Why not just remove thermostat?

[Paul Workman]

Originally Posted by Dynomite

And................installing a radiator Debris Screen

Radiator Debris Screens

Oh, YEAH! I was just tutoring Ami in the do's n don't whether it be her 69 Vette or a Z: Avoid those grass clippings that some people spread out in the middle of the road (when mowing). Avoid - go around if possible, like it was a mud pit!

[A26B]

Originally Posted by Paul Workman

......................................

Heat transfer efficiency for any given ambient air temperature can be increased by-

• increasing the surface area between the radiator and the air, i.e., BIGGER radiator
• increasing the differential temp between the (radiator) and (specifically) the air e.g, removing the heat-saturated air from the heated radiator surface.
• proper coolant level and additive (e.g., antifreeze or whatever).

I would add: Increased air flow through the heat exchanger, i.e. the radiator.
Increasing the surface area of the radiator in the LT5 can be accomplished only by adding additional cores. Adding additional cores increases the resistance to air flow. Compensation for reduced air flow due to the increased restriction of more cores can only occur with greater air flow.

So, the facts are -

• heat transfer gets better as (coolant) temps increase.
• The lower the engineered equilibrium temp is to the ambient temp (of the air, in this case) the greater the need for increased radiant transfer area and exchange of heat soaked recipient medium (air) to maintain the highest differential temp difference between the source and the receiving medium).

I might suggest "increases" in lieu of "gets better." The actual transfer of heat doesn't actually get any better with higher input.

Originally Posted by Hog

There is 2 CTS, 1 for the gauge located in the waterneck, and 1 for the PCM in the drivers side cylinder head.

Here is the location for the LT5 sensors.
.

Originally Posted by Bob Eyres

#9 is the most relevant here Paul.

I don't know for sure, but I think an LT5 without a thermostat would blow the plastic components of the stock radiator apart.

Although not a good idea to remove the thermostat, its removal would actually decrease flow resistance and would not cause the plastic tanks to blow off.

Damage to radiators has occurred from excessive restriction of the "bypass system" which was part of the LT5 cooling system, designed to prevent radiator damage.

Originally Posted by KILLSHOTS

I can see that such a high-compression engine running at high RPM could put serious stress on the non-metal parts of the cooling system without a stat. In this case, the stat makes a more compelling case as a water baffle than a temperature regulator.........

Not so with the LT5. Look at the coolant flow diagram. The thermostat is downstream of the radiator. It is actually a component of the resistance causing backpressure which is generally attributed to the radiator alone. The LT5 thermostat does not function as a baffle. The bypass system is proof of that.

Originally Posted by KILLSHOTS

........And I don't understand the assertion that a 160-degree stat isn't meant to KEEP it at that temp; I think that's generally understood. The point is that it opens the coolant flow and STARTS the cooling 20 degrees earlier, which will keep the LT-5 from achieving such lofty temperatures in the first place.

Paul, Dynomite & others have explained the function of the thermostat very well.
You need to understand that thermostats DO NOT regulate MAXIMUM temperatures, but only MINIMUM opening temperatures.

• Maximum temperatures are limited by the capacity of the radiator. Efficiency of the stock radiator can be restricted by debris within the fins and in front of the radiator (as others have stated).
• Efficiency of the stock radiator is improved by the stock cooling fans which can be "turned on" earlier at lower temperatures.
• More air flow to further improve the capacity of the radiator, can be achieved by adding additional or higher capacity cooling fans.
• Improved coolant flow rate through the radiator can be achieved by drilling two to four 1/8" holes in the flange of the stock, 180F thermostat. This increases the total flow capacity of coolant through the thermostat and thereby reduces restriction through the radiator. Originated by Lingenfelter and the biggest bang for the buck to make the LT5 run cooler.
• Bigger is not always better when it comes to radiators for street driven ZR-1 Corvettes. Going from a 2 core stock radiator to a 5 core Ron Davis Racing Radiator. It's a beautiful & expensive piece. A 5 core radiator requires more air flow through it to function as designed. The key word in Ron Davis Racing Radiators is "Racing." They are designed for high speed which obviously means more air flow that street driven cars don't achieve.

In summary,

• A 160F t-stat is not going to help your high operating temperatures
• Remove your stock radiator and either (1) replace with a new one or (2)have yours thoroughly cleaned of debris in the fins & any trash in front of it.
• Do have you prom programmed to turn the cooling fans on earlier
• Drill three 1/8" holes in the stock 180F t-stat flange

[Schrade]

Good stuff there Jerry...

Colder-rated thermostat for cooler running temps is one of the biggest myths I know of.

But Hog said his twister DOES turn "so much so" cooler, with only the lower-rated stat.

Originally Posted by Hog

I agree with everything Dyno, makes sense. Just a tidbit, lets say your max. temp is going to be 210º no matter the temp of therostat used. If you have a 180º stat, and I have a 160º stat, my car will take longer to reach that 210º max than your 180º stat. Why? Because my stat has started to open at 160º and has been removong heat from teh system, while your car has NOT been removing heat from the system. Assuming all else equal of course.

Your arguements come across as sound to me, but whenever I have swapped from a stock OEM stat to a 160º stat, the engine coolant gauge has always been lower. SO much so, that I swap between my 160º stat for warm weather and the OEM stat for Winter as the interior heat is lacking with the lower rated stat.

There has to be something else at play here. (my experience with stats is not LT5 related-if that matters?)

Is this only because the temp sensor is close to radiator flow???

And are you surprised that Jim Nolan's cooling system doesn't keep his mill running closer to 185', which his ECM is re-coded for?

Originally Posted by Jim Nolan

I have a 160 thermostat in mine and the fans programmed to come on at 185 and off at 180. In the summer months it normally runs 190, some times 200 in slow traffic. I never liked it stock running at 220-230 and on a really hot day in traffic 235.

Originally Posted by A26B

I would add: Increased air flow through the heat exchanger, i.e. the radiator.
Increasing the surface area of the radiator in the LT5 can be accomplished only by adding additional cores. Adding additional cores increases the resistance to air flow. Compensation for reduced air flow due to the increased restriction of more cores can only occur with greater air flow.

I might suggest "increases" in lieu of "gets better." The actual transfer of heat doesn't actually get any better with higher input.



Here is the location for the LT5 sensors.
.




Although not a good idea to remove the thermostat, its removal would actually decrease flow resistance and would not cause the plastic tanks to blow off.

Damage to radiators has occurred from excessive restriction of the "bypass system" which was part of the LT5 cooling system, designed to prevent radiator damage.



Not so with the LT5. Look at the coolant flow diagram. The thermostat is downstream of the radiator. It is actually a component of the resistance causing backpressure which is generally attributed to the radiator alone. The LT5 thermostat does not function as a baffle. The bypass system is proof of that.



Paul, Dynomite & others have explained the function of the thermostat very well.
You need to understand that thermostats DO NOT regulate MAXIMUM temperatures, but only MINIMUM opening temperatures.

• Maximum temperatures are limited by the capacity of the radiator. Efficiency of the stock radiator can be restricted by debris within the fins and in front of the radiator (as others have stated).
• Efficiency of the stock radiator is improved by the stock cooling fans which can be "turned on" earlier at lower temperatures.
• More air flow to further improve the capacity of the radiator, can be achieved by adding additional or higher capacity cooling fans.
• Improved coolant flow rate through the radiator can be achieved by drilling two to four 1/8" holes in the flange of the stock, 180F thermostat. This increases the total flow capacity of coolant through the thermostat and thereby reduces restriction through the radiator. Originated by Lingenfelter and the biggest bang for the buck to make the LT5 run cooler.
• Bigger is not always better when it comes to radiators for street driven ZR-1 Corvettes. Going from a 2 core stock radiator to a 5 core Ron Davis Racing Radiator It's a beautiful & expensive piece. A 5 core radiator requires more air flow through it to function as designed. The key word in Ron Davis Racing Radiators is "Racing." The are designed for high speed which obviously means more air flow that street driven cars don't achieve.

In summary,

• A 160F t-stat is not going to help your high operating temperatures
• Remove your stock radiator and either (1) replace with a new one or (2)have yours thoroughly cleaned of debris in the fins & any trash in front of it.
• Do have you prom programmed to turn the cooling fans on earlier
• Drill three 1/8" holes in the stock 180F t-stat flange

[Dynomite]

Originally Posted by A26B

I would add: Increased air flow through the heat exchanger, i.e. the radiator.

• A 160F t-stat is not going to help your high operating temperatures
• Remove your stock radiator and either (1) replace with a new one or (2)have yours thoroughly cleaned of debris in the fins & any trash in front of it.
• Do have you prom programmed to turn the cooling fans on earlier
• Drill three 1/8" holes in the stock 180F t-stat flange

Excellent Jerry

I would add........

Turning the cooling fans on earlier has the same effect as opening your thermostat earlier (160 deg). After a steady state coolant temperature is reached where your fans and my fans are both on no matter when I turned my fans on the cooling effect is the same.

But then again ....if you are operating where the coolant temperature is 218 deg (just below the secondary fan normal operation) then turning on your fans at say 200 deg would be a definite advantage. Same goes for the coolant temperature at which the primary fans turn on at 228 deg. If you have coolant temperature of 227 deg then turning on your fans at a lower temperature will be an advantage. But if we both have a standard radiator and the coolant temperature is at least 228 deg where both your fans are on with my fans turning on at a lower temperature...there would be no advantage to me turning my fans on at the lower temperature in that situation.

Now having said that......There is a caveat

My fans come on at 205 deg and off at 200 deg but then again I have a Ron Davis Radiator. Turning my fans on earlier (at a higher temperature than my 180 deg thermostat) will have a greater cooling effect (because of the Ron Davis Radiator). My coolant temperatures are actually less than the standard fan turn on temperature of 228 deg or 219 deg (I recall Secondary fan turns on at 228 deg F and Primary fan turns on at 219 deg F.
I also recall fans turn off with a drop of 11 deg F more or less). With a chip....Marc sets the fans on at 205 deg F and off at 200 deg F.

Both our fans are on at 205 deg (Programmed in the modified Chip) but my fans are pulling air through a Ron Davis Radiator and can take advantage of the lower coolant temperature operation fan turn on programmed by Marc.

In other words....because of my Ron Davis Radiator I would be normally running the ZR-1 with the fans OFF (because I am below the normal coolant temperatures that would normally turn the fans on). So....I turn my fans on sooner (Marc Chip) where the full advantage of the Ron Davis Radiator can be experienced.

Dynomite aka Cliff

I hope I made my self clear
I know.....clear as mud

[GOLDCYLON]

Originally Posted by PhillipsLT5

GC had luck running a stock radiator in Phx as a daily driver
With his new motor he went to a different radiator & fans
I have luck but running Marcs chip with fluidyne radiator, it really helped over stock radiator, but these cars need to be moving to keep cool in Phx
You can open it @ 160 or 180, but you will be lucky to run at 190-200
Sounds like you may have the typical blocked radiator due to fans sucking air thru along with dirt and blocking flow after years
Ron Davis is local/buy a new stocker/remove & clean 20yr old rad/Dewitts
You do not want to overheat & blow head gasket

I also am running the Big Mouth Air Dam with a debries screen and the SPAL Fans on early at the PROM. Mines a daily driver and a desert runner. Phil is right these cars like to run. On the freeway in 6th gear not a issue. Stop and go the temp will climb. For a stock LT5 the original radiator is fine.. as long as the front air dam system is in good shape and the fins are clean. Killshots (Chris) if you need another radiator I have a 6 month new stock delco replacement I used for 6 months up in the attic before I went to the larger radiator and fans. These older 20 plus year radiators swell at the plastic ends and some grit you cant get out of the fins.

[KILLSHOTS]

Originally Posted by GOLDCYLON

I also am running the Big Mouth Air Dam with a debries screen and the SPAL Fans on early at the PROM. Mines a daily driver and a desert runner. Phil is right these cars like to run. On the freeway in 6th gear not a issue. Stop and go the temp will climb. For a stock LT5 the original radiator is fine.. as long as the front air dam system is in good shape and the fins are clean. Killshots (Chris) if you need another radiator I have a 6 month new stock delco replacement I used for 6 months up in the attic before I went to the larger radiator and fans. These older 20 plus year radiators swell at the plastic ends and some grit you cant get out of the fins.

Thanks Daryll! Based on input from you and Phil and the other brothers, I actually decided that step 1 was cleaning my radiator. So I had it removed yesterday and WHAT A MESS!!! Probably a pound of crap came out of the cooling stack, the majority of which was on the rad itself. Only drove it a couple miles afterward, but it was about 110 out and with the A/C on it didn't seem to get much over 200. I'm confident that it's going to be MUCH better now. With only 16K on the car, my radiator looked pretty much new, after it was cleaned.

[PhillipsLT5]

Originally Posted by GOLDCYLON

I also am running the Big Mouth Air Dam with a debries screen and the SPAL Fans on early at the PROM. Mines a daily driver and a desert runner. Phil is right these cars like to run. On the freeway in 6th gear not a issue. Stop and go the temp will climb. For a stock LT5 the original radiator is fine.. as long as the front air dam system is in good shape and the fins are clean. Killshots (Chris) if you need another radiator I have a 6 month new stock delco replacement I used for 6 months up in the attic before I went to the larger radiator and fans. These older 20 plus year radiators swell at the plastic ends and some grit you cant get out of the fins.

GC parts bin to the rescue

[KILLSHOTS]

Originally Posted by PhillipsLT5

GC parts bin to the rescue

No kidding Phillip! Someday, Daryll, I PROMISE I'm going to buy something out of your attic!!

See you at C&C on Saturday, Phil? Daryll, can you make it?

[Dynomite]

Originally Posted by XfireZ51

True, but there's lots of tiny dirt particles that over time clog the areas between the coils. For a vehicle, coming from the Southwest for example, that kind of dirt restricts airflow. Before swapping T-stats, I'd blow out the rad.
Look at what Chevy found by doing the "flo-tie" on the Z28. Increase airflow by 3%. just from that amount of increased area.

Great point....yep...I delicately use a pressure washer connected to HOT water once in a while especially if there is any kind of previous oil that is contaminating the radiator cooling fins

Especially on the passenger side where the oil cooler hoses are located.

[PhillipsLT5]

Originally Posted by KILLSHOTS

Thanks Daryll! Based on input from you and Phil and the other brothers, I actually decided that step 1 was cleaning my radiator. So I had it removed yesterday and WHAT A MESS!!! Probably a pound of crap came out of the cooling stack, the majority of which was on the rad itself. Only drove it a couple miles afterward, but it was about 110 out and with the A/C on it didn't seem to get much over 200. I'm confident that it's going to be MUCH better now. With only 16K on the car, my radiator looked pretty much new, after it was cleaned.

Yesterday hottest day of year so far @ 110, 200 is GREAT!, check coolant level after refill, do not use dexcool
http://zr1specialist.com/HAT%20Web/a...%20Coolant.pdf

http://zr1specialist.com/HAT%20Web/a...d%20Gasket.pdf