My spark table after tuning with electronic det cans
#1
My spark table after tuning with electronic det cans
I must say that I was a little surprised by the sensitivity of the elec. det cans. It concerns me that dyno operators don't seem to use this type of device as common practice. Tners seem to base it on audible knock, what has worked on "Other" cars, afrs, or whatever. No hard evidence from my experience. So, if we consider every car different, then shouldn't professional tuners be using some kind of knock detection device during tuning???? Point being, at what point do you trust that your spark table is 100% safe?
Moving on......Is there a level of detonation that is really inconsequential? It's so low level that it isn't really doing any damage? Like a bird wiping it's beak on a 1 sq ft marble block.....one day a bird could wear through it. To most though, "It's not going to happen." is a pretty fair statement.
IF there is a "safe" level of detonation, are our knock sensors and det cans sensitive enough to detect it? In the past we worried about audible knock. Now here I am tuning out the small tic noises I here in my det cans. As I lower the timing in certain cells, I start hearing noticeably fewer ticks until they are nonexistent.
If the above is true, then it is reasonable to assume that tuning the spark table with det cans will result in a 100% safe spark table with a margin. That margin being the low level non threatening knock. My limited experience suggests that there is quite a margin between no knock, and the audible knock that is assumed to kill engines. Hell, there is a wide margin between no knock and a lot of knock in the det cans.
FYI: My flickering oil pressure gauge corresponded 100% with the detonation I heard with the det cans. No detonation, no flickering gauge.
I would like this thread to be a place for people to post their timing maps with reference to how it was tuned.
Mine started as a combination of many maps I found on MT.net, dynotuning, then finally I tuned the boost cells with the electronic det cans.
Post your spark table, and state if it was tuned with/without a knock detection device.
Electronic det cans from past group buy
Moving on......Is there a level of detonation that is really inconsequential? It's so low level that it isn't really doing any damage? Like a bird wiping it's beak on a 1 sq ft marble block.....one day a bird could wear through it. To most though, "It's not going to happen." is a pretty fair statement.
IF there is a "safe" level of detonation, are our knock sensors and det cans sensitive enough to detect it? In the past we worried about audible knock. Now here I am tuning out the small tic noises I here in my det cans. As I lower the timing in certain cells, I start hearing noticeably fewer ticks until they are nonexistent.
If the above is true, then it is reasonable to assume that tuning the spark table with det cans will result in a 100% safe spark table with a margin. That margin being the low level non threatening knock. My limited experience suggests that there is quite a margin between no knock, and the audible knock that is assumed to kill engines. Hell, there is a wide margin between no knock and a lot of knock in the det cans.
FYI: My flickering oil pressure gauge corresponded 100% with the detonation I heard with the det cans. No detonation, no flickering gauge.
I would like this thread to be a place for people to post their timing maps with reference to how it was tuned.
Mine started as a combination of many maps I found on MT.net, dynotuning, then finally I tuned the boost cells with the electronic det cans.
Post your spark table, and state if it was tuned with/without a knock detection device.
Electronic det cans from past group buy
#2
We occasionally use det cans while tuning, but we've found Miata engines often let you run way more advance than will make good power before they start knocking, so I'm not sure how much det cans contributed to the map currently on our test car.
A case in point: You're running about 10 degrees more advance at 100 kPa than what we found makes good power in that area. Looks like that map started out as a small block Chevy map and had some areas tuned for a Miata, but it looks like the high RPM / 100 kPa or more were not.
A case in point: You're running about 10 degrees more advance at 100 kPa than what we found makes good power in that area. Looks like that map started out as a small block Chevy map and had some areas tuned for a Miata, but it looks like the high RPM / 100 kPa or more were not.
#4
I've only just gotten mine together. Haven't been to the dyno yet. However, when I do, I plan to bring along a homemade det can.
I plan to do most of my fuel tuning ahead of time with MS logging and wideband (AFRs to be confirmed during dyno runs). My dyno session will be dedicated to spark tuning.
For each target RPM and MAP, I'll shoot for the lower of MBT or 3°(?) away from detonation. As Matt pointed out, I would expect most cells to end up being MBT driven. I think it is a mistake to spark tune only based upon detonation margin. You also need a way to monitor your torque and identify whether you've hit a peak.
I plan to do most of my fuel tuning ahead of time with MS logging and wideband (AFRs to be confirmed during dyno runs). My dyno session will be dedicated to spark tuning.
For each target RPM and MAP, I'll shoot for the lower of MBT or 3°(?) away from detonation. As Matt pointed out, I would expect most cells to end up being MBT driven. I think it is a mistake to spark tune only based upon detonation margin. You also need a way to monitor your torque and identify whether you've hit a peak.
#6
We occasionally use det cans while tuning, but we've found Miata engines often let you run way more advance than will make good power before they start knocking, so I'm not sure how much det cans contributed to the map currently on our test car.
A case in point: You're running about 10 degrees more advance at 100 kPa than what we found makes good power in that area. Looks like that map started out as a small block Chevy map and had some areas tuned for a Miata, but it looks like the high RPM / 100 kPa or more were not.
A case in point: You're running about 10 degrees more advance at 100 kPa than what we found makes good power in that area. Looks like that map started out as a small block Chevy map and had some areas tuned for a Miata, but it looks like the high RPM / 100 kPa or more were not.
So, i fit doesn't make any difference, is it best to run the minimum advance necessary?
Pretty conservative at 180 and 230 IMO
I guess I should lower my 180, 230, and 300 rows to very conservative, and just add in slowly to each.
#8
This map causes my oil pressure gauge to flicker, and I can hear detonation with my electronic det cans. When I back the timing off to where I hear no det, then the gauge stops flickering.
I don't think the method of "increase until you don't gain any power", and then back off slightly, necessarily means that there is no detonation.
#10
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So are you adding timing until you hear knock while driving? If so, then you will need to remove several degrees from where you heard knock. Every setup is different, but we usually see a notable drop in torque on the dyno before we can hear knock.
If you want to do it right, tune your spark map on a load dyno.
If you want to do it right, tune your spark map on a load dyno.
#11
This is my spark map tuned on a load dyno. OP gauge flickers and I hear det in boost between 180 and 260 kpa
Is everyone suggesting that since it was tuned on a load dyno, and the timing was increased until it stopped gaining torque that this is a good tune? I should ignore the detonation that I hear in the det cans and ignore the flickering OP gauge which corresponds exactly with the det I hear in the det cans??
#13
My current logging and listening suggests that the advance in the 180 kpa row wan't causing any problem, even at 19*. It's the 230 to 300 rows. I've got limited resolution so I can run really weak right at 300, or split the difference.
I just thought about that for a sec. I should run really low at 300 since my target is only 270.
What seems reasonable at 230? 30* seems to work.
I just thought about that for a sec. I should run really low at 300 since my target is only 270.
What seems reasonable at 230? 30* seems to work.
#14
Is everyone suggesting that since it was tuned on a load dyno, and the timing was increased until it stopped gaining torque that this is a good tune? I should ignore the detonation that I hear in the det cans and ignore the flickering OP gauge which corresponds exactly with the det I hear in the det cans??
Your tuner did a lousy job if he left you with a car that detonates.
You should tune for an advance setting that is the LOWER of MBT or a safety margin away from knock. MBT can only be determined on a dyno.
#15
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I made this table and tested it with the manifold glowing yellow with a 3000-7500rpm pull on the dyno:
I also recorded the det-can music on my mp3-player at TWS where my car goes up to 156mph and heard no knock. I'm also on a low compression engine.
The 156-180kpa shift is pretty drastic, but that's MBT-3*.
I also recorded the det-can music on my mp3-player at TWS where my car goes up to 156mph and heard no knock. I'm also on a low compression engine.
The 156-180kpa shift is pretty drastic, but that's MBT-3*.
#20
Ok, I found the thread where Hustler was talking about MBT.
https://www.miataturbo.net/showthrea...&highlight=MBT
It sounds like the tuner found MBT while on the dyno under the conditions at the time.
https://www.miataturbo.net/showthrea...&highlight=MBT
It sounds like the tuner found MBT while on the dyno under the conditions at the time.