Knock module for MS3 (beta test)

Testing and development of Megasquirt 3

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wes kiser
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Re: Knock module for MS3 (beta test)

Post by wes kiser »

It has been WAY too long since I checked this forum. I don't have time for testing anymore, but will certainly buy one when they are released.

To the poster who mentioned second octave, I have been around when an aluminum ford modular was tuned to the second octave. We had combustion analysis equipment connected to verify knock.
86 Rx-7, swapped to 2.3 ford turbo (BW EFR 6758), ms3/ms3x sequential fuel /waste spark, ls2 coils
88 Tbird 2.3t, Microsquirt Module (PIMP), TFI ignition
Dookie454
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Re: Knock module for MS3 (beta test)

Post by Dookie454 »

elaw wrote:Well your settings look pretty good, although if knock is running 40-50 when driving (and the engine is not knocking), you might want to raise the thresholds a bit - I'd try increasing them by 10 or even 20 percent at all RPMs.

Also I wonder if this could be a quirk related to the fact that your maximum retard is set to 0? Have you tried setting it to a > 0 number?

One thing I've noticed on my setup is that I get a single very high spike in the knock number at startup - if yours is doing the same thing that might explain why it's showing knock from the moment the engine starts.

If you continue to have trouble, you probably should take a data log and post it too - that might help identify the problem.
My stock and heavily modified low compression 96 Trans Am read knock during crank/startup.
MS3X on 2010 Camaro LS3 + Whipple @ 10psi + HPT + AEM 30-0333/0334 WB
MS3 Knock Module + JBPerf Dual VR v2.1 (Removed), didnt play well with LS3 DBW Motor, works for VSS.
OLD: 1997 Chevy Z71 Vortec 350, + BOSCH 0261231036 WB Knock Sensor
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Reverant
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Re: Knock module for MS3 (beta test)

Post by Reverant »

Tested my board last night on a quite noisy engine (forged internals, wild cams with stiff springs, etc), seemd to have 3-5% with the engine off and 11-17% with the engine idling at 1400rpm (bloody cams).

Can we please not have the KNOCK indication show up in red in the dashboard unless the knock level is actually above the threshold?

Dimitris
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jsmcortina
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Re: Knock module for MS3 (beta test)

Post by jsmcortina »

Reverant wrote:Can we please not have the KNOCK indication show up in red in the dashboard unless the knock level is actually above the threshold?
Didn't I already say that I'll look at that for the next alpha?

James
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tpsretard2
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Re: Knock module for MS3 (beta test)

Post by tpsretard2 »

u did :)

just turn it off Reverant and make a gauge for ignition retard, or knock retard, not in front a computer with ts on it so i forget exactly what it is
elaw
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Re: Knock module for MS3 (beta test)

Post by elaw »

Hey... just wanted to offer a little feedback. I've been driving around since I got the module with it doing pretty much nothing since I had no knock sensing prior and thus had the engine tuned basically to never knock.

Today at lunch I finally had time to test like I've been wanting to: add a bunch of advance in the middle-MAP ranges of my timing table, and go for a drive while logging to see what happens.

Initially I thought I hadn't added enough advance because I didn't hear the engine knock at all. But apparently the sensor board did - you can see from the attached log that it did a fantastic job of detecting knock (maybe a little *too* fantastic - I think I'm going to reduce the sensitivity a little) and pulling timing.

So I am 100% happy with this thing - thanks James!
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

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bmw5002
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Re: Knock module for MS3 (beta test)

Post by bmw5002 »

James any news on this? Development status? I could def use one of these in the next few months. Kudos for being the first to release an affordable, well functioning knock system for the ms community and doing it right with the right components and software configurability. Simply awesome. I think I speak for the masses when I say that your level of dedication and hard work for the sake of ms and its community is astounding and very much appreciated.
elaw
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Re: Knock module for MS3 (beta test)

Post by elaw »

Okay, there's been a hiccup... :(

When I started the car this morning, I noticed the knock readings seemed higher than normal - approximately double. I didn't think too much of it, as I'd left the car outside and it was cold so I figured that was the reason. However, as the car warmed up it was apparent the problem wasn't going away. Even after the engine had been running ~25 minutes and the coolant and oil were both up to temperature, the knock readings were around double the values I was seeing on my drive home yesterday and it was detecting knock and retarding the timing much more than it should.

Toward the end of my drive, I parked the car, let it idle for a moment to see what the knock level was reading - it was bouncing between about 14 and 17. I then stopped and restarted the engine. As soon as it settled to idle, the knock reading was much lower - generally between 6 and 8 which is what it usually reads at idle.

Edited log showing before/after restart and msq attached.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
tpsretard2
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Re: Knock module for MS3 (beta test)

Post by tpsretard2 »

Ok, strangely enough i noticed this this morning also.
I made a lot of changes to the gain and a few other things.

I took it for granted that some did not take and needed a power cycle, but then the laptop went dead so i could not confirm.

i will look at it tonight when i have to go back out.
elaw
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Re: Knock module for MS3 (beta test)

Post by elaw »

Hey just a couple more probably-useless data points: I watched and datalogged when I went to lunch today, 4 startups total. The problem did not occur, so it's definitely not reproducible on demand.

Also more than once I've seen knock values > 100% (not *much* greater, all below 105% I think) in the log. Not sure if that could be related but I thought I'd mention it.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
jsmcortina
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Re: Knock module for MS3 (beta test)

Post by jsmcortina »

elaw wrote:Also more than once I've seen knock values > 100% (not *much* greater, all below 105% I think) in the log. Not sure if that could be related but I thought I'd mention it.
102.3% is the max. That's because it is a 10bit number and I'm just dividing by 10 and then calling it a percentage.

James
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gross polluter
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Re: Knock module for MS3 (beta test)

Post by gross polluter »

100k resistors on the stock 2JZ knock sensors seem to have attenuated the signal enough to be usable. Things are looking good on my side. Soon I'm going to try attenuating a little more to see if I can get resolution into the WOT range. Right now the knock output maxes out beyond 4000rpm.
88 RX-7 TII - MS2 Extra 1.0.2
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aarc240
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Re: Knock module for MS3 (beta test)

Post by aarc240 »

bubba2533 wrote: ... I have a difficult time remembering all of the uses and the designations for each pin/pad and function for all of them ...
Try the attached doc, it might help.
It's my way of keeping track so feel free to use & modify as you wish.
Art,
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y8s
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Re: Knock module for MS3 (beta test)

Post by y8s »

Got my knock module installed and ran it for the first time this morning.

I started out with these settings:
Bandpass Frequency: 3.43 (based on f=900/pi*boreradius--which I just checked is actually 6.9? guess I forgot to divide by two...)
integrator: 150 (default)
gain: .85

I also put some random values in the settings page but raised the threshold to 100 over all RPM ranges just to log.

Knock window left to default values 0° start and 20° end.

The response from the sensor seems about right with average noise floor sitting around 10-15 and spiking into the 50-60 range at tip in and under boost.

I don't yet trust the spikes since I show a period of cruise (3400 rpm @ 60kPa @ 15%TPS) just before a period of boost (4200 @ 150kPa @100%TPS) with similar sized spikes. The ones in boost are sharper, but with my bandpass frequency halved, it's hard to say what is going on.

First off, I don't doubt for a second that I've got knock. I run a relatively high amount of boost for a high compression motor without much for safeguards.

---
Question time:

James,
You mentioned that the knock for each cylinder was logged in sensor09-sensor16. Are these firing order? so sensor09 is cyl 1, sensor10 is cyl 3, sensor 11 is cyl 4, and sensor12 is cyl 2?

Also, is the "knockin" value only showing me a filtered version of the sensor09-12 data? a sum or something else?

Pretty cool though... to know I've been destroying my motor for 60,000 miles. :)
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Re: Knock module for MS3 (beta test)

Post by jsmcortina »

y8s wrote: James,
You mentioned that the knock for each cylinder was logged in sensor09-sensor16. Are these firing order? so sensor09 is cyl 1, sensor10 is cyl 3, sensor 11 is cyl 4, and sensor12 is cyl 2?
They should be in numerical order i.e. 1,2,3,4 (up to 8)
Also, is the "knockin" value only showing me a filtered version of the sensor09-12 data? a sum or something else?
That is the latest of those values, not averaged, peaked or summed. (Yet.)

James
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y8s
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Re: Knock module for MS3 (beta test)

Post by y8s »

sorry I should have asked if the knock sensor09-12 correspond to spark 1-4 respectively. sounds like that is the case.

so in my case things would look like this?:

Code: Select all

cylinder: 1,  3,  4,  2
spark:    1,  2,  3,  4
knock     9, 10, 11, 12
jsmcortina
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Re: Knock module for MS3 (beta test)

Post by jsmcortina »

No.
sensor09 = cyl 1
sensor10 = cyl 2
sensor11 = cyl 3
sensor12 = cyl 4
sensor13 = cyl 5
sensor14 = cyl 6
sensor15 = cyl 7
sensor16 = cyl 8

Code: Select all

        /* record which cylinder it was on */
        cyl = ram4.fire[knock_chan_sample];
        outpc.sensors[7 + cyl] = outpc.knock; // store digi input (temporary)
(range bounding removed for clarity)
That code converts from the spark output order A,B,C,D = 1,3,4,2 into cylinder number order 1,2,3,4. Just like the way the injector pulsewidths shown in TS relate to their cylinder number. i.e.seq_pw2 = cyl2

James
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y8s
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Re: Knock module for MS3 (beta test)

Post by y8s »

oh. I must have been thinking of another engine management system. That would explain the Engine and Sequential Settings dialog for firing order. :oops:
ragepower
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Re: Knock module for MS3 (beta test)

Post by ragepower »

Hi

I have a suggestion to do.

I have a friend that have a peugeot 306 XSI and he told me that OEM ECU adjust the advance angle in function the Octane rating of gas (In portugal we have 95 and 98) and the bmw do the same. He notice when he change from 95 to 98, the throttle response increase and engine power maybe, but didn't measure it, after a while.
Probably it do with the knock sensor, maybe this way, from times to times, it try more advance, and if there is no knock, it keeps that advance.

What you think?
tpsretard2
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Re: Knock module for MS3 (beta test)

Post by tpsretard2 »

i finally caught the dam thing on a datalog.

Started up this morning, was cursing on a back road, went to accell the car is it did not feel right, Pulled over fired up the laptop and the knock was all over the place.

Started the datalog, turned off and turned back on, the knock was where i figured it should be.
The msq and the log are attached.
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