- Wed Sep 04, 2024 4:18 am
#69382
Yes, altering a cylinder's fuel and timing is due to engine flaws. All engines have flaws, some more, some less. You can look at the cylinder head flow data of two or four ports and find some rather wide variation. Add to that differences in each intake runner, each exhaust port and tube or runner, etc, and pretty soon it can be shocking.
Yet more issues are due to heat or cooling, such as the famous Mopar I4 turbo engines (2.0, 2.2, 2.5, etc) that have poor coolant circulation for the last cylinder. It is a design flaw, and it's not common to 'fix' it. So, they de-tune the engine enough to avoid knock in #4 on pump gas. Or, buy higher octane. But the alternative is to alter the tune to allow all the cylinders to run at their capacity, not held back by that hot one. That's ICFT for flows, and ICIT for heat.
I would say integer timing increments are fine. Most that need this kind of attention are requiring perhaps 2 or 3°, or more, and less than that is a minor issue and not worth the time. I see this when reading plugs and checking knock, and it may show some varied but similar signs of knock onset. But, if one cylinder sticks-out with heavy signs, or no signs, that's when it's worth looking closer for some special treatment.
IMO - while we can assume that race teams and competitors would find quick performance use of these features; getting a hot cylinder to not knock on a hot day in commuter traffic can be just as useful for engine safety and longevity on that last fill-up from that 'other' fuel station. Here's hoping you have that capability and do not need it.
Yet more issues are due to heat or cooling, such as the famous Mopar I4 turbo engines (2.0, 2.2, 2.5, etc) that have poor coolant circulation for the last cylinder. It is a design flaw, and it's not common to 'fix' it. So, they de-tune the engine enough to avoid knock in #4 on pump gas. Or, buy higher octane. But the alternative is to alter the tune to allow all the cylinders to run at their capacity, not held back by that hot one. That's ICFT for flows, and ICIT for heat.
I would say integer timing increments are fine. Most that need this kind of attention are requiring perhaps 2 or 3°, or more, and less than that is a minor issue and not worth the time. I see this when reading plugs and checking knock, and it may show some varied but similar signs of knock onset. But, if one cylinder sticks-out with heavy signs, or no signs, that's when it's worth looking closer for some special treatment.
IMO - while we can assume that race teams and competitors would find quick performance use of these features; getting a hot cylinder to not knock on a hot day in commuter traffic can be just as useful for engine safety and longevity on that last fill-up from that 'other' fuel station. Here's hoping you have that capability and do not need it.
-= If it was easy, everyone would do it =-
Impressive.
- By Mappie