Stabilizing Cooling Temps With A/C Fan???

[Dom426h]

Dont forget about Oil Temp
This thread would be Bad advice for most 94,95,96,&GEN2 owners as we have a bypassvalve that cuts flow to the oil cooler when the AC is on under certain conditions:
When the oil cooler gets hot enough (trackdays, or idle/sitting still with no airflow, or even slow stop&go traffic) the valve will bypass the oil around the oil cooler to help the AC perform better with the detriment of your oil running Hotter.


Sitting still after a track session with the AC on like mjorgensen said would basically take already Hot oil and bypass it around the cooler making the oil temp hotter. I'd prefer to turn the Heat on full blast to help bring the coolant back down to temp(after tracksessions/autoX's) or simply let the viper work as designed and cool itself down.

 

[dave6666]

in traffic-not a lot no, but it will allow the water to reach the radiator 40 degrees faster which would allow the car to operate cooler and keep the tempature from escalating at a faster rate. which would you rather have on black top with the clock ticking? an engine who is starting off at 160 degrees or one that starts off at 195 degree?
ill take the 30 degree cooler one. it buys some time until you get the car moving again.
i deal with racing engines on a dailey basis. thats my career. so yes, i do KNOW that a cooler t-stat will allow the engine to run cooler. you are allowing the engine to disapate its heat energy at a faster/cooler rate.
and here where i live it does reach over 100 degrees dailey in the summer. and i spend a LOT of time road race courses where the black top is always 130 degrees plus. so anytime you can get water into the radiator quicker, it helps.

Apples to oranges. I've done road courses in the summer heat - 100+ degrees - and my car runs at the t-stat. It reaches equilibrium at 70 mph or above. In other words, at speeds below 70 my temps will go up from the t-stat setting.

Leaving the office in the afternoon it will hit the t-stat about the time I get to the edge of the parking lot when it's 100+ degrees out. With traffic lights 1 to 2 miles apart, and often closer together than that, there is no cool down time to get ready for the next stuck at a light episode. My temperature will run at whatever the car is capable of cooling itself to independent of the stat temp. When I changed my stat from 195 to 180 it made no difference stuck at a light with ambient at 110 and pavement temps of usually 150 to 160. That's why I designed my 3 fan setup. Airflow is king, and at speeds under 70 I need air.

Dave, professional smart guy that has been testing Gen 2 cooling mods for over 4 years now in this sauna we call

 

[cfiiman]

Dont forget about Oil Temp
This thread would be Bad advice for most 94,95,96,&GEN2 owners as we have a bypassvalve that cuts flow to the oil cooler when the AC is on under certain conditions:
When the oil cooler gets hot enough (trackdays, or idle/sitting still with no airflow, or even slow stop&go traffic) the valve will bypass the oil around the oil cooler to help the AC perform better with the detriment of your oil running Hotter.


Sitting still after a track session with the AC on like mjorgensen said would basically take already Hot oil and bypass it around the cooler making the oil temp hotter. I'd prefer to turn the Heat on full blast to help bring the coolant back down to temp(after tracksessions/autoX's) or simply let the viper work as designed and cool itself down.

Ok so this is a new piece of information, certianly wouldn't want to spike oil temps but there are no means of monitoring that without an aftermarket gauge mounted somewhere which I don't really want to do. This would be a big vote for the ROE kit then b/c you get the same cooling effect from the fan without the a/c working or the oil bypass, my question is does the oil heat up enough to worry about it? I mean certainly the engineers that designed the car and put AC in it designed it to be used right...

 

[Dom426h]

I mean certainly the engineers that designed the car and put AC in it designed it to be used right...

No, they didnt, The AC was an afterthought, which is why it didnt work so well which is why they had to add this bypass crap.

 

[ROCKET62]

You guys crack me up. It's 20 degrees outside and we're expecting a foot of snow and you're talking about air conditioning.

Only good thing is the storm should blanket PA on wednesday - so the groundhog won't see his shadow and spring should be right around the corner.

 

[Leslie]

My '01 used to run around 190, higher sitting in traffic.

Now runs at 160 driving around on the street. I decided to try some simple things first and they are working for me so far! ...30/70 combination of coolant/distilled water+2 bottles of water wetter.
I also clean out my radiator regularly, have a 170 tstat.

If it DOES get really hot I turn on the heater, but havn't had to do that since I started doing all the other stuff.

 

[dave6666]

OMG if I ever had to use the heater to cool the engine in the summer it would be sell time.
I can do aggressive traffic driving in that 110+ stuff and have never needed that.
Fix the car properly and keep the heater off in the summer.

 

[ViperTony]

...30/70 combination of coolant/distilled water+2 bottles of water wetter.

I recall the 30/70 combination from Sean Roe. I did this in 2006-2009 and temps were lower with this combination. When I switched back to a 50-50 mix, my temps were slightly higer (normal operating temps). I added a 170 degree t-stat but based on my experience it didn't do much. I have also have the Roe Front Duct kit which helps on the track/highway speeds. Since adding an SCT tune which turns my fan on sooner, my temps have not breached 190. In the end, I think air flow is key over a t-stat. But what Dave6666 accomplished with his fan setup in that Texas heat is incredible.

 

[Leslie]

I recall the 30/70 combination from Sean Roe. I did this in 2006-2009 and temps were lower with this combination. When I switched back to a 50-50 mix, my temps were slightly higer (normal operating temps). I added a 170 degree t-stat but based on my experience it didn't do much. I have also have the Roe Front Duct kit which helps on the track/highway speeds. Since adding an SCT tune which turns my fan on sooner, my temps have not breached 190. In the end, I think air flow is key over a t-stat. But what Dave6666 accomplished with his fan setup in that Texas heat is incredible.

Yeh I learned the 30/70 mix from John Archer! Works great for me

 

[JoelW]

So, I am a bit curious about all the thermostat changing. Seems to me in a fuel injected motor with all that aluminum that there might be some problems changing thermostats to cooler temps. I know cooler might seem better but thermal efficiency would seem to suffer. I also wonder about expansion rates of the aluminum parts etc. Am I wrong?

 

[Dom426h]

Yes & No. It can be debated both ways. The Gen2 comes stock with a 195, and the Gen3 comes stock with a 185.

The Wizard recommends a 180 for the Gen2 which one could think cant hurt if the Gen3 is runnin a 185...
If you do switch to a lower t-stat then it is advised to reprogram the ecu to turn the fans on sooner and off sooner. Otherwise there will be a bigger temp swing which one could argue about the negatives of thermal expansion like you brought up.

Here is some of the pro's commenting on the Gen3:
Woodhouse(mjorgensen) http://forums.viperclub.org/srt10-srt10-coupe-discussions/603222-170-degee-thermostat.html
ViperSpecialty(Dan Lesser) http://forums.viperclub.org/srt10-s...s/607340-what-temp-thermostat-stock-06-a.html

 

[ViperTony]

The Wizard recommends a 180 for the Gen2 which one could think cant hurt if the Gen3 is runnin a 185...
If you do switch to a lower t-stat then it is advised to reprogram the ecu to turn the fans on sooner and off sooner. Otherwise there will be a bigger temp swing which one could argue about the negatives of thermal expansion like you brought up.

I agree with this and this has been my experience. The Wizard warned me not to use the 170 degree because it may cause the engine to run rich, I forget the exact explanation the man has spoken. I installed a 180 degree t-stat plus SCT tune to turn the fans on/off sooner and this combination does the job well, IMO. Air flow is key in this equation, however.