Should I leave the car running?

[Will]

To keep the yellowing side sills down to a minimum (I have already had them replaced once under warranty), I let my fan complete it's cooling before killing the engine.

In my opinion, most of the sidesill damage is done AFTER you shut down the engine (due to the large amount of heat built up in the chamber with nowhere to go).

-Will

 

[Marv S]

You might want to check into one of these VIPER FAN KIT CLICK HERE

 

[Ron]

<FONT face="Comic Sans MS">It appears that we're talking about two separate things here...

Radiator Fan / Engine cooling and Side Sill Cat temps.

I don't see how idling the engine until the water temp gets below 201 degrees (when the fan cuts out) would minimize the side sill temp. Nor do I see how a fan relay kit, which allows the fan to run until 201 with the engine off would help either. In fact, it would probably increase the heat as I'd guess that idling while stationary is the worst thing you could do for side sill temp.

I have a few questions.

Is there any airflow under forward movement in the side sills that aids in cooling?

Do non-silver Vipers have a side sill discoloring risk with extensive idling, like you'd find in traffic?

Is there any advantage to running the fan after engine shut off? If so, why doesn't the timer come standard as it does in some other less expensive vehicles?

Lastly, How would a 180 degree thermostat help keep the engine cooler in low speed conditions when the fan doesn't kick on until 207 degrees anyway?

Thanks
</FONT f>

 

[Marv S]

Ok, Are you asking for side sill reasons or for heat soak reasons? I took it as heat soak and not a side sill question. I have seen these cars turned off when the temp is so hot that the high speed fan is on and they go into an over heat soak that will boil out some coolant. In that situation the right thing to do is let it idle a bit to get the temp down.

Where did the 180 t-stat thought come from? It's a non issue when the car is anywhere above it's opening temp.

Sean's kit has pulled down temps of track cars after sessions faster than cars that do not have his kit, that I have seen. Sean can give the details on why.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by myothercarsaviper:
Do I need to hear the cooling fan shut down before I kill the engine?
94 R/T
99 GTS<HR></BLOCKQUOTE>

 

[Sean Roe]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ron:
<FONT face="Comic Sans MS">
I have a few questions.

Is there any airflow under forward movement in the side sills that aids in cooling?

Do non-silver Vipers have a side sill discoloring risk with extensive idling, like you'd find in traffic?

Is there any advantage to running the fan after engine shut off? If so, why doesn't the timer come standard as it does in some other less expensive vehicles?

Lastly, How would a 180 degree thermostat help keep the engine cooler in low speed conditions when the fan doesn't kick on until 207 degrees anyway?

Thanks
</FONT f><HR></BLOCKQUOTE>

Good Morning Ron,
Here are some answers for you:

1. Yes, while the car is moving, and not moving with the fan on, air does pass through the side sills. Not sure how much cooling its worth.

2. Some cars have enough heat at the cat to discolor the side sills, some don't, no matter the color. The stock cats have a long substrate area and get extremely hot.

3. Yes, there is an advantage to running the fan after the engine has shut off. Back when I first built the fan kit, I had to respond to a birrage of questions which led to extensive testing and proved the product as worthwhile. Why Dodge didn't do it, I don't know. Considering that if you shut your car off with the fan at high speed (over 217) it can boil over, I think all Vipers should have it. Well, at least about 245 or so do

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.

4. You're correct, the lower temp thermostst does nothing for low speed (stopped at idle) to reduce temperature. The only way the lower temp thermostst helps is if you're getting enough air through the radiator to reduce the radiator outlet temperature. A stock Viper will not run much, if at all, cooler on the racetrack with a lower temp thermostat. One with our duct kit that redirects the air will though.

Hope that helps.