi works too), or a VW Polo rear main trigger ring(requires removal of trans and drilling of the block to pass the sensor wire through.

034 60-2 Damper
http://www.034motorsport.com/product...products_id=50

034 60-2 flywheel
http://www.034motorsport.com/product...roducts_id=678
Not sure it'll work on a 016 trans like that in your 200.

VW Polo solution

http://www.s2forum.com/forum/showthread.php?t=36034

[amd is the best]

I tired this using Jean Belinger's trigger board(changes the 2 VR and 1 hall sensor signals to a understandable form for megasquirt) and never had any real success. The best I got was a good idle and revs to 3000 rpm. At that point the signal would start dropping out. I ended up just switching to VEMS due to this and I wanted to other features as well. I got a deal on it and ended up about spend the same amount since MS has no WB02 built in.

If you are going to use megasquirt I would install a 60-2 wheel in some form combined with the hall sensor in the distributor. There's 3 options to get 60-2. The easiest is probably use a modified crank pulley/balancer(034 sells this and a bracket), a 60-2 flywheel(034 sells a custom steel one and supposedly one from a later Audi works too), or a VW Polo rear main trigger ring(requires removal of trans and drilling of the block to pass the sensor wire through.

034 60-2 Damper
http://www.034motorsport.com/product...products_id=50

034 60-2 flywheel
http://www.034motorsport.com/product...roducts_id=678
Not sure it'll work on a 016 trans like that in your 200.

VW Polo solution
http://www.s2forum.com/forum/showthread.php?t=36034

Thank you for the response!

Between the Megasquirt kit, the 034 pulley and bracket and a wideband controller I am getting closer and closer to the VEMS kit minus the frustration of getting at all to work properly...

I may just end up picking up the VEMS kit instead. I do enjoy building the MegaSquirt units and assembling one off engine harnesses but it may just not be worth it in this situation.

[ShadowofBob]

I came to the same conclusion, ended up selling my built unit to a BMW friend and cutting my losses. VEMS has a lot more features too and is generally more expandable. If I was to do Megasquirt again I would wait for v3 to come out anyways. Addresses some of v2's shortcomings(sequential injection, better map resolution), but still no WBO2 or automotive quality connectors and cost is no yet known.

[a4kquattro]

Thank you for the response!

Between the Megasquirt kit, the 034 pulley and bracket and a wideband controller I am getting closer and closer to the VEMS kit minus the frustration of getting at all to work properly...

I may just end up picking up the VEMS kit instead. I do enjoy building the MegaSquirt units and assembling one off engine harnesses but it may just not be worth it in this situation.

If you still want to "DIY", the VEMS hardware is available in parts as well, about the same price as the megasquirt stuff. LOTS of work to make it equivalent to the plug and play version, but all the pieces are available.

[amd is the best]

I came to the same conclusion, ended up selling my built unit to a BMW friend and cutting my losses. VEMS has a lot more features too and is generally more expandable. If I was to do Megasquirt again I would wait for v3 to come out anyways. Addresses some of v2's shortcomings(sequential injection, better map resolution), but still no WBO2 or automotive quality connectors and cost is no yet known.

VEMS is looking better and better. Correct me if I'm wrong here but is VEMS based off of MS somehow? I see it uses Megatune.

If you still want to "DIY", the VEMS hardware is available in parts as well, about the same price as the megasquirt stuff. LOTS of work to make it equivalent to the plug and play version, but all the pieces are available.

Interesting. Would you be able to point me in the right direction as to where and what specific parts would be needed for my 3B?

Also, just out of curiosity...where would I be able to find a PnP kit?

Thanks again guys!

[ShadowofBob]

VEMS is looking better and better. Correct me if I'm wrong here but its VEMS based off of MS somehow? I see it uses Megatune.

I am not 100% on this, but I believe that VEMS was an offshoot of Megasquirt initially. It went closed design after it was thought that someone was ripping off their design. I think the megatune software is used in part because of its roots, but also because it's open source. VEMS is trying to pull away from it's megasquirt history and is releasing it's own tuning software VEMSTune relatively soon. Last I heard a first release is due this month.

[A80Avant]

depending on firmware use, VEMS can still be used with megatune software and be stable.

trigger wheels website has megasquirt hardware and ECU as well if you want megatune instead

[amd is the best]

depending on firmware use, VEMS can still be used with megatune software and be stable.

trigger wheels website has megasquirt hardware and ECU as well if you want megatune instead

Thanks. What is trigger wheels website url?

[A80Avant]

http://trigger-wheels.com/

[GazzaG60]

will the 3b dizzy and ignition amp from a vw 16v and matching wiring not work? its around 4-5 years since i looked at an msns.

[chezz]

KV distibutor - 5 evenly spaced windows may be suitable for your timing, although it will only be "batch fire" rather than sequential. It may solve your problem.
Look for a possible 5cyl US equivalent that uses CIS (Audi 4000?) and you may have your solution.
Gazza G60 is your man for further info.

[a4kquattro]

Interesting. Would you be able to point me in the right direction as to where and what specific parts would be needed for my 3B?

Also, just out of curiosity...where would I be able to find a PnP kit?

Thanks again guys!

The parts are all listed on the VEMS.hu webshop. I have all of the parts in stock at the same pricing (converted from euro to USD) in the USA if you want to go that route. For instance, this is the bare mainboard:

http://shop.vems.hu/catalog/genboard-p-29.html

you would also need a case:

http://shop.vems.hu/catalog/alubos1600-p-38.html

endplates:

http://shop.vems.hu/catalog/alubos-endplate-p-34.html

http://shop.vems.hu/catalog/alubos-motronic55-frontplate-p-132.html

endplate gasket (2):

http://shop.vems.hu/catalog/alubos-gasket-p-46.html

motronic connector:

http://shop.vems.hu/catalog/vems-motronic55-p-122.html

map sensor (400kpa, 5v, sawtooth connection for rubber hose):

http://shop.vems.hu/catalog/alubos-gasket-p-46.html

injector / WB02 fets (10)

http://shop.vems.hu/catalog/injector-wbo2-heater-driver-p-30.html

ignition FETs (depends on what config you want, for most audi setups you need just 2, but it depends on what kind of coils you want to drive.):

http://shop.vems.hu/catalog/ignition-driver-p-49.html

stepper chip (usually used to drive TTL coils):

http://shop.vems.hu/catalog/idle-stepper-motor-driver-p-61.html

brass nipple, for MAP connection on the endplate:

http://shop.vems.hu/catalog/brass-nipple-p-133.html

thermal pad, for clamping the FETS in an electrically isolated fashion (get the 3 lines version):

http://shop.vems.hu/catalog/ignition-driver-insulator-sheet-p-75.html

clamping plates, to secure the FETs to the case (heat dissapation). you'll need 2 if you are driving TTL coils, 3 if you are driving IGBT coils

http://shop.vems.hu/catalog/clamping-plate-p-62.html

Due to the complexity of building one of these things from scratch, the best I can offer support wise is the documentation in the wiki on how to put it all together. But, if you are comfortable building your own megasquirt board this isn't that much more difficult. The components are smaller since the board uses SMT (surface mount) components, so the soldering skill required is a bit higher. All the super small stuff is already soldered onto the main board however (such as the main CPU, etc).

[amd is the best]

Thank you for the VERY detailed response. I really appreciate it however I'll just end up picking up a PnP kit from you in the near future. Also, I'd like to run the individual coils on my car and you say on your website to specify that this will be installed on a 3B 200. What does the extra harness include? Does the VEMS have built in coil drivers to be used with dumb coils or would I need coils with drivers built in (smart coils)? Also, at that point the disty will stay in the car for it's trigger correct?

Sorry so many questions!

[a4kquattro]

Thank you for the VERY detailed response. I really appreciate it however I'll just end up picking up a PnP kit from you in the near future. Also, I'd like to run the individual coils on my car and you say on your website to specify that this will be installed on a 3B 200. What does the extra harness include?

The extra harness contains a relay and an inline fuse to supply juice to individual coil packs. its an extra $100 on top of the VEMS base price. The harness is pin-compatible with the AAN coil packs, so you can either run a stock AAN coil setup or any of the other compatible "high output" options out there (ls2, etc).

Does the VEMS have built in coil drivers to be used with dumb coils

your choice, although I recommend you stay away from IGBT coil drivers because it can interfere with the ECU grounds on a plug and play box.

or would I need coils with drivers built in (smart coils)? Also, at that point the disty will stay in the car for it's trigger correct?

dizzy stays for the triggering (hall sensor), correct.

Sorry so many questions!

no problem. Hope that helps!