Tuning in winter vs. summer
just messing around last night I put a very aggressive timing map in my car and was getting less than 3 counts of knock...the ambient air was 5 degrees f outside.
this afternoon i did some pulls with the same map and i was getting more than 3 counts.... ambient air was about 40. I don't have any logs, but i just know because i am using the CEL light flash knock sensor from tephra.
This is in no way proof, but it's just what i'm seeing out of my own car.
On a side note:
I have been helping my buddy tune a high horsepower NA motor for the last 2 days on a dyno. We noticed that barometric pressure had a much greater effect rather than temperature change.
Toruingbubble: do you have a density altitude meter? if so, you should give the DA(density altitude) when you log the runs.
Thanks for posting the logs... I hope to see more.
this afternoon i did some pulls with the same map and i was getting more than 3 counts.... ambient air was about 40. I don't have any logs, but i just know because i am using the CEL light flash knock sensor from tephra.
This is in no way proof, but it's just what i'm seeing out of my own car.
On a side note:
I have been helping my buddy tune a high horsepower NA motor for the last 2 days on a dyno. We noticed that barometric pressure had a much greater effect rather than temperature change.
Toruingbubble: do you have a density altitude meter? if so, you should give the DA(density altitude) when you log the runs.
Thanks for posting the logs... I hope to see more.
I don't think I'll be able to re-create the issue I saw in the fall when the knock started popping up. I had tuned in ~100* heat and the knock started up in around 50* temps I think. I mean, I'm all for trying to figure this out ... but I'm not going to make my car knock to test this stuff.
I'd go make some pulls tonight, but I re-tuned the car yesterday to get rid of that weird load curve. I also added a little fuel since I was running around 11.8:1 in those logs I posted. I have logs from last night where I was dialing it in and could compare those to tonight, but I honestly adjusted the boost and AFR based on the last log and didn't make another pass, so the AFR and boost tonight will be different.
I'd go make some pulls tonight, but I re-tuned the car yesterday to get rid of that weird load curve. I also added a little fuel since I was running around 11.8:1 in those logs I posted. I have logs from last night where I was dialing it in and could compare those to tonight, but I honestly adjusted the boost and AFR based on the last log and didn't make another pass, so the AFR and boost tonight will be different.
Newbie
Joined: Jun 2006
Posts: 25
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From: Glendale Heights, IL
How do professional tuners compensate and create a safe/proper tune for all four seasons (all temperatures) while only having your car one day, at one temperature, w/ one humidity? I don't know enough about tuning or how the car's sensors compensate in order to properly understand. Can anyone help?
It will depend on if there is a seasonal change in fuel, as well as the systems being tuned.
If it's a standalone, or non trim compensating system then it simply cannot be done properly, IMO.
Sure, you can dumb it down, but to do it RIGHT, you need to revisit it.
OBD based systems, if done right will adapt, but the only way to really understand is if the tuner has an extreme understanding of the region, and personal experience (say, with a personal car) to be able to know the type of trends and tuning with them, not around them.
I can elaborate further if you'd like.
Jorge (RiftsWRX)
www.ProjectWRX.com
I know I've been out of this thread for a little bit, but I've been watching this thread https://www.evolutionm.net/forums/sh...d.php?t=318623
for a little while now and it might hold some sway as to why the timing increases happen.
for a little while now and it might hold some sway as to why the timing increases happen.
How do professional tuners compensate and create a safe/proper tune for all four seasons (all temperatures) while only having your car one day, at one temperature, w/ one humidity? I don't know enough about tuning or how the car's sensors compensate in order to properly understand. Can anyone help?
Humidity actually plays a very small roll in the way your car runs. Temperature on the other hand plays a much larger roll. Inlet air temperature increases octane requirements by 0.5 per 10 degree temperature increase. Cold air is denser and more oxygen molecules are present in the air which in turn increases cylinder pressures. This is why a car feels faster on cold days but it also inhibits proper atomization of fuel which can affect the combustion process in other ways. Hotter air intake temps directly raise combustion temperatures, which in turn increases the probability of knock.
TouringBubble, it's possible that the table changes cold start or cold idle parameters. If you saw advanced timing then that is what it should be doing since a car will run and idle better in cold weather if the ignition timing is advanced somewhat - this counteracts the issue of poor fuel atomization.
AFR is most affected by temperature (colder temps will require more fuel to achieve the same AFR due to increased oxygen content) but a MAF is able to read the increased "mass" or density of the air so it is able to fuel appropriatly for the additional air molecules.
I suggest logging the car at idle and on a cold start. I think your likely to see more changes in your experiments.
AFR is most affected by temperature (colder temps will require more fuel to achieve the same AFR due to increased oxygen content) but a MAF is able to read the increased "mass" or density of the air so it is able to fuel appropriatly for the additional air molecules.
I suggest logging the car at idle and on a cold start. I think your likely to see more changes in your experiments.
Last edited by Mr. Evo IX; Feb 4, 2008 at 03:55 PM.
Off-topic, but I am the originator of this thread....can someone help me out with my newbie LC1 question?
https://www.evolutionm.net/forums/sh...d.php?t=323185
https://www.evolutionm.net/forums/sh...d.php?t=323185
Joined: Jul 2010
Posts: 26
Likes: 0
From: Live in Jacksonville,NC from Upstate NY
Gunna bump this to the top. Id like to see if there has been any new methods regarding tuning in the winter and how your car will run in the summer. Last post was in 2008!!
Lets hear it!!
Lets hear it!!
agree +1 with you
I'm going to have to disagree about knocking more in the winter.
Knocking occurs when cylinder temps are too high for the given fuel,ie the "flashpoint". In the winter you see the lowest IAT's resulting in lower cylinder temps resulting in less detonation. People generally run the best MPH at the track when its cold.
in the winter, yes you are seeing more volume of air in the cylinder(PV=nRT, for those who have take high school chemistry) but at a lower temperature. You would think that the increased boost would cause more detonation, but actually its the oppostite.
plus, in the winter the cars cooling system can maintain lower temperatures because of newtons law of cooling
T(t)= T(actual) + [T(radiator)-T(actual)]constant
Which basically states, the greater the difference in the cars radiator and ambient air temperature the faster it will be cooled. This temperature thing obvious to most people but you'd be surprised.
Most detonation starts from hot spots on the head, and the cooler you can keep the head, the less likely you are to see knock or detontion.
I suck at writing but i hope i got my point across.
Knocking occurs when cylinder temps are too high for the given fuel,ie the "flashpoint". In the winter you see the lowest IAT's resulting in lower cylinder temps resulting in less detonation. People generally run the best MPH at the track when its cold.
in the winter, yes you are seeing more volume of air in the cylinder(PV=nRT, for those who have take high school chemistry) but at a lower temperature. You would think that the increased boost would cause more detonation, but actually its the oppostite.
plus, in the winter the cars cooling system can maintain lower temperatures because of newtons law of cooling
T(t)= T(actual) + [T(radiator)-T(actual)]constant
Which basically states, the greater the difference in the cars radiator and ambient air temperature the faster it will be cooled. This temperature thing obvious to most people but you'd be surprised.
Most detonation starts from hot spots on the head, and the cooler you can keep the head, the less likely you are to see knock or detontion.
I suck at writing but i hope i got my point across.
What would be considered a "normal" fluctuation between cold weather/warm weather AFRS and boost? Are we talking ~.2-.3 difference in fueling or what?
Also, anyone care to explain modifying this temp compensation map?
thanks
Also, anyone care to explain modifying this temp compensation map?
thanks
mrfred said the correct way would be to tweak the air density table
Does anybody know how to do this? I'm looking at the relative air density vs Temp for airflow hz and I'm clueless what to do with it.
Does anybody know how to do this? I'm looking at the relative air density vs Temp for airflow hz and I'm clueless what to do with it.