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The temps the last 2 days have been in the 40-60F range instead of the normal 15-30F, and with winter fuel in the tank and it's higher butane content (among other things to increase volatility in the cold), it seems to be causing a LOT more knock than normal. When it's in the 10-30 degree range I will sometimes get a single knock in a couple cylinders on the way to/from work, but never over 1. This morning, however, with its warmer temps (40+) and me hammering on it to get to work because and we had an issue come up (and I was supposed to be off today), I ended up with 3 in cylinder 4 and 1 in cylinder 3 on a single 3rd-gear run down an on-ramp, and stomping on it to get around somebody in ~45-mph traffic in 3rd gave me another 2 in cyl 4 and 1 in cyl 3. Normally cylinder 4 is the problem child on mine due to it being the last in line for cooling (from what I've read), but still... it was apparently ticked at me for not giving it the day off, too...

It seems to only do so upon initially hammering on it and not further up in the rpms based on when the knocks occurred (I was watching knock counts), but still it's a pain in the neck on these warmer days... Can't wait to get the WMI kit installed, but until things calm down with house shopping, that's probably not going to happen unless I just HAVE to go work out in the garage to de-stress. Still have to run the electric wires, wmi line, and boost line, but at least I have the parts now....

The temps are supposed to drop back to the 30's and 40's over the coming days and things should be back to normal, but was just wondering if anybody else saw this with their tuned car?
 

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The temps the last 2 days have been in the 40-60F range instead of the normal 15-30F, and with winter fuel in the tank and it's higher butane content (among other things to increase volatility in the cold), it seems to be causing a LOT more knock than normal. When it's in the 10-30 degree range I will sometimes get a single knock in a couple cylinders on the way to/from work, but never over 1. This morning, however, with its warmer temps (40+) and me hammering on it to get to work because and we had an issue come up (and I was supposed to be off today), I ended up with 3 in cylinder 4 and 1 in cylinder 3 on a single 3rd-gear run down an on-ramp, and stomping on it to get around somebody in ~45-mph traffic in 3rd gave me another 2 in cyl 4 and 1 in cyl 3. Normally cylinder 4 is the problem child on mine due to it being the last in line for cooling (from what I've read), but still... it was apparently ticked at me for not giving it the day off, too...

It seems to only do so upon initially hammering on it and not further up in the rpms based on when the knocks occurred (I was watching knock counts), but still it's a pain in the neck on these warmer days... Can't wait to get the WMI kit installed, but until things calm down with house shopping, that's probably not going to happen unless I just HAVE to go work out in the garage to de-stress. Still have to run the electric wires, wmi line, and boost line, but at least I have the parts now....

The temps are supposed to drop back to the 30's and 40's over the coming days and things should be back to normal, but was just wondering if anybody else saw this with their tuned car?
I don't ever have problems with knock, even with the not-so-ideal 91 octane here in Kansas.
 
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Discussion Starter #3
Our gas here in CO is garbage, especially around Denver.. I was having knock issues in the summer on 91 that surprised even Brian @ JST. Not sure if it's the very low humidity or the tree huggers adding stuff to our blend to make it worse, but it's crap.
 

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Discussion Starter #9
I've been watching knock count per cylinder instead of timing corrections recently, which enables me to see totals for each time I drive. It also allows me to notice more easily where they hit when I get on it since it's not usually changing digits so quickly like it does when watching ignition corrections.

FWIW, I did switch to the gauge layout that shows timing corrections and it went to +2.6 on all cylinders except for cylinder 4, which topped out at +1.8 before I backed out of it in 3rd. So, technically I got at least 1-2 higher knock count this morning than my earlier totals since it pulled some advance from cylinder 4 on that run. It still ended positive (since my knocks normally hit early on), but cylinder 4 usually is the one which lags if it's going to knock.

@ddfred, I thought negative timing corrections were brought about by knock count (and intensity of it)? That was my understanding, so if it's not, please educate me as I'd like to learn how it all works.

OAR hasn't changed, but I'll set that gauge up on the way home to see if it does at all.
 

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I've been watching knock count per cylinder instead of timing corrections recently, which enables me to see totals for each time I drive. It also allows me to notice more easily where they hit when I get on it since it's not usually changing digits so quickly like it does when watching ignition corrections.

FWIW, I did switch to the gauge layout that shows timing corrections and it went to +2.6 on all cylinders except for cylinder 4, which topped out at +1.8 before I backed out of it in 3rd. So, technically I got at least 1-2 higher knock count this morning than my earlier totals since it pulled some advance from cylinder 4 on that run. It still ended positive (since my knocks normally hit early on), but cylinder 4 usually is the one which lags if it's going to knock.

@ddfred, I thought negative timing corrections were brought about by knock count (and intensity of it)? That was my understanding, so if it's not, please educate me as I'd like to learn how it all works.

OAR hasn't changed, but I'll set that gauge up on the way home to see if it does at all.
I think some of this varies by tune. Are you Stratified? Strat even says their strategy is to have a higher initial correction intentionally the first time knock is heard to compensate for performance as drive time increases.

Either way, I'm not far from @Duece McCracken and get some minor negative corrections too on some pulls with this winter blend in PA.
 

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I've been watching knock count per cylinder instead of timing corrections recently, which enables me to see totals for each time I drive. It also allows me to notice more easily where they hit when I get on it since it's not usually changing digits so quickly like it does when watching ignition corrections.

FWIW, I did switch to the gauge layout that shows timing corrections and it went to +2.6 on all cylinders except for cylinder 4, which topped out at +1.8 before I backed out of it in 3rd. So, technically I got at least 1-2 higher knock count this morning than my earlier totals since it pulled some advance from cylinder 4 on that run. It still ended positive (since my knocks normally hit early on), but cylinder 4 usually is the one which lags if it's going to knock.

@ddfred, I thought negative timing corrections were brought about by knock count (and intensity of it)? That was my understanding, so if it's not, please educate me as I'd like to learn how it all works.

OAR hasn't changed, but I'll set that gauge up on the way home to see if it does at all.
I have no idea how all these computer gizmos work; I do know that when I data log, occasionally I will get small negative corrections without getting knock.
 

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Discussion Starter #12
I have no idea how all these computer gizmos work; I do know that when I data log, occasionally I will get small negative corrections without getting knock.
I only ever saw neg. corrections that corresponded with a knock in that particular cylinder. Would be odd for you to see negatives without a knock, I'd think. 🤔??
 

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I think some of this varies by tune. Are you Stratified? Strat even says their strategy is to have a higher initial correction intentionally the first time knock is heard to compensate for performance as drive time increases.

Either way, I'm not far from @Due and get some minor negative corrections too on some pulls with this winter blend in PA.
No sir, JST. When you say "minor negative corrections", what do you mean? My ignition corrections always end up positive in a 3rd gear pull and it's seldom less overall timing advance than ~1 degree for the lagging cylinder, but it definitely gets some tip-in knock sometimes... some days more than others (such as today).
 

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No sir, JST. When you say "minor negative corrections", what do you mean? My ignition corrections always end up positive in a 3rd gear pull and it's seldom less overall timing advance than ~1 degree for the lagging cylinder, but it definitely gets some tip-in knock sometimes... some days more than others (such as today).
Generally nothing more than -1.00 - usually -.050 sometimes, but will immediately correct to positive on a pull, it won't stay that way. Could also be PA's bumpy roads causing it during a pull.
 

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Where are you getting gas at? I know some stations are better than others. Are you running the JST 91 or 93 tune? I have the JST 91 tune and have been fine lately. I also live in your area and have only used exxon synergy since my tune..mostly just to get a baseline. In not sure if its good gas or not, but it's supposed to be for D.I. turbo motors, and I've done pretty well on it. You can always run by flyers and put a gallon of 100 in :). My biggest correction was yesterday at ~1.58. Usually they are .5 or less than 1 and I would consider that pretty normal after talking to JST.
 

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Discussion Starter #16
I've run Costco fuel (try not to anymore because of how much 85 I ended up getting with the fill-up), King Soopers (Kroger), and Exxon. The problem I have with Exxon is that their 85 is around $2.45 right now and the 91 is north of $3.00, which is insane. Around here they gouge you for around 80 cents difference between the swill (85) and 91. I've been running King Sooper's for the last 3 or 4 fill-ups and only had an issue this time around once the temps got higher. FWIW, their cost difference between 85 and 91 is around 45 cents, so much less than Exxon. Mileage (mpg) between Exxon and KS fuel isn't much different, either, so saving $4.00+ per fill-up adds up pretty fast when I'm running out a tank each week.

I'm on a JST 91 tune, btw. I was running Exxon pretty exclusively for a while until prices started climbing so much. Exxon kinda of breaks it off in us around here and I can't justify the price gap between their 91 and KS' 91 at this point.
 
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I only ever saw neg. corrections that corresponded with a knock in that particular cylinder. Would be odd for you to see negatives without a knock, I'd think. 🤔??
I stated this incorrectly. I should have said lower positive corrections instead of negative corrections; as in seeing +4 or +5 instead of +5 or +6 degrees. Sorry for the confusion.
 
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Forgive what may seem to be a stupid question to some, but what is the go with winter fuel vs summer fuel?
I'm in Australia, so we have the same fuel no matter the season as we don't generally experience the extreme lows some of you doo.
Where I am coldest is generally 8-10C and hottest 45C (not in the same season generally)
 

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Forgive what may seem to be a stupid question to some, but what is the go with winter fuel vs summer fuel?
I'm in Australia, so we have the same fuel no matter the season as we don't generally experience the extreme lows some of you doo.
Where I am coldest is generally 8-10C and hottest 45C (not in the same season generally)
Winter fuels in the U.S. generally are lower quality due to the detergents required to to keep the higher volatility in check. Winter fuels evaporate more quickly, and are more unstable.

Summer fuels have detergents that allow less evaporation and more energy. It's really all because of emissions mandates and controlling fuels evaporative properties based on the air temperature/climate.
 
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