160 Deg. Stat Fan Settings?

[n8dogg]

Hey guys, just wondering if you mind sharing what settings I should use for my fans with a 160 deg. thermostat. 04 Z06 (LS6), bolt ons.

[Taz]

Hello n8dogg,

Your stock fan settings (G0901 - G0920) are based on 195 degree F thermostat. Stock settings for an ’04 Z06 are generally:

Fan #1: 226 F / 219 F (on / off)
Fan #2: 235 F / 227 F (on / off)

Using a 160 degree F thermostat, you could reduce these 35 degrees F as a start point, and adjust from there as necessary. It really depends on what temperature you wish to stabilize the ECT. The limiting factors are the thermal efficiency of the radiator, capacity of the electric cooling fans (CFM), the climate where you live, and how the vehicle is to be used. Stop and go commuter traffic in the summer months in Arizona can really test the cooling system. Pleasure use in the northern states, not so much.

Once you’re happy with “normal” on / off temps - the fan delay / run time, A/C temp / pressure, as well as vehicle speed parameters (G0904-5) can be adjusted accordingly.

As a side note, normal operating ECT may effect emissions / fuel consumption / component wear, as well as power output. Loosely categorized operating temperatures:

195 - 210 degree F

reduced emissions output
higher fuel economy (use less fuel)
reduced engine component wear
reduced power output (compared to 160 degree F)

160 degree F

increased emissions output
increased fuel consumption
increased engine component wear
increased power output

If the vehicle is strictly pleasure use, and doesn’t see many miles during the year, the 160 stat should not be a problem. If however, the vehicle is your “daily driver” in the summer months, or driven frequently (every evening, all day on weekends) engine wear may become a concern. For a vehicle that will see a lot of use, I generally prefer a 180 degree F stat as a compromise.

Also, depending on how stringent the emissions requirements are in your area, combined with the modifications to the vehicle, and the overall condition of the engine - using a 160 degree F stat may make meeting emissions requirements more challenging.


Regards,
Taz

[n8dogg]

Thanks for the input Taz,

I guess I was under the impression that with lower temps comes reduced engine wear, so do you mind explaining to me how I could be seeing increased engine wear?

The car is basically daily driven from Spring to Fall except on rainy days. Roughly 6,000 miles per year. I'd rather steer away from potentially harming the engine so maybe the 180* stat would be a better option. That is if I would still see a performance increase of course. Other wise I will just broom the idea.

[joecar]

What Taz said.

Wear increases when the oil doesn't reach operating temperature soon enough, 160 keeps coolant "cold" enough to significantly slow down the rise in oil temp (you have to beat on it hard to get the oil temp up).

180 is a good compromise between 195 (thermodynamic efficiency, reduced wear, improved NBO2 and catalytic operation) and 160 (increased cylinder airmass, increased timing, reduced knock).

160 is typically used for a drag racecar (short period of intense load).

Also, a thermostat typically starts to open at its rated temp, and it is not fully open until about 10-15°F later, so the low speed fan (Fan 1) turn off temp should be set to at least 5°F above that.

[WeathermanShawn]

n8Dogg:

The 160F Thermostat is somewhat going out of popularity as a bona fide performance mod for the LS series engines. I am not as well versed in engineering as Taz, but likewise understand cooler is not necessarily better for these aluminum engines.

I run a 180F, which in reality keeps the ECT about 190-195F when fully opened. Fan settings are about +15-20 above that.

Some tuners/engine builders construct their own thermostat and have it open at an exact temperature. So, perhaps 180-190F would be ideal?

Do you consistently run above 200-210F in your climate? What about interstate cruising speed. What does your ECT run at?

[n8dogg]

n8Dogg:

The 160F Thermostat is somewhat going out of popularity as a bona fide performance mod for the LS series engines. I am not as well versed in engineering as Taz, but likewise understand cooler is not necessarily better for these aluminum engines.

I run a 180F, which in reality keeps the ECT about 190-195F when fully opened. Fan settings are about +15-20 above that.

Some tuners/engine builders construct their own thermostat and have it open at an exact temperature. So, perhaps 180-190F would be ideal?

Do you consistently run above 200-210F in your climate? What about interstate cruising speed. What does your ECT run at?

With my current fan settings, stock thermostat, I am running right around 200*, sometimes it goes a little over. I'm in western NY, so Spring to Fall I will see 40*-100*.

[WeathermanShawn]

I vote for the 180F Thermostat..:)

[Chalky]

I went the 160 and 180- route with my LS6. My 160 was open by 160. Car never got warm. I settled on the 180. Find out where the car temp is when running down the road with fans off. If 190 is a norm, set fans to come on maybe 10* higher just to keep them from running all the time.

Someone with racing experience can talk to this but max power comes from higher oil and water temps and cold air intake. I believe Smokey Yunich talked about engine temps in 230 range for max power in cast iron blocks. I am guessing aluminum, same thing.

LS6 Z06 is a great engine/car combo BTW! One of my favs.

[Taz]

Hello n8dogg,

Joecar and WeathermanShawn did a great job of augmenting what I had missed, and clarifying my rambling !

I should have mentioned that tolerances in an engine (“blueprinting”) are often temperature dependent. Dissimilar metals expand and contract at different rates (while heating or cooling). Even similar metals, of different manufacture (cast / forged / billet) expand and contract at different rates. So while an engine's components are moving “over” each other, they are also moving “around” each other.

Most people would agree that damage may occur from overheating an engine – in extreme cases causing parts to come into contact that were not designed to – as all tolerance is eliminated (reduced to zero).

“Underheating” an engine may cause wear - especially under high load - as designed tolerances are never reached (too great a gap between components).


Regards,
Taz

[n8dogg]

Thanks for every ones input. It is much easier to learn when people are informative and to the point.

I just received my 180* thermostat in the mail. Before I put her in I want to get my fan settings ready for loading. So based on what was said for a 160*, should I drop the on/off temps 15*?

Right now I have her at Fan #1: 200/196 Fan #2: 205/201

[Chalky]

Leave the fans right there. Just make sure the fans are not running all the time. Air moving over the radiator at highway speeds should keep them off. Not all thermostats open at indicated temps. Your 180 might maintain a 180 or a 185. Drive it and monitor ect and fans. See what you have. You can alway add +5* if you choose..

[macca_779]

Yeah there can be alot of variance in thermostats. I have a 160F (71c) in my car that never maintains ECT that low. Best case in low ambient conditions @ highway speeds it will regulate to 170F (77c). Worst case peak I see is ~185F (85c) in 45c ambient conditions. I set my Fan speeds around the Thermostat years ago by driving at 100km/h to see where ECT sat with the Fans forced off and added a few degrees. I'd have to pull up my tune but IIRC I have Fan1 on @ 82c off @ 80c. Fan 2 on @ 85c off @ 82c.

[ScarabEpic22]

Good read everyone, Id like to put a 180* tstat in my TBSS in the future and I was considering a 160* one until I read this. Its my DD in the NW so I need it to warm up quickly in the winter, but would like the power output of the cooler tstat.