1. No I havnt had any negative experiences.
2. Stick to Mobil one synthetic.
3. Yes, you CAN mix regular and synthetic.
4. Yes, you can go longer between oil changes. I still change mine at 3-5k to be safe, depending on what sort of driving my car see's during those miles.

-Mike

 

If you mix synthetic and conventional you now run synthetic blend. However most of your Blended oils have 10% synthetic in it anyways.

 

to me this sounds like alot of opinions and garage science put together through personal experience. if you really want to know i recommend Emailing some of the motor-oil companies for the facts on the products. Most are more than happy to give you the right info you need. I use Quakerstate Sythetic in my honda, for the first 2k i noticed improved gas milage just by 2-3... probably because the other oil was very very old.

 

I can give you some info on pennzoil oils from my work. Hell I have some info laying right here on our 15w40 long life oils and some of our gear oils.

 

i have done this. i also had a cousin who was a chemical engineer for exxon/mobil who gave me plenty of technical info. far more than what i would ever need. some of the data that i collected (i did heavy-duty data collection between brands) was wayyy too much info for the average motorhead!

blends ARE about 10% synthetic across the board! AmsOil has the best specs regarding heat. Mobil1 has the best flow rate out of syth oils. Redline has best detergent qualities. i believe (if memory serves me right) the same in conventional oil goes like Castrol GTX, Pennzoil, Kendal GT1.
word to the wise, though! there are other mitigating circumstances such as ash and antimony content that i did NOT tally-in.

 

A good idea except for the problem of the huge bias the companies have towards their products. Of course they're going to recommend their [most expensive] product. It would be stupid not to. You can't run the tests needed to despute thier claims. Most of them are public companies; their number one goal is to make money.

 

haha the only reason i bought the brand I did was because i saw quakerstate's commerical about how they got a 10% friction decrease and that the teams they sponsor in nascar use the same oil. i thought if its good enough for nascar engines, its good enough for my honda!

 

If your car burns oil....(they all do to some degree or another) dino oil will lower the octane rateing of the fuel/air charge...
synthetic will not..
having said that, it is my expirence (I used both in the teg extensively) that you will burn about twice as much synthetic..