Why Premium Gas?
 

I was just wondering, why do we use premium gas? The reason I ask is because my uncle just informed me when he used Claire for the past month he filled her up with regular unleaded 87 octane gas. At first I was horrified, but then I realized that I had not heard a knock or anything. I thought regular would heat up and cause a misfire? But then again it is winter..in the south..
:p

Rover's do not use an EGR system on their engines, which leads to higher temp's on the intake side. It needs the higher octane to prevent pre-detonation from the hi temps. And it prevents the valves from carboning up.

But, Rover's are also equiped with knock sensors, so if it was pre-igniting, it would retard the ignition to compensate0- no percieved knock or ping.

I have run 87 octane when I couldn't get anything else, and didn't get any noticible effects, but because of carbon build-up, I don't do it often.

Thanks, hit the answer on the first try!

i mostly use 89 octane (here its the same price as my 87) and I use BG. I actually get best results with 89 oct....i tried 93-91-87..with 89 i get mid 14.5mpg

Here is the bottom line on why you need to use premium gas...because the people who designed the engine say so.

But then you get into conversation about how Automobile companies are helping oil and gas companies by suggesting higher octane fuels. Then people start talking about how they went on 87 octane for blah blah amount of years and have been fine instead of using the suggested 90+. Then people start talking how only race car drivers only use high octane and that the government has a conspiracy of monopolizing gas in their country or taking over other countries supplies..

yeah we did this in class today, so I was just wondering what other parts of the world thought haha

Well in Europe they sell 3 kinds of motor fuel, 95 octane petrol (gasoline), diesel fuel and LPG (liquefied propane gas)
That it, kerosene is sold as a heating fuel, bio-diesel is also sold.
In Europe they even sold leaded gas until the late '80's and gas engined cars didnt even have catalytic converters until the early to mid '90's.
If you read the Rave manual for the UK spec V8 you will find no emissions controls until '96?

Here is the kicker...unless you have a gas station that has three seperate gasoline lines hooked up to the station for each grade...you will never ever get "true" 91 octane...or any true grade for that matter (unless the previous guy put in 91)

Now days there are some gas stations (especially mom and pop) that will only fill up one tank and sell it on all grades..

My gas station only serves 89 octane...nothing else..so I always know its true 89

Best chance of getting the best gas is busy travel stops...they have at least 2-3 trucks a day coming in for gasoline (its always fresh daily) my friend works for flying j

Ooo nice ammunition, so I should start the argument up again tomorrow haha.

Btw I don't have emissions testing here in MS. So if I wanted could I chop off the cat (which rattles btw) and just weld a pipe (down pipe xD) instead? 2.5" inlet and outlet right?

Good luck finding someone that will "hack" off your cat...if I could I would..in a heartbeat