A new analysis of Premium vs. Regular

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Mar 5, 2015 | 07:44 AM
  #481  
Quote: Where are those pertinent "results"you promised us?
Still waiting for warmer temps. It's been below 20F here for most of the last 2 weeks. I don't see much value/benefit in making the test runs when it's that cold.

I think ideally it's be best to wait until it's at least above 40F, which may come in the next week or 2...

Does anyone have thoughts about whether a 3 degree timing pull can be attributed to knock?
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Mar 5, 2015 | 05:32 PM
  #482  
Sounds good, man. Keep us posted and stay warm.
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Mar 6, 2015 | 04:10 AM
  #483  
Quote: A few things that need to be said.

The knock sensor is reactive, not proactive. It can only react to detonation, it can't prevent it. Relying on the knock sensor as a form of tuning by either an individual or a manufacturer is wrong. The knock sensor is there to soften the blow for a short period of time, such as the owner accidentally running 87 once or twice.
This is true in most vehicles, but not in the case of the TL I'd say. For the TL, it's not even what I would consider reactive, as it cannot be for any active method of intercepting and reducing knock. I disagree though that it is there to 'soften the blow' for accidental use of a lower octane. In fact, Hondata has shown that the main ignition tables are MBT on a very high octane fuel, under which even 93 would knock if it were not for the knock control methodologies. In this case, I'd say the knock sensor DOES prevent detonation on a proactive basis, and you can't trust it to be reactive fast enough.

Quote: I can't hear mine until there's about 12 degrees of knock retard occurring. By then it's too late and I have a blown head gasket.
How do you 'hear' knock retard? The entire point of it being retard is that the knock sensor 'predicts' knock, and won't let the engine knock. Are you hearing a different 'engine sound'? It's surely not knock you are hearing, because then it wouldn't have 12 degrees of knock retard. I was just on the dyno yesterday and the knock sensor is stupid, and extremely sensitive, and its 'predictable' logic is annoying. I had NO knock counts, so it never knocked, but in some pulls, the knock control was higher, and it retarded timing, up to 6 degrees in some instances. Guess what you didn't hear? Any knocking, because it wasn't, and it surely wouldn't with 6 degrees less timing. Only after I desensitized the knock sensor, decreased the KIL tables and increased the MBT table did I get any true knock, and boy could you hear that! But once again, the reason it knocked was because there was NO knock retard, so I'm interested in your hearing knock retard.

Quote: The TL will detonate on 87. It might not do it constantly but it will detonate, period. Your ears are not the best tool for hearing the detonation, keep that in mind.
It MIGHT be able to knock a bit, but again, the TL's knock control method is so sensitive and weird that I bet you'd be running around with knock retard all the time based on a higher knock control %, rather than experiencing tons of knocking.
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Mar 6, 2015 | 02:32 PM
  #484  
Quote: ...In this case, I'd say the knock sensor DOES prevent detonation on a proactive basis....
I don't believe this is true (proactive), but how would this happen if true? Isn't the knock sensor just a microphone with no logic?

FWIW, in 11 years and 190K miles, I've never experienced audible knock coming from my engine, even in 100F Louisiana temps.
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