Megasquirt and DASC - Need info....

[haledj]

oops

[haledj]

One of the VR sensors is the cam and the other will be your crank.  I think the crank is the base, and the cam is the 2nd, but it might not matter.  I do not have specific #'s for the trigger wheel but I am sure someone does, or you can count them.  As for spark, just make a conservative map up to 100kpa, then have them drop off as boost. You will want less advance than a turbo car, because of the lack of intercooling.  Look at what the m50/s50 people are doing for advance, and copy it but more conservative at higher MAP.  you can always add in more advance once it runs.

Hope this helps

[nuvolarossa]

OK this is why I still don't have megasquirt lack of info about settings on m42/4 and lack of tuners in my area to solve my doubts
There are a few here with MS, waiting for their answer.
Try to send a PM to http://www.m42club.com/forums/member.php?u=27 . he has MS2 extra on his M42
 
Do you have the m44 engine wirings? You calibrated stock sensors or you bought GM ones?

[JiXer]

Do you have the m44 engine wirings? You calibrated stock sensors or you bought GM ones?

Yes. I have a full m44 wiring harness and will run it all the way through the firewall and make my splices to the Megasquirt harness there.

One of the VR sensors is the cam and the other will be your crank.  I think the crank is the base, and the cam is the 2nd, but it might not matter.

Yeah, I don't think you need to worry about the second one. It should just run off the crank wheel and not need the second one for anything.

I do not have specific #'s for the trigger wheel but I am sure someone does, or you can count them.

Yeah. I'm sure I can figure it out. Just haven't gotten around to it. Figured the info was out there.

 As for spark, just make a conservative map up to 100kpa, then have them drop off as boost. You will want less advance than a turbo car, because of the lack of intercooling.  Look at what the m50/s50 people are doing for advance, and copy it but more conservative at higher MAP.  you can always add in more advance once it runs.

Yeah, again, I figure there is better info out there than that. Hoping others will chime in.

J.

[JiXer]

OK, so here's an update. Got the math wrong on the coil firing, but the concept was the same. As a group, they would fire 14,000 at redline.
Individually, it would be 3,500 as opposed to stock which is 1,750.

However, in talking with Matt at DIY, there are some issues with getting the MS to run sequential ignition. I have never done it before; always ran wasted spark. So, I don't know much about it.

Matt gave me these choices:
1. Use two coil outputs and a wasted spark coil pack - this is a very well proven setup.
2. Modify it for four coil drivers that fire in wasted spark - simple to wire up, but one we haven't tested for ourselves. Most people who have run this setup apparently don't have very much trouble with it, though I have seen occasional reports of setups like this having trouble starting in very cold weather. (Usually these reports come from Scandinavian countries where the winters are pretty brutal.)
3. Modify it for four sequential coil drivers. This would require a cam sync input and consequently would make for significantly more expense, plus the second VR circuit is not easy for us to bench test out.

#2 seemed like the route to go as I have the 4 coil drivers.
#1 isn't an option b/c I don't want to over work the coil drivers at high revs
#3 is preferred, but he makes it sound sketchy

I am new to this one, so if anyone can point me to some info, other posts regarding it, etc. I would be stoked. There isn't as much M42 info out there on MS set ups.

J.

[JiXer]

OK, so here's an update. Got the math wrong on the coil firing, but the concept was the same. As a group, they would fire 14,000 at redline.
Individually, it would be 3,500 as opposed to stock which is 1,750.

However, in talking with Matt at DIY, there are some issues with getting the MS to run sequential ignition. I have never done it before; always ran wasted spark. So, I don't know much about it.

Matt gave me these choices:
1. Use two coil outputs and a wasted spark coil pack - this is a very well proven setup.
2. Modify it for four coil drivers that fire in wasted spark - simple to wire up, but one we haven't tested for ourselves. Most people who have run this setup apparently don't have very much trouble with it, though I have seen occasional reports of setups like this having trouble starting in very cold weather. (Usually these reports come from Scandinavian countries where the winters are pretty brutal.)
3. Modify it for four sequential coil drivers. This would require a cam sync input and consequently would make for significantly more expense, plus the second VR circuit is not easy for us to bench test out.

#2 seemed like the route to go as I have the 4 coil drivers.
#1 isn't an option b/c I don't want to over work the coil drivers at high revs
#3 is preferred, but he makes it sound sketchy

I am new to this one, so if anyone can point me to some info, other posts regarding it, etc. I would be stoked. There isn't as much M42 info out there on MS set ups.

J.

[JiXer]

OK. here's the update on the cam sensors:
M42 = VR
M44 = Hall

The upper timing cover from the M44 and M42 are different and I have to use the M44 cover to match the head.

So, the M44 upper timing cover has the hall sensor mount on the intake cam and utilizes a plate mounted to the cam gear (see image below) to trigger it.

I have removed the M44 cam gears in favor of my nearly new m42 cam gears and I confirmed that the trigger plate will mount to the M42 gear. I do know that I CANNOT mount the M42 VR sensor to the M44 upper timing cover as it sits too far in and the sensor contacts the cam gear. So, changing over to the M44 hall sensor seems to be the only option.

I also know that the intake cam gear on the M44 is slightly different and I don't know if it matters. The one I have isn't in that bad of shape, so I think I might swap them simply to avoid it as a potential problem. There seems to be a slightly different profile to it which might effect how closely the sensor comes to the spinning plate. Not sure if a hall sensor is that sensitive, but I know VR sensors can be.



So this puts me in a place where I can run sequential ignition. Now I just need to read up on how to make it work.

Thoughts anyone?

[tim_s]

hello! sorry for delay onyl just got your pm, not been on here much, lost interest in my car as my new engine is noisy and still using oil from cyl 4, so i need to do some work over christmas. just been driving it an ignoring issues for a while until I have some energy to fix it.

As for MS, I run WS on the original coils, I'd recommend doing this yourself as a starting point, is a straightforward setup that works well. Then you don't need to worry about the cam position sensor at all. I always intended to start WS for simplicity and go sequential ign at some pt, but I started using MS maybe 2 and a half years ago on my M42, and haven't ever felt the need to change from WS, it works great.
As for trigger settings, I can't remember 100% if there are 19 or 20 teeth past the missing teeth at TDC, i'm pretty certain it's 20, though for some reason I have it in my head that I have 114 degrees set in my MS2, suggesting 19! Next time I have my megasquirt fired up I'll check for you, I have MS2 extra though and so work in degrees rather than teeth. What code are you using? What other questions do you have? Feel free to let me know and I'll gladly assist.
Tuning - for safety make sure you enable IAT based retard and use it aggressively when first running the car. Use a map deliberately too retarded when first running the car, use the best fuel you can too. Also start off running your map too rich rather than too lean. Use EGO feedback if not feeling confident. Start off by tuning idle, then revving and holding rpm to get a feel for other rpm values, then start tuning some light load sites at low speed, you'll start to get a picture of what the map will look like by doing this and can make estimations for other sites. Datalog and use megalogviewer to help your understanding, it's a great tool. If you follow the above and make sure you've read the megasquirt docs etc, you should have no reason to worry about running the car on megasquirt. If it's not too late already, set up megasquirt on the standard engine first, then add SC, then retune megasquirt.

Additionally, if your car is still running on Motronic, what I usually do is do some datalogging with MS T'd into the crank sensor, and make sure that on the datalog you have a perfect VR signal under all RPMs and all conditions. A good stable crank signal is critical to getting a great tune.

that was a bit meandering, feel free to hit me with some specifics! Also feel free to send msqs, datalogs etc

[TheNeek]

Interesting thread. I plan on a very similar build. Purchased a small sc and will be taking advantage of an electric clutch to turn on and off the supercharger. I've been reading the mega manual site for the past three mornings (gettng the car ready for paint in the afternoons) some very knowledgable folks around here.  My question is about signal integrity. Is there a spec on maximum harness run from the sensors to the ms unit and back?  Are some of the marine installs using long harnesses like that?

[nickmpower]

bump, you guys ever sort out the tuning with these?