The next incarnation of MegaSquirt, ULTRAMEGASQUIRT is going to have onboard DIS and a driver for the Bosch LS4u wideband 02 sensor. The whole package on 1 board. I can hardly wait. Imagine no more worrying about a dirty dizzy, springs, putting oil on the felt, vacuum advance. Time it once and forget about it (course that one time is gonna be b***h). Run better gas and a hotter chip for the track with a little more advance.
The whole system will use real automotive connectors, no more DB 37 pin connectors. Sounds like the little kid on the block is growing up.
Anyone have a crank trigger on their 4? The only spot I can see for one is replacing the spacing washer behind the fan with a machined trigger wheel. It appears that you could mount the sensor off the studs that attach the oil cooler
This is gonna be one long winter. I got a s**tload of things to do.
Dave
FINALLY.
Thanks for the update Dave.
This is GREAT news.
B
Dave,
Ever think of using the flywheel to trigger the sensor(s)?
Any compentent machine shop can index it for you.
Some Motronic systems (like on the 3.6 911 motors) use the flywheel.
All 944's and all 3.2 engines... all Boxster engines/996 engines..
Yeah.. I would say a "few" use the flywheel.
B
A few gotcha's to watch for if you are going to try using the flywheel:
1) Where are you going to mount the sensor?
2) Will your magnet/sensor combo provide the ECU with a sufficient signal width?
What I mean is, that the farther you move the magnet/sensor from the centerline of the crank the less time the magnet will activate the sensor with each pass. My ECU requires each sensor event to be maintained for about 4 degrees of crank rotation. Using the hall sensor and magnets I have on hand (same as unit sold by SDS) this means the sensor can't be more than about 4 inches from the centerline of the crank (ie. an 8" wheel/ring) or the trigger event width falls below 4 degrees of crank rotation and at higher RPM the ECU will start dropping sensor events. You could get around this by using larger magents that held the signal longer on each pass, or by using another type of sensor. What do the late P-cars use? Is it adaptable?
-Ben M.
So.. the resolution is "crappy" on these Elcheapo systems ??
B
I gotcha.
Porsche counts teeth.
B
Hey Ben,
I agree with you on the diameter/timing resolution relationship, however, the Motronic uses more teeth (130 and 60 depending on system) than the old school systems like my early Haltech or even your Autronic.
http://frwilk.com/944dme/math.htm
The Ford EDIS uses a 36/1 count wheel with a diameter of ~4".
Some of the newer Nissans have small encoder wheels with a line count of 360 so that the system will count each degree of rotation (360°'s) !!!!
Dont most new systems have two methods ?? Like counting a cam wheel and flywheel too double check everything ??
B
Actually my plan right now is to use an adaptation of the Ford EDIS with a 36-1 tooth wheel and the Ford VR sensor. Easy and cheap. However the plans for the unit are that it could use a Hall sensor or other tooth wheels so I'm not going to lock into anything specific.
As I get more information I'll try and settle on one way or another. Right now I'm happy to learn that my idea of using the space behind the fan could work. Only problem I see is that it would be a B***h to tinker with.
dave
Yes. And the sensors do fail from time to time.
B
Stardard Trigger: Synchronising pulse for each ignition event (4 cylinder will have 4 pulses)
Multi-Tooth: Counts the teeth and is triggered by the missing teeth or by a "home" trigger
The Subaru is the only one that I know of that measures crank angle and Cam angle, but I wouldn't be surprised if more manufactures used this method.
Ben'
That's interesting info. i'm still looking to learn a lot. I really hadn't thought of the problems with timing during cranking but all that makes a lot sense. Where are you by the way? Eastern Washington State is a very large area.
Dave
SDS says that they have only had one reported failure of the crank trigger that was fault of the sensor and they haven’t used that type (brand) since the mid ‘90’s. They have had many a trigger wrecked by improper installation.
I think the SDS trigger would be next to imposable to mount on the flywheel. The sensors are mounted in a 1 ½ X 2 inch aluminum plate. It runs off of three magnets, two triggers and one sync magnet.
The big one is you have to time it with a strobe to get the base line in the computer. I think that I will start and time the engine on the floor then do the install. I just think that it will be easier.
I’m hoping that I can go at the install this weekend. As long as all goes well this week at the ol’ grind.
For what its worth, the original design Bruce and Al developed to supply ignition for the Megasquirt crowd involved using a daugter card with the processor on it to provide the programmable map portion of the ignition. This then provided the signal to the Ford EDIS module which provided the power to the coils. Basically a hacked EDIS and messy. Still I went to the wreaking yard and got the EDIS of an old Escort. I now have a trigger wheel and sensor. Interestingly the wheel has an outer ring with the teeth that was pressed onto the serpentine pulley so, it will be really easy to adapt to a machined spacer behind the fan.
Currently there are a couple of options for ignition. One is MegaSpark which is essentially a recoded Megasquirt that drives CDI like MSD. It uses Hall effect and can triggered from a locked down dizzy. It provides a mappable ignition. It's attractive because it is very simple but I'm concerned about accurate triggering and you still have to run the spark back through the rotor and cap.
The new version of the ignition will provide all the EDIS electronics and code so it will not be as messy. The EDIS system is attactive because of capacitive discharge. It is wasted spark, however, I suspect by using the coil pack off of a V8 and tweaking the software you could end up with a coil per plug. Anyway it should be interesting and I'm sure I'm going to learn a lot.
Target date is this fall but everthing these guys have done has taken longer than they expected.
Dave
Speaking of coil on plug... Motec does it.. can this MS be made to fire them ??
B
Brad I don't know the answer to that. There has been some talk about it. We'll have to wait and see the final configuration when they release it. I wouldn't be suprised. All I know is that I'm going to go find an EDIS off an 8 at a pick and pull just in case.
Dave
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