Alright....

My situation is as follows,

When the car is running, the primary cooling fan runs all the time, till I shut the car off, which to me is great.. the cooler the better.

The problem is that ever since I had a custom burned PROM put into my car, my temp. never gets above 190*, so it never gets hot enough to activate that 2nd fan..

I want that 2nd fan to run ALL the time just like the primary fan does...

I want BOTH fans to run as long as the car is running.

What do I need to do?

 

you could run a wire from the relay of the first fan to the relay of the 2nd fan, or just out a switch on the second fan. however, if the car runs too cool it will never reach operating temp and run worse than running at 200*. just something to think about

 

The car has no problem or any kind of long delay getting to 190* with just one fan running all the time, would the addition of the other fan really be that big of a difference?

 

Yeah those fans should run offa straight 12 volts, If it were me I would just wire that second fan into a relay and put a nice switch on the inside of the car. Personally I would run it through the fuse box to switched power though, so when you turn the car off the fan stops.

Wouldn't want constant power myself, cause I know there would be a day I left that damn fan running.

Head over to your local auto shop, pick up some wire, a switch, and a relay. That's about as simple as it gets

EDIT:

Maybe poppin in a new therm stat might help you hit those optimum temps. Running a 350 at 190 sounds not so bad. My old 350 ran around 185-195 and it loved it there. The one time the rad hose blew I drove it home and engine temps hit almost 270, and the engine was 100% fine. Though that engine was a 1969 350, stroked to 383 and 4 bolt main... So :P

But seriously, why would you want that fan running anyways? 190 is fine, and that fan can just chill in case your engine does heat up its always there as a backup

 

That is exactly what I want to happen, when the key is at the position right before you crank it (RUN position I assume?) the fans kick on, and when it's not in that position, they shut off.

This would be extremely helpful at the track that way I can be cooling down between runs.

EDIT:

I have a 180* thermostat in there.

How cold is *too* cold for an engine to run?

I am probably going to end up running the 2nd fan to a switch, just need to figure out how.

 

Well keep in mind that running the fans while the engine isn't running won't do **** all to your engine temps. The fans blow air towards the radiator cooling off the coolant, having them run while your car is turned off is just pointless.

What you should do is make a spot in your deepfreeze, get yourself some of those shallow planting pot things. The really long ones that are about 2 feet long, 6 inches wide, and maybe 2 inches deep. Fill em an freeze em. The day of the race pull them outta the pots and toss the bricks of ice into some kind of plastic bags ( I use pillow cases overtop of the bags ). Haul em to the track, toss em in the shade. Between runs drape those bags all over your engine bay. Across the intake and plenum (if youve got TPI). Let it cool off the engine with some good ol ice, super cheap and definitly works.

As a general rule of thumb...

Carbs 190 - 195 degree thermostats
Injection 160 - 180 degree thermostats

Everyone says a chevy runs better cooler, In my opinion 180 is just about right.

 

Actually you're backwards. The fans pull air through the radiator and blow on the engine. Therefor the coolant in the radiator cools off for as soon as the car starts, and the engine itself is cooled as well. I'm not going to argue if you disagree, just do a search.

Also, I'm not sure about carbs, but FI doesn't like the cooler temps. You want the intake and plenum cold to keep the air from being heated on it's journey to the cylinders, but overcooling the engine as a whole will kill emissions/performance/mileage if not properly set up for the cooler operation. They're designed to run at 190*+ for a reason. I do agree that 180* is a good temp for a thermostat though.

 

so running the fans when the car isnt running is a good thing?

 

It won't hurt anything, but just consider what the fans do in the first place. They cool down your antifrezze as it sits in your rad... If your waterpump isn't going to move the fluid around... What use is the fan? It'll just spin in there moving the warm air around under your hood. And even if you open the hood... Imagine holding a regular fan over top of your engine just blowing air on it... Def won't cool it down enough to make a difference

And as for firebirdjosh, all sounds good to me mate. I'm not a major mechanic

 

Have you ever considered an oil cooler?

 

Why the hell would you want both fans running all the time? This is a waste of HP, since the electrical load on the alternator with fans running is huge, and takes a lot of power from the engine to turn. Ideally you just modify the fan on/off temps in your chip and you are good to go. Fans spinning on the highway blocks more air than anything else.

 

The alternator is already putting out "X" number amps, regardless of the electrical drain. So, regardless of zero amp draw, or 50 amps of draw, there isn't going to be a HP draw between 1 fan, 2 fans or none.

The HP draw on the engine from an alternator is negligible for a street car anyways. I wouldn't worry about any HP loss from a fan.

 

That is 100% not true. An alternator has a field current that varies based on the voltage regulator. High amp draw will cause the regulator to strengthen the alternator's field current, causing higher output but more HP loss. An alternator can easily cause more than a 10 HP loss at high currents. The alternator's output IS based on electrical drain. A DC generator's output would be constant, but an alt. has a variable field.

Read up at

http://www.alternatorparts.com/under...lternators.htm

Under "regulator" for an explanation of how this works.

Maybe this is why people are under the mistaken impression that running electrical fans all the time is okay?

 

that's true cuz sometimes when I kick on a fan or something hi draw, the alt. belt will squeal for a little bit.

 

So what is the optimal operating temperature for a 350 fuel injected? I am used to owning newer cars and on the temperature gauge, it never goes beyond the quarter mark. However with my IROC, temperature gets to close to 230-240 degrees before the fan kicks on and only one does at that time. What makes the second fan come on, when it hits the red zone? It only gets that hot when the car is stationary at redlights or in park. Is this normal or maybe i should be doing something to try to get the fan to kick on sooner? Thanks for any help.

 

The ecu controls the temperature, it has nothing to do with the "red zone". The factory gauges are standalone from the ecu, and are not even that accurate. Your stock fan will not even turn on until 225. There is probably nothing wrong with your car, and it is normal for the factory gauges to be inaccurate. You can have the ECU reprogrammed to change the fan turn on/off temps. An engine is more efficient when it is hotter (not too hot though, then you start breaking stuff). I do my own chips for the TPI computers and set the fan on around 195.

 

I've got a 190ON and 180OFF setting in my chip with a 170 thermostat. I have a switch on the second fan, and I rarely flip it on. I am very pleased with the setup. I'd never consider running the 2nd fan all the time.

 

what is the most accurate way to measure the exact engine temperature? how do i make the gauge more accurate, would i have to get an aftermarket one?

 

A good quality aftermarket gauge is probably your best bet. With my GTA the temp the ECM is seeing is hotter than what my gauge sees. When my gauge is indicating 212F, the ECM is seeing 232F.