Add an LED to indicate activity on the Knock sencor circ?

[flubyux2]

i used to see people talk about a Knock sensor LED mod when i was into DSM's... however, it worked based on the ECU's reaction to detecting knock. so if the ECU did nothing, then you wouldnt know there was knock, even if the knock sensor was creating voltage. see, DSM's have a Boost control solenoid which opens or closes to bleed off the pressure signal going to the WG actuator. when there was no knock, the solenoid would be open and bleed off enough pressure to create an extra 1-2 psi of boost. when the knock sensor sent a signal to the stock ECU, the ECU would energize the BC solenoid and close the "leak" and the boost would revert to 7psi on WG spring.

however, our knock sensors or piezo-electric right? i beleive this to mean that sound vibrations are converted into a small voltage signal. would there be a way to tap a 1.3v 500mch LED into one of the Knock sensor circuits so that it would illuminate any time the knock sensor created voltage?

 

[Mr. Y]

You can't do adequate knock detection using LED only.
I have Link KnockBlock connected to stock knock sensors, so I can hear my engine via headphones... Although KnockBlock has built in filter, there are ALOT of noise after 4000RPM.
Of course, You can definately say, that it is just noise (you hear it), but LED can not =)
And you can not just use algorithm "if noise is louder than.." because slight knock is quiter than noise at high RPMs.

If you are still looking for some knock detection device, look at J&S safeguard. Looks like it works on other cars fine(I don't know about 7M's), but it is not cheap.

 

[MDCmotorsports]

The only thing I can add to this is look into the Grand National car clubs. They have a little "black box" with different color LED's. More knock, red LED. Less knock, green LED.

 

[dbsupra90]

The only thing I can add to this is look into the Grand National car clubs. They have a little "black box" with different color LED's. More knock, red LED. Less knock, green LED.

yep! all you need is a gm esc and a caspers knock monitor.

here is a pic

they offer them in a few other faces and colors. $84 plus youd need an esc from either a parts store or junkyard. casper also offers an add on buzzer for audible knock detection.

 

[Mr. Y]

yep! all you need is a gm esc and a caspers knock monitor.

Are you sure that such combination will show actual knocking (not just noise)? If you want just another gadget in your car - you are welcome, but if you are looking something to detect/monitor detonation, I wouldn't trust that casper's thing.

 

[dbsupra90]

zdraste!

i know what you are saying. i dont run one on my car, but back several years ago there were a few that did. in theory, the way it works is the esc is connected to the knock sensor. if knock is detected, it will drop voltage out of the esc. and when that happens, it will trigger the gauge. the more the drop, the more severe the knock, the more lights you get on the gauge. the original design was much like ours. the gm cars used them to retard timing when knock was present. ours do the same thing, just using a different design without the esc. sure, there is noise. but, it is supposed to only drop enough voltage to trigger something under actual knock.

like i said, i dont run one on my car so i cant be certain how well it works. but, the few i know that have ran it, said it worked well.

either way, it would work 1000% better than an led. but not as well as a more complex system as a j&s or the like.

 

[jetjock]

I assume you're referring to this, although there are better ways.

http://tinyurl.com/2qklxl

pozhalasta

 

[Mr. Y]

dbsupra90
privet! =)
I don't know much about GM cars... That blackbox can work flawlessly on GMs but not good in 7M...
I see two reasons at least:
1) GM's ECU might be using signal from that box with engine position in mind (knock window and so on).
2) that box has filters that are tuned for GM engine (remove noise, amplify det. frequency, etc)... 7M is totally different engine and it must sound different...
So, does that GM box+casper gauge work? yes. What does it actually show (on 7M)? Who knows...

 

[flubyux2]

well one way to definitly tell if the ESC is calibrated in such a way that itd be totally useless for the 7M applicatoin is to install it and free rev the motor. the mechanical harmonics at any given RPM should be close enough to the same noises created when under load. but obviously, there shouldnt be any knock to add another variable. so if the Casper guage freaks out during free-revving, then there would be no way to rely on it to accurately portray a knock-condition under load.

 

[shmuggums90]

I bought a TurboXS Knocklite - have yet to hook it up. Maybe an other option......

http://www.turboxs.com/more_info.php?ID=212

 

[tekdeus]

Anyone have success installing the Casper or XS knock displays?

Write-up here: http://oldschool.supracentral.com/htm/ks_mon.htm

 

[zurud]

I think 89TURBOTOY from Cincinnati, OH running one. He showed me the gauge in his glovebox. Ask him.

 

[shmuggums90]

I tried the TurboXS Knocklite - never did work as described...........

 

[4U2QUIK]

just a thought.
couldn't you use a lm741 op amp and a pair of diodes as a filter in order to make this work?

 

[trydrew]

I think 89TURBOTOY from Cincinnati, OH running one. He showed me the gauge in his glovebox. Ask him.

Yeah, he is running one, and it's got a GN turbo 6 symbol on it.

 

[grimreaper]

IIRC, the knock lights can be quiet picky and difficult to setup. If you knew what frequency the ecu looks for to determine knock that would help although its going to be a lot of trial and error to get it to be accurate. IJ?

 

[89turbotoy]

my gn knock monitor works graet, i'm on a stock hg w/ 20 psi of boost @ 355 hp and 386tq to the wheels. the olny reason i don't have a BHG is because i don't detonate b/c i can monitor it on the knock monitor, the basics of how it works is such, All pz-electric knocks sensors work the same way, you could run any pz ks in our cars and the ecu would respond to knock the same way. so the only difference between our cars and the gm this knock guage is made for is the ESC or electronic spark control module. on the gm cars it is basicly a knock sensor amplifier b/c the gm pcm bases it's reaction to knock on a different input voltage. in our cars the only thing we would use the ESC for is to run the guage, think of it as the sending unit, our ecu still responds the same way to knock now we can just monitor it. Also this particular one is not picky or difficult to set up, just some wiring and mounting the guage also if u have not done the ks re-wire it would be a good idea to do so when u put in the guage.

-Zac

 

[grimreaper]

Thats good to hear then, tap into ks signal wire and run it into the esc so the gauge has a signal? seems too simple lol...

 

[tekdeus]

my gn knock monitor works graet, i'm on a stock hg w/ 20 psi of boost @ 355 hp and 386tq to the wheels. the olny reason i don't have a BHG is because i don't detonate b/c i can monitor it on the knock monitor, the basics of how it works is such, All pz-electric knocks sensors work the same way, you could run any pz ks in our cars and the ecu would respond to knock the same way. so the only difference between our cars and the gm this knock guage is made for is the ESC or electronic spark control module. on the gm cars it is basicly a knock sensor amplifier b/c the gm pcm bases it's reaction to knock on a different input voltage. in our cars the only thing we would use the ESC for is to run the guage, think of it as the sending unit, our ecu still responds the same way to knock now we can just monitor it. Also this particular one is not picky or difficult to set up, just some wiring and mounting the guage also if u have not done the ks re-wire it would be a good idea to do so when u put in the guage.
-Zac

Did you tap into the stock knock sensor wires at the ECU? Both of them or just one? Or is it better to have a separate dedicated knock sensor just for the ESC module?

 

[89turbotoy]

i tapped into both @ the ecu