Magic this thread is a grate inspiration for us EFI wannabees, and I'm now geting serious about doing the convertion my self.

I have a couple of questions for you: What is the point of the IAC, and how is it connected? Are you using MAP sensor? I cant find that you mention a MAP.

Thanks.

Most people are going MAP alone without a MAF. For a street car, you much better using MAP and not just straight preformulated fuel maps. Without MAP and O2 your realing reducing the EFI to near MFI levels. Yes, I'm running both and MFI sounds cool but not as flexible or maximized.

Thanks Luke. On a NA engine, the MAP will mostly register vacume, correct? On a turbo charged engine, the intake manifold air pressure will be negative (vacume) before the turbo spools up, and then positive once the turbo provides boost. The VE map will then have entries for both negative and positive pressure. Is this correct?

I'm noob, so you all have to excuse me :-)

Anyone know if the VW VR6 coilpack is suitable for Megasquirt II?

Yes, you must have a MAP sensor. My engine is currently mapped with TPSvsRPM with MAP compensation. This is throttle position vs RPM, the MAPcompensation table removes or adds fuel from the main fuel map based on load. I do have the option to switch to MAPvsRPM but have not tried it yet. At 100kpa there is no compensation but above and below 100kpa it adds or removes fuel. The map compensation ends up being almost linear (20% additional fuel at 120kpa, 50% at 150kpa, 90% at 190kpa, conversly on the vacuum side; at 20kpa the compensation table removes 95% of the fuel).

The IAC is the Idle Air Control, this is optional but then you would need to keep the stock AAV valve, otherwise you may need to put your foot on the throttle to keep the engine running when it is cold. Once the engine is warmed up the IAC is not really needed. Getting the IAC valve to work properly has taken a lot of time and fiddling with various settings.

Stay away from the VW VR6 coil pack, mine only lasted about 8 months before it started giving me trouble. It's also an overpriced coil, has ignitors in its base which may need to be removed and it is difficult to locate the plug that fits it.

Check out M&W coils or if you want a pack then Alan at DTA sells a nice Bosch unit. I have also heard of people using a chrysler coil pack. I am currentlly running some Honda/Acura coils (one per plug)

Thanks Magic.

If I don't remember wrong, Tbitz dropped the TPS, and used only the MAP for his SC-EFI conversion. How would that work on a 930 do you think?

Its actually supposed to be better on a turbo to use MAP since it varies a lot and is a better measure of engine load. The only reason I have not done it is because I started with TPS and have had good success. Switching over now would take a lot of time to log all the conditions and make new main fuel and ignition maps.

When I recently did a google on the vw coil, the first 50,000 hits were about that coil, the recall and all the trouble it caused:(

For the price though, $130-150 new, especially if it has ignitors, it's pretty reasonable it would seem. I'd hope that the problems been fixed by now. A bosch 3 channel ignitor itself is about that price.

M & W double ended(two post) coils are $100 ea, so $300 or $600 depending on how many plugs you need to fire.

David, are you running that vw coil in waste fire mode, off 3 channels? And if so, have you had any issues with fouled plugs? Or does that coil run direct and have 6 triggers?

I am no longer running the VW coil. It was triggered from 3 channels and run in waste spark. One of the reasons I got rid of it is that it produced a miserably weak spark and I was getting a lot of misses. Theoretically a waste spark system should keep the plugs cleaner, but I think clean plugs is more a function of the correct mixture.

Interesting David, I've been seriously considering the Link system and in my talks with Neal at Performance Developments(rebuilding helidoc's 962 motor) he really recommends cdi, and the troubles you and a few others have reported seem to back that up.

I found that AEM has an interesting 4 channel cdi box with dual dump caps for $300 that can be retrofitted between coils and ignitors, just need to do some more research to check its reliability.

Keeping this thread alive,, Great stuff, updates?? anyone?