Hello all, I just got the connectors to do the F8->D12 jumper mod for controlling the second fan from the ECM. I also put in a 180 degree thermostat with the intention of running a bit cooler than stock. What are some good values for the enable and disable temps for the primary and secondary fan?

 

Weekday bump. The F8->D12 jumper works great by the way, not quite as much control as having a separate input for the high side switch but plenty good enough.

 

The answer depends highly upon are you driving it year round? Is it only a summer car?

I have a 180° thermostat. With the fans coming on at 200° in the wintertime (which in Houston means the temps approach freezing), the 200° turn on is "adequate, but not great." It's not too cold inside the car. But you never feel that toasty hot feeling you get in a car with a 195° stat and regular fan turn on temps.

Stock primary fan on temp is 223°.

If the car is only driven during the summertime, I would aim for 190-195° on temp and 185° off temp.

 

I go 180* with a 180* Thermostat.
I like my fan on just as fluid starts to flow.

I use adjustable,temperature controlled, fan controllers each on its own circuit.

My primary fan comes on at 170* because its mounted on a large trans cooler.
The other on at 180* with a 180* thermostat.
The car stays in the 180* to 190* most of the time.
200* in heavy traffic.

 

I like 20-30F over the thermostat that way the thermostat is not constantly cycling during short stops and red lights and guarantees that the thermostat is fully open when the fan is on to maintain the fan temp. I keep mine at 210 and a 180 stat. My fan rarely comes on unless I am stopped for a long time and never goes above 215 even in heavy traffic. Although honestly as long as the engine stays under 240ish you are fine factory temp is 235 fan on. The only thing you should really watch out for is don't put the fan sensor in the radiator put the sensor in the heads which are generally hotter than the rest of the system you want your fan to reference the hottest part of the system.

 

I'll probably have it come on around 200 degrees then. How much overlap are you guys running for the secondary? Should I have it turn off at the point the primary usually turns on?

 

95c on 85c off works well

 

Just want to be sure to highlight this tid-bit !

 

No worries there, still using the stock location for the temperature sensor. But definitely good advice for people coming across this thread. I'm very happy with the tiny F8->D12 wiring mod. A couple of ECM crimp connectors and a piece of wire and you have secondary fan control without having to run wires in the engine bay.

 

Honestly speaking I drive year round with a 350 that runs no hotter than 178*F in normal driving. The heater will cook you out of it after only a few miles. My Ram had a 170*F thermostat and ran in the 176*F range and my Infiniti M56S has a 144*F thermostat and runs no hotter than 170*F and the heater will cook you out of it on a 20*F day. I honestly do not know how you would want the air blowing out any hotter than they do even with a 160-170*F thermostat. Anything hotter and I would be adjusting the temperature mix to cool it down.

 

You must have lots of insulation and probably better windows in the Ram and Infiniti.

My old Sunbird had the thermostat underneath the radiator cap. Switching them out was a 30 second job. I damn near froze to death driving home at midnight in freezing weather with the 160 stat in there. It was a 2 hour drive and I had it on the hottest setting with max fan speed the whole way. 180 was better. It would actually warm you up. But never to the point of being too hot. 195 was HOT.

The GTA is much the same. The 180 stat gets the job done. But it could be better. I'm thinking that giant glass window behind me isn't doing me any favors in the winter. It doesn't get roasty hot like the Blazer does with it's stock 195. The Blazer has a 4.3L V6. Sunbird was a 2.0L 4 cylinder. GTA is 5.7L V8. Sunbird and GTA both have had heater cores replaced. So that's not it.

I would basically make the comfort comparison that
160 stat = heating your home with electric baseboard heaters.
180 stat = heating your home with electric furnace.
195 stat = heating your home with natural gas furnace.

I probably like it a bit warmer in the car because it's one of the few times I can warm up during cold spells. The jokers at my apartment complex replaced our old 3.5 ton central A/C with a 4 ton central A/C (for 1300 sq ft) but only put in a 2 ton electric heater. So I'm getting 77-80°F blowing out the ducts at home when it's freezing outside. It feels colder until the heat shuts off. Heated air at below body temp will do that to you. 1600 cfm for 1300 sq ft is waaaay too much airflow. Realistically it should have a 2.5 ton A/C and 3 ton heater with about 900 cfm of airflow.

 

It certainly doesn't help that my windows don't line up with the weatherstripping very well, or the notoriously bad ducting on these cars for the HVAC. So far the 180 stat is doing OK in the colder temps. I think if I had all the weatherstripping updated and proper insulating material around the car it would be better though.

 

It's your call. I don't think it hurts the thermostat to be the arbiter of engine temp. It's one of two ways. I think it also depends on what is controlling your fans.

I gave up on the ECM control for engine temp (still use it for AC) and use a thermostatic fan switch on the radiator inlet.

I set the fans to come on as the thermostat opens.

Engine stays solid 180.

As far as ECM control, I do have a tune for a 180 thermostat and the fans are set to come on at 195. So the idea there is to keep the thermostat open. I did notice more temp swing with this than the way I do it now.

 

Maybe I am just not a fan of having much heat. When I go camping in my 23' travel trailer I often use a 1,000 watt electric space heater rather than the propane fired furnace. The air tends to become too dry when it is heated that hot to me.

I ran a 170*F in my TPI G20 van for several years and never noticed an issue there either. I had a 160*F in my Express van and it would get toasty too and it has a lot of glass that is not well insulated.

Just for the hell of it, with the windows rolled partially down this week on a 45*F morning, the heater set to 90*F, I was about to cook out of the Infiniti. The heater was blowing 145-150*F out of the dash vents with coolant running 168*F. I had heat within 1 mile of driving. I literally drove out of the business park my hobby shop is in to the on-ramp about 2 blocks away (maybe 1/2 mile) and by the time I hit the end of the on-ramp at 80 mph I had heat.

 

All these years I've been monitoring what the A/C is blowing out the ducts, yet I've never measured the heat in the wintertime. I think I'll try that sometime.

Your Infiniti sounds like it has a system like a Bonneville I used to drive. You could watch the temp gauge on the Bonneville rise nearly in real time even when it was freezing outside. It didn't take much time nor heat to warm you up. Insulation was obviously better than most vehicles.

I think vehicles that blow heat at your feet tend to feel hotter faster. The GTA blows the heat out the side of the radio bezel. So your shin gets the heat, but your feet don't.

I've noticed that homes with oil furnaces don't need the thermostat set that high to be hot. Yet heat pumps require you to crank the thermostat much higher to feel warm. Heat pumps have systems much like my electric furnace setup. Monster amounts of cool air heating the room.

Then you get places like Walgreens in the summertime. You can walk in there hot and sweaty and feel cold and dry immediately, about 3 seconds after walking in. Yet you never feel cold no matter how long you're in there...... It takes about 20 minutes after walking in the front door at home to feel the same comfort level, even though the thermostat is set right where you want it.

 

bit of a side-question, just wanted some thoughts since it is a cooling related situation

I have never had a problem in the 7 years since I removed my entire HVAC system....and I somehow wired (cant remember specifics) things for BOTH of my two puller fans to be on whenever the ignition is on. As In, I turn the key and both come on and stay on. The car takes longer to warm up. and even in dead stopped traffic will rarely exceede the 180* temp that the thermostat is set at. sometimes while really racing the hell out of the car and hot lapping it on a road course or long strehes on the highway the temp will get close to the 220* mark, but then once I lay off on the throttle a bit it will cool back down and hang steady at 180*

the question is, is there anything wrong with having both fans running whenever ignition is on?

 

I believe a stock setup will turn the fans off at around 50 mph. The reason being that natural airflow works better without the fans at higher speeds. This would explain why the car cools amazingly well at slow and stopped speeds. But cools slightly worse at higher speeds.

Is there anything wrong with this? Not really. Getting close to 220 is not overheating. I get that in summer weather all the time (dense city traffic, rush hour)

 

Its not overheating but on an ECM controlled Chevy the ECM will be retarding substantial amounts of timing by that temperature to keep the engine from knocking. Factory tune is usually removing 2-3° of timing by 210°F and more as it runs hotter not to mention hotter running also raises the IATs and those can pull 6-8° more above 140°F IAT. My Express van was a DOG at 220°F and 160°F IAT. Put a big block radiator, duramax fan blade, and a 170°F and it ran so much better it was like a different vehicle on a 105°F summer day. My Infinit takes it a step further and reduces the throttle opening via DBW when the oil temp is over 210°F which is practically always in 85°F and beyond temps. Feels like a 4 cylinder. I dropped the thermostat temp, enabled the fans at a lower temp and higher pulse width when stopped to cool it and added a massive setrab oil cooler and that completely transformed the cars performance in hot weather.

 

I run a 160* thermostat and unless I'm in heavy traffic the car never gets over 180*. If it starts to get to 220*ish in heavy summer traffic I flip the a\c on so both fans come on and back to 160* it will go. It does take a lil longer for my car to warm up in the cabin on cold winter days but we don't get too much cold down south anyhow.

 

Today it was 42° on the way into work. 180° thermostat in the GTA. I got out my digital temp probe and measured the heater temp coming out the dash vents. 127°F was the result at peak. (Slightly above 180° coolant temp). Once coolant stabilized at 180°, my dash temps dropped down to 122°. This is with the windows closed.

I suppose this is why I say 180° thermostats are "OK" for heat output. But not nearly as comfortable as 195° thermostats. Your Infiniti looks to have a much more efficient heater core design.

 

Lots of variables Reid, no doubt.