fastyz400

Octane boosters are great once in awhile, however with the MMT or MMx (forgot the name of the stuff that they put in) that they put in it to raise octane may hurt your O2 sensor if used to often. That's why, go with unleaded race fuel.

I've done a lot of research into this.

Too much octane will actually slow your car down, if it's not built for it. Meaning - more octane the harder it is to ignite. However, the explosion is greater making more hp. That's why you don't get engine knock. On the other end, if you use low octane fuel, the fuel may ignite before the cylinder is at top dead center, thus causing the knock, meaning as the piston is traveling up, the heat inside the chamber ignites the lower octane fuel before the spark plug ignites.

You want the fuel & air mixture to ignite a little after the piston is on the down stroke. That's why you need octane, so the fuel will not ignite prior to top dead center.

If you are not experiencing any engine knock, i wouldn't worry about it. In colder weather, you can reduce the octane or in higher elevations. But when you have high ambient temperatures or increase boost that's when you need the higher octane.

Too much octane, if you don't have high enough boost or compression ratio then your ignition can not burn the mixture completly, that's why you will actually make less hp.

My suggestion our current setup, use higher octane only when you hear engine knock. Start at 89, if you hear it, next tank move to 91, if you hear it, try mixing with some race fuel. Then when it gets colder outside, you can try reducing octane to save some cash.

moparman53

I got my CSRT-4 on 06/06/08, and have 1400 miles on it so far. The sales guy filled it with 03 and I ran 2 tanks of 89 and then a tank of 93. I honestly can't tell any difference. I can get a 3rd gear chirp even with a fat passenger.

fastyz400

moparman,

would that be your wife?

Bodnar4

HAHAHAHAHAHAHA

EVLPMKN

Man that's harsh

__________________
2008 Caliber SRT4
1998 Ford Mustang
1965 Chevy C10 (EVLPMKN)
1963 Ford Falcoln Convertable

SUNBURSTORANGE08

PETRO CANADA in BC has 94 i run that with a STP octane boost for a 104 octane ...the octane boost is about 4 bucks a bottle at you local parts outlet and oddly i get about 650 clicks off a tank of that.

EVLPMKN

From what I remember reading in HRM the octane boosters do not even raise the octane level one point. It’s probably cheaper to just put 91 (or 93 if you have it in your area) in your tank.

__________________
2008 Caliber SRT4
1998 Ford Mustang
1965 Chevy C10 (EVLPMKN)
1963 Ford Falcoln Convertable

fastyz400

104 octane race fuel $60 for 5 gallons.

moparman53

charliemurfie

I've run 94 from Sunoco since I got the car in March - filled it up with 87 on the long strech home and noticed approx. -100km difference in mileage for one tank...