Detonation/knocking question
08-14-07, 03:31 PM
#1
Rotary Enthusiast
Thread Starter
iTrader: (1)
Join Date: Aug 2005
Location: Canada
Posts: 1,315
Likes: 0
Received 0 Likes
on
0 Posts
Detonation/knocking question
How do I prevent it? Is that what the knock sensor is for? If I am detonating, what sound does it make?
I found all the easy fix:
Detonation can be prevented by:
The use of a fuel with higher octane rating
The addition of octane-increasing "lead", methylcyclopentadienyl manganese tricarbonyl (MMT), isooctane, or other antiknock agents.
Increasing the amount of fuel injected/inducted (resulting in lower Air to Fuel Ratio)
Reduction of cylinder pressure by increasing the engine revolutions (lower gear), decreasing the manifold pressure (throttle opening) or reducing the load on the engine, or any combination.
Reduction of charge (in-cylinder) temperatures (such as through cooling, water injection or compression ratio reduction).
Retardation of spark plug ignition.
Improved combustion chamber design that concentrates mixture near the spark plug and generates high turbulence to promote fast even burning.
Use of a spark plug of colder heat range in cases where the spark plug insulator has become a source of pre-ignition leading to detonation.
What else can I do?
I found all the easy fix:
Detonation can be prevented by:
The use of a fuel with higher octane rating
The addition of octane-increasing "lead", methylcyclopentadienyl manganese tricarbonyl (MMT), isooctane, or other antiknock agents.
Increasing the amount of fuel injected/inducted (resulting in lower Air to Fuel Ratio)
Reduction of cylinder pressure by increasing the engine revolutions (lower gear), decreasing the manifold pressure (throttle opening) or reducing the load on the engine, or any combination.
Reduction of charge (in-cylinder) temperatures (such as through cooling, water injection or compression ratio reduction).
Retardation of spark plug ignition.
Improved combustion chamber design that concentrates mixture near the spark plug and generates high turbulence to promote fast even burning.
Use of a spark plug of colder heat range in cases where the spark plug insulator has become a source of pre-ignition leading to detonation.
What else can I do?
08-15-07, 01:07 AM
#8
F yo couch!
iTrader: (6)
Join Date: Feb 2007
Location: Belleville, NJ
Posts: 2,321
Likes: 0
Received 0 Likes
on
0 Posts
i dont know what your so worried about, things like that almost never happen when your treating your car right....unless your being a bad little cookie, or have messed with the engine.....and even if it does minor detonation is almost never fatal to the engine unless it was going to begin with....
also because of how different the engine is, those little pops in the exhaust are ok, and actually sorta normal, if you only have one cat then loud pops and ocasional backfire i normal, if your running on no cats then spitting flames is normal and perfectly ok
its the way the engine is made that makes these things ok, when it would be fatal for a piston,
also running a lower octain aka regular...is also ok, it even says it on all the info sites that have ever been made on our cars, thats why we are an optimum sports car, were built to do what others cant
also because of how different the engine is, those little pops in the exhaust are ok, and actually sorta normal, if you only have one cat then loud pops and ocasional backfire i normal, if your running on no cats then spitting flames is normal and perfectly ok
its the way the engine is made that makes these things ok, when it would be fatal for a piston,
also running a lower octain aka regular...is also ok, it even says it on all the info sites that have ever been made on our cars, thats why we are an optimum sports car, were built to do what others cant
08-15-07, 08:48 AM
#10
i dont know what your so worried about, things like that almost never happen when your treating your car right....unless your being a bad little cookie, or have messed with the engine.....and even if it does minor detonation is almost never fatal to the engine unless it was going to begin with....
also because of how different the engine is, those little pops in the exhaust are ok, and actually sorta normal, if you only have one cat then loud pops and ocasional backfire i normal, if your running on no cats then spitting flames is normal and perfectly ok
its the way the engine is made that makes these things ok, when it would be fatal for a piston,
also running a lower octain aka regular...is also ok, it even says it on all the info sites that have ever been made on our cars, thats why we are an optimum sports car, were built to do what others cant
also because of how different the engine is, those little pops in the exhaust are ok, and actually sorta normal, if you only have one cat then loud pops and ocasional backfire i normal, if your running on no cats then spitting flames is normal and perfectly ok
its the way the engine is made that makes these things ok, when it would be fatal for a piston,
also running a lower octain aka regular...is also ok, it even says it on all the info sites that have ever been made on our cars, thats why we are an optimum sports car, were built to do what others cant
__________________________________________________ _____________
FWIW, the owners manual in my TII says I can run 87 octane......I don't, but just saying
If you hear detonation. you should be looking for your compression tester when you get home. The noise is extremely distinctive, and sticks out like a sore thumb over the rest of the engine noise.
If you are extremely paranoid about it, retard your timing a couple of degrees. But running higher octane in itself on a mostly stock setup will be enough of a saftey net honestly.
08-15-07, 11:01 AM
#12
Rotary Enthusiast
Thread Starter
iTrader: (1)
Join Date: Aug 2005
Location: Canada
Posts: 1,315
Likes: 0
Received 0 Likes
on
0 Posts
If you hear detonation. you should be looking for your compression tester when you get home. The noise is extremely distinctive, and sticks out like a sore thumb over the rest of the engine noise..
If you are extremely paranoid about it, retard your timing a couple of degrees. But running higher octane in itself on a mostly stock setup will be enough of a saftey net honestly.
Thanks Classic, again.
Helgah, FYI, a backfire is not detonation.
Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder has been ignited by the spark plug and the smooth burning is interrupted by the unburned mixture in the combustion chamber exploding before the flame front can reach it. The engineered combusting process ceases, because of the explosion, before the optimum moment for the four-stroke cycle. The resulting shockwave reverberates in the combustion chamber, creating a characteristic metallic "pinging" sound, and pressures increase catastrophically. It can range from hardly noticeable to complete engine destruction..
08-22-07, 12:10 AM
#15
F yo couch!
iTrader: (6)
Join Date: Feb 2007
Location: Belleville, NJ
Posts: 2,321
Likes: 0
Received 0 Likes
on
0 Posts
my apologies i did not mean do miss inform, rather i misunderstood...and for the most part was confused......since i am a big boy i will admit i was wrong....and further more to show my maturity i wish to learn.....
so how can you tell the difference between detonation and those little backfires?(this is what threw me off by the way)
so how can you tell the difference between detonation and those little backfires?(this is what threw me off by the way)
08-22-07, 12:47 AM
#16
well, one (backfire) is a loud pop, like a gunshot, usaully preceded or followed by the sound of a flamethrower (kinda). The other (detonation) sounds like metal exploding. Not a good sound. If you heard THAT sound you would be like.... ****... my engine just blew up.
Thread
Thread Starter
Forum
Replies
Last Post
Nosferatu
2nd Generation Specific (1986-1992)
7
09-05-15 02:13 PM