Think of it this way...

Agreed with all previous.

IF you are experiencing knock in your n/a car on 87, try going to 89 (or even 91).

IF you are NOT experiencing knock, the higher octane will do nothing for you.

You are most likely to experience knock under heavy load (flooring it, lugging up a steep hill, pulling a trailer/heavily loaded, etc.).

If you are experiencing significant knock driving normally on a level road, either your fuel rots (is OR fuel as bad as CA fuel? ), something'* broken (vacuum leak, plugged cat, etc.), or your car needs some serious maintenance (e.g., new plugs, de-carbonizing).

P.*., ONLY use unleaded fuel, whatever the octane...leaded will kill your O2 sensors and catalytic converter.

i dont tihnk my car has a knock. is it something noticable? it idles fine and drives fine. i was just thinking that better fuel might be better for the car. but seems like theres not much diff sence my car doesnt require it i wont benifit from it. ill keep with unleaded.

and can somone tell me a little about knock? this is my 3.8

There'* two different knocks.

1: Frequently called predetonation, or a side effect of predetonation anyway, when the flame front of predet hits another flame front (like from the spark plug), that is knock. Not always audible. If it'* bad, it may sound like a rapid rattle.

2: Work crank or rod bearings create enough slop that there is play. The part can bounce around enough to be heard.

[quote]i dont tihnk my car has a knock [quote]



i very hard to have 0 kr whit a L36 in the summer heat but you need to have a scan gauge to know it
but if youre not using youre car for heavy load or drag racing you don't need high octane

If you're curious, go ahead and try a higher octane fuel. Like JWikoff says, check your mileage on regular, run mid grade or premium for a while (a couple months or so) and monitor the mileage. See what you get. If it'* better, great...if not, go back to the less expensive fuel. This experiment will not damage your craft.

03Bonny, ALL fuel at the pump is unleaded, including low, mid, and high octane.

If you think something is 'wrong' with your car that you just can't quite put your finger on, bring it by sometime. I'll look it over. I don't have a scantool for your year, but I have a pretty good eye and ear for things under the hood.

I can give you a much clearer verbal explanation of what timing and KR do.