false knock in boost?
 

So I am working on my timing table with some detcans, as soon as I hit boost it sounds like knock IMO, I can pull a ton of timing and the sound doesn't go away, does anyone know of any detcan recordings of a boosted car, in boost, that's not pinging?

I just had the head off the car and there are absolutely no signs of det that I could find.

Google it and there's a ton of clips/recordings of det/knock.

Sounds like something rattling around in a tin can most of the time.

IF you're pulling out a ton of timing and its still there its probably something rattling around in the bay or a heat shield or something

Show us your spark table; where do you live? If you want to bring it by, I'll give it a listen.

What is fuel doing when MAP ramps? Just because you can't see det, doesn't mean it's not happening and not happening with extreme heat. I assume you have forged guts, making it less likely to show light det.

What do the AFRs look like?
What turbo? Boost?
Are you running cold plugs?
Intercooled?

After looking at the numbers on his car, the car sounding like it's running ~10-14 psi on a 2560, I think it's detonating.

1.6 stock guts, 2560, 14psi, IAT's are +10 over ambient after a 2-4th gear pull. I am located in Arlington.
AFR's are mid 11's, plugs are BKR7EIX.
I have road raced the car for a season w/o any issue (det wise)
I pulled 2,4,10 degrees in boost from the table below, no change. As soon as the boost gauge goes over 0 it sounds like a very consistent pinging to me. I also checked to make sure the trigger angle was correct, it was perfect.

I got a very consistent knock sensor hit on the black car on the dyno at around 5,600 rpm. Pulled timing and dumped fuel and it never went away so we decided it was a harmonic anomaly in the engine. I have the same thing in the red car but around 300 RPMs higher. The red car has a different longblock but the same turbo. If you 'event' starts when you enter boost and stays through the whole range regardless of spark and fuel, my vote is something is loose.

I remember a huge spike when logged with the adaptronic somewhere between 4-5.5 with same symptoms. Never heard any audible knock tho

I need a log to see enrichments and I need to hear the car to tell you anything else.

I think there is too much spark angle in the 2300 and 2900 columns and not enough spark up top but there is no way to tell here. I found numbers like that beyond MBT in my car and others.

Where is your hook-up point for the det-cans?

I was going to say: 15-18* at peak load on 14psi on pump gas on stock engine is pretty liberal.

But you say taking away 10* does nothing so its gotta be false knock or rattle

Where the OE knock sensor is on the later cars, it's a bosch donut sensor going to a J&S knockguard which has audio out.

https://www.miataturbo.net/attachmen...ine=1364439076

something makes me think that thing is just picking up a weird frequency

When I was on the dyno most recently with the red car and the other engine, we again pulled timing and dumped fuel over that range and got the same noise. This was on the adaptronic with the MSM knock sensor. In both of my cases, it was just a BP rattle that didn't seem to cause any other problems.

We need to see a log for AFR on enrichment.