Ok, first, my car:

1991 t2
manual tranny
all stock except for hks bov

the problem
my temp is normal. just a tad under halfway.

when i boost, it drops to about 10mm above the C

i have 2k on a rotary ressurection engine (bought the car from kevin landers)

i have coolant. the resovior looks fine.

why would my temp drop under boost?

this is my first turbo car so id like to know

also, i havent full throttle boosted or anything with only 2k on the engine, just maybe 2 or 3psi, so in a hilly area or merging onto the freeway ill notice my temp gets low

thanks guys

 

I'd check the water pump. Make sure that its doing its job. And, make sure there are no 'air pockets' in the coolant.
If the thermostat/belts aren't new, replace them.

And, the dash gauge is nothing special. You need to get an aftermarket gauge for accurate water temps. You could have an electrical problem with the dash or wiring.

 

i must mention as well... its been like 30 degrees out here in jersey

 

wait wait wait....your temps get lower? And your complaining about this?

 

I've been told the s5 temp gauge is particularly bad

 

Might be an electronics problem.. The wiring in these is shitty for one, and the coolant gauges - s5 especially - can do funky things every now and then.

 

well im not complaining, more like wondering. i know its great im not overheating lol

but when something is amiss, i fix it.