Vaughany Posted June 12, 2004 Share Posted June 12, 2004 Hi all Camn someone please clarify the following for me as I am not entirely sure. 1) What is detonation? 2) What causes it? 3) How can you stop it? 4) How can you tell if your Supra has it? Thanks Quote Link to comment Share on other sites More sharing options...
Digsy Posted June 12, 2004 Share Posted June 12, 2004 Det is uncontrolled ignition in the combustion chamber. There is a subtle difference between detonation and pre-ignition. IIRC pre-ignition is the nasty one. Det can be just as bad if not caught quickly though. Det (also known as "pinking" or "knock" because of its characteristic noise) is caused by multiple ignition sources in the combustion chamber. The sound that it produces is caused by the collision of the flame fronts with in the combutsion chamber. The associated vibration can be picked up by piezo-electric sensors which can tell the ECU to adjust the engine tune to take the engine out of det. Possible causes of det are: High cylinder temperatures (poor engine cooling or intercooling). High ambient temperature. Lean mixture. Too much spark advance. Hot spots in the combustion chamber. Too low an octane fuel for the state of tune. Symptoms are a light metallic knocking noise from the engine under high load. Wheather you can hear this is another matter. Eventually det will erode the piston crown away due to the localised shock loading as the flame fronts in the combustion chamber collide above it. The solutions to det is basically getting your fueling right for the level of tune you are running, Quote Link to comment Share on other sites More sharing options...
Miguel Posted June 13, 2004 Share Posted June 13, 2004 heres a link that puts it quite nicely although Darren has explained it spot on:thumbs: http://www.misterfixit.com/deton.htm Or heres another that totaly contradicts the 1st explanation http://www.streetrodstuff.com/Articles/Engine/Detonation/ Quote Link to comment Share on other sites More sharing options...
dude Posted June 13, 2004 Share Posted June 13, 2004 And this can be the result Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted June 13, 2004 Share Posted June 13, 2004 Ahh, valve lightening! Quote Link to comment Share on other sites More sharing options...
dude Posted June 13, 2004 Share Posted June 13, 2004 Gas flowing !!!! Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
Wez Posted June 13, 2004 Share Posted June 13, 2004 Originally posted by Darren Blake Symptoms are a light metallic knocking noise from the engine under high load. Wheather you can hear this is another matter. If you are using some head cans you can hear det, the normal engine noise sounds very smooth and uninterupted and det/knock sounds like someone dropping a pin into a tin can. Quote Link to comment Share on other sites More sharing options...
dude Posted June 13, 2004 Share Posted June 13, 2004 Originally posted by Wez If you are using some head cans you can hear det, the normal engine noise sounds very smooth and uninterupted and det/knock sounds like someone dropping a pin into a tin can. Wez i'll let you have a go of my electronic ones when you come down !!!! Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
Wez Posted June 13, 2004 Share Posted June 13, 2004 Hey John, I couldn`t find anywhere to buy some so ended up making a set, where did you get yours from? Quote Link to comment Share on other sites More sharing options...
dude Posted June 13, 2004 Share Posted June 13, 2004 Originally posted by Wez Hey John, I couldn`t find anywhere to buy some so ended up making a set, where did you get yours from? Mac tools , i can monitor 6 diff points for noise , ideal for tracking down chassis squeaks /knocks etc as well as DET . Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
Vaughany Posted June 13, 2004 Author Share Posted June 13, 2004 Thanks for the info everyone. So the chances are that I wont be able to hear if my soop is suffering from DET. The car has been dynoed and the fuelling is fine so I am hoping that everything with car is good. If I am unable to hear the DET without specialists equipment, is there any other way that you can tell if you are getting DET. Does the drive alter etc, can I take the Car to a tuner who will be able to test for det using Headphones etc. If so does anyone know of one in the Northamptonshire area. There is a company called G Force in Aylesbury that I believe have a rolling road and all the necessary eqpt to test for Det. Has anyone used them before and what is their opinion of the place. I have been lead to belive that they specialise in Porsches and Imprezas so not sure if they will know anything about Supras. Thanks Quote Link to comment Share on other sites More sharing options...
Jake Posted June 13, 2004 Share Posted June 13, 2004 Originally posted by Vaughany So the chances are that I wont be able to hear if my soop is suffering from DET.That's right. My car Dets at 1.3 Bar but I can't hear it on the road, only on a Dyno. If I am unable to hear the DET without specialists equipment, is there any other way that you can tell if you are getting DET. Yep! Quote Link to comment Share on other sites More sharing options...
Wez Posted June 14, 2004 Share Posted June 14, 2004 Originally posted by Vaughany If I am unable to hear the DET without specialists equipment, is there any other way that you can tell if you are getting DET. http://www.mkivsupra.net/vbb/showthread.php?threadid=22174 Quote Link to comment Share on other sites More sharing options...
heckler Posted June 14, 2004 Share Posted June 14, 2004 Originally posted by dude Wez i'll let you have a go of my electronic ones when you come down !!!! Dude:flame Dev and they make you realise how noisy the valve gear is... I had a listen to mine when I had my car down at Dudes.... How Noisy?! Quote Link to comment Share on other sites More sharing options...
carl0s Posted June 14, 2004 Share Posted June 14, 2004 Originally posted by Darren Blake Det (also known as "pinking" or "knock" because of its characteristic noise) I've always been unsure, but now it makes complete sense - it's pinging, not "pink"ing, surely. I think a lot of people say "pinking" when it should be "pinging". Quote Link to comment Share on other sites More sharing options...
dude Posted June 14, 2004 Share Posted June 14, 2004 Pinking /pinging .... you say Tamaaatow i say Tomatoe !!!!! Either way its bad news if you saw my motor you'd agree Dude:flame Dev Quote Link to comment Share on other sites More sharing options...
carl0s Posted June 14, 2004 Share Posted June 14, 2004 bizzare. It seems us British call it pinking, while everyone else calls it pinging. I reckon someone british misheard once upon a time, because a 6,400Hz knock could be described as a 'ping' , but hardly as a 'pink' :-) Quote Link to comment Share on other sites More sharing options...
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