enacer

Just curious if I should run regular or plus in my hoe.

73shark

Regular unless you've modified your ECM w/ a tune. Premium will do nothing except lighten your wallet.

ifwechoose

So true. Use regular...

The only reason people use anything higher than regular is when they have a performance or tuned car. The higher the octane, the higher the compression needed for compression. If you use regular in a car that calls for premium then your engine will knock and ping, however, if your car calls for premium then it most likely has knock sensors. These sensors retard the spark and it sparks the gas while the piston is lower in the cylinder. You'll notice less performance and poor gas mileage when this happens

Now, if you use premium in a car that calls for regular. You'll just eat away at your wallet. You're just using more gas to get you to the same place.

Look at it this way...you need a certain amount of gas for your Camry but a Mercedes sports car uses the same amount of gas that's pushed into a smaller space, so it needs to be more tolerant of pressure. In this case, you use Premium. The pressure tolerance doesn't get you better performance...the pressure the gas is put under does.

SabrToothSqrl

http://en.wikipedia.org/wiki/Octane_rating

atis

Also higher octange fuels burn slower...so on my 91 Stang I run 91 octange...but I have my timing set at 14* BDC instead of the stock 10* BDC so I can build up the extra compression as the fuel burns and trys to expand. If I run 87 and leave the timing at 14* I get lots of knock and the idle goes to crap.

On a side note, its good for an extra 5 rwhp...incase you were curious as to why I did it.

JimJ

Top tier Shell regular. Haven't found anything better. Sometimes a half tank of premium as I have heard that it has 5x as much detergent as required by whom I don't know.

ifwechoose

In 1995 the EPA introduced the minimum gasoline detergent standard. Ironically some gas companies reduced their detergent levels after years of offering higher levels.

In 2004 BMW, GM, Toyota and I think Honda was on the boat too, set their own proprietary standards and called it Top Tier Detergent Gasoline - because it has more detergents than the standard set by the EPA. The same year the standard was introduced into gas stations such as Shell.

I've always liked shell before all this anyways. I can't remember what the two standards are...it's been 3 years since I wrote the essay in school.

73shark

If you're concerned about detergents, it's a lot cheaper to run a bottle of Techron thru it once a year.

ousig2408

agreed 100%. I stay away from the old run down places that do not have much traffic. But I can't imagine any newer station with lots of traffic having any worse gas than the station across the street.

ifwechoose

Yup, $10 a year is much better than an extra 20 cents a gallon each fill up.