Ecotec LS Coil Driver

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SilentBob
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Re: Ecotec LS Coil Driver

Post by SilentBob »

It's not so much a time issue as it is a current limit. It's just referenced as a dwell period because most people tuning will be changing dwell times. I don't have the exact numbers but for example the coils could take 8ms at 7v before they self discharge and only 5ms at 13.8v. I had some issues with the d585 coils when testing.

In reality it's probably not going to be a problem, but it's easier to not recommend these types of coils to save someone the hassle of finding an issue if it comes up.
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Re: Ecotec LS Coil Driver

Post by OZ38 »

antus wrote:The protection is a thing with most the LS coils. I dont think it'd be a problem, > 5ms dwell is a long time. Handover to PCM is usually 400 rpm, so with a safety margin you could measure what dwell the stock coilpack provides and subtract 5ms and if it travels less than 10 degrees in the time of the early fire it wont knock. So say its 8ms dwell, subtract 5ms as the dwell you'll still get, it'll be 3 ms early, so if its less than 10 degrees at 500 rpm (100rpm safety margin, and as its targeting 10 degrees BTDC) then it should be fine. No I dont have the maths for that, its just an idea :)
Thanks for the reply.
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Re: Ecotec LS Coil Driver

Post by OZ38 »

SilentBob wrote:I had some issues with the d585 coils when testing.

In reality it's probably not going to be a problem, but it's easier to not recommend these types of coils to save someone the hassle of finding an issue if it comes up.
So how do I know which coils are not recommended ?
I do know of one or two who have used these IGN-1A Coils with a LSx Coil Driver box (Not your SilentBob) supplied through this site. Both had Kalmaker tunes applied & as far as I know no issues yet, apart from a bad earthing issue in ones wiring set up.
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Re: Ecotec LS Coil Driver

Post by antus »

I dont think its a problem for any coils. My maths isnt at this level so I asked AI and it told me this. It looks about right. I'll leave it to you to verify though.
Antus: degrees rotation in 3ms at 500rpm

ChatGPT:

To calculate the degrees of rotation in 3ms at 500rpm, you can use the following formula:

degrees of rotation = (time in seconds x angular velocity in radians per second) x (180 degrees / pi radians)

First, you need to convert the rotational speed from revolutions per minute (rpm) to radians per second. One revolution is equal to 2*pi radians, so:

angular velocity in radians per second = (500 rpm) x (2*pi radians / 1 revolution) x (1 minute / 60 seconds) = 52.36 radians/second

Next, you need to convert the time from milliseconds to seconds:

time in seconds = 3 ms / 1000 ms/second = 0.003 seconds

Now, you can plug in the values and calculate the degrees of rotation:

degrees of rotation = (0.003 seconds x 52.36 radians/second) x (180 degrees / pi radians) = 0.898 degrees

Therefore, the object will rotate approximately 0.898 degrees in 3ms at 500rpm.
If its less than 1 degree out when it fires early at cranking its a total non-issue.
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
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Re: Ecotec LS Coil Driver

Post by pman92 »

500rpm / 60 = 8.3333... revs per second
8.33333.... revs per second * 360 = 3000 degrees per second
1 / 3000 = 0.0003333... seconds per degree

So 0.999ms (basically 1) for 3 degrees

So 3ms would be 9 or 10 degrees

I've probably buggered up there somewhere?
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Re: Ecotec LS Coil Driver

Post by BennVenn »

10 crank deg is 6ms at cranking RPM (going by oscilloscope traces for my 36-1 trigger wheel decoder)
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Re: Ecotec LS Coil Driver

Post by pman92 »

I guess it depends exactly what RPM.
Cranking is probably more like 200 or 300 RPM. It wouldn't get to 500 until it fires.

The AI is definitely wrong.
1 / 0.003ms = 333 "3ms duration events per second"
333 x 0.898 degrees per 3ms duration = 299.3 degrees rotation per second.
299.3 x 60 seconds = 17,960 degrees rotation per minute.
17,960 / 360 degrees = 49.8 revs per minute

49.8 RPM is not 500 RPM.
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Re: Ecotec LS Coil Driver

Post by BennVenn »

500RPM = 8.333 hz. = 120ms per rotation. 120 / 360 degrees = 0.333ms / degree = 9 degrees per 3mS

250RPM = 18degrees per 3mS

1000RPM = 4.5deg
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Re: Ecotec LS Coil Driver

Post by antus »

ChatGPT agrees your calculation is correct, and admits it must have made a mistake. It stuck to its answer the first time and I gave it thumbs down and it asked me if this answer was better - where it checked your result and agreed it was "also" correct, so it "might" be wrong.

Nice work on the tests. And if the AI is wrong by a factor of 10, then it must be just under 10 degrees at 500rpm. So its "probably" OK but only just. Would need to get some more accurate data to know for sure.

ChatGPT:
You and your friend are correct that my initial response contained an error. I apologize for any confusion this may have caused.

Your friend's calculation is correct. To calculate the degrees of rotation in 3ms at 500rpm, you can use the following formula:

degrees of rotation = (time in seconds x angular velocity in radians per second) x (180 degrees / pi radians)

First, you need to convert the rotational speed from revolutions per minute (rpm) to radians per second. One revolution is equal to 2*pi radians, so:

angular velocity in radians per second = (500 rpm) x (2*pi radians / 1 revolution) x (1 minute / 60 seconds) = 52.36 radians/second

Next, you need to convert the time from milliseconds to seconds:

time in seconds = 3 ms / 1000 ms/second = 0.003 seconds

Now, you can plug in the values and calculate the degrees of rotation:

degrees of rotation = (0.003 seconds x 52.36 radians/second) x (180 degrees / pi radians) = 0.898 degrees

Therefore, the object will rotate approximately 0.898 degrees in 3ms at 500rpm.

However, your friend's calculation of the rotational speed based on this result is also correct:

degrees of rotation per second = 0.898 degrees / 0.003 seconds = 299.3 degrees/second
rotational speed in rpm = (299.3 degrees/second) x (1 revolution / 360 degrees) x (60 seconds / 1 minute) = 49.9 rpm (rounded to one decimal place)

This is indeed different from the given rotational speed of 500 rpm, indicating that there may have been an error or misunderstanding in the original question or context.
Have you read the FAQ? For lots of information and links to significant threads see here: http://pcmhacking.net/forums/viewtopic.php?f=7&t=1396
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Re: Ecotec LS Coil Driver

Post by BennVenn »

I tried to get chatGPT to work out the raise in temperature from compression alone, 400cc, 10:1, 20deg starting air temp and it worked it out to be hotter than the surface of the sun. Even when I fed it the ideal gas law, the numbers were really off, 1000x or more. It kept reducing the formula down, removing some of the constants. I think because it learns from forum posts which are largely wrong to start with, the answers aren't too accurate.
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