160* Vs 187* Thermostat

[Eagle]

My operating temp is NOT 205-215. It is more like 175-185 on my truck with my current mods. As far as going into closed loop, what do you think because someone has a 160 stat that they do not go into closed loop? Wrong. I know that AFR doesnt do anything as far as power because I was there when Justin did all those AFR test on MY truck on the dyno to prove this AFR hype.

---------- Post added at 09:01 PM ---------- Previous post was at 08:58 PM ----------



So I see you do not have Data Logging capabilities. I have EFI LIve to log/tune the truck. IIRC these engine go into closed loop at 140, therefore 160 coolant temps would still be closed loop operations. I can even say my truck has ran that cold (160) ever since I have owned it.

you are right... no datalogger anymore.

I agree, it was ambiguous of me not to have added "on some vehicles" to the end of 'falling out of closed loop'.
I assumed incorrectly that people could READ what I wrote, instead of jumping to conclusions. And I was sure that itfit was not the case on these LSx engines someone would let me know.


This engine is designed to operate between 190 and 210 judging by the the materials used and the tolerances spec'd, and supported by the OE choice of t-stat temp (185F).

08 5.3s run at ~200 for example, on a 185F Tstat. You state you are running about 185 on a 160 t-stat... see the pattern? I did exaggerate by 5-10 degrees to make a point, that you are not running the PHYSICALLY specified operating temp, rather you are running 15 degrees below it and <apparently> playing with electronics to band aid it.
There are two things to look at though, electronic requirements and the physical specifications of the piston to block interface. Lets just say if you rebuilt with hyperuetic pistons you would design the gap to be much tighter and operating temp would be far less of an issue.
Last time I checked, GM was using cast pistons in our blocks which means that proper operating temp IS A PART of controlling piston to wall gap, and thus increasing internal efficiency.

ONe thing everyone also forgets is that hotter helps burn off the contaminates that accumulate in oil when the vehicle doesn't reach the manufacturer's specified operating temps. It makes no difference whether that be because of a cooler T-stat or very short commute, it is bad for your engine.

I have no idea what you mean with the gibberish about 'AFR making no difference'... Feel free to expound on that, if you would, because as written it makes no sense.


Now on to asking non-rhetorical questions:
Are you stating that at 140F on a stock computer (not yours) it is both closed loop and on the power map?

what is the changeover temp for warm up maps and the temp required for super cruise (hopefully it exists on these fat SOBs) and optimal power maps?


On older trucks/cars it was NOT that low (hell Spirits ran an OPEN LOOP SYSTEM into the 90s!), and I can tell you on my DSM it was not that low either, ~ 170 IIRC. What are the conditions for supercruise/lean burn (if it exists)?



Cliffs:

I still do not understand why people don;t simply keep a proper t-stat, instead of changing everything just to use a $5 feel good part that does nothing to improve power, economy, or reliability and ultimately is only trouble or a bandaid.
You disagree, and that is fine.

Seems a lot of trouble to go thru to correct a problem that doesn't exist.
Now Joe above, he was doing the same thing with the lower t-stat we were doing back in the TBI and carb days for the same reason- he needs a bigger radiator, or better airflow thru the core.

 

[WICKEDOWESIX]

you are right... no datalogger anymore.

I agree, it was ambiguous of me not to have added "on some vehicles" to the end of 'falling out of closed loop'.
I assumed incorrectly that people could READ what I wrote, instead of jumping to conclusions. And I was sure that itfit was not the case on these LSx engines someone would let me know.


This engine is designed to operate between 190 and 210 judging by the the materials used and the tolerances spec'd, and supported by the OE choice of t-stat temp (185F).

08 5.3s run at ~200 for example, on a 185F Tstat. You state you are running about 185 on a 160 t-stat... see the pattern? I did exaggerate by 5-10 degrees to make a point, that you are not running the PHYSICALLY specified operating temp, rather you are running 15 degrees below it and <apparently> playing with electronics to band aid it.
There are two things to look at though, electronic requirements and the physical specifications of the piston to block interface. Lets just say if you rebuilt with hyperuetic pistons you would design the gap to be much tighter and operating temp would be far less of an issue.
Last time I checked, GM was using cast pistons in our blocks which means that proper operating temp IS A PART of controlling piston to wall gap, and thus increasing internal efficiency.

ONe thing everyone also forgets is that hotter helps burn off the contaminates that accumulate in oil when the vehicle doesn't reach the manufacturer's specified operating temps. It makes no difference whether that be because of a cooler T-stat or very short commute, it is bad for your engine.

I have no idea what you mean with the gibberish about 'AFR making no difference'... Feel free to expound on that, if you would, because as written it makes no sense.


Now on to asking non-rhetorical questions:
Are you stating that at 140F on a stock computer (not yours) it is both closed loop and on the power map?

what is the changeover temp for warm up maps and the temp required for super cruise (hopefully it exists on these fat SOBs) and optimal power maps?


On older trucks/cars it was NOT that low (hell Spirits ran an OPEN LOOP SYSTEM into the 90s!), and I can tell you on my DSM it was not that low either, ~ 170 IIRC. What are the conditions for supercruise/lean burn (if it exists)?



Cliffs:

I still do not understand why people don;t simply keep a proper t-stat, instead of changing everything just to use a $5 feel good part that does nothing to improve power, economy, or reliability and ultimately is only trouble or a bandaid.
You disagree, and that is fine.

Seems a lot of trouble to go thru to correct a problem that doesn't exist.
Now Joe above, he was doing the same thing with the lower t-stat we were doing back in the TBI and carb days for the same reason- he needs a bigger radiator, or better airflow thru the core.

GM uses hyperutectic pistons NOT cast. As for AFR I was refering to it is simply thermal protection and chaning (lean/rich) AFR will not yeild more power. Playing with electronics to bandaid? Please explain. Yes at 140* the computer goes into closed loop on stock computers.

 

[clean454]

i have a hypertech chip in my 95 and it came with a a new t-stat a lower one ive had it in for about 4 years
and love it truck runs cool and fine. i think its a 160

 

[Eagle]

GM uses hyperutectic pistons NOT cast. As for AFR I was refering to it is simply thermal protection and chaning (lean/rich) AFR will not yeild more power. Playing with electronics to bandaid? Please explain. Yes at 140* the computer goes into closed loop on stock computers.

thanks fo r the info. are these ECUs advanced enough yet to run closed loop under WOT or partial acceleration (or both)?

As to your assertion regarding AFR not having an effect on power.
It absolutely will and does man. I can;t say it any plainer, despite your 'experience'.
Anyone who has ever tuned a carb can tell you afr does affect power.

Either you guys were on the wrong map for what you were testing or you weren't changing the values enough to see it (overly conservative) or you jsut didn;t have the equipment and resolution to get valid results. To really see it you need a steady state dyno, not multiple runs on a mass acceleration dyno, where the error factor of 3-5 hp per run completely obscures the values you are looking for.


I've picked up 35 hp by merely leaning out WOT by the equivalent of a full point over stock on a 2.0 Turbo car, down to 12.5:1 from 11.5:1. I've picked up 30+ lb/ft of usable power in the midrange by leaning out partial throttle and partial load maps on the same car.
Timing is NOT the only thing to tweak, load maps and partial load maps can be made leaner and show significant improvements... though fuel quality and maintenance then becomes far more critical.

I agree with you that minor changes to AFR on these relatively low specific output engines will probably not be hugely noticeable




Sure changing AFR will... it absolutely will. Changing steady state target AFRs will not change power on an acceleration map... but leaning it out cell by cell on on an acceleration map WILL, and it is a change in AFR.


Do you have a link to where GM switched to Hyperuetic pistons in the LSx engines, especially in our Truck variants? Everything I have seen indicates they are cast aluminum pistons, including the cold piston slap issue.

 

[WICKEDOWESIX]

thanks fo r the info. are these ECUs advanced enough yet to run closed loop under WOT or partial acceleration (or both)?

Partial acceleration yes depending on the TPS. At WOT the PCM goes into open loop.

As to your assertion regarding AFR not having an effect on power.
It absolutely will and does man. I can;t say it any plainer, despite your 'experience'.
Anyone who has ever tuned a carb can tell you afr does affect power.

We are talking FI not carb which really doesnt matter though. PM Jenna and ask her about it. Justin from Black Bear Perforamnce did these AFR tests on my truck on a Dyno Dynamic Dyno (steady state tuning dyno), with a wideband oxygen sensor and EFI Live software to porve these AFR hypes. We actually lost power leaning it out. from about 11.8-12.8 AFR there is not any power difference worth changing thus leaving WOT AFR at 12.5:1.

Either you guys were on the wrong map for what you were testing or you weren't changing the values enough to see it (overly conservative) or you jsut didn;t have the equipment and resolution to get valid results. To really see it you need a steady state dyno, not multiple runs on a mass acceleration dyno, where the error factor of 3-5 hp per run completely obscures the values you are looking for.


I've picked up 35 hp by merely leaning out WOT by the equivalent of a full point over stock on a 2.0 Turbo car, down to 12.5:1 from 11.5:1. I've picked up 30+ lb/ft of usable power in the midrange by leaning out partial throttle and partial load maps on the same car.
Timing is NOT the only thing to tweak, load maps and partial load maps can be made leaner and show significant improvements... though fuel quality and maintenance then becomes far more critical.

I agree with you that minor changes to AFR on these relatively low specific output engines will probably not be hugely noticeable




Sure changing AFR will... it absolutely will. Changing steady state target AFRs will not change power on an acceleration map... but leaning it out cell by cell on on an acceleration map WILL, and it is a change in AFR.


Do you have a link to where GM switched to Hyperuetic pistons in the LSx engines, especially in our Truck variants? Everything I have seen indicates they are cast aluminum pistons, including the cold piston slap issue.

GM has been usuing hyperutectic pistons since the LT1 engine and has not run cast pistons ever since. Go on GM performance parts website and look under the info and you will see that they all use hyperutectic pistons.

 

[Eagle]

ok, you just stated it does have an effect... which is what i said.
You are stating that LEANING out AFRs ON THESE TRUCKS won't INCREASE power because they are already leaned out to best power. No surprise since they are so well tuned from the factory. But as you then indicate, AFR DOES have a result on power. You leaned it out more and lost power, proving my exact point. If you had fattened it up some more you would have lost power too.


Perhaps the way I phrased it is what threw you for a loop?


BTW I can;t find any OEM pistons for sale on GMPP.
What I have found is NUMEROUS references to the LM7 (and early LS1) having cast pistons...
and one reference that says that later ls1 switched to hypers because of piston slap issues.

http://www.smokemup.com/tech/ls1.php
http://www.maxchevy.com/tech/2008/iii_6-lm7-1.html
http://www.fbody.com/3gen/72431

I have not found anything ANYWHERE that says the LM7 uses hypers, Sorry. Not even something NON-authoritative.

 

[WICKEDOWESIX]

BTW I can;t find any OEM pistons for sale on GMPP.
What I have found is NUMEROUS references to the LM7 (and early LS1) having cast pistons...
and one reference that says that later ls1 switched to hypers because of piston slap issues.

http://www.smokemup.com/tech/ls1.php
http://www.maxchevy.com/tech/2008/iii_6-lm7-1.html
http://www.fbody.com/3gen/72431

I have not found anything ANYWHERE that says the LM7 uses hypers, Sorry. Not even something NON-authoritative.

Here ya go.

Pistons
The LS9 is the only production LS engine with forged aluminum pistons; all the
other engines use hypereutectic (cast) aluminum alloy pistons—varied mostly
by diameter to accommodate various bore sizes. LS cast pistons shouldn’t
be used on applications greater than approximately 550 horsepower. The LS7
piston’s inner bracing and larger pin diameter require the use of the matching
LS7 connecting rod. The same is true for LS9 pistons; they require the use of LS9
connecting rods.

Its on page 190 http://www.gmperformanceparts.com/_res/pdf/GMPP_2009_Catalog.pdf


http://www.gmperformanceparts.com/EngineShowcase/tech_specs.jsp?engId=LS1&engine=LS1&sku=25534322&engCat=ls

 

[Eagle]

thanks man, great info to learn.

 

[WICKEDOWESIX]

thanks man, great info to learn.

Your welcome. I am trying to find another link that I came across that tells you everything about the LS family engine.