thermostat and rad. cap

thanks for the input however I want to know if anyone has actually done what
I wrote and what happened. Also do you know what temp coolant/water boils at
under 12lbs of pressure compared to 16. thanks
"Shades" <shades_1970(at)netins(dot)net> wrote in message

> Going to a cooler thermostat with your OBD II system might not be the best
> thing without a slight reprogramming. I definitely wouldn't go to a lower
> pressure cap. Water in a pan boils at 212degrees, but the more pressure
> its under, the higher temp it takes to make the water boil. The area where
> the coolant contacts the cylinder can be like dumping water into an empty
> pan on the stove that has been on a full up burner for 5 minutes...If the
> coolant cant contact the metal, it cant cool it.
>
>
> "Gary" wrote in message
>
>> Has anyone changed their thermostat to a cooler one 195 to 180 for
>> example and or has anyone changed their cap from 16 to 10/12 lbs and
>> what where the results..Thanks. 97 5.7 auto
>>
>
>
 >> Stay informed about: thermostat and rad. cap 

"Gary" wrote in message

> thanks for the input however I want to know if anyone has actually done
what
> I wrote and what happened. Also do you know what temp coolant/water boils
at
> under 12lbs of pressure compared to 16. thanks

you gain aprox 2.8 degrees for every pound of pressure, so a 15-16 pound cap
will raise the boiling point of the coolant 45 degrees . The computer
system expects to see a certain operating temperature. If the vehicle does
not reach a high enough temp the computer assumes the engine is cold, and
the fuel management system runs on a preset set of parameters called open
loop, i.e. it doesn't read from knock sensor, it retards the timing, it
ignores other sensors. Its basically like driving with the choke on on a
carb. In the early days of replaceable prom chips, there were chips
designed to work at 180-190 degrees instead of 212. Fuel mileage still
suffered. The whole idea of running at higher temps is to get more
efficient burn of fuel. The engineers would love to see 250, but pistons,
heads, and gaskets aren't there yet.
As stated in another post, there are surfaces internal to the engine that
exceed the temp you see on the gauge. The boiling point for the coolant
must exceed these temps, or we have problems, remember early 400 small
blocks before they added steam ports to cylinder block decks and the heads?
(400 blocks the cylinders were siamesed, ie there was no clearance between
the cylinders in the cooling system)

Whitelightning
 >> Stay informed about: thermostat and rad. cap 

"Whitelightning" wrote in message

>
> you gain aprox 2.8 degrees for every pound of pressure, so a 15-16 pound
> cap
> will raise the boiling point of the coolant 45 degrees .

I had a feeling you were gonna chime in with the right degree increase per
PSI...Thanx
 >> Stay informed about: thermostat and rad. cap 

Another issue with a lower thermostat is the cooler water temp might 'fool'
the computer into thinking the engine is not up to temp and run richer as if
the engine was still in warm-up mode.

>G<


"Shades" <shades_1970(at)netins(dot)net> wrote in message

> Going to a cooler thermostat with your OBD II system might not be the best
> thing without a slight reprogramming. I definitely wouldn't go to a lower
> pressure cap. Water in a pan boils at 212degrees, but the more pressure
its
> under, the higher temp it takes to make the water boil. The area where the
> coolant contacts the cylinder can be like dumping water into an empty pan
on
> the stove that has been on a full up burner for 5 minutes...If the coolant
> cant contact the metal, it cant cool it.
>
>
> "Gary" wrote in message
>
> > Has anyone changed their thermostat to a cooler one 195 to 180 for
> > example and or has anyone changed their cap from 16 to 10/12 lbs and
> > what where the results..Thanks. 97 5.7 auto
> >
>
>
 >> Stay informed about: thermostat and rad. cap