Which petrol?

[176bob]

G'day gang, Just wondering what is the best option for the 4G32B unmodified except for twin throat weber?. Thanks Bob.

[davetrees]

The 4G32 is a low compression motor (8.5:1) so as a daily driver there's probably no point running anything more than 91 octane in it.

My GB rally car has a Weber 32/36 on it & I don't notice any significant performance difference on the highway between 91, 95 or 98. It's maybe slightly more economical on 98, but not enough to justify the (stupidly inflated) price difference of 10c/L.

I usually run 98 in it on events, largely because that's what I had it tuned on and it seems to be a more "consistent" fuel in terms of quality. It does tend to "go off" more quickly than lower octane fuels though if it sits in the tank for weeks between rallies.

[176bob]

Thanks Dave, much appreciated. All the best, Bob.

[robbert]

My car loves united fuels 100 octane. Better mileage and a bit more responsive.

[Scorpma82]

What sort of price is that?????

Is the extra mileage worth the extra cost?????

I personally like to use E10 in my car (03 Fairlane) although, being an older car.....you make want to make surethat ur can use it

[75wagon]

I have found that E10 gets very poor performance in my wagon, and also makes it smell fuelly.

It performs better on 98 (not that I have dyno proof or anything), but I get better mileage out of 98. It's been that long since I've run E10, I can't even remember how low the mileage was.

When I had my Lancer hatch it was a difference of more then 50km's a tank better to run 98 around town (so that was about 390kms on E10, and 440 to 470kms on 98).

[webby]

Not exactly a relevant example, but on my last trip to Wollongong my Commodore did from here to the Marulan cervice centre on just under a tank of BP 98, around 340km. Same trip back, filled it in Fairy Meadow with BP 91 and had to stop and refill in Boorowa, which is around 270km. Car is a bone standard pov-pack VC with the L14 202 and Trimatic gearbox.

On a slightly more relevant note, my Scorpion used to get an average of about 400km/tank on BP 91, and around 460/tank on BP 98. Stockish 2.6 Astron 1 (had Astron II carb and a 2L cam), Jap 5spd, standard 3.308 ratio diff. Not sure what it'd get now, as it has a lukewarm 2L and a 4.6:1 rear end.

[Scorpma82]

yeah older engines dont like the E10 fuel i've noticed

My 03 Fairlane gets better performance on E10 than 91 without sacrifice on fuel economy (im guessing its because E10 is min 94 octane rating and the car is also made with this already available....so they motor would have been built to tolerate this fuel from the word go)


Interesting tho, i used to use 98 in my old sigma and it used to condensate inside my tank......the 2nd i used 95 (well after a tank or two)...the engine stopped carrying on and i got a noticable gain in power, response and economy......i believe that super/leaded fuel was still at every petrol station....it had a rather high octane rating also...(im sure someone can clear this up for me)

[amehel0]

NOS!

[2Lgalant]

Cars back in the day ran on super 95 octane so why put lower in now e10 stuffs your carbys up even fuel injection cars too but mainly the carbys it eats away at the gaskets IMHO I wouldn't even put e10 or anything lower then 95 even in my mower but it's everyones choice just a no go for me

[176bob]

Thanks fellas. I think I'll stick with the unleaded standard and see how it goes. Thanks for all the info. Bob.