if you want to be particular on temps, perhaps should take oil temps.

personally didnt really have coolant temp fluctuations, just sit at middle.
from obd also 5-10ish degrees (80-90? maybe) up down depending on condition

OBD based? most stock car do not have oil temperature/pressure (well afaik majority of car only detects where it's low pressure or not, no values included) monitoring.

you'll have to get a sandwich plate between the oil filter and have extra gauge.

that's what we've discussed a little few pages back.

=edit=
what car/engine anyways since you're willing to use 300v? quite rare i must say haha

ooo nice car

btw ever thought of torque app on android/mobile? XD

ah i see

btw what prompted you on the xw30 viscosity selection?

most people here would choose something thicker, especially when it comes to turbocharged engines.
checked your manual viscosity charts?

from the top of my head, evo x is on xw30 specification, while R35 GTR is on xw40

ah sorry didnt know, was under the impression all imprezas are turbocharged

and yea those watery esters... very interesting stuff on the tachometer

care for signature series and long OCI like 40k km/1 year?

i got UOA on first page and the detergents/additives/TBN is crazy lol

heres the thing though, i would personally suspect that it's due to worn engine (considering the age of your car/that particular model) as i never had any oil loss on my 3rd 300v usage in a row(drained twice).

in fact during track, my engine oil only increased due to liquid expansion from heat and that's just mind boggling since that never happened on other car/lubricants

in fact the way how esters can deal with high temperatures, it is very unlikely that the 300v evaporated, more likely that it is leaking somewhere. (eg: the piston rings, and just combusted out from the engine)

honestly there isn't much solid ways to tell besides maybe a ph indicator paper to tell how acidic the oil has become and maybe visually inspect how viscous/thin the oil is compared to how it originally was.

feeling oils from your engine would be very detrimental to your personal health and i would advise doing so.

it should also not be honey like transparent as the oil obviously didn't do a good job in making sure your engine is clean. all my oil drains turns out pitch black after usage regardless of any brand/make so far.

if you want, you can try building a high temperature resistant filtration unit or something of the sort, and maybe have it filtering in between the drain pan or something during an OCI, see if you can visually inspect anything.
if you could, consider it being a damn serious case as the wears on my UOA are not visually inspect-able.

http://pmep.cce.cornell.edu/profiles/extoxnet/TIB/ppm.html
it's pretty much microscopic levels lol.

walau racing oil vs mainstream (although top of the line) long oci (40k km LOL) oil

amsoil racing line is dominator series XD

Ravenol is good shit. Expensive but good.