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[walter]

hi dudes, today i got a knock sensor i ordered for my brother's car (SR20DE) so i was wondering if i can use that sensor for my knock sensor im using.

nissan knock sensor is this:



what im using is this.

http://www.d-series.org/forums/diy-forum/95756-diy-electronic-detonation-detection-det-cans-under-25-dollars.html

not sure if i can to splice two wires to that knock sensor and get it working..

any idea how to make this works good?

[ryan89crx]

You want something that monitors knock full time? If you just need it for tuning, this would be much easier
http://www.d-series.org/forums/diy-forum/104254-diy-stethoscope-det-can.html

[walter]

i want something that can listen perfectly, not every noise in engine bay. i make same, not using stethoscope and works too just it-s hard to easy good...

[Joseph Davis]

Walter, stethoscope and the human ear > any electronic means.

That KS is not attuned to the bore size of a D16, much less how a 75mm bore sings through aluminum.  You are taking a KS that is not meant for the frequency that detonation occurs at in your motor, and running it through a bunch of crappy slow speed analog circuitry with it's own signal distortion problems, and then play it out through a speaker that's assuredly not going to correctly reproduce the sound of knock.  Or just use a stethoscope.

[walter]

i see.. problem with the last detcans is what i said, but what do you think about this?

http://home.netcom.com/~bsundahl/knock/listen/listen.htm#Amplifier

using lm380 amplifier.. what i dont know is how to get works it alone since my car doesnt have ks.

[Foowee]

We hired a former GM engine dyno operator here at work.  I asked him about det. cans n knock detection once.  He had never heard the term "det. cans" but he told me to get some annealed/flexible copper tubing and smash one end flat, drill a hole in the flat end, bolt it to the block, run the flex copper into the cabin through a grommet.  That's how the road test tuners would listen for knock.

He said they would do same from dyno cell to the operating room.  And no matter what other detection equipment they used, the copper tube+the human ear could not be replaced...

Make sure the metal tube touches as few things as possible.

http://www.coppertubecoils.com/about-copper-tubing/types-catagories/flexible-copper-tubing.html

Supposedly, knock sounds like dry pieces of rice being dropped on foil.  I've never been ballsy enough to run my motor into knock.  Don't want to flake my coatings...

[Joseph Davis]

i see.. problem with the last detcans is what i said, but what do you think about this?

http://home.netcom.com/~bsundahl/knock/listen/listen.htm#Amplifier

using lm380 amplifier.. what i dont know is how to get works it alone since my car doesnt have ks.

This is exactly what I built seven years ago, and exactly what I just told you about.

[walter]

ill build another det can using stethoscope then, thanks

[jabberwock]

Stethoscope or $5 ear protection, $3 in fittings, and some fuel hose.  That's what I got, with the crimped copper tube on the end bolted to the block.

Makes your shit run motha fuckin tizzite for 60k miles, guaranteed.

[HiProfile]

Supposedly, knock sounds like dry pieces of rice being dropped on foil.  I've never been ballsy enough to run my motor into knock.  Don't want to flake my coatings...

I was messing with my friend's ka24det that was 9.5:1 CR (got teh forged pistons cheap), and the maps he was trying would detonate with light throttle. Sounds fairly close, but a little "angrier" - like heavier rice on heavier foil if that makes sense...


BTW that sensor won't work with a personal hearing amp. Knock sensors use special circuitry to pick out spikes that resonate. I don't claim to know much about it, but you're better off just picking out detonation yourself. It will be very noticable above normal engine noise, since it will come and go. Everything else will just change in volume (based on load) or frequency (based on engine rpm).

THe only thing that will throw a wrench in that equation would be an EBC's solenoid. In that case I'd just use an MBC while you tune it.

[jabberwock]

With 1/16" of piston slap, DSM injectors, open WG dump... you can still hear the rice in a pie pan  ;D

[Robb]

With 1/16" of piston slap, DSM injectors, open WG dump... you can still hear the rice in a pie pan  ;D

LOL on the integra, you could hear the wrist pins popping on the rods. Engine block = Megaphone.

[TTC]

Are you really going to see any damage from light load knock though? Hardest part I found with my electric detcan pos was trying to seperate shitty distortion noise from the actual detonation.

[Joseph Davis]

Are you really going to see any damage from light load knock though?

Small detonation adds up over long time.

[d112crzy]

Are you really going to see any damage from light load knock though?

Small detonation adds up over long time.

This.

Stock cast pistons will hate you.

[Joseph Davis]

So will forgings.

So will your upper rod bearing halves.

[TTC]

Good to know. So we are talking knocking at like part throttle in and out of boost and during cruise?

[nock]

a 75mm bore is about a 7khz knock freq.

so far as i know all the bosch sensor are true accelerometers with large counter weights and resonant freq around 10hz or less. so a bosch sensor will work on any engine the bad part is that you'll hear all kinds of crap if your listening to 10hz-20khz, also there output is much smaller meaning your amp needs more gain and so electrical noise is now a problem.

using a resonant sensor that is orignal to the engine (or similar engine) would be the way to go. when i made mine i had to build the lm380 amp, the hearing aid one that i made didnt do shit because it cut off everything above 3khz.

the next one i build will have an ignition pickup that will sync up an mcu with the engine and turn down the volume on all the piston slap and lifter chatter, basicaly everything before the spark and just after TDC. this way your listening to the knock window only, somthing alot of commercial knock sensor tunning products dont even do.



here is a good thread with the founder of J&S talking about knock sensors:
http://www.eng-tips.com/viewthread.cfm?qid=54276

[Gold DA9]

hmm... the stethoscope one looks like something that i could actually make and not fuck up. hmmm.. does it have to be bolted on the front of the block?

[Joseph Davis]

here is a good thread with the founder of J&S talking about knock sensors:
http://www.eng-tips.com/viewthread.cfm?qid=54276

Two questions.  Have you ever used one to determine how well/if it works, and you are aware that he didn't make them for several years because he was "waiting for jesus to tell me" when to make more.

[nock]

no, ive never used a J&S before. and why some people think it dose anything a good stand alone wont, i'll never understand. but i bet he knows how to hookup a knock sensor.

grasshopper you must haul ass for jesus 

[Joseph Davis]

I think he's a couple steps beyond any standalone's KS implementation, and maybe even a couple OEMs, but at the end of the day the results you get out of a universal box is going to vary a lot.  Wish I had one to poke at - there's one for sale on this forum, and I'm tempted, but ultimately I don't need it so it's one of those waste of money propositions.

I always determined the hottest cylinder(s) and tweaked fuel/timing to suit so that all cylinders ran the same - or as close as can be managed given the condition of some of the cars people bring in for tuning.

[nock]

i have noticed that to, some oems will just use genric shit like this:
http://focus.ti.com/lit/ds/symlink/tpic8101.pdf

while other oems develop there own DSP window detectors that are so accurate they can tell the difference between an ant and a fly pissing on your motor.

knock also has a telltail signature, a single wave sweeping several hundered khz from high to low once evey power stroke. so far as DSP's are concernd somthing that well defined is really not that hard to detect. i cant understand why some oems dont even try. hell if you had some sorce code you could make a peice of crappy speach reconigtion software detect it.

[Joseph Davis]

I'm going to politely disagree to a certain extent.  Some modern cars seem to do an adequate job - even in hot streetcar trim - with their KS handling, but always and without fail it is undermined by stupid shit like firmer engine mounts or exhaust rattles.  For the majority of modern cars, a KS is still a bit of a joke.

I'm sure it will get better with time, and relatively soon.  But that day isn't today. 

The unspoken push in electronics is to make seamless integrations between analog and digital electronics, so that you no longer have to be a hardware badass to make a small to medium complexity electronic board but can pick components out of a catalog near-blindly and make shit that works after three tech school programming classes.  Complexity is ubiquitous, and these chip designers have to be masters of it, but for the end user it's a huge loss of manpower - the designs that work easily are the designs that sell.  So it will be with DSP stuff, in fact the technology already exists it's just priced out of OEM's affordability.

[jabberwock]

How long until cylinder heads come with a second spark plug hole for a pressure sensor to check for unexpected/ill-timed pressure spikes?

[nock]

GDI + 1 year

dont quote me on that

[Foowee]

GDI + 1 year

dont quote me on that

GDI seems as if it's gonna be a big jump for everyone.  Unlike port injection you can wait 'till the piston is after tdc, to squirt the fuel, and you don't have to squirt it all at once(I think it's being called a stratified burn)... 

So will all this knock detection jazz even be necessary?  If there is no fuel in the hole before tdc, there is nothing to auto-ignite...

[jabberwock]

Honda is about the only manufacturer without GDI... I sent JD an article a few weeks ago.  Honda doesnt plan on dong GDI any time soon. 

Diesel cycle gas engines ftw though...

[Robb]

Ion sensing is less than a year from being on the street oem, and will be in the aftermarket a few months later. Knock sensor= obsolete.

[Joseph Davis]

Ion sensing is less than a year from being on the street oem, and will be in the aftermarket a few months later. Knock sensor= obsolete.

Saab's had it for years.