I've got the stock setup on my L98. Fan on at 238 off at 220, I don't know what stat I"ve got but it seems to be around a 195? or 200?. I say that becuase during normal cruising on the interstate that's where the temp gage rests.
I've read everything from 160 to the 200 that I have is the best. What do you guys recommend and run.
What degree stat should I use?
Should I change the ECM memcal to put the fans on sooner?
If so, when, on and off?
Should I put in a new temp sensor to tell the fan to come on sooner?

I'd like to know what you guys are running and how you got there?
Thanks,

 

The cooler the engine runs the cooler the incomming air and so more power, within limits of course. You'll get a lot of differing opinions on this topic but here's mine.

I run a 160 deg stat. I have the dual fan (front/rear) setup and so I installed a 160 deg aux fan sw in the block between #1 & #3 spark plugs and wired it to also control the main fan relay.

On the highway and at the strip it runs at 155 deg until the air temp goes above about 75 deg; then coolant temp will climb a little. I still get over 30mpg highway winter or summer and enjoy the extra 10hp too.

Your cooling setup may differ but a similar technique could likely be applied. If not, get a chip with a 160 deg fan control point (or whatever temp you decide on). If you don't race your Vette maybe a 180 deg setup would be preferable.

 

yeah, i have the 160 degree stat to and love it. my temps used to hover around 190 or so, and would peak at stoplights at 230! now that i have the cooler stat, i cruise at 160 and never get over 200 while idling. now i just have to wire the fans together and ill be set

 

tpivette89, I went to Radio Shack and got two insulation displacement splicers and a short run of wire. First I crimped a spade lug onto either end of the wire and plugged em into the splicers. Then I clipped one plicer onto the wire from the aux fan sw and burried it inside the large harness on the inner fender well; the other is clipped onto the main fan relay grn/wht wire on the rear of the same fender well.

Both fans come on when the aux fan sw this setpoint and the ECM can still bring em on if the A/C pressure line goes too high.

 

Jim (65Z01) is right on as always :yesnod:

 

In GA, you really need to run a 160 tstat, with fans coming set to come on at about 195-200 and off at 170-175

 

changing the stat will not be a problem, should I try one of those flush and fill kits first from the autoparts store?
Also, to get the fans on earlier, I can jump the main fan to come on from the aux fan switch? Can I just cross them and have the aux fan come on from the ECM? The aux fan is really noisy, I don't want it running all the time. That way the main fan will always keep the temps around 200 max and the aux fan can kick in at 238 if things go wrong.
Whatcha think?
Also, does any of this effect the fan coming on with the A/C?

 

For primary street use, you really don't want fan control from the aux temp switch and here's why:

The temp switch only knows hot and cold, not air flow. There is no need for fan operation over about 35 MPH. The aux fan switch will tell the fan to run ONLY dependant upon temperature sensed.

Now stick with me. At about 35 MPH the speed of air crossing the radiator from foward motion exceeds the speed of air the fan can produce. At this point there are two possible detrements to the fan being on: 1.) Fan motor wear is increased, perhaps dramatically, 2.) Air flow may be reduced by the obstruction of the fan running, actually blocking cooling air flow.

This is why the aux fan comes on at such a high temp (and why on modern pcms the aux fan is computer controlled). Also, this is why the main fan on an L98 is shut off by the ecm when over 35 MPH is reported to the ecm.

The "best" and also most expensive street use scenario if the desire of the owner is to reduce coolant and running temperature is to use both a reduced aux fan temp switch (lets say 200* on) and also a reprogrammed ecm main fan on setting (sufficient below the aux fan switch to give some insurance that the aux fan only runs when stuck in traffic condition) of lets say 195* or perhaps a little less. This with a 180* stat. With a 160* stat use lower settings. Oh BTW, this also allows the ECM to turn on the main fan, under the normal programming when AC is requested. However you cannot have both as suggested in the above post (nor is that necessary or better).

When doing this consider the "on" and "off" temps of both the ecm as well as the aux temp switch and the low temp limit which is set by the thermostat (also btw, any typical thermostat will open just below it's rated temp).

 

Thanks PeteL,
Here are my plans:

a) Flush radiator and generally clean the system. (Can I use a flush and fill kit from autozone, pep, advance, etc....?)

b) Change to a 180 stat. I've tried 160 stats, and don't care for the lack of a heater in the winter.

c) Get chip burned to reset main fan on and off at 220 on and 200 off. (any ideas of who on the forum can do this for me? I already have a spare Memcal with the EGR function turned off, so I can send it to them for the burn)

d) Find an aux fan temp switch that will turn on the aux fan at 235-240 instead of the factory 260 range. (any ideas where to find this?)

Anybody else, please feel free to answer or throw your 2 cents in.
Thanks,

 

Just put a 180 in mine, the 160 was too cold for me. Old argument I guess but these engines were not made to run at 160 (bearings, ring wear, etc) I can now see a difference in the oil pressure, it used to stay above 65-70+ even when warmed up now its about 55 or so crusing down the highway. Haven't reprogrammed the chip yet so slow traffic driving isnt' helping me much yet.