View Full Version : listening for det?
SCHWARTZ
29-05-2012, 17:27
I want to run some more boost but am afraid of det. Is bolting a cheapy 5quid stethoscope to the head ok, or will I need something better? Whats the best way of listening for it?
A steth is ok I find but it still can be difficult to pick it out amongst the rest of the engine noise.
A few tips are
Bolt it to the front of the block(less valve train noise)
Pipe it into the cabin using 6mm nylon hard pipe.
Buy a decent steth, the part you bolt to the block won't last 5 mins if it's cheap.
Make sure you know what det sounds like, very hard to describe, I liken it to someone scrunching up a crisp packet very fast........:wasntme:
SCHWARTZ
29-05-2012, 21:37
I have some 6mm hard pipe so can do that. Guessing its just a case of cutting the pipe and sticking the tube in:cooter: can I loosen the knock sensor and fit it behind that?
it's worth pointing out here that with a wet liner c1j you want to listen to the cylinder head, but yes, with b18ft you should be listening to the top of the block. stethoscopes are OK but you need to be carefull that the nylon hose doesn't rattle against body work as it enters the cabin. Don't use silicone or rubber hose to extend the stethoscope, it damps high frequency too much.
andybond
29-05-2012, 22:39
Its almost as if you need someone stood by the side of the car with a decent steth , or det cans who knows what they are listening for ?
Imagine if there was such a place where you could drive really fast and someone could be stood by your car and still listen.
It would be as if we HAD BECOME GODS
;)
SCHWARTZ
30-05-2012, 08:49
Would one of the electric ones be better the ones that use a 9v battery as its a wire going into the cabin so less interference, or are they just a load of:jerkoff::laugh:
SCHWARTZ
30-05-2012, 08:50
Its almost as if you need someone stood by the side of the car with a decent steth , or det cans who knows what they are listening for ?
Imagine if there was such a place where you could drive really fast and someone could be stood by your car and still listen.
It would be as if we HAD BECOME GODS
;)
Sadly I am a mere mortal:sad2::laugh:
i used a knock sensor from a Megane F7r. bolted to the block and then used the old connector and soldered a long wire to it.
soldered a jack plug on the other side which i put into the aux on my radio.
it isn't perfect because when putting on some power you cant really seperate all the sounds but it gave me some idea. headphones would work better as u won't be bothered by engine and air filter/turbo noise.
you could make that using a 5quid memo device, cut the mic loose, solder long wires to it and connect them to a knock sensor. then plug your headphones into the memo device and listen :)
http://www.youtube.com/watch?feature=player_embedded&v=yPnDbRZ5Ih0
The problem is keeping the inteference out, HT noise, etc. The good knock boxes have good power supply decoupling or are battery powered. They usually have a band pass filter to cut out what you don't want to listen to. I'd say if you're building your own you need an amplifier that runs from batteries to avoid inteference from the car's power, use good screened cable to the knock sensor and use in-ear head phones, the type that block off external noises. The cable to the sensor should avoid HT, etc. And don't be tempted to run them at high volume, your ears are better at discriminating at lower volumes.
My own knock detection is the culmination of a lot of trial and error. I use a knock-box (trade mark name) knock detection box which having tried a few, is the best. (build quality is not though!). But I found that with headphones it was hard to keep external noise out so I use a stethoscope on a short hose to a sealed box containing a little 0.5w plastic cone speaker which is fed from the headphone jack of the knock box. I can detect individual pings of knock even at high rpm.
Recently I had to test/configure some "knock-lite" knock indicators in some supercharged MX5's. I was amazed how good it is. It was able to detect knock at almost the same time as I could with the knock box. I don't know who they're made by, they're a small chrome tube with a bright LED in the end like a shift light. They're configured by holding the engine at different RPM's without load so the unit can set a base line threshold, or however it does it. Then it'll illuminate orange if it detects minor knock and red if it detects a lot. I had it working by deliberately inducing some knock on the dyno, I was very impressed :)
SCHWARTZ
30-05-2012, 10:59
I have a hearing aid thing I bought from maplins, so if I took the Mic off and wired that to my knock sensor. Is it ok for the knock sensor to go to the ecu and some det cans (if you could call it that).:laugh:
SCHWARTZ
30-05-2012, 11:40
Chris those knock sensors sound spot on, exactly what I'm looking for as I guess that can be left in constantly like a shift light then, so I don't allways have to concerntrate listening for det.
SCHWARTZ
30-05-2012, 11:43
Chris is this the kiddie?
http://www.knocklite.com/
Thats the one mate, I was quite impressed.. I was more impressed because it worked on an MX5, which have engines that are notoriously difficult to hear knock with because they're noisier than most when you listen to them with a knock box.
SCHWARTZ
30-05-2012, 12:47
Cheers matey think il give it a go if I can find a supplier:rolleyes:
Romil Davda
30-05-2012, 12:52
Cheers matey think il give it a go if I can find a supplier:rolleyes:
Dude, can you also get one for me? or let me know where you source it from?
Group buy perhaps??? :scratch:
SCHWARTZ
30-05-2012, 13:19
Il look into it when I get home, phone is no good for that. Group buy sounds good.
Very interested too, Sounds promising!
SCHWARTZ
30-05-2012, 14:06
Seems like there is a bit of interest in these. Chris is this something that efi parts could sell?
Can't find any suppliers atm, only price i've found is 129usd. Not much for a piece of equipement which can save your engine!
soapymech
30-05-2012, 14:24
Chris have you experienced the rom performance ones on eBay?
nice
found this one
http://www.fastwrx.com/tuknli.html
and this one
http://thmotorsports.com/turbo_xs/turbo_xs_knocklite/knock/i-245587.aspx
groupbuy sounds good :)
Second one is only 105 :agree:
P.s: heb je de groeten nog gehad Sieger?
Chris have you experienced the rom performance ones on eBay?
No sorry. I have to say that most are junk though, they don't have an RPM based variable threshold, so they're next to no use at detecting knock at anything less than full RPM. You should look to see how it's threshold is set. If it isn't RPM based I wouldn't bother.
Chris, would you say the knock-lite is worth it however if setup correctly? it seems another worthy addition to the forest of gauges and info piling onto my dash is all! :smokin:
Second one is only 105 :agree:
P.s: heb je de groeten nog gehad Sieger?
nope, nog geen een ervan gesproken :)
Chris, would you say the knock-lite is worth it however if setup correctly? it seems another worthy addition to the forest of gauges and info piling onto my dash is all! :smokin:
Maybe, I've only set up 2 with FI'd MX5's, but the MX5 community love them and give them good reviews. I don't know what they cost but if they're not too expensive then worth a punt, especially if you're in to experimenting with boost, etc.
sounds a decent addition, i'll get myself over to the mx5 forums see if theres a uk supplier!
I love to tinker and cars already pretty much at limit of the map but I reckon I can tweak a little with the knock as well as AFR/boost/temp inlet and ambient to go off :smokin:
cheers for the reply fella!
Romil Davda
30-05-2012, 18:03
I've just sent 2 emails to the websites on the post above, i have asked if they will sort out a Group discount and more importantly, if they will post to the UK.
Will keep you all updated...
Some good info here guys! :goodpost:
SCHWARTZ
30-05-2012, 18:58
found an old face book page and a link to amazon of all places where you could buy them but no only add them to your wish list:sad2:
SCHWARTZ
30-05-2012, 19:35
found these on the bay, what ya think? dont say how it reads knock tho:scratch:
http://www.ebay.co.uk/itm/Subaru-Turbo-Knock-Det-Alarm-Engine-Detonation-Detector-Visual-LED-Alarm-/190684333294?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c65ac04ee#ht_1959wt_1396
DaveL485
30-05-2012, 22:18
TurboXS is still actively selling on eBay.com but nothing on knocklite. Reckon its discontinued, everything is a dead end.
Me and one of the other 21 lads built something for this for when we did our base map on the Adaptronic with Dave G, a few years back. It was very, very effective; the knock was glaringly obvious when we advanced the timing, he nearly punched me in the head from the back seat (it was his car after all :laugh: )
I'll see if I can find out what bits we used.
Detecting knock and the onset of knock are very different though, so really they're just warning devices for when something goes wrong and shouldn't be used for tuning.
Romil Davda
31-05-2012, 10:54
Responce from http://www.fastwrx.com/
Hi,
I'm sorry, but that product has been discontinued.
--Dan
Mach V
_____________________________
Please include all previous email with your reply.
Mach V Motorsports
45690 Elmwood Ct. #170
Sterling, VA 20166
(571) 434-8333
:sad2::sad2::sad2:
rofl, oh well it was a nice idea whilst it lasted :laugh::disagree:
SCHWARTZ
31-05-2012, 13:07
Also found this bit pricey but looks good.
Link: http://www.ebay.co.uk/itm/PHORMULA-KS-3-KNOCK-DETECTION-KIT-PROTECT-YOUR-ENGINE-/180431754314
Romil Davda
31-05-2012, 15:13
Also found this bit pricey but looks good.
Link: http://www.ebay.co.uk/itm/PHORMULA-KS-3-KNOCK-DETECTION-KIT-PROTECT-YOUR-ENGINE-/180431754314
OUCH :eek: - Let me get on the phone to Mr Bank Manager...
Romil Davda
31-05-2012, 15:17
Quick Update for you peeps, can anyone answer the question regarding "piston bore (cylinder diameter)" please?:
Email recived from Boris:
In that case you want Knocksense kit which includes all the wiring, Red LED
and the signal cable with a two pin Bosch connector attached.
I need the approximate piston bore (cylinder diameter) to set up the filters
in Knocksense.
Red LED comes mounted in a bezel and wired to a length of twisted pair.
Used and tested sensors that we stock:
http://www.viatrack.ca/Knock/Boschalf261231121.jpg (http://www.viatrack.ca/Knock/Boschalf261231121.jpg)
Bosch: It has a brand new two pin connector that
plugs into the signal cable.
http://www.viatrack.ca/Knock/261-231-046.jpg (http://www.viatrack.ca/Knock/261-231-046.jpg)
http://www.viatrack.ca/Knock/Bosch06.jpg (http://www.viatrack.ca/Knock/Bosch06.jpg)
Bosch: They are also used but cleaned up and tested.
http://www.viatrack.ca/Knock/siemens2.jpg (http://www.viatrack.ca/Knock/siemens2.jpg)
This is Siemens sensor. Same as Bosch but Beige in color.
I also have Denso sensors that Volvo uses in their later models. Looks
similar to http://www.viatrack.ca/Knock/Boschalf261231121.jpg (http://www.viatrack.ca/Knock/Boschalf261231121.jpg)
except that cable is little shorter and thicker. New connector.
You need:
Knocksense - $50 (comes with wiring and instructions - nothing to solder)
Knock sensor ( used tested ok) -$25 ****Pick one from the list above****
Shipping $14
Options: (add)
White LED option - $5
Blue LED option - $3
Amber LED option $1
All LEDs are poke you in the eye bright.
Teflon Signal cable option - $15 (recommended for high temperature)
http://www.viatrack.ca/Knock/KSTEFT.jpg (http://www.viatrack.ca/Knock/KSTEFT.jpg)
My Paypal is borism@sympatico.ca
Please include your shipping address with the order.
On Wed, 30 May 2012 23:14:06 +0100, you wrote:
>Hi,
>
>Knocksense. We are after a unit which will tell us when the engine is
>knocking, a flight flashing or such?
>
>Romil
OUCH :eek: - Let me get on the phone to Mr Bank Manager...
Someone else I know retails Phormula :)
http://www.efi-parts.co.uk/index.php?categoryID=90
But yes, not so cheap. :crap:
Bit of a hijack but related .
I have a knackered knock sensor on an Espace V6 lump on the side of the block and on GTA turbo mounted on the inlet manifold between the V .
They are both the same style threaded fitment ,ie screw direct in not bolted through ,same plug etc just different shape and colour .
Can I use the GTA one as a replacement ?
When I used the piezo microphone and amplifier feeding headphones (that I made in maybe 2004) I heard knock at mid frequencies. Literally a knock sound, not the loud repeating crack that happens later.
One if those linked to above was talking about 6 to 9kHz, I presume that 6kHz. That would be he loud crack and it ;s a bit late by then as bit of cylinder head and piston are possibly being damaged.
My detector was wide band and needed the headphones, not a lamp. It was very sensitive and I could hear a lot of engine sounds clearly. I made a version 2 with filters but didn't complete that as I no longer had a car that det'd.
Two problems I encountered were when using the Piper 270 cam shaft, the tapping noise was so loud it all but blanked out the det sound.
If the HT leads were not screened well enough a clack sound was induced into the detector.
Quick Update for you peeps, can anyone answer the question regarding "piston bore (cylinder diameter)" please?:76mm diameter I think? Actually I've forgotten. Scoff should know? Also you'd need the 1.7 litre and probably a 1.8 and a 2 litre?
-----
Two problems I encountered were when using the Piper 270 cam shaft, the tapping noise was so loud it all but blanked out the det sound.
-----
This is where it gets tricky Ian, you have to rely on experience to distinguish it in these cases. Accurate knock detection for tuning purposes isn't all that easy.
Listen to the audio in the last video here:
http://www.efi-parts.co.uk/index.php?productID=269
It demonstates the sound of heavy knock. You'll probably want to listen to the clip with headphones. :)
In my 5GTT, not stripped out but maybe with the Ktec side exit, I think the loud crack sound of knock is easily audible such that no equipment beyond one's ears and brain are needed to detect it.
The subtle knock is obvious too, to me anyway, although some other people appeared to not be able to sense it.
With a very loud cabin and maybe a helmet or ear plugs in, maybe these visual indicators are useful.
When driving my 5, if it did do the subtle knock, I seemed to be able to 'feel' it as much as hear it.
I guess I could get the detector I made going and sell it to someone here to try. They could then sell it to to someone else, etc. It's similar really to the large one in Scoff video clip. But that probably has fancy audio band pass filters that mine doesn't.
I seem to recall that my 5 used to knock at about 3500rpm but not above or below that. Just needed the ignition timing taken back a bit at that rpm perhaps?
Thats it ian, it'll usually knock at peak torque in the GTT. Most engine's do, and so you end up with a dip in the timing curve at that point. The GTT's dip is at about 2500rpm I think, so not much use when the turbo is T25 or T28.
If you can hear knock with the naked ear then that is a lot of knock. You do well to keep the engine together. Good knock sensing will let you hear individual pings which might happen as much as 4-5 degrees earlier than you being able to hear it from the cabin (and when sometimes it is too late to save the engine)
do you have personal experience with a diy stethoscope det can Chris?
do you have personal experience with a diy stethoscope det can Chris?
Yes, thats what I started with :) OK if you follow the rules above.
The listen gadget I made was showing up individual knocks. Not the loud crack that happens with higher boost, etc. It did that as well of course.
I went along a dual carriageway at a steady rate with Mike Spenser driving his 5GTT and me listening to my gadget. He was adjusting the boost incrementally until we got the slightest knock. But the car was quiet and I anyway could hear it with my ears.
SCHWARTZ
31-05-2012, 18:51
I would like something like the lights that's blatently obvious to see when its knocking. I would be leaving it in constantly so having to concentrate on listening out for it is no good really. I know most people would just use it when setting up and leave it alone when its done. But surely having a little warning light constantly is good then you could add det cans as well when pushing for more boost etc...
SCHWARTZ
31-05-2012, 18:54
I have no idea what det sounds like as most prob a lot of people don't so to me a light sounds the best solution to us mere dummies:laugh:
http://www.youtube.com/watch?v=GGJZ6kKzLus
SCHWARTZ
31-05-2012, 19:10
this is what the guy said about the knock sensors on ebay for £120.
does this sound right or are they just cheapy bin fodder?
what sort of questions do i need to ask?
Hi,
Once the knock sensor is bolted to the engine block and the KnockAlarm is connected up to that and a 12v ignition source there is no fiddling about or special setup to be carried out. That's it.
It's very simple to install and comes with full instructions, and it's active and listening for knock as soon as you start your engine. It's not rev dependent because knock can happen at low revs as well as high revs so it listens across the whole rev range. Knock happens at a very specific frequency regardless of rpm.
Hope this helps.
SCHWARTZ
31-05-2012, 19:13
http://www.youtube.com/watch?v=GGJZ6kKzLus
that sounds very obvious what to listen for but i wonder if thats how it really sounds:D
http://www.youtube.com/watch?v=GGJZ6kKzLusThat has the bass and treble very steeply cut off.
Without audio filtering you hear a sound like you knocked a table with your knuckle. Then if the det is worse you hear more of a crack.
The sound is going to be modified by the size, shape, etc of the head, block, etc. A drumstick hitting a large drum makes a different sound to a very small drum.
then have a look at my homemade knock sensing device thru the radio again:
http://www.youtube.com/watch?feature=player_embedded&v=yPnDbRZ5Ih0
i have a video where you can hear the knock too but it isn't on the net:crap:
SCHWARTZ
06-06-2012, 17:24
how about these the price seems good even though you need to supply a knock sensor but anyone know if these are any good?
http://www.ebay.co.uk/itm/Knock-Sensor-Conditioner-Detonation-Detector-Knock-monitor-pinking-detector-/300721016547?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item46045e8ee3#ht_758wt_932
that sounds very obvious what to listen for but i wonder if thats how it really sounds:D
Thats a good example of a lot of knock, but with a turbo motor you can kill the engine with a lot less knock than that, so you need to be able to hear the onset long before you get to the stage presented in that vid. You will hear infrequent pings of knock before it gets "busy" like in this video. It's also a lot easier to hear it at lower RPM than it is at high RPM. :)
this is what the guy said about the knock sensors on ebay for £120.
does this sound right or are they just cheapy bin fodder?
what sort of questions do i need to ask?
Hi,
Once the knock sensor is bolted to the engine block and the KnockAlarm is connected up to that and a 12v ignition source there is no fiddling about or special setup to be carried out. That's it.
It's very simple to install and comes with full instructions, and it's active and listening for knock as soon as you start your engine. It's not rev dependent because knock can happen at low revs as well as high revs so it listens across the whole rev range. Knock happens at a very specific frequency regardless of rpm.
Hope this helps.
I'm not keen on that unless it somehow sets an RPM dependant threshold itself somehow ? He's right of course, knock can happen anywhere, but the problem is that the engine's backround noise is often greater at high RPM than it is at low RPM. So if you configure the units threshold so that it detects knock at high RPM it might well go un-detected if it happens at lower RPM. The Knocklite works by having different thresholds at different RPM which in my experience is what makes all the difference. I was able to get them detecting faint knock at 3000rpm in turbo'd MX5's. With a fixed threshold that wouldn't have happened :)
SCHWARTZ
06-06-2012, 18:24
I'm not keen on that unless it somehow sets an RPM dependant threshold itself somehow ? He's right of course, knock can happen anywhere, but the problem is that the engine's backround noise is often greater at high RPM than it is at low RPM. So if you configure the units threshold so that it detects knock at high RPM it might well go un-detected if it happens at lower RPM. The Knocklite works by having different thresholds at different RPM which in my experience is what makes all the difference. I was able to get them detecting faint knock at 3000rpm in turbo'd MX5's. With a fixed threshold that wouldn't have happened :)
I have emailed a few of the companies that used to stock the knocklite to see if they had any left and would like to arrange a group buy, still waiting for a reply.
SCHWARTZ
06-06-2012, 18:26
chris what about the knocktek for under £60 a few posts up? have you had any experiences with these?
chris what about the knocktek for under £60 a few posts up? have you had any experiences with these?
No experience mate, sorry :(
I didn't think highly of any of them really until I had to set a couple up for MX5 guys, which changed my opinion of that type at least. I can't speak for other brands, suspect they won't be as good without RPM based thresholds.
SCHWARTZ
06-06-2012, 18:49
the phormula knock that you stock does that have a rpm based threshold? is it a worthwile bit of kit?
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions Inc. All rights reserved.