^how can u be so sure, unless you've done dyno runs.



+1

 

Because as purecoda said premium gas burns slower and it permits the pistons to reach a higher compresion before it ignites ,the oposite to regular gas that burns faster and dont permites the piston to reach full compression on the ignition time.
The ecu adjust the timing for compensating this. Thats why you (and I) feel more power on premium than on regular.also I get more mpg on premium than on regular.

 

Thats what I found. Even the dealer recommended Premium for better mileage (well the metric equivalent :P) - not that dealers are the all knowing ones, but even when I bought it they gave the choice of like $20 of regular or premium, and said the premium was best.
Usually run on Shell Premium, I think its like, 95 octane or thereabouts

 

My car kinda choke'd on premium the first time I tried to put it in, all it did was create a nice hole in my wallet, and didn't make me all that much faster, all in all I regret doing it but we learn from our mistakes.

 

Choked?

FQ 162 - sounds clever Someone actually marketing it as that or is that just you?
The UK Evo FQ's are hot
Effing Quick !

 

whoa, what? you only got it half right there. compression is set by the engine, not the gas you put in it. by your logic every car that uses premium would benefit from it and this is definitely NOT the case.

the fact of the matter is you will get LESS power putting premium in your ralliart. it will not burn as completely and you will have both lower power, worse gas mileage and additional (needless) strain on your cat.

look, if you're really worried about the power, go get it dyno'd for real.

 

PAYING FOR PREMIUM GAS CAN BE A WASTE OF MONEY

Many people use premium gasoline in the belief that it's better for engines than regular. That can be a costly mistake, especially during times of high fuel prices. Most cars are designed to run just fine on regular gasoline. Octane grades don't represent a "good, better, best" choice; they simply measure the resistance of fuel to knocking or pinging, a condition in which gasoline burns uncontrollably in the engine's combustion chambers. Knocking and pinging can damage an engine.

While high-octane formulations resist knocking better than lower octanes, most engines are designed to take regular gas, which has an octane rating of about 87. Engines requiring premium gas are typically the more powerful ones found in sports and luxury vehicles. Those engines use a very high compression ratio, making them more vulnerable to knocking, so recommended fuels have octane ratings of 91 or higher. Using premium gas in an engine designed to run on regular doesn't improve performance. We have found that the differences aren't perceivable during normal driving.

Some engines for which premium gasoline is recommended can run on regular without problems. That's because the engine's knock-sensor system detects the presence of uncontrolled burning in the chambers. When it does, the engine's computer-control system retards engine timing, eliminating the knock but slightly reducing power. If you don't mind giving up some performance, you can run these engines on less-expensive regular gasoline. To check whether your engine is capable of running on regular gas, read your owner's manual or ask your dealership's service department. However, if your car "pings" or knocks with lower grade fuel, buy premium.

more fuel saving driving tips
http://autos.msn.com/advice/CRArt.as...tentid=4024120

 

o yea i forgot, why are you listening to what he recommended.

 

more linky goodness - http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

 

just what I was looking for... That FTC page goes in my bookmarks and I'm printing it out too =)

Mike

 

Sounds like your low on MIVEC fluid. Better run to autozone (or an equivilent) and refill...

 

fuel loses octane while it just sits in the gastank. by the time your car gets down to that last bit of gas, its not new gas and the car doesnt have all the octane. granted, you dont need high octane gas in our cars, the compression is not high enough. it shouldnt make a difference in the performance though, like said before more gas=more weight= car slower but when you lose octane and lose weight, it should all be the same performance as when you started

 

According to the manual use "Unleaded of 90 Octane or better"
Regular here is 89.
Its not that huge a difference in price either.

 

No symptons. Recently serviced etc... brakes, handling all good. No mods. I use normal regular unleaded 91 fuel.

However, I filled up the gas today and put in a full tank of Unleaded Octane 98 and the car is much more resposive and I feel as though it's back to normal.

True, but the less fuel, the less fuel to burn, hence less power.

+1 on that.

Sweet, I'll check it out. I think I have to purchase that from Mitsubishi Motors, not sure if Autobarn, Supercheap Auto (the equivalent here) sell it. It's done about 3780 kms, so do you think the Mivec fluid is about finished?

 

Btw, the gas I use is sometimes:

1. Shell
2. BP
3. Caltex