Ok I want to know why using standard motor oil lets say gives you 180 HP and about 15 MPG. But adding something like Royal Purple to your engine gives you (allegedly) 190 HP and 17 or 18 MPG. But then other oil additives like Zmax and the like do absolutely nothing. What makes Royal Purple so special?

Also, what kind of motor oil does everyone use with engine size and gas mileage.

 

I use used castrol GTX syntec 10w30 in my 88 dak.(I just put the used oil outta the 99 in it)

synthetic oil is all I use now. but I think I get like 15mpg in the 88 and I get 20-21mpg in the 99.



and Iuse lucas oil products too.

 

I've been using Mobil Clean 5,000 10W-30 with the grey bottle of CD2, and get about 12MPG city, up to 19.5HWY (at 65).

 

I use Mobil 1 synthetic in my 96 Saturn, 03 Tribute and my girlfriend's 96 Dakota. In my experience there is no substitute. I recently experienced the cleaning power of synthetic with my girl friends 96 Dak. It had been neglected, the oil was sludge and a lifter was sticking, plus it idled rough and was noisy. After two oil changes in six months with Mobil 1 all the buildup is gone, even the baked on stuff under the valve cover I could chip off with my fingernail, the sticky lifter isgone and it runs smooth and quiet. Because of that, Irecommend synthetic and nothing else.

 

I have always used Havoline 10w-30 in my truck. In my higher mileage car I used 10w-40. And with all the tear downs I have had to do I never saw any build up or experienced any oiling issues. I guess thats why I stick with it. I am getting 13 in town driving and 16 on the highway in my trucks 318.

 

92' Dak 318 - ran synthetics pretty much sinec new upto about 130kish switched over to Havoline now at 188k engine is spotless inside and out, mileage with the lower ratio 4.10's truck is gettin exceptional mileage 16 in town and 21 on the hwy at 110km/hr