Originally Posted By: aquariuscsm
Originally Posted By: Jetronic
Originally Posted By: deven
Originally Posted By: Jetronic
do you run high revs mostly? go thinner with your oil if you like.
Low revs? Get a thicker viscosity.
I run my car's engine at 1000 to 1500 rpm mostly, so I went a grade higher {acea C3 vs C2 in my case) and this oci even added a small amount of vg100 POE
Hmmm....I would think it would be other way around. Most race engines get a higher viscosity oil because they are run at high rpms and run really hot. These oils are able to hold more heat and dissipate it.
Originally Posted By: aquariuscsm
Yep,same here. Seeing as we have Valvoline VR1 SAE60 and Pennzoil GT SAE60,etc.
No.
To increase the load bearing capacity of an oil film you can increase the sliding speed (rpm), or you can use a higher viscosity.
If you rev your engine, you can therefor use a lower HTHS. If you drive at low RPM, you need the thicker viscosity as the sliding speed (both in the bearing or in the piston assembly and valvetrain area) is low. Furthermore, at higher rpm the friction inside the oil itself becomes higher, and a thinner oil will be wasting less fuel. A thin oil at low rpm will however depend more on his additive package to keep wear down, and fuel consumption might suffer.
So then why do so many mfg's recommend 40-50 weight oils if the vehicle is to be tracked,raced,or driven at constant high rpm?
tracking and racing imply maximum power, which is different from high rpm. That's a HIGH load on the bearing, not comparable to public road usage at all.