Regular versues Premium

[Swims350]

I guess atv's are alot different then because it requires reg. and I put in prem. and notice a HUGE difference, but I never did on vehicles.

 

[jeff's88silverado]

Same here no difference in my truck with the different grades. But we have a 93 buick regal 3.1 that calls for reg. but has a rough idle and if you put prem. in it it'll idle smooth and feels like it has a lot more on take off. Then again it really just depends on the vehichle