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i think the low octane is what the ECM reverts to at a certain point if it keeps detecting knock every time it tries decaying KR. could be wrong, but i've never had an issue with both tables mirrored.
Im not saying its not doable. Just dont think there is a reason to if the option to retain both is available
 

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I guess i should correct that it can pull but only what is in that table. It cant pull more if necessary or revert down to the lower table.
dug this up. Spark Tables and knock sensors

if i understand that right, i think what happens is that you effectively disable knock learn. it can't "blend" in between the two tables. it will still pull timing when it sees knock, but if it's constantly knocking, it can't learn, since regardless of the learn factor it is always using the same values for base timing.

so if you're running around flooring it on 87 you may be F'd. if you have the occasional knock, you should be ok.

which makes sense based on what i am seeing in terms of the values and tables under engine/spark/retard for an E40.

you make a good point for having the low octane value have less overall timing for a boosted motor, though. things are a lot more sensitive to timing and you can more readily blow up some stuff.
 

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Discussion Starter · #403 ·
did you notice any unusual heat from around the floor pan or coming from the center console at any time?

do a wot run on an open road and then stop and get out, take a good look at your cats. see if you can see them getting red. check them with an ir thermo.

dropping them and slapping a pair of test pipes in shouldn't be too hard.
I assume with that first comment you are curious if the clutch is slipping. It is not. When sitting on the dyno for a couple hours the shifter boot was luke warm, but it was not at all warm when we were driving around doing the street tuning. Tuner even commented that the clutch was not slipping.

The cats are Kooks high flow cats. I talked about replacing them with Kooks Green cats or Magnaflow ceramic substrate cats but I didn't do that (yet). The Kooks cat pipes are 3 inch pipe in and out and match the 3 inch collector outlet on the headers. The MF catback is 2.5 inch all the way out.

The day of tuning was nice, only about 75 degrees out, but he kept commenting that there was no knock or knock retard going on. That is why he kept adding timing as long as the added timing took the power curve up. We stopped at 22 because anything beyond that was asking from trouble knock or no knock.
 

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dug this up. Spark Tables and knock sensors

if i understand that right, i think what happens is that you effectively disable knock learn. it can't "blend" in between the two tables. it will still pull timing when it sees knock, but if it's constantly knocking, it can't learn, since regardless of the learn factor it is always using the same values for base timing.

so if you're running around flooring it on 87 you may be F'd. if you have the occasional knock, you should be ok.

which makes sense based on what i am seeing in terms of the values and tables under engine/spark/retard for an E40.

you make a good point for having the low octane value have less overall timing for a boosted motor, though. things are a lot more sensitive to timing and you can more readily blow up some stuff.
limited to what the knock max table is vs having the low octane table. guess the point is mute though either way.

even with the dyno chart it doesnt mean much. mine is posted in my thread if you want to compare at least
 

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Discussion Starter · #409 ·
any chance you got some lousy gas?
Always get gas from the same place for all my cars. Never got bad gas there even once. If they were throwing out bad gas I'd have noticed on my daily and also the same tank of gas was partially used while it was NA and it ran just great. And well, honestly, it runs great now, just not the output that was expected.

Tuner suggested shrinking the plug gap a bit more and then of course doing our cat/air filter testing.
 

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I see what you guys are saying about HPtuners and agree. But if you are paying a professional with a dyno isn’t his job to dial it in and make it run right? If I went to a shop for a full tune and dyno AND had to run around and log stuff and figure it out myself with HPtuners what am I paying for?
 

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I see what you guys are saying about HPtuners and agree. But if you are paying a professional with a dyno isn’t his job to dial it in and make it run right? If I went to a shop for a full tune and dyno AND had to run around and log stuff and figure it out myself with HPtuners what am I paying for?
Yes but as @Logan71 just had issues youre stuck relying on someone vs gaining a little knowledge and being able to diagnose anything yourself.

To each their own. I think learning it has a huge benefit over someone just handing their car over
 
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