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Discussion Starter #1
so us turbo guys always want the most consistent boost with no pull back. over the last while i have experimented with gas from all companies and before i go further shell optimax 91 octance made me think my car was broken so i won't even mention them.

my test staitions included:
Esso (a.k.a. Exxon)-max 91 octance
Chevron-max 94 octane:cheesy:
Mowhawk/husky gas -high ethanol contene gas, 94 octance is 20% ethanol:)
Pero-canada-max 91 octane
:evil:shell

for as long as i have driven (not long, under a year, i have been very loyal too esso, most of the time i got 91 octance, but if it was expensive i went with plus and got 89 octance, never regular-87 octane (except on my 84' n/a) i do nearly 900km of driving a week, so i have tested in many consistent driving situations.

i found the worst gas to be shell, when boosting hard i got 3/4 boost, never higher, and i would feel it pull back, two tanks revealed the same conclusion. so i went back to the same esso 91 octance, first fill i noticed a difference from shell, about 4 fills on 91 octance-consistent performance, most of the time full boost, however much pulling back up hills, sometimes to 2/3 on steep freeway hills.

Petro-canada was the same performance as esso, no notable difference on thier highest 91 octane.

Mowhawk gas i think i got better fuel economy on thier ethanol 94 octane, but the performance was the same.

then one day my friend who works at chevron gave me a gas certificate for $10. i was nearly empty and thoought i will pop in some 94 octance chevron on nearly an empty tank. so the car was already warmed up, went for a drive thru the city to make a delivery and i was just merging onto the highway when a semi was fast approaching, i slammed the car into 3rd and hit the gas, the turbo spooled in no time and went a tad bit into the red (something i only seen the car do once before, pulled down into 4th, same thing, merged, then again in 5th-SUPER HIGH BOOST, put a smile on my face. kept boosting the car and the turbo was just max! went up the big hill where it always cut back before, it cut back from a bit on the red to the border or red yallow and stayed there for 10 seconds up the hill! after an hour or so of driving i went and filled my car at esso, force of habbit. i went a jumped back onto the freeway to go to my other job and i noticed a difference in performance. so last nite i filled up with chevron (never used to be a fan) and the super performance was back. so i have now switched! 94 chevron gas makes my car happy:lol:

My friend who works at the gas staition told me how gas is mixed and some lessons in quality. 89, 91 ect, is jsy the pump mixing the 94 and 87, it seperates in your tank over time and is prob why 91 was so jumpy as it wasn't super consistent. she said chevron takes much pride in their 94 octance, and is is used by car companies ot test emissions and peromance. she claimed the gas quality to be so high that it is worth the often 20 cents more over regular unleaded per litre:eek: thought the results to be interesting enough to tell people-give chevron a try.
 

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Hooray for me! I've always bought Chevron, so this is good news. Unfortunately, around here the best I can get is 91 octane :cry:.
 

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Over about 2 years of driving my 91 900S 2.1, I've naturally migrated to chevron also.

My casual results for my 900S in Atlanta are as follows:

Best preformance:
Chevron Premium

******Clearly makes my car pull harder in all acceleration situations. Thats enough to sell me on it! Car runs smooth, but it seems like the BP might be smoother.

Medium High preformance:
Mobil Premium

******Nearly indistinguishable from the BP, but a slight slight edge

Medium Preformance:
BP/Amaco Premium

*******The motor seems to rev more refined and quiet on BP


Poor Preformance:
Quick Trip Premium****


QT gas turns my check engine light on within 50 miles of the fill up. I didn't belive that it was related at first....so I kept doing it. Now I know its related, Its done the same thing 4 times in a row after switching back to QT...from different stations. The car seems very harsh while on the QT gas.

I have not used shell enough times to have an opinion on it.

Conclusion: I get chevron whenever I can, and BP most of the other times.
 

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I only ever use Shell Optimax. I've tried all the other brands except BP Ultimate and I boost higher and longer with Optimax. In addition I don't have an APC, so I need as high an octane as possible, and Optimax is 98.5 in the UK.
 

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fuel additives

Have you tried any additives? I've tried a few, there's one called 'Nitrox' or something like that, it's a bit on the expensive side but is fun to use every nown and again for a bit of extra boost.
 

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Discussion Starter #6
Jezzadee said:
I don't have an APC.
could your engine be knocking and you wouldn't know it? i have heard many horror stories about shell. shell as a petrolum company for years has focused their work towards a more enviromentally freindly gasoline, unless your car is much much newer the high ethanol content along with the other refinery processes may not be that good for your old saab. for years chevron has been working at making a more performance gas which extends engine life becuase it is very high quality. i never paid attention to this before, as for the longest time i thought all that "optimax" "techron" ect. was a marketing gimmick, its not!
 

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Discussion Starter #7
Si said:
Have you tried any additives? I've tried a few, there's one called 'Nitrox' or something like that, it's a bit on the expensive side but is fun to use every nown and again for a bit of extra boost.
never thought to do this as i have always been told it is bad. if anybody with further knowlege would like to share something on this it would be appreciated!
 

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woywitka said:
could your engine be knocking and you wouldn't know it? ...the high ethanol content along with the other refinery processes may not be that good for your old saab
It's unlikely to be knocking, as it has been driven right up to the red line and above on several rolling roads while the A/F mixture was measured, and fuelling has always been fine with no knock detected. There is absolutely no doubt, though, that if I was running regular 95 octane I would be far more likely to experience knock.

As for ethanol in fuel, having just had a look round some petrol forums (such places really exist :D ), the consensus is that while other brands may do, Optimax in the UK contains no ethanol.
 

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Discussion Starter #9
interesting. i think you guys might have a different blend! 95 octane is regular!!!!!! here regular is 87 octane!!!!!!!!! what is with that? our max octane is 94 and in the states it only goes to 91 or 92 i think.
 

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You use a different system of octane calculation in North America. http://en.wikipedia.org/wiki/Petrol#Octane_rating . Basically 95 in Europe would be 90 in the US and Canada. Optimax octane varies elsewhere around the world as well - in Germany they get something called V-Power which is even higher octane, and in Australia Optimax is said to be lower rated than the European kind. If there's ever a thread on here about people about to go on a dyno or rolling road in the UK, almost every single one of them will fill up with Optimax first.
 

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Here in Southern Ohio, the best I've seen is 94 Octane from Sunoco. Nobody else seems to go to 94. I haven't tried Chevron, I'll check them out.

Shell offers V-power around here, too. Here it's the same octane as everybody's premium, but has injector-cleaning additives.
 

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optimax crap!

Initially thought Optimax was good but after experimenting here in Australia for a year. The car is an 89 900i, I find the best fuel available here is mobile synergy 8000 (think 98octane) following by BP version. I think the shell optimax available here in Melbourne is lower octane than elsewhere as I find my car pinks quite noticeable on the stuff. Will stick with mobil 8000 high octane.
 

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Best gas I ever used was Phillips66 104 Octane racing fuel :cheesy:

In my old 900 if I wanted to put a big smile on my face I would mix 1/2 a tank of this with 1/2 a tank of 94 Octane. You want to talk about boost :eek:

Of course it was kind of expensive
 

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I've used nothing (and I mean nothing) other than Chevron Supreme since purchasing my current auto. I noticed differences in my old 75 Volvo 164e when experimenting with different brands and grades, and always had the best results with Chevron Supreme. I know the previous owner of my current SAAB also used nothing but Chevron Supreme - why mess with tradition?:)

Chevron is part of the same entity that owns Texaco and Caltex fueling stations, though I'm fairly certain their fuels and blends are not the same across the board...

As far as additives, never used 'em in my SAAB, though I did dump a bottle of fuel system (injector etc) cleaner into the old Volvo every so often and it did reduce rough running. A tune-up and air/fuel mix adjustment is a better place to start, in my opinion... A cure rarely comes in a bottle, unless you're trying to cure a hangover.;)
 

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Hello!

I use always SHELL Vpower 100 octaan, only in Gemany as i now!
The car knocks with Vpower at 1.2 bar, with 95ron at 0.8 bar.
And the Vpower cost the same as 95ron in Holland :cool: and only 10 kmph driving for me :p .


Gr, Bennie
 
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