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Re: 3 liter, 24 valve engine project

Posted: Wed Feb 02, 2011 10:04 am
by Luis
You can have full sequential ignition whith MS2 and you can drive directly Bosh coils whitout resistors in line like the schematics for the VB921.

Outputs:

Image

Re: 3 liter, 24 valve engine project

Posted: Wed Feb 02, 2011 10:25 pm
by Michael
Zamani wrote:About MS2, are using the wideband with closeloop? I wonder how good does it compare with Autronic's autotune.
Yes - the process is quite simple. I have a Zeitronix Wideband O2 sensor (which MS Extra supports natively). One edits the AFR target table simply stating the desired mixture for each cell. The Megasquirt determines if you were lean or rich using the current setting in the Fuel VE table and adjusts in steps accordingly. Its quite amazing to feel the car get smoother as you drive:
TunerStudio_AFR.JPG
TunerStudio_AFR.JPG (59.56 KiB) Viewed 9694 times
I think tuning the fuel tables is a non-issue now. I'm still thinking about the spark table since setting this table involves lots of trial and error:

Re: 3 liter, 24 valve engine project

Posted: Wed Feb 02, 2011 10:27 pm
by Michael
Luis wrote:You can have full sequential ignition whith MS2 and you can drive directly Bosh coils whitout resistors in line like the schematics for the VB921.
Hi Luis - you would still need a cam position sensor though?
I think the 164LS engine has accomodation for thsi though.

Re: 3 liter, 24 valve engine project

Posted: Fri Mar 25, 2011 1:39 am
by grant
Tuner studio is nice, I tuned someone's car on it a couple of weeks back.

What I didn't like was how finicky MS was about grounds. Did not give me a very robust feeling.....
Software was great.....hardware was a bit shaky.

Most N/A engines like the spark advance to come on hard up to about 5000, then keep it there till redline. Also, you have to be careful with advance at peak torque where VE is greatest.

Re: 3 liter, 24 valve engine project

Posted: Mon Apr 18, 2011 10:43 pm
by Michael
April 2011 Update.
My GTV6 is running pretty well on Megasquirt-II (PCB V3.57) MS2/Extra except that at light throttle (just barely open) I have a misfire which I have not been able to solve yet. Other than this, runs really well and feels powerful... To cure the misfire, I have gone so far as to install 6 stock 164LS COP coils. To use this, I had the Megasquirt modified to fire 6 ignition coils in wasted spark mode using 6 BIP373 ignition drivers. Unfortunately, this seems to have had the effect of causing the Megasquirt ECU to reset which usually occurs because the ECU is unable to correctly monitor the 60-2 wheel to determine crank position. I suspect that having 6 high current drivers mounted in the ECU is causing electrical noise which in turn is affecting the very low voltage signal generated by my VR (crank position) sensor.
So, I think I need to have an external igniter box (to remove the electrical noise) & fortunately Toyota used just such a device in the mid 90's:
http://www.msextra.com/forums/viewtopic ... 71&t=38902
In the Megasquirt community, these are often used by BMW folks because the BMW COP's seem to lack built-in igniters, just like the Bosch COPss used by Alfa on the 164LS engine. There are a bunch of these units for sale - finding one with both connector plugs attached is proving challenging though...
Another great thing about this is that my ignition setup will be ready for sequential COP - all I'd need would be a cam sensor which the engine already accomodates. But thats a project for next year...

Re: 3 liter, 24 valve engine project

Posted: Mon Apr 18, 2011 11:40 pm
by MD
Michael,

Are you using a shielded cable along the full path of the crank angle sensor to the ECU and is this shield grounded at one end? If not, this will contribute to your spurious electrical noise.

Re: 3 liter, 24 valve engine project

Posted: Tue Apr 19, 2011 10:28 pm
by Michael
Yes of course - that and a handful of other remedies recommended by the Megasquirt community. The reset issue only showed up when I added the 3 extra coil drivers (nothing else changed) so there is strong correlation between the new components and the sync loss.

Re: 3 liter, 24 valve engine project

Posted: Wed Jun 22, 2011 8:32 am
by Michael
The misfire/ECU Reset/ sync loss events have been resolved. I believe that the high current coil drivers mounted in the ECU case were causing interference with the tach signal. So I removed the coil drivers from the ECU case and used the standard low current ignition trigger circuits to drive a Toyota Supra sequential igniter - mounted in the engine compartment well away from the ECU. It drives stock 164LS coil packs - so no more spark plug wires for me :-)
Description is here:
http://www.msextra.com/forums/viewtopic ... 01&t=39731

To summarize my current configuration:
Standard Megasquirt-II PCB 3.57
MS2/Extra 3.1.0
Stock 164LS coils being run in wasted spark mode via a Toyota 1JZ/2JZ 6-channel igniter (Toyota part number 89621-22030)

Next step is to change around my intake system to what Jim did here:
viewtopic.php?f=5&t=4044

Also, today is the first track day in years - a good opportunity to try out the car some more & do some tuning.

Re: 3 liter, 24 valve engine project

Posted: Thu Jun 23, 2011 9:21 am
by Melvivio
Sounds good!

Be sure to make lots of pictures! Or even better a movie!

Good work! I hope for you the car will run like a beast!

Re: 3 liter, 24 valve engine project

Posted: Thu Jun 23, 2011 4:26 pm
by Michael
The car ran pretty well:
http://youtu.be/zCq-cSw88ZU
http://youtu.be/-qvt2kaazj8
You can see the wide band air fuel ratio gauge on the bottom left - looks like Megasquirt was hitting the AFR targets :-)
Sounds nice too :wink:
I plan on taking it back to the dyno so I can get a new baseline with the Megasquirt tuned.

Re: 3 liter, 24 valve engine project

Posted: Sat Jun 25, 2011 1:58 pm
by Melvivio
Looks; Great
Sound; Great
Enviroment; Great

This all on camera, priceless :)

The little battle with the Corvette was fun. But a poor driver :) Great fun! You'll enjoy this summer I'm Sure!

Re: 3 liter, 24 valve engine project

Posted: Mon Jun 27, 2011 11:30 am
by kevin
Michael, that exhaust note is superb . I would even argue it sounds as good as the the legendary 2.5 whine and swirl except with more punch behind it :wall:

Re: 3 liter, 24 valve engine project

Posted: Mon Jun 27, 2011 10:18 pm
by Michael
Thanks Melvivio & Kevin:

Looking at the logs later, I was only hitting 6200 - 6400 or so. Next time I'll be shifting closer to 7000 (need a shift light since the rev counter is not too accurate). The engine pulls much better up high. I might even have been able to run down the Vette on the straight as well as in the corners... :)

Re: 3 liter, 24 valve engine project

Posted: Tue Jun 28, 2011 6:25 am
by Mats
Very nice video, seems like you have the car sorted well. :)

Re: 3 liter, 24 valve engine project

Posted: Tue Jun 28, 2011 2:26 pm
by MD
Congrats Mike. Good to see stuff going right for you.

...I need that sort of encouragement at the moment and with Kevins' brakes, I think he does too.