det...
12-12-2003, 08:04 PM
#41
I understand how its created.....you fail to see you can't detect it...
OK
My car blew up, mike said it ran out of fuel, surely det.....erm sounded mint....
Oli's blew up @ dono, sounded like it pinked incar......
OK
My car blew up, mike said it ran out of fuel, surely det.....erm sounded mint....
Oli's blew up @ dono, sounded like it pinked incar......
12-12-2003, 08:21 PM
#44
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Even with engineering maths, I fail to see how the equations that would lead to an engine that didn't det' (cylinder pressures, various temp's etc) could be correct if the you don't know at what point an engine would suffer det'
We both know engines CAN det' so it stands to reason that to avoid it, you HAVE to be able to detect it, else how do you know WHAT you are avoiding or HOW to avoid it?
LOL @ sales - that doesn't mean people cannot learn other things after being in sales......I wasn't always able to program a computer, but it doesn't mean that because it wasn't my first job that I can't now
We both know engines CAN det' so it stands to reason that to avoid it, you HAVE to be able to detect it, else how do you know WHAT you are avoiding or HOW to avoid it?
LOL @ sales - that doesn't mean people cannot learn other things after being in sales......I wasn't always able to program a computer, but it doesn't mean that because it wasn't my first job that I can't now
12-12-2003, 08:26 PM
#45
No people in sales can learn to blow yer car up.....ahmed one.....WRC mapper.......really, doing it now is he.....
ENgines can det.....
How do you aviod it, map the fucker properly and don't guess...
Bill, most sales people talk bollox to get the sale, that never ever changes mate.
ENgines can det.....
How do you aviod it, map the fucker properly and don't guess...
Bill, most sales people talk bollox to get the sale, that never ever changes mate.
12-12-2003, 09:38 PM
#47
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Dingy,
I think the point Bill is trying to make is this:
If you map a car to a point where it begins to det, and then take it back a few degrees, how do you know when to retard the ignition at the point of det if det is undetectable?
I think the point Bill is trying to make is this:
If you map a car to a point where it begins to det, and then take it back a few degrees, how do you know when to retard the ignition at the point of det if det is undetectable?
12-12-2003, 10:08 PM
#52
RichardPON,
how do you know when to retard the ignition at the point of det if det is undetectable?
how do you know when to retard the ignition at the point of det if det is undetectable?
dingy,
Thought u knocked it back when it ran lean...?
Thought u knocked it back when it ran lean...?
Maybe at this point its time to admit you havent the slightest clue what the fook your talking about, and go open another beer Steve?
13-12-2003, 11:23 AM
#57
Norris Motorsport
In answer to how an engine is engineering to cope with Det, well that happens when the OE manufacturer first validates and maps the engines! It often takes months if not years on 10's of dynos's to validate an engine.
We as tuners cannot in the limited time we have, set up an engine to guarantee it wont det in all conditions. (dont forget as en engine ages conditions change) We can certainly detect pre-ignition and by experience retard the ignition so that we can hopefully prevent pre-ignition in all conditions.
Sadly the same for det cannot be said, and all we can do to try to make the engine 100% reliable is either run the engine as the engine came from the factory (i.e. fully validated for the bhp/rpm/all temperatures) or use our own experience to engineer the engine correctly. (e.g. choosing the correct combustion chamber design, keeping cylinder pressures acceptable, hence correct C.R. and so on.)
In an ideal world we could engineer an engine to be det free and validate this by continual destructive testing on dyno for all conditions, but out on the road we cannot possibly guarantee safety 100% of the time. (e.g. poor quality fuel, temperatures, air quality, engine age etc!)
May I lastly point out that over the years I spent at Jaguar depsite state of the art dynos, whilst pre ignition is easily audiable, localised detonation was not, and an engine that was sat on dyno sounding sweet running well within it's set parameters with the correct fueling and ignition, could and did often damage a piston, which upon investigation was attributed to localised abnormal combustion!
This is why we hope an engine is engineered well from the factory so that the limited methods we have of monitering combustion usually gives results reliable enough to last!
We as tuners cannot in the limited time we have, set up an engine to guarantee it wont det in all conditions. (dont forget as en engine ages conditions change) We can certainly detect pre-ignition and by experience retard the ignition so that we can hopefully prevent pre-ignition in all conditions.
Sadly the same for det cannot be said, and all we can do to try to make the engine 100% reliable is either run the engine as the engine came from the factory (i.e. fully validated for the bhp/rpm/all temperatures) or use our own experience to engineer the engine correctly. (e.g. choosing the correct combustion chamber design, keeping cylinder pressures acceptable, hence correct C.R. and so on.)
In an ideal world we could engineer an engine to be det free and validate this by continual destructive testing on dyno for all conditions, but out on the road we cannot possibly guarantee safety 100% of the time. (e.g. poor quality fuel, temperatures, air quality, engine age etc!)
May I lastly point out that over the years I spent at Jaguar depsite state of the art dynos, whilst pre ignition is easily audiable, localised detonation was not, and an engine that was sat on dyno sounding sweet running well within it's set parameters with the correct fueling and ignition, could and did often damage a piston, which upon investigation was attributed to localised abnormal combustion!
This is why we hope an engine is engineered well from the factory so that the limited methods we have of monitering combustion usually gives results reliable enough to last!
15-12-2003, 09:52 AM
#59
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Originally Posted by Stu @ M Developments
RichardPON,
how do you know when to retard the ignition at the point of det if det is undetectable?
how do you know when to retard the ignition at the point of det if det is undetectable?
dingy,
Thought u knocked it back when it ran lean...?
Thought u knocked it back when it ran lean...?
Maybe at this point its time to admit you havent the slightest clue what the fook your talking about, and go open another beer Steve?
24-11-2005, 03:57 PM
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Originally Posted by Billabong
I meant 'engineered to avoid detonation'
Detonation can be caused by either excessive temperature or excessive pressure of the fuel-air charge. Take that for granted - but how can you engineer a motor not to det' if you can't actually detect when you have reached the point of detonation? I mean you can obvioulsy ensure that cylinder head temp's etc are kept within tolerance, but if you cannot detect it, you don't know what the tolerances are....
Detonation can be caused by either excessive temperature or excessive pressure of the fuel-air charge. Take that for granted - but how can you engineer a motor not to det' if you can't actually detect when you have reached the point of detonation? I mean you can obvioulsy ensure that cylinder head temp's etc are kept within tolerance, but if you cannot detect it, you don't know what the tolerances are....
