zakkb787

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Sep 29, 2014
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Somewhat on topic, but does anyone know at what temp these engines switch from speed density or MAF tuning? Just wondering how altering the operating temp to lower temps could affect other things.
 

JoshH

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Does the L5P cooler easily retrofit onto older blocks?
I know the one from a 17-19 will. I have one sitting here I was going to install on my truck, but after seeing the improvements made for 2020, I want to get one of those now.
 

Bdsankey

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I know the one from a 17-19 will. I have one sitting here I was going to install on my truck, but after seeing the improvements made for 2020, I want to get one of those now.

Please keep us posted. I know it is something I would do to both my tow rig and built motor truck if that is the case.
 

Chevy1925

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Oil temp will probably come down but at the cost of heating up coolant temp as well.

the moment i put the aux radiator on, i saw oil temp stay much lower when pulling grades as i had more capacity for the heat. oil only saw a 20* difference from coolant compared to the 40* i usually saw. Ill be curious how it does this summer but in the tow home from the dunes, its been the most significant difference ive seen to date. That was with a cracked head and/or blow HG as well.

id love to see if a 2020 would fit and if i could ditch the air to oil cooler using it.
 

Bdsankey

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Oil temp will probably come down but at the cost of heating up coolant temp as well.

the moment i put the aux radiator on, i saw oil temp stay much lower when pulling grades as i had more capacity for the heat. oil only saw a 20* difference from coolant compared to the 40* i usually saw. Ill be curious how it does this summer but in the tow home from the dunes, its been the most significant difference ive seen to date. That was with a cracked head and/or blow HG as well.

id love to see if a 2020 would fit and if i could ditch the air to oil cooler using it.

10-4, I've been debating about mounting a large oil cooler somewhere probably near the cooling stack.

With the mishimoto thermostats my temps stay very consistent (low temp, 185F) and have rarely seen it hit 200-205 towing my 30ft 5th wheel. I haven't hooked to my gooseneck yet with this truck so I don't know what ECT will go to. I am planning on adding an oil temp gauge as well to both trucks.
 

Chevy1925

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10-4, I've been debating about mounting a large oil cooler somewhere probably near the cooling stack.

With the mishimoto thermostats my temps stay very consistent (low temp, 185F) and have rarely seen it hit 200-205 towing my 30ft 5th wheel. I haven't hooked to my gooseneck yet with this truck so I don't know what ECT will go to. I am planning on adding an oil temp gauge as well to both trucks.

youre not in the same outside heat josh and i are, thats a totally different world.
 

Bdsankey

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youre not in the same outside heat josh and i are, thats a totally different world.

Correct. Even then one would venture to say that oil temps still are above coolant while pulling a grade. Decreased oil temp means increased oil life and higher maintained viscosity so I can only make it better.
 
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DAVe3283

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Sep 3, 2009
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Somewhat on topic, but does anyone know at what temp these engines switch from speed density or MAF tuning? Just wondering how altering the operating temp to lower temps could affect other things.
I am most familiar with the LB7, and it will remain in MAF based tuning until the MAF fails (logically, not necessarily physically), then it still runs MAF based but instead of using the MAF value, looks up the expected airflow table. Went down that rabbit hole when my MAF physically failed and my expected airflow tables were WAY too low, making my truck so slow it was dangerous. AFAIK all "MAF-less" tuning for these trucks simply fails the MAF logically and maxes out the MAF fueling limits, so it doesn't restrict fuel at any time.

If you take the thermostats out or have extremely low temp t-stats, the only thing that might happen is setting a code for thermostat performance, which can be disabled. There are a couple limiters and multipliers based on ECT, but as long as you ensure those do what you want at the temperatures you expect to run, it will run fine.
I know the one from a 17-19 will. I have one sitting here I was going to install on my truck, but after seeing the improvements made for 2020, I want to get one of those now.
Please keep us posted! I also see lower oil pressure than I would like after a long hill climb, despite an aux oil cooler and my coolant temps staying in check, so I think my current limitation is getting oil heat into the coolant, not coolant heat out to the environment.
 

Chevy1925

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I am most familiar with the LB7, and it will remain in MAF based tuning until the MAF fails (logically, not necessarily physically), then it still runs MAF based but instead of using the MAF value, looks up the expected airflow table. Went down that rabbit hole when my MAF physically failed and my expected airflow tables were WAY too low, making my truck so slow it was dangerous. AFAIK all "MAF-less" tuning for these trucks simply fails the MAF logically and maxes out the MAF fueling limits, so it doesn't restrict fuel at any time.

If you take the thermostats out or have extremely low temp t-stats, the only thing that might happen is setting a code for thermostat performance, which can be disabled. There are a couple limiters and multipliers based on ECT, but as long as you ensure those do what you want at the temperatures you expect to run, it will run fine.

Please keep us posted! I also see lower oil pressure than I would like after a long hill climb, despite an aux oil cooler and my coolant temps staying in check, so I think my current limitation is getting oil heat into the coolant, not coolant heat out to the environment.

a lot of people think that.... :D
 

DAVe3283

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Sep 3, 2009
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a lot of people think that.... :D
I've followed your adventures closely, and I do realize you are in a hotter environment than me and tow on a bigger tune. But you seem to fight both coolant and oil temps, while my coolant stays right at 95°C for the whole hill.

I plan to put a bigger oil cooler on this summer and see what that does, and I really should add an oil temp gauge so I'm not just guessing. I might just do the trick of moving the fuel temp sensor to measure oil temp instead, as I never have high fuel temps.

I do wonder why GM would increase the size of the oil cooler if that wasn't a limitation? If it bolts on, I'll try it and let you know how it goes. I'm not too proud to admit I was wrong if it doesn't work.

Or are you suggesting that as soon as I get the oil heat into the coolant, then I'll have coolant temp issues? Because I could see that happening...
 

Chevy1925

don't know sh!t about IFS
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I've followed your adventures closely, and I do realize you are in a hotter environment than me and tow on a bigger tune. But you seem to fight both coolant and oil temps, while my coolant stays right at 95°C for the whole hill.

I plan to put a bigger oil cooler on this summer and see what that does, and I really should add an oil temp gauge so I'm not just guessing. I might just do the trick of moving the fuel temp sensor to measure oil temp instead, as I never have high fuel temps.

I do wonder why GM would increase the size of the oil cooler if that wasn't a limitation? If it bolts on, I'll try it and let you know how it goes. I'm not too proud to admit I was wrong if it doesn't work.

Or are you suggesting that as soon as I get the oil heat into the coolant, then I'll have coolant temp issues? Because I could see that happening...

my fight as gone back and forth over the years, not really both at the same time. oil temp, then coolant temp, then back to oil temp, then back to coolant temp. after the derale oil cooler/spal fan, i could ways keep oil temp at max, 40* higher than coolant. that meant my normal 200* coolant temp i could get the oil to range from 210 to 240 towing. the moment i hit 240, boom, coolant and oil started increasing temp with the same 40* separation. Neither going higher or lower than the other. the killerbee setup i had to be going 50-55mph for it to help at all. the fuel cooler, radiator, fan clutch, thermostats have all been small improvements that have added up but nothing like i have been looking for. the aux rad "seems" to have gotten what im after but wont know till end of may. im still going to run a smaller tune and then work it up from there.

but yes, what im saying is you increased the surface area for oil to transfer heat into the coolant but did not increase the capacity coolant can hold for heat. the 01-10 trucks seems to be on edge of heat capacity when you get to triple digit temps. you bump one thing up and its the waterfall affect.

remember, the oil cooler isnt the only thing GM upped in size here. i would put money the cooling system in general on the 2020 has been up sized a good amount as well.
 

Mikey52

Active member
Sep 20, 2018
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Have you seen the picture of the fan on the 2020. I’ve seen planes with smaller props.
 

gmduramax

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Jun 12, 2008
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I wonder if they’re planning to up power on the 2020. The 17/18 have no issue that I have seen with oil temp unless you’re in James territory. Why up the cooling capabilities?
 

M.A.M.

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Jan 9, 2016
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The 2020 body style gives people a reason to upgrade from the first gen L5P.
Give them a few years, they’ll up the power numbers again to give everybody another itch to scratch, LOL...


Sent from my iPhone using Tapatalk
 
Sep 19, 2012
47
1
6
Ordered the KD fan clutch. I'll let everyone know how that goes. I'll definitely switch to synthetic oil after break in to help as I have a feeling I won't be able to get oil temps below 230 pulling hills.


I'm not burning any oil. Is it cool to switch to synthetic?
 

JoshH

Daggum farm truck
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Feb 14, 2007
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Oil temp will probably come down but at the cost of heating up coolant temp as well.

the moment i put the aux radiator on, i saw oil temp stay much lower when pulling grades as i had more capacity for the heat. oil only saw a 20* difference from coolant compared to the 40* i usually saw. Ill be curious how it does this summer but in the tow home from the dunes, its been the most significant difference ive seen to date. That was with a cracked head and/or blow HG as well.

id love to see if a 2020 would fit and if i could ditch the air to oil cooler using it.
I don't doubt that, but I feel like my oil temps will come down a lot more than my coolant temps will rise. I think if I can keep oil close to the same as coolant, the truck will have a better chance at keeping everything in check. It seems like once the oil temp has gotten so high, the coolant just can't keep it knocked down, and the coolant temp suffers as a result. I will probably throw on the L5P cooler I have and see what it does before I get the 2020 one since they probably won't be available for a few months.
 

OregonDMAX

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Apr 28, 2013
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I don't doubt that, but I feel like my oil temps will come down a lot more than my coolant temps will rise. I think if I can keep oil close to the same as coolant, the truck will have a better chance at keeping everything in check. It seems like once the oil temp has gotten so high, the coolant just can't keep it knocked down, and the coolant temp suffers as a result. I will probably throw on the L5P cooler I have and see what it does before I get the 2020 one since they probably won't be available for a few months.

same issue, once oil temp starts to rise above coolant temp, coolant temp cant be helped.
 

Chevy1925

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I don't doubt that, but I feel like my oil temps will come down a lot more than my coolant temps will rise. I think if I can keep oil close to the same as coolant, the truck will have a better chance at keeping everything in check. It seems like once the oil temp has gotten so high, the coolant just can't keep it knocked down, and the coolant temp suffers as a result. I will probably throw on the L5P cooler I have and see what it does before I get the 2020 one since they probably won't be available for a few months.

maybe im wrong but it goes against what ive seen. its a real thin line what you are talking about but i very well could have had this hg issue long ago and its only slowly gotten worse, making me think its just a cooling issue.

hows the 17-19 cooler compare? have not seen one in person yet.
 

JoshH

Daggum farm truck
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It looks to be a good amount larger than the older coolers. I think I took a picture of an LML and L5P cooler side by side. I'll post it if I can find it.
 

Chevy1925

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Well now I kinda wanna throw one on with the heads but I won’t see the net change with just the aux cooler. Damn it...