How cool is too cool?
10-09-2016, 01:18 PM
#1
Melting Slicks
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Member Since: Nov 2013
Location: Greater Cincinnati Area.
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How cool is too cool?
With the high compression (85, 355, Vortec swap) my car just can't run the stock temperatures. If it is sitting in town, any, even quazi-judicious application of the throttle, causes pre-ignition.
So, I swapped the fan switch out for Wells 190/215 and installed a 160 thermostat.
I think it is too cold though. On the highway it hangs around 158, 160 ish.
Is this a problem? I mean, there's the computer to consider but also expansion and sealing.
Is this too cold? Should it go back up to a 180, say?
So, I swapped the fan switch out for Wells 190/215 and installed a 160 thermostat.
I think it is too cold though. On the highway it hangs around 158, 160 ish.
Is this a problem? I mean, there's the computer to consider but also expansion and sealing.
Is this too cold? Should it go back up to a 180, say?
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confab (10-09-2016)
10-09-2016, 04:26 PM
#6
Team Owner
Pro Mechanic
I' also feel that 150 is fine. So is 170...maybe even 140! What is "fine" or "right" depends on your combo, your criteria and goals. Some will say that this temp or that temp is too cold, but I don't believe it.
Boats run at 150-160 and last a long, long time (always "going up hill").
Every car is different, but in one of my cars, I was able to run more timing and go faster in the 1/4 mile at 160* than I could at 180*. So for that car, and that mission, 160 was better.
Last edited by Tom400CFI; 10-09-2016 at 04:28 PM.
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confab (10-09-2016)
10-09-2016, 07:30 PM
#8
Melting Slicks
Hi
The factory advance curve may not suit the vortec engine,
remember the factory ecm will allow a lot of advance when cruising.
When you suddenly accelerate and you hear it ping suggests the knock sensor is not working right.
Whenever I run poor quality gas and floor it, she may ping for a moment then the ecm will see the knock and retard the ignition.
The knock retard is pretty savage and it should never ping for more than second or so, I would back the timing till it doesn't ping and use good quality gas.
I run a 190f thermostat and have an adjustable cooling fan temperature switch, I set it to maintain 190f and when going for a long distance drive let the ecm regulate the engine temperature for best burn and economy.
If you run below 180f your ecm may never go to closed loop, fine for a performance car but not a road car that needs to do good mpg.
Get your car tuned, find out the advance curve spec for the vortec engine. Get a custom chip done to suit.
I run a blower and don't have a problem running 190f, she may ping a little on a hot day running 230f loading the engine. 190-210 is fine.
The factory advance curve may not suit the vortec engine,
remember the factory ecm will allow a lot of advance when cruising.
When you suddenly accelerate and you hear it ping suggests the knock sensor is not working right.
Whenever I run poor quality gas and floor it, she may ping for a moment then the ecm will see the knock and retard the ignition.
The knock retard is pretty savage and it should never ping for more than second or so, I would back the timing till it doesn't ping and use good quality gas.
I run a 190f thermostat and have an adjustable cooling fan temperature switch, I set it to maintain 190f and when going for a long distance drive let the ecm regulate the engine temperature for best burn and economy.
If you run below 180f your ecm may never go to closed loop, fine for a performance car but not a road car that needs to do good mpg.
Get your car tuned, find out the advance curve spec for the vortec engine. Get a custom chip done to suit.
I run a blower and don't have a problem running 190f, she may ping a little on a hot day running 230f loading the engine. 190-210 is fine.
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confab (10-09-2016)
10-09-2016, 07:31 PM
#9
You could try it at 0* and move up till it starts pinging under your symptoms. It's not going to cost anything to try. On these EFI engines you will lose mpg if you run them too cool. It could be as much as 4 mpg lower then with the stock running temp. If anything, run a 180 stat.
Have you tried higher octane fuel?
Have you tried higher octane fuel?
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confab (10-09-2016)
10-09-2016, 09:31 PM
#11
Safety Car
10 :1 compression is high for cast iron heads, you need to keep the temperatures near 160 to keep that combination out of detonation.
I also agree with the comment that vortec heads work best with around 32 degrees of WOT timing, so you may need a tune to reduce your total timing.
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confab (10-09-2016)
10-10-2016, 07:00 AM
#18
10-10-2016, 07:39 AM
#19
Safety Car
I checked the tune on a 1985 stock chip and i see I it enables closed loop earlier then the 1986 and latter tunes. Closed is enabled at 104.5 degrees F., that means there is no additional fuel enrichment after that temperature while that car is running in closed loop. If you start the car or go WOT you will see that all additional added fuel is eliminated by 132 degrees.
Last edited by bjankuski; 10-10-2016 at 07:52 AM.