ewingr

I can set the warning target in my Dakota Digital guages for Oil Pressure, and Water Temp.

What do you recommend setting the warning at? I know that LS engines today run hotter than the old 350s I used to run.

Project GatTagO

iTrader: (7)

I'd set oil pressure at 15...water temp at 220...

Andrew

ewingr

Thanks Andrew

Michael Yount

iTrader: (1)

How are you controlling cooling fans Roger? Your warning light set point should be slightly above whatever temp the fans are controlling to.

ewingr

So, as an example, if the fans come on at 210, then the warning should be at 215 or 220'

I'm controlling them from the temp unit in the front of the left head, which is wired into the PCM harness. I'll have to investigate what temperature that is set.

Thanks for that thought process. It makes sense.

Michael Yount

iTrader: (1)

If my research was correct, the 08 Corvette ecu I'm using turned one fan on at 226F and off at 220F, the second fan on at 236F off at 229F. In that case your warning light would be on constantly once the car warmed up - kind of defeating the purpose of a "warning" light.

Project GatTagO

iTrader: (7)

I think this varies. The GMPP ECU in my GTO turns the fans on at 212 and off at 205. All this with a stock 189 degree thermostat.

I'd want a warning if it was getting above 220, even though I would not be concerned unless it started climbing. So if I had a warning at 220, then I can start to see what was going on more closely.

My Cougar rarely gets above 205 on the stock thermostat and I think I have a warning set in my Holley dash at 220...


Andrew

Michael Yount

iTrader: (1)

Absolutely Andrew, which is why I referenced my ECU by year/make...so I think each user needs to understand what their ECU or stand-alone fan controller is doing and why before they decide what the appropriate warning temp indicator is set at. However, given the number of "standard" tunes that lower fan temp -- I believe higher fan temp actuation (say, 220F+) is quite common with stock/OEM GM ECU's.

FWIW, I'm using the ground provided by the ECU to activate the first fan on mine (on at 226F) to turn on one of my un-used idiot lights as a warning, much as you are. My t'stat is stock (new crate LS3) and began to open at 186F - fully open by 188F. With enough airflow across the rad under cruise (winter anything above 20 mph or so, summer 35mph) the sender for the ECU head temp sits right at 195F-196F in mine. I have my variable speed fan controller set at 202F and when the fans are on, I'm seeing 199F-200F head temp pretty consistently. Hopefully, I'll never see my warning light come on.

Project GatTagO

iTrader: (7)

Michael,

Sounds like your setup works very much like my Cougar. When moving, the fan barely comes on. I am using PWM to control the fan speed. I was driving it today and it got to 200 and fan speed got to a max of 20% and the temps started to drop. This was in stop and go traffic...

I ramp the fan speed pretty aggressively above 210, but I never get there under normal driving conditions. Having a hole in the hood helps a lot!

Andrew

Michael Yount

iTrader: (1)

I use a Delta Current Control PWM controller on mine - flawless at driving twin 11" shrouded SPAL fans and a 7" fan on the oil cooler. We even crafted a 'fan tach' -- the face is of the Volvo turbo boost gauge; the guts are a Volvo 52mm tach modded to accept the signal out of the PWM controller. 7AM is 0% fans (off) - 5PM is 100% fan speed. They're rarely above 40%. Except when A/C is on, they come on about 85% all the time that the clutch is engaged. However, I wired that activation wire through a switch on the dash, so when I'm under cruise out on the Interstate for example, I can flip the switch and kill the A/C activation so I'm not needlessly running fans running down the Interstate. I also took the oil cooler fan off the controller and put it on a switch activated relay. This aluminum block is so much more effective at quickly putting heat into the oil that once the oil gets up to 210F or so, it works better to just put the oil cooler fan on all the time.

Project GatTagO

iTrader: (7)

Michael...

That's good stuff there!!!

There is a way to implement PWM control with your stock ECU. Also, as I understand it, you can install a AC pressure sensor (0-5v) and have full control of the fans with a table that is engine temp vs. AC pressure. This will give you the optimal control. The speed will take care of itself...

Here is the thread:

http://www.lateral-g.net/forums/showthread.php4?t=40215

It is long but has a ton of useful information, should you go that way.

Andrew

Michael Yount

iTrader: (1)

Thanks for the reference -- I had the DCC controller with my previous 5.0L Ford set up in the car. It's worked so well I simply re-used it. I always had thermal switches/relays before. Got tired of the on/off nature of the system, the wide range of operating temps (stock GM ecu in mine has you running from 195F to 236F!) and the big hits to the electrical system when big-amp fans come on all at once. PWM soft starts everything and only runs them as fast as needed to maintain operating temps. And now my operating temp range is about 5F - 195F-200F. SO MUCH better than my previous fan control methods. If it ever fails, I'll have the info in the thread you linked as a starting point for a replacement.

Jimbo1367

I totally agree. Its too late to try to understand it all for me. LOL> Hopefully some sleep will clear me head.


OP,
Thanks for posting the thread. Very informative!