Engine temps

Brett Dikeman brett at cloud9.net
Wed Jul 27 21:15:40 EDT 2005

On Jul 25, 2005, at 12:06 PM, Brandon Rogers wrote:

> 1 - With the a/c running do the engine temps go down around town  
> due to cosntant fan in use?  Or go up due to more strain on motor.

Well, it's not just strain on the motor; temperature of air entering  
the radiator goes up a fair bit too.  I think it depends on ambient  
air temperature whether this causes things to cool down or warm up;  
especially in cooler weather, there's much less of a load on A/C.

Are you running the auxiliary radiator?  These help a fair bit, and  
an oil cooler is practically mandatory, especially if you intend to  
take it on the track (you're in Canada, right?  You ARE coming to  
Tremblant this year, right? :-)

> 2.  Which fan speed activates 1, 2, or 3?

Should be 1, although I think there is a high-pressure switch that  
can turn on 2?  Check the Bentley; if you don't have one, email me  
and I'll take a peek tomorrow.

> 3.  Does the fan run constantly - like even when you'r cruisng at  
> 80 on the highway?

Yup- I suspect that it is either necessary, or doesn't have much  
impact on mileage (electrical load should be less if the fan isn't  
doing any work).

Note that the MFTS sends a cutoff to both the CC head and the ECU if  
an overheat is detected.  Also, as Peter Schulz discovered, the  
200q20v's have a first-gear cutout switch.  Though an UrQ is probably  
better due to light weight, the 200q20v can be a real dog out of  
first gear with the A/C on until boost really kicks in.

As others mentioned, stage 3 will come on right before the car  
overheats, and you know it's on, because you can hear it over the A/C  
on high, and a voltmeter reading of well under 12v :-)  The dots  
towards the right of the needle on a 200q20v dash relate to fan  
stages (they're actually test points) I believe...can't recall off  
the top of my head.

"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin

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