flak monkey
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| posted on 8/4/10 at 07:16 PM |
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Spot the knock?
Just looking for a double check on the results of my knock testing on my engine. This is a link to a sound file of the engine running up to 6500rpm
under load (3rd gear) as recorded throuh my phormula knock analyser pro.
http://gtslocost.locostsites.co.uk/sample2.wav
I dont think I have any knock - anyone else care to have a listen and see what you think?
Once I am confident I am not getting any knock then I can set up the dash mounted display to show the current peak and give an alarm should it be
exceeded. 
Thanks,
David
Sera
http://www.motosera.com
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MakeEverything
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| posted on 8/4/10 at 07:23 PM |
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Is there not a bit of a rumble a third of the way in? on decelleration?
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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locoR1
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| posted on 8/4/10 at 07:34 PM |
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Sounds OK to me, I assume if it was knocking you would here a pinking type noise?
would it be possible to deliberately induce a Knock at low rpm so you know what your listening for?
 
Description
Check out my CB500T Cafe Racer build diary
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flak monkey
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| posted on 8/4/10 at 07:41 PM |
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Knock usually shows as a sharp 'splat' type noise, I dont have a sample with knock in, theres a couple of vids on youtube with the
sound
http://www.youtube.com/watch?v=GGJZ6kKzLus
Thats quite a good one.
I could always purposefully try and induce knock at low rpm to see what it would sound like through my system.
The overrun is waaay lean and lots of misfires so not too worried about that at the moment.
Thanks
[Edited on 8/4/10 by flak monkey]
Sera
http://www.motosera.com
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Danozeman
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| posted on 9/4/10 at 06:59 AM |
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let me drive it sunday and ill tell you if you have a knock 
Dan
Built the purple peril!! Let the modifications begin!!
http://www.eastangliankitcars.co.uk
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atspeed racing
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| posted on 9/4/10 at 11:57 AM |
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assuming this is a supercharged engine..
depending on power and boost levels, you dont always hear knock - so be wary.
on most engines knock could be explained as a fast metallic rattle, as the noise resonates through the engine block. knock will start on top of the
top piston ring. many forged pistons will have "anti-det" grooves machined in the top ring land above the top ring, to alllow room for the
pressure spike to be absorbed, hopefully without any damage.
on high boost, high output engines, knock can appear as a faint fluttery type misfire.. one way to monitor this is by monitoring water pressure. if
knock occurs then pressure will blow between the headgasket, and show up as fluctuations in water pressure.
knock meters in most cases are just a second set of ears, and by the time youve seen the display its already too late. sometimes the old fashioned
ways are the best... a piece of copper pipe bolted to the engine block, or inlet manifold, and a length of rubber hose poking through a set of ear
defenders will enable you to hear the early signs of knock
if you would like a second opinion, why not drop the car onto our dyno, and we can listen out and check for you.. we will be able to put the engine
under any load, at any chosen RPM.
- colin.
[Edited on 9/4/10 by atspeed racing]
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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flak monkey
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| posted on 9/4/10 at 12:02 PM |
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Yep its a sample from a run last night on my SC duratec. The recording is from a knock sensor bolted to the block in the OEM position theres no signal
processing going on other than amplification through the Phormula Knock Analyser Pro box.
If you are competant with megasquirt then I may just take you up on that later in the year.
I have a few other issues to resolve before then
Sera
http://www.motosera.com
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atspeed racing
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| posted on 9/4/10 at 12:12 PM |
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hi flak monkey
we have tuned many megasquirt, megajolt, or similar based systems (vems, predator, m-tech etc) using tuner pro or megatune software on a wide variety
of vehicles... not our prefered system but its certainly something we can do. providing the basic parameters and set up is correct, the main tuning is
pretty much straightforward.
if you were to send me a engine spec and map file, i could have a quick look over the map for you, and possibly see any problem areas in the
ignition.
- colin
www.atspeedracing.co.uk
[Edited on 9/4/10 by atspeed racing]
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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