LT4 Best way to turn on fans early - 1996 LT4?

[Rich96c4ce]

Froggy47,
I did a lot of reading, but in the end, cooler was better for power. Maybe, emissions suffer, but the computer deals with that, and there are no engine lights. Also, the oil temperature still is high, 190 or 205. Mobil 1 is used. When you go back to think about thermostats, in the 1960's they were 160, then the 1970's were 180, then the 1980's were 195, in the 1990's they were 205. Seems to me that wear has nothing to do with it; it is entirely emissions. Maybe an engine 40 degrees cooler will wear more, but with Mobil 1, maybe you're okay. I can't tell you by experience about lowering thermostats, but I really like Mobil 1. I have a 115K Caravan, a 180K Caravan, an 85K Club Wagon, and a 111K Vette. They don't seem to burn oil, and are still peppy enough.

If you have a shop manual, see page 6-158 for a electrical diagram of the cooling fan circuit. If you use a double pole, single throw switch and separately ground relay #1 terminal 86 and relay #3 terminal 86, both fans should operate in high speed, and operate only when the ignition is on. That is much less expensive than the Programmer, but a lot of manual operation. It would be great on a hot day at the track in the starting lanes, though.

BTW, I put the thermo in first and the gauge reading went down a little from the OEM thermostat. I was disappointed. I eventually put in the Programmer, not as much for the fan control, but for the total package of options. The change to the fan programming really dropped the temperature as stated in the original post. (The programmer will be used to change the programming from a 2.59 axle to a 3.75 axle, in about two months.)

Cheers.

 

[froggy47]

Thanks for the post, you are going to explode off the line w/ 3.75. Buy recommendation -- stock in tire company.

See Ya!

 

[vettered91]

Hi there,

Froggy47, yes we are going the almost the same way. My next move is the change from 2.59 to 3.54 (new work for the programmer) and I believe is the best improvement in my project. I will decide this week if I am going to San Antonio Tx in the vette and get the 3.54 kit, MSD coil, NGK Iridium Spark Plugs and the adjustable fuel pressure regulator.

Rich, I think you are right; mobil 1 is the best. About temps, this afternoon I was in my daily highway paseo and the coolant temp was 176° but the oil temp was 190° all the way! (+-75 miles p/h)

See you!

 

[larryfs]

In the first place.... the LT4 has a 2 speed fan setup. both fans run in low speed, or both fans run in high speed. If you don't know that, don't go cutting into the wires. It has a 3 relay setup to get the 2 speeds out of the fans.

also the stock stat from the factory is 180. I currently run a 160, and it works fine, but of course the temp creeps up in traffic. The L98 guys freak out when they see 160 degree thermostat cause they don't know the LT4 comes with a factory 180.

the best way is to reprogram the computer and change the low speed and high speed settings of the fans.
Of couse I havn't done that yet... cause I havn't found an easy way to do so.....

 

[Rich96c4ce]

Dear Froggy47 and other interested parties,
Here some referenced to desireable oil temperatures. Bottom line is that any temperature seems okay as long as it is not too high. 180-200 F seems desirable because it is cool enough to not damage most oils, and warm enough to vaporize any condensed water in the oil. So with my 160 F thermo, fans turning on sooner, and oil at 175, I'm completely satisfied.

http://www.permacool.com/Catalog/Cat_page02.html

http://www.aeroshell.com/faq/answer.php?id=12

http://www.aeroshell.com/faq/answer.php?id=24