How can you trust a tune? (tune noob)

[Tromatic]

MAT (Mutually Assured Testing). Trust, but verify.

[Phantobe]

Originally Posted by Toyarzee

"Detonation (Spark Knock ) is a form of abnormal combustion that results from too much heat and pressure in the combustion chamber. The fuel ignites spontaneously causing a sudden rise in cylinder pressure. The result is a sharp hammer-like blow on the piston that produces a metallic knocking or pinging noise. Light detonation is considered normal and should not cause any damage, but heavy or prolonged detonation can crack rings, pound out piston ring grooves, punch holes through the tops of pistons, smash rod bearings and blow head gaskets." -AA1CAR

From a performance tuners perspective, detonation is likely to exist simply from too much timing advance and lean afr's. On an already high compression motor, this is more likely to happen and can have a greater adverse effect on the motor.

Long story short, yes, you can blow your motor driving hard when you hear knock. The sound under heavy load should be a sign to immediately stop what you're doing.

I have caused engine failure while road tuning on a piggyback after introducing a separate methanol controller into the tuning mix and under certain loads, the methanol motor would stop pumping and the afr would climb instantly.

I understand what knock is but given the correction methods of modern ECUs & the ability to instantly pull timing to compensate.

I can't imagine how someone could blow their engine unless they had a piss poor tune.

[steve99]

Originally Posted by Phantobe

I understand what knock is but given the correction methods of modern ECUs & the ability to instantly pull timing to compensate.

I can't imagine how someone could blow their engine unless they had a piss poor tune.

Their are limits to the amount of timing the ecu can pull, on an NA car the tune would have to be pretty bad to exceed those limits if your running the correct fuel.

here is a Stock car stock tune on South Africian 95ron fuel , that the best fuel they get, their horsepower is down but they don't blow up.
IAM=0.2 and still pulling -3 degrees its starting to get to limits of ECU compensation IAM=0 and -6 flkc is limit i believe.
Those guys were first to get DI seal problems though on the early ROM revisions which could lead to engine failure

http://datazap.me/u/steve99/south-af...ata=2-20-27-28

but on a boosted car everything is amplified and your pushing the engine much harder, small tuning problems/errors can lead to much larger knock/fueling or overboost events leading to engine failure.

[sidesleeper]

Originally Posted by Phantobe

I understand what knock is but given the correction methods of modern ECUs & the ability to instantly pull timing to compensate.

I can't imagine how someone could blow their engine unless they had a piss poor tune.

There are plenty of other failure modes that blow engines, that have nothing to do with knock or tuning.

[aagun]

ohh damn topic
lets talk with mathematics
Detonation insured by heat
heat came form fuel burn
fuel cool the cylinder if it is not burn
more rich = Reduces TQ and HP
timing advance insurance the heat = to rich to cool cylinder
timing retread = Reduces TQ and HP = cool cylinder = Reduces Detonation
hot IAT + hot air temps = insurance Detonation
cold IAT + cold air temps = Reduces Detonation
leaning = insurance Detonation = insurance TQ and HP

so tuning = insurance TQ and HP + Reduces Detonation * ( {hot IAT +AT} - {cold IAT +AT} )
Reduces Detonation = timing retread + cool cylinder

all controlled by tuner except IAT +AT so 80% of Detonation cozed by heat and 10% by leaning the map table and 10% by timing advance with 1 degree

[Kodename47]

You forgot to add that too much retarded timing causes high EGT, causing potential exhaust valve issues as well as cat problems for those that care.

[Phantobe]

Originally Posted by steve99

Their are limits to the amount of timing the ecu can pull, on an NA car the tune would have to be pretty bad to exceed those limits if your running the correct fuel.

here is a Stock car stock tune on South Africian 95ron fuel , that the best fuel they get, their horsepower is down but they don't blow up.
IAM=0.2 and still pulling -3 degrees its starting to get to limits of ECU compensation IAM=0 and -6 flkc is limit i believe.
Those guys were first to get DI seal problems though on the early ROM revisions which could lead to engine failure

http://datazap.me/u/steve99/south-af...ata=2-20-27-28

but on a boosted car everything is amplified and your pushing the engine much harder, small tuning problems/errors can lead to much larger knock/fueling or overboost events leading to engine failure.

That's crazy, that at least helps me understand the limits of the FLKC. Which kinda proves my points (at least on NA) that it'd be hard to blow up via knock, unless you have absolutely no idea what you're doing, don't log & blindly trust a tuner.

Yeah it totally makes sense as far as boosted cars, all the components are under a lot more stress.