I've been working on EBC tuning lately. As SOTH told me months ago, it takes 'patients', so I'm here exercising whatever patience I have to try to get things dialed in. Progress is being made for sure.

That said, one of the things I'm a bit confused about is how to determine what is actually 'knock' vs noise. I've seen some readings on the knock sensor in the mid 40% range, but from some of the old threads I've read, this may apparently just be noise. Is there a a reasonable way to find the threshold between noise and true knock?

I'm running what may be a slightly more aggressive leaning timing map. I may switch to a slightly less aggressive map and add in a bit of boost in the higher revs to get where I am now with a bit less timing...

Knock threshold should only be determined by listening or by installing a more modern knock sensor with a light module.
Old Miata knock sensors (pre-06) can't be trusted exclusively by graphs. In my application, actual knock is 12-15% spikes in the data logs.

I'm attaching two of my logs from tuning EBC. I think I should be looking into pulling a bit of timing. I'm going to attach 2 recent logs and my current tune.

Edit: I pulled some timing from the areas that seemed to have higher knock values and smoothed the tables out in that area. I'll check the next log and see what's happening there.

Results of timing experiments:
https://www.miataturbo.net/megasquirt-18/itt-knock-vs-driveline-noise-nb-knock-sensor-94405

Uh something got fukked up, sorry for the random post.

Thanks Aidan!

Que?
What did Aidan do?

In other news, been tuning spark a lot recently. Did a few warmed up 'pulls' in neutral to see what the engine 'noise' was like in terms of knock. Need to do a more deliberate slowwww one to eek it out, but it looks pretty in range. I'm actually pretty interested to see what the generalized 'noise' looks like.

I'd been playing with a few maps and decided to see one through. Went through and pulled timing whenever I saw anything resembling knock so things look pretty solid right now. At 12 psi right now, I'm seeing 230-240 rwhp and 200-210 rwtq according to VD.

Currently tuning PID for EBC just to get spool working better. I first saw 12 psi at 3800 and now see it at 3600. I'm almost maxed out on the sensitivity slider and P terms and I still don't see any oscillation, so I'm a bit confused. My next step is going to be increasing I till I get a bit of oscillation, then dial it back, and finally add in some D to smooth things out. I'm hoping to hit 12 psi by 3200-3400.

An associated question. If I'm that close to maxing out the Sensitivity slider and P/I terms, does that mean that I'd see benefit moving to a stiffer wastegate spring?

I expect your thread was showing up below SOTH's on the mobile site.

Did some more EBC tuning today. I see 12 PSI by 3400 in 4th now. I should be able to get that down to 3200-3300 soon. I'm still only getting about 200 rwtq. I want to go higher, but it honestly hasn't changed since I started upping the boost. Might dial it up a couple more PSI before I have to put the car away for the winter in the next month or so.

As an aside, I have a few exciting updates... But for now is anyone looking for a set of ARP rod bolts? I seem to have ended up with an extra unopened set!

I got a fun suggestion for how to measure knock. Hold the RPMs at certain levels, and have a pal whack your engine with a hammer to see what a violent spike looks like on the knock sensor. That way you can gauge what spikes look like.

My Subaru's 4EAT just shit the brick. Currently daily-less. Good times.

That's a pretty great idea!

Lets try it on your car when I get back to town.

Hi!

https://cimg4.ibsrv.net/gimg/www.mia...a56cdd5f0f.jpg

Colipto got a ride along in the car over the weekend and had a blast. 97moarbewst or whatever the heck his tag is took him out for a drive.

Things were going pretty well for the miata till this happened...


https://cimg6.ibsrv.net/gimg/www.mia...96abb62b45.jpg
https://cimg8.ibsrv.net/gimg/www.mia...d0f93b6840.jpg

Driving on the mass pike, I passed through a construction site and I'm pretty sure that a tie down belt got kicked up and lodged somewhere right in the pulley shearing it right off... Well fuck. I walked around after and found a couple of them. Found the belts way down the road when one of the massdot trucks gave me a few loops to see if we could figure something out.

Down to 0 running cars right now. Took a ride with the tow truck back home and then back to western mass. I have a ride home and after that I guess we'll see what insurance says for the road hazard hit.

Are you sure you hit something? That's a fairly common failure point on Miatas. Happened to me at MRLS.

Pretty certain I was off boost when it happened. The area I was in was also a construction area with those belts freaking everywhere.

Was your block okay after that happened? I need to get the car running over the weekend so I have something to drive unless I get a rental through insurance.

Boost has nothing to do with it. Mine let go while turning in at the corkscrew.

And yes, my block is fine. you remove the crank bolt, remove the plate that the pulley bolts to, drill out the old bolts and reassemble with new bolts. Use Loctite, and don't overtorque them -- usually that's why they break.

Ouch...

Or get a supermiata damper and not have to worry about the bullshit

Sure. but not really as necessary for a street car. If you don't overtorque the bolts and use Loctite, they should last pretty well.