Here's something strange I just found:
I was looking at the PDS for QSUD and QS Dexos blend. Both oils meet Dexos but the blend is only $17 at Walmart.
The Dexos blend has a lower pour point (-45 vs -42), a lower viscosity at -30 (4180 cp vs 4980 cp), and a very similar flash point (235 degrees vs 237). The dexos blend is also thicker at operating temperature (11.3 vs 10.8)
http://www.quakerstate.com/en_us/product..._dexos1_TDS.pdf
http://www.quakerstate.com/en_us/product..._Motor_Oil_.pdf
What do you guys think? The Pennzoil blend is reported to be 50% synthetic, so this may be similar. I assume they use a similar add pack, but I'm not sure.