danmo349

I'm currently wiring in my ms3 pro harness to an s4 tii engine my question is the harness has a wire labeled knock in can I use the factory knock sensor or is that not a feature in ms3 pro for rotary knock sensing?

muythaibxr

You can use it but I have not heard of anyone who has tried yet so you might be on your own figuring out how to make it work well for that engine.

RX-S7V7N

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Hello, i was also looking to the Knock Sensor Settings on my MS2V3, to try to understand it, and to figure a way to use it to protect the engine from lean condition.


The detection is low or high input, this means 0 to 5V, so it use an external unit that is reading (earing) the knock sensor frequency, and send the output result
as high or low, the MS canīt do it direct, i think MS3PRO is the same.

On this case for example, if the signal is low, than the MS do its job as we have define it before, retard timing to prevent knock.


muythaibxr please read this and tell me your opinion about it.


What i was thinking is simple, an external unit that reads RPM-TPS-MAP-AF.

Than with the correct values it can output a high or low signal to tell MS that is something wrong, so the ignition is retarded.


We all know that the main problem on rotary is knocking if we go high on boost with lean condition, so, we must control lean, and always try to be on the safe side.


Imagine that the settings on MS2V3 for knock can be change to a different window in order to do like this.

if RPM higher than 3500
and TPS higher than 75%
and MAP more than 10 psi
and AF (air fuel) more than 12.5

Than retard ignition 10š, or cut ignition 1 second , this will make the engine lose power and save it from detonation, by stop it from keep running in lean
condition that sometimes goes to 13, 14 or higher.

Lean condition is related to several things on the engine, fuel pump failure, injector failure, wrong VE settings, boost in cells were it donīt use to see boost,
waste-gate stuck and many other problems.

If the software have this type of option with all that values user define, than we can protect more our engines, because above the settings we give, if there is
some lean condition like 12,7 or 13 AF, it will cut power by retarding or ignition cut to prevent running on the lean side.


Sorry to present this idea here, but it have come from the point of using the knock input, with an external small MCU to read that values and send to the
MS a high or low signal to prevent the lean condition.

If it is a good idea, and possible to add, donīt forget also to put it on the MS2V3 board firmware.


Regards.

danmo349

That's a fantastic idea and kinda what I was asking for a way to safe guard our engines from detination

RX-S7V7N

Yes, the idea is good, why waiting for the knock to come, if we can prevent it to start due to lean condition, still knock can be related to too much advance,
and on this case the knock sensor is the solution, and the IGN Table is were comes this advance.

The idea may be fantastic, but it need skills and "power" in order to implement it on the software, but this we have to leave for the ones that can do it, and here
is for the programmers like muythaibxr and others.

The good thins is, it will not need any hardware modification, only a new window with calculations and variables that in the end will do almost the same as a high
input from the external knock unit, without need the input.

Needless to say, that the MCU must have "room" space for this on the memory, most of the times is not that it will not work, just donīt have were to put it inside.


I think that many people will love this ideia, also on piston engines, because sometimes from 11.5 AF to 12.5 AF is enough to rise the EGTīs and burn
something, so this option will not only prevent knock due to lean condition, but also prevent high EGT due to the same problem with lean burn.


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muythaibxr

Unfortunately, we're about out of RAM on ms2, so there won't be any more major features there most likely.

MS3 already has a pretty advanced knock detection feature though, probably even better than what you're asking for.

Ken

RX-S7V7N

Ok, i understand, like i have already say, it needs a place to fit inside the software, about the MS3 knock detection, how good it is ?


I believe it is better, but iīm shore it will not prevent from running lean and rise up the EGTīs, still, the suggestion i made also prevent other failures,
or the same, in case the knock sensor is not used, because this option donīt need new hardware, and some cars donīt have place for it without mods.


Regards



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RX-S7V7N

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Hello muythaibxr, if you have the time tell me what you think about this.


What is presented next is based on what i know or understand about MS2, so since
my knowledge is limited, if any mistakes please tell me and advise the best way
to do it.



we have "output port Settings", were we can chose a output port like PM2 of
PA0 "knock Enable", (this one i still didnīt read how it works).


After we chose the channel we make it enable and tell it the power on value 0 or 1
next the trigger value the same.

From what i understand this will send a signal 5v or 12V on port PM2, or make go down from
one of that values, and this will depend on conditions to make it work.


Now imagine this way

(random values by default)

Output Channel__________Threshold_____Hysteresis
WBo2_en1_________> _____1850_________180

AND

AfrLoad1___________>_______75%__________0.0
(or) Maf-Map________>_______176__________0.0

If iīm not wrong if we define the Threshold of WBo2_en1 to a value for example 13 AFR this channel will become active above that value if the AND boost is already there also.


Than we still need the condition of the AfrLoad1 or MAP to complete the AND in
order to have the 2 channel with the correct value so that Port (PM2) may
become active.

After this we have one output that will be high or Low if we have for example
WB02_en1 with AFR => 13,,, and this will be important only if we have the MAP
or the AfrLoad ( or other) in the range were we normally have boost or load.

(it also can work with N/A engines, if the load is high and the AFR goes over the predefined value.)

If we connect this output (PM2) to the Knock input AD7/JS4, than we have the
idea that i talk before working, because based on boost/load and lean condition, it will
send the Low signal to the Knock sensor input, and it will retard ignition, the best
way was to cut ignition, but knock donīt have this.

An external LED or buzzer will also inform the driver that it is running LEAN on boost/high-load area,
and at same time the ignition is retarded.

Also if knock instead of (knock ignored Above MAP kpa) if it have (knock ignored if Map lower than) this will be perfect,
but is not important, because we already have chose it on the AND channel, but could be another option that let us use TPS % on the output port.

If the Knock Sensor Settings have a local input, than we didnīt have to use
output port and one input port, or maybe if this window could be changed
with simple 2xAND and 2 or 3 more options it would do the job, but never mind
iīm trying to use what is available at the moment.

This is the idea that i have based on the options that the software give, but i
donīt know if this will work, also the WBo2_en1 have 1850, and i donīt know
what it means, maybe is the value in Millivolts or something similar.

So tell me if you understand what i have explain, and what you think about it, will it work like this ?,,, any other thing that i forget or have say it wrong ?

Still this is a good idea for the MS3, i think that the other after market ECUīs donīt have this type of protection, it will be nice to be the first.


Regards


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Aaron Cake

iTrader: (1)

There's no reason the stock knock sensor wouldn't work but as mentioned as far as anyone knows it hasn't been used with the MS3-Pro knock amplifiers. You'd want to check the FSM though because as I recall the stock knock sensor has a very narrow range. Something like between 2000 and 3500 RPM. Beyond that it's just noise. Using a more generic wideband knock sensor (check the MS Extra manual) is likely a better option.

Thing is, I honestly don't know how one would tune it without inducing knock. I guess just lowering the knock threshold until the sensor starts tripping then raising it above that point.