Spark Knock at 10PSI? 92/93 Fuel
#1
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Spark Knock at 10PSI? 92/93 Fuel
I noticed this last night while driving. I believe I'm hearing spark knock / detonation / bacon frying at full boost. I'm only running wastegate pressure which is about 10-11 PSI depending on the day. I don't feel any loss of power, just hear a crackling sound as boost increases.
This seems odd because my spark map is fairly conservative as far as I can tell. It's from DIYautotune's Turbo basemap.
Relevant info:
Stock Coils/Wires
NGK BKR8 EIX
8.6:1 Wiseco
BP4W head
92/93 octane (92 currently)
11:5 AFR in boost
I don't have a log currently but can grab one over lunch.
My exhaust is pretty loud so I guess I'm just looking for some opinions / ways to troubleshoot. Any way to verify this is knock? build a set of DET cans?
I'm going to take about 5 degrees out of the boost areas and see if that makes a difference. I may also try to loosen the wastegate and see if I can run more like 7-8 PSI to verify.
This seems odd because my spark map is fairly conservative as far as I can tell. It's from DIYautotune's Turbo basemap.
Relevant info:
Stock Coils/Wires
NGK BKR8 EIX
8.6:1 Wiseco
BP4W head
92/93 octane (92 currently)
11:5 AFR in boost
I don't have a log currently but can grab one over lunch.
My exhaust is pretty loud so I guess I'm just looking for some opinions / ways to troubleshoot. Any way to verify this is knock? build a set of DET cans?
I'm going to take about 5 degrees out of the boost areas and see if that makes a difference. I may also try to loosen the wastegate and see if I can run more like 7-8 PSI to verify.
#6
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Crazy, looking at the logs it almost looks like the RPM flattens for a moment. Log is attached.
With -5 timing I definitely heard the cracking less. My log didn't capture those pulls (shitty usb cable). I'll try to get another.
With -5 timing I definitely heard the cracking less. My log didn't capture those pulls (shitty usb cable). I'll try to get another.
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If this is truly knock I bet it's also why I'm seeing increased metals in my oil.
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This is kind of what I was doing with backing the timing off 5 degrees. I still heard something, but much less of it. I can look around and see if I can get race fuel locally. I'm gonna do some digging on the knock sensor situation too.
#13
Check grounds and make sure your coil is bolted down correctly. I had that issue i confused for det and retarding the timing lessened they symptoms, but still existed. Nothing on detcans I turned boost down and it vanished. I noticed one of my coil bolts backed off and plug wires was questionable. Fixed those 2 things and it ran fine.
Some feller on here made electrical det cans and i still use em. Try some detcans. They will tell you for sure.
Some feller on here made electrical det cans and i still use em. Try some detcans. They will tell you for sure.
#15
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Cleaned the coil grounds. It's currently grounding to the back of the bottom half of the intake, I wasn't sure if that was correct so I added another ground going to the head itself. The plug wires are old but there's no cracking, I may just replace them.
Checked the timing, snapped a pic of it. I believe this is correct, yes?
I also snapped a lazy pic of my ignition settings (no internet in the garage).
Does everything look kosher?
Checked the timing, snapped a pic of it. I believe this is correct, yes?
I also snapped a lazy pic of my ignition settings (no internet in the garage).
Does everything look kosher?
#16
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Whew the mobile upload kills the resolution. Here's imgur links.
https://imgur.com/WTtrfKx
https://imgur.com/EB5camH
https://imgur.com/WTtrfKx
https://imgur.com/EB5camH
#18
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...holy ****
https://www.miataturbo.net/general-m...ry-here-89510/
I even posted in that thread. This is blowing my mind. What the hell was I thinking?? That means I've put almost 4,000 miles on this engine with it timed 10 degrees too far. Maybe 3000 of those boosted.
How can I tell if I've done any serious damage? I've had increased lead in my blackstone reports. Bearing damage? I may be able to scope my pistons to see if they show any signs of pitting.
https://www.miataturbo.net/general-m...ry-here-89510/
I even posted in that thread. This is blowing my mind. What the hell was I thinking?? That means I've put almost 4,000 miles on this engine with it timed 10 degrees too far. Maybe 3000 of those boosted.
How can I tell if I've done any serious damage? I've had increased lead in my blackstone reports. Bearing damage? I may be able to scope my pistons to see if they show any signs of pitting.
Last edited by Onyxyth; 10-08-2017 at 01:02 AM.
#20
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Ugh. Makes my stomach turn thinking about it. I'm gonna buy a leak down kit today, already have a comp tester. I'll borrow a scope to look for pitting/sandblasting on the pistons. Change the oil. Cross my fingers.