"premium" fuel (gas) in DOHC model?

[bluedraco]

hey guys

i'm in australia so our fuel ratings are different from say the US, but i was wondering if it is worthwhile in me putting "premium" (the higher of the two common fuels here in oz) fuel in my 1990 model DOHC galant?

would it give increased performance in any way? i'm aware it probably increases fuel economy but i was wondering if our car's ecu (or whatever) can make use of the higher octane fuel?

any advice?

[marktheblake]

Shell has a bunch of info at
http://www.shell.com.au/optimax/ ('http://www.shell.com.au/optimax/')

I believe that any unleaded petrol car can use it, no problems at all. Personally I have been meaning to try it out at the next refill (for the last few years)

[Proud Galant Driver]

premium has a higher octane level. engines are designed to run at certain octane levels. the manual should tell you which fuel to use. its not good to use a different octane level as far as i know. i know my friends old car you had to use 91 but mine i only used 87. or maybe he used 89. but thats not the point. the point is that i am pretty sure that because of the air/fuel ration your engine will only run at optimum performance using one type of gas. i don't really no much about this though. thats just what i think. basically, just check your owners manual.

[pro_sniper]

Most cars should never use a lower octane level than the one specified in the car's instruction manual. A higher octane gas causes no problems according to several of my informed sources (mechanics, both Mitsu ones and other brand mechanics), and can in fact be a good thing....

Jan Kenneth

[bluedraco]

guys, i might have come across as a bit of a noob or something (judging from your responses) but i'm not and i actually understand very well the differences and stuff between fuels...

what i wanted to know is whether the galant model that i have will make proper use of the extra fuel (eg. better power) or if i'm just throwing money down the drain?

my previous car (mazda mx6 turbo) didn't REQUIRE better fuel but if i put premium in i gained quite a lot of extra power (as reported in the owners handbook)...

my galant's handbook says nothing about it and i can't seem to find any info stating if the ecu will advance the timing or whatever else it does to make use of the higher octane fuel...

that's all i wanted to know - nothing less, nothing more https://www.thegalantcenter.org/style_emoticons/default/smile.gif

if you don't know, don't respond as it's not answering my question and just wastes both your and my time! thanks for trying anyway but i should have made myself a bit clearer! https://www.thegalantcenter.org/style_emoticons/default/smile.gif

[pro_sniper]

Several of my friends have tried this on different car brands and say they have slight power increases.

Like marktheblake was talking about, I too have been thinking of using premium to see what kind of power gains, if any, would result.

I don't know if this would work on our cars, but I would definately consider betting that it does. https://www.thegalantcenter.org/style_emoticons/default/laugh.gif
I'm certainly going to try, as it would be a ridiculously easy way to gain some power. Why don't you just fill it up and try? Just make sure the tank is on the brink of empty before filling it up :wink:

[bluedraco]

i have tried but damned if i can tell the difference! https://www.thegalantcenter.org/style_emoticons/default/smile.gif

of course, if there was a difference (probably is for a high-revving car, and certainly for turbo'd cars) it would probably only be a few kw at the most anyway and since that is only a few percent, it's hard to tell the difference...

a full exhaust might give 10%, and that's noticable but 2 or 3% would be very hard for 99% of people to notice...

i'm running premium at the moment...if i can't ever find any difference then i'll just fill it up every second time or whatever on premium depending on fuel prices...if one day i do notice a difference then i'll just stick to premium...if i notice an increase in fuel economy with premium then i'll stick to it but i haven't tried it that many times (only had the car since august)! https://www.thegalantcenter.org/style_emoticons/default/smile.gif

what i wanted to know is whether the galant model that i have will make proper use of the extra fuel (eg. better power) or if i'm just throwing money down the drain?

my previous car (mazda mx6 turbo) didn't REQUIRE better fuel but if i put premium in i gained quite a lot of extra power (as reported in the owners handbook)...

my galant's handbook says nothing about it and i can't seem to find any info stating if the ecu will advance the timing or whatever else it does to make use of the higher octane fuel...
1.) No you won't get extra power, unless the car adjusts positively for higher octane fuels. So far, the subaru WRX/sti are the only cars that advance timing for good fuel. Using lower octane fuel, on the other hand is bad. bad bad bad. If your car is equipped with a knock sensor, it will retard the timing and give you much less power. If it isn't, well then go drain your gas tank right now so you don't blow your engine up.

[marktheblake]

Cobber, the only way to truly tell the difference is to measure the fuel economy v. the increased cost.

The old man logged his K's and litres, and worked out that he saved money by using premium in his 95 Fairmont. I guess it would take you about 4-5 full tankloads to measure it out with reasonable accuracy.

Premium fuel is supposed to save you money apparently, and help maintain your engine better, so even if the power increase was negligible it may well still end up being cost effective.