One thing everbody is overlooking. What pistons are you running?
If your running a stock style casting with oil cooling in high preformance engine like I am you should really shy away from synthetics. Synthetics stand up to heat better by simply not absorbing heat nearly as well. This means your pistons will be cooled more effectivly with a Dino oil. This has been told to me by Mahle (Makers of the LB7/LLY pistons) and others.
Another thing to think about is your change intervals and how hard your running it. Take my truck for example. I doubt I will put 3000 miles on it this season . But the miles it gets will be hard. 300' feet at a time hopefully!
My oil will need changed often simply to deal with the risk of fuel contamination.
I think synthetics are great but not for me. Pennzsoil 15-40 has served me very well over the years.
only part of this is true,
regular oil has a temp life weather it's under psi or not, the average oil temp of a stock diesel with regular oil is about 220-250 depending on where you get your sample, regular oil starts to break down around 220* @ 0 psi. once more psi is introduced to the oil, I.E.pushed thrue the oil circulation system, the oil becomes more unstable, taking away yet even more of the saftey buffer zone. higher rpm, high egt's, high boost, higher engine temp. ect will all contribute to a far worse oiling condition for the engine.
regular oil has no more heat carring abilities that synthetics, the only difference is that synthetics can take way more heat before they will start to breakdown, oxidise,sludge up, increase friction, and wear your engine . thats why the most expensive forms of racing and even military or nasa jet engines use synthetics from a tier 4, or 5 catagory and nothing less!!
for mahle to tell you that regular oil carries more heat away boggles my mind because it's simply not true and cant be backed up or verified by ANY testing method that i have ever seen. i suspect that you talked with some one not in the know.......
i only say this because we all know that the oil temps in the piston, exhaust area are way higher than the rest of the system and a diesel will produce temps above 300* + oil temps in that area, and regular oil is very , very close to complete breakdown at that temp, while a true synthetic tier 4 will not even start to breakdown untill about 390-430*+ oil temp, tier 5 or pure easter can go into the 500*+ range and not skip a beat.
