FAST, MS, or BS3?
10-24-2005, 05:16 PM
#61
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Brains,
If you can get one of the MS so it can run a gen3 v8 with a harness I would like to try it. How much do you expect it to cost with the harness and controller? Will it have individual cylinder spark control?
Kurt
If you can get one of the MS so it can run a gen3 v8 with a harness I would like to try it. How much do you expect it to cost with the harness and controller? Will it have individual cylinder spark control?
Kurt
Originally Posted by Brains
Yes, work has started and is coming along nicely 
I've got it prototyped and sitting on my desk at home, hooked up to the computer. I've got a little more code to write, and then some testing on the bench, then testing in the car. Its a simple unit though, I don't expect much problem with it working. All it has to do is read the LS1 crank and cam sensors, then accept a trigger input from the MS for timing. Dwell time is handled by my box, figured it was easier that way 
It reads the car's battery voltage to adjust dwell for a strong or weak coil voltage as well. I am ignoring the dwell commanded by the Megasquirt, because with a single spark output you would run out of dwell time at high RPM's -- the pulse widths need to overlap. In other words, you need to start charging the next coil in sequence BEFORE the current coil has even fired. That's the flaw with many EDIS systems, distributor ignitions, etc. -- you simply run out of time to charge the coil betweek firing events. Coil per cylinder solves that issue, since you can charge as many coils at once as necessary.
I wrote the code so it can easily be dropped into MS once the larger pin-count microcontroller is implemented, and then we won't need this module at all. If I get fancy, I might at some point in the future code it to read the rising edge of the crankshaft reluctor so it knows exactly where the engine is in the firing order in only 90 degrees of crankshaft rotation. All that really does is make the engine light off faster, and as-is it works like every other aftermarket EFI with sequential ignition -- it waits for a cam sensor transition to set the current step in the firing order (which takes up to one full crankshaft rotation).
I've got it prototyped and sitting on my desk at home, hooked up to the computer. I've got a little more code to write, and then some testing on the bench, then testing in the car. Its a simple unit though, I don't expect much problem with it working. All it has to do is read the LS1 crank and cam sensors, then accept a trigger input from the MS for timing. Dwell time is handled by my box, figured it was easier that way It reads the car's battery voltage to adjust dwell for a strong or weak coil voltage as well. I am ignoring the dwell commanded by the Megasquirt, because with a single spark output you would run out of dwell time at high RPM's -- the pulse widths need to overlap. In other words, you need to start charging the next coil in sequence BEFORE the current coil has even fired. That's the flaw with many EDIS systems, distributor ignitions, etc. -- you simply run out of time to charge the coil betweek firing events. Coil per cylinder solves that issue, since you can charge as many coils at once as necessary. I wrote the code so it can easily be dropped into MS once the larger pin-count microcontroller is implemented, and then we won't need this module at all. If I get fancy, I might at some point in the future code it to read the rising edge of the crankshaft reluctor so it knows exactly where the engine is in the firing order in only 90 degrees of crankshaft rotation. All that really does is make the engine light off faster, and as-is it works like every other aftermarket EFI with sequential ignition -- it waits for a cam sensor transition to set the current step in the firing order (which takes up to one full crankshaft rotation).
10-24-2005, 09:58 PM
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Kurt, price depends on whether you want to sweat over a soldering iron or not The MS unit itself can be had as cheap as 130 bucks in kit form. You'd need a harness, WBO2 sensor, etc. to make it a complete system for "typical" use.
If you build it from a kit, I'm guessing the cost would probably be around 450 bucks or so with everything you would need - including the wideband O2. Buying it pre-built would add about 150 bucks. I'm just going on "street" prices, and hopefully I can get a vendor I've been working with on board here as a sponsor so we have a direct avenue for sales on them.
Between myself, Scott, and other interested hackers I'm confident we can make this a viable option for more folks. I'd like to make the unit "grow" to be a more complete and packaged solution for the LS1 community, that does what we need it to do -- all while giving back to the original community that developed it. My goal isn't to compete with any other EFI solution, or try to "win people over" but I feel more choice is always a plus.
This will not have individual cylinder control. The MS is still limited to an alternating bank-fire injection scheme, since they only built the unit with two injector driver channels. If you want to run staged injection, its batch fire 8+8. In the future, there's talk about going to a higher pin-count micro which will open up the option to do sequential injection and individual cylinder trim - but who knows how far off that is. Who knows, maybe this little project sparks a group of hackers here to push that along?
69firebird -- there's already plans to run a batch of boards so other folks can make use of it. At least a half dozen people so far have expressed interest.
The MS unit itself can be had as cheap as 130 bucks in kit form. You'd need a harness, WBO2 sensor, etc. to make it a complete system for "typical" use.If you build it from a kit, I'm guessing the cost would probably be around 450 bucks or so with everything you would need - including the wideband O2. Buying it pre-built would add about 150 bucks. I'm just going on "street" prices, and hopefully I can get a vendor I've been working with on board here as a sponsor so we have a direct avenue for sales on them.
Between myself, Scott, and other interested hackers I'm confident we can make this a viable option for more folks. I'd like to make the unit "grow" to be a more complete and packaged solution for the LS1 community, that does what we need it to do -- all while giving back to the original community that developed it. My goal isn't to compete with any other EFI solution, or try to "win people over" but I feel more choice is always a plus.
This will not have individual cylinder control. The MS is still limited to an alternating bank-fire injection scheme, since they only built the unit with two injector driver channels. If you want to run staged injection, its batch fire 8+8. In the future, there's talk about going to a higher pin-count micro which will open up the option to do sequential injection and individual cylinder trim - but who knows how far off that is. Who knows, maybe this little project sparks a group of hackers here to push that along?
69firebird -- there's already plans to run a batch of boards so other folks can make use of it. At least a half dozen people so far have expressed interest.
10-25-2005, 10:19 AM
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Originally Posted by 427
Brains,
If you can get one of the MS so it can run a gen3 v8 with a harness I would like to try it. How much do you expect it to cost with the harness and controller? Will it have individual cylinder spark control?
Kurt
If you can get one of the MS so it can run a gen3 v8 with a harness I would like to try it. How much do you expect it to cost with the harness and controller? Will it have individual cylinder spark control?
Kurt
The plan is to have sequential spark control (not wasted spark).
Kurt have you ever used individual cylinder spark trim? Is there a need for something like that? Won't be able to do cylinder fuel trims until someone comes up with more injector drivers and a way to control them.
but Brains has us up to speed, we're hoping to work from his design and have something going in the next week or so. We'll report progress.
Who here can source GM harness connectors - Kurt, aren't you part of the GM inner circle???
True ploug & play would be sweet. The FAST that Jim won from Drag Week came, apparently, plug & play.-scott
10-25-2005, 11:20 AM
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Idividual spark/fuel control I normally use the most on power adder cars. I have used ind spark on NA engines in a class car in the past.
Most GM connectors can be sourced by anyone. You just need to ID what one you need which can be difficult.
Kurt
Most GM connectors can be sourced by anyone. You just need to ID what one you need which can be difficult.
Kurt
Originally Posted by dieselgeek
The plan is to have sequential spark control (not wasted spark).
Kurt have you ever used individual cylinder spark trim? Is there a need for something like that? Won't be able to do cylinder fuel trims until someone comes up with more injector drivers and a way to control them.
but Brains has us up to speed, we're hoping to work from his design and have something going in the next week or so. We'll report progress.
Who here can source GM harness connectors - Kurt, aren't you part of the GM inner circle??? True ploug & play would be sweet. The FAST that Jim won from Drag Week came, apparently, plug & play.
-scott
Kurt have you ever used individual cylinder spark trim? Is there a need for something like that? Won't be able to do cylinder fuel trims until someone comes up with more injector drivers and a way to control them.
but Brains has us up to speed, we're hoping to work from his design and have something going in the next week or so. We'll report progress.
Who here can source GM harness connectors - Kurt, aren't you part of the GM inner circle???
True ploug & play would be sweet. The FAST that Jim won from Drag Week came, apparently, plug & play.-scott
10-25-2005, 11:49 AM
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Whoops, I missed where you said individual SPARK control. That's only a software change -- but would that by itself be useful? I hadn't planned on coding that into the box, but it definitely could be added. I can understand individual fuel control to help account for manifold variance runner to runner. I'm trying to wrap my mind around an application for individual spark control though. Share with me, oh wise one
10-25-2005, 12:54 PM
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Originally Posted by Brains
Whoops, I missed where you said individual SPARK control. That's only a software change -- but would that by itself be useful? I hadn't planned on coding that into the box, but it definitely could be added. I can understand individual fuel control to help account for manifold variance runner to runner. I'm trying to wrap my mind around an application for individual spark control though. Share with me, oh wise one
I think he meant sequentially-fired spark, AKA 8 separate spark channels (not running the COPs in wasted spark mode).
Which is what I want to do anyways... I have concerns about doubling the average power requirements on stock ignition power supply... even though the 2JZ guys run them at 3x factory duty cycle (wasted spark to 7500+rpm, running them at 19 volts, but with beefed up power supply and massive demands).
I was referring to "timing trim" - I've seen a few guys here use both fuel trims and even ignition timing trim. Brains, doing this your way would make timing trim pretty easy. My software guy was asking if we wanted that...
man I'd like to add on a sequential EFI driver at the same time.
I think there's some potential in a plug & play kit. Seeing the nicely-packaged, plug & play FAST over at Jim's has me newly motivated to put something together.
-scott
10-25-2005, 12:57 PM
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Heck, there's really no reason we can't -- but then it raises the question "why don't we just fix the MS to do it?" or even "why don't we fork the project and make our own unit?
