mcholdfast

Yes, it has a metal belly pan installed and flaps removed. I was in stop and go traffic through downtown Atl a couple of weeks ago with the A/C on. It climbed about the width of the pointer above the last white line and stopped there. Just enough to make me nervous but no overheating. Once I got going again, it cooled off a bit. The temp outside was 102.

pcar928fan

If you learned THAT in 7th grade then it was a 7th grade for science/math prodigies!

dprantl

I remember learning that in 2nd year too (that's the 7th grade equivalent in the english system).

Dan
'91 928GT S/C 475hp/460lb/ft

Erik N

Not to get off topic, but what is the law for liquids?
PV=nRT was at work (I thought) for example when gaining elevation and water then boils at a lower temp, or when you pull a vacuum in an A/C system to vaporize off condensation.

dr bob

It's the perfect gas law, not the perfect liquid law. Steam is not quite a perfect gas. OK, nowhere close...

AngelP

Ok folks here are my roundabout coolant temp. story. All coolant components original equipment except thermostat, and water pump -89 GT. It’s always run the same which is to say warm, typically about 1, perhaps a bit more, needle width with below the last white hash mark. Eons ago when I used to track the car it would run a bit past the last white hash mark but not overheat. It made me quite uncomfortable though. Next I need to set the stage with a seemingly unrelated aspect; For quite a while after getting Autothority chips I had a detonation issue, which was improved but not totally eliminated with a new rising rate fuel pressure regulator. Always used premium gas. One day an idea popped into me noggin’ and this went something like this; I’d always wanted to JET-HOT coat the exhaust manifolds to keep the engine bay as cool as possible and allow the engine to run more efficiently. So I reasoned that perhaps doing this would not only allow the engine to run “better” but also perhaps eliminate any tendency to develop hot spots in the head which might produce detonation. SO, about four years ago I had the opportunity to do this and voila, no more detonation, even while now using only plus gas, AND getting back to the original point of this story, the coolant temp is lower overall. When running up a hill on a hot day it still can get say up to the last white hash mark, but in general it stays cooler. Two issues resolved with not a trivial mod, but in my book it ranks as second best besides retrofitting the twin plate clutch. Almost forgot, since I’ve put off replacing my original hoses( believe it or not) I bought the 7psi cap from 928 motorsports and have been using it for a year now. It’s a bit of a bitch to remove, and initially I seem to recall coolant fluid evaporating more readily, though not unexpectedly, due to the lower pressure cap, but lately even in this hot weather I haven’t had to add any distilled water. In any case the car keeps running cooler even with the 7psi cap. Hope this was of interest...

dprantl

Any update on this Andrew? I am curious. Today I was blasting down the highway again with both A/C's on full at ~80mph, digital dash showing 103 deg F for outside temp (heat index today is 104 - 108). Slow down to 55, then 8psi boost to 80 several times to try and make it hotter, yet the temp line was glued to the low side of the last white line, never higher. The most the ST2 ever read was 95 deg F. As soon as I got off the highway and got into stop-go traffic, ST2 temp dropped down to 92 deg F and the temp gauge went to a needle width below the last white line.

Dan
'91 928GT S/C 475hp/460lb.ft