Does Shell still have ethanol free gas?
#16
Rennlist Member
Ultra 94 is the best fuel available for our cars (997TT) in Canada. 91 is fine for NA cars but with boost you need octane. 997TT factory tune is based on 93 octane - 91 octane, even Shell V-power 91 without ethanol, results in timing retard and power being reduced. Maybe not noticeable by the seat of the pants, but clear as day when looking at the data logs.
I am only referring to turbo charged cars. If my car was NA I'd be a V-power 91 customer and I was when I had my C4S.
I am only referring to turbo charged cars. If my car was NA I'd be a V-power 91 customer and I was when I had my C4S.
#18
Rennlist Member
Cobb Tuning warns on their website that if you're using Canadian 94 octane you need to run their least-aggressive ACN91 map, which they have purposefully dialed everything back due to the poor fuel quality in those three states. I couldn't believe our Ultra 94 had to be matched with the hobbled mapping from Cobb. So of course I did some logging using Ultra 94 and Cobb's 93 octane map. ECU was pulling 10 degrees of timing across all cylinders, it was clearly not liking the situation. So then I changed the mapping to Cobb's 91 octane map and again data logged. Still lots of knock sensor activity! Sure enough and as promised by Cobb, I switched to the ****ty ACN91 map and that's the only map that had knock patterns similar to stock tuning. I couldn't believe it but it's true - and no one can empirically explain why our 94 octane fuel has significantly less knock resistance than USA's 91 octane.
As a result of my testing, I sold the Cobb Accessport and decided to do a customized tune with Kevin @ UMW instead - specifically for my car, using Ultra 94 fuel. Not cheap and unable to be resold at a later date, but I like the peace of mind that the car is tuned professionally & safely for the exact fuel I'm using.
Would love if someone out there 'in the know' could actually explain the knock resistance difference between Canadian and USA gasoline. The same question has been asked across every tuner platform out there including GTR's, Subaru, JDM, etc... No firm answers.
#19
^+1 for custom tuning, EPL 'track' tuned on 91oct, is a freight-train no matter the conditions
#20
Race Car
#21
Anything in particular? custom tuning vs OTS (off the shelf) allows you to dial in the car via datalogs and/or dyno... a track tune is slightly more conservative(boost/timing, boost 'hit') vs the industry norm street tuning to account for higher operating temps(IAT's in particular) experienced while tracking, also custom tuning allows you to dial-in how the throttle/boost mapping is done
also get 2-step, change OBC readout for bigger injectors,etc
also get 2-step, change OBC readout for bigger injectors,etc
#22
Burning Brakes
Chevron has 94 no ethanol
thats what I always buy
thats what I always buy
#24
Burning Brakes
#26
#27
Nordschleife Master
I have the 996tt GIAC tune. Not sure about changing it, I run Shell 91 and have run ultra 94. Doesn't seem to matter which one I use I see no difference on top speed on the back straight at Mosport. From what I can tell it run greats with the giac tune.
#28
Racer
#30
Instructor
Join Date: Mar 2003
Location: Port Hope, Ontario, Canada
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In Ontario except for ESSO and petro canada all gas is the same, it all comes from the same refinery. ESSO and petro canada come from a different refinery in Montreal.
The big thing for me is I want super from a station that sees high turnover on the premo. No such thing as mid-grade from the refinery, it's mixed reg and super at the pump that's why it's 5% methanol.
Turbo's would actually benefit from methanol, besides boosting octane it has a cooling effect in the burn.
Modern cars don't really have a problem with methanol, as long as it doesn't sit in the tank long. Over winter storage use pure gas and stabilizer.
Easy gas/methanol test is take a glass jar (small, tall and skinny is best) and fill it with some gas, add 10% water to it, give it a shake and let it stand for a few minutes.
If the water on the bottom looks like it doubled in volume that's 10% methanol. No change in the 10% water level no methanol.
I've tested super at costco, shell, ultramar, etc., the premo is pure.
The big thing for me is I want super from a station that sees high turnover on the premo. No such thing as mid-grade from the refinery, it's mixed reg and super at the pump that's why it's 5% methanol.
Turbo's would actually benefit from methanol, besides boosting octane it has a cooling effect in the burn.
Modern cars don't really have a problem with methanol, as long as it doesn't sit in the tank long. Over winter storage use pure gas and stabilizer.
Easy gas/methanol test is take a glass jar (small, tall and skinny is best) and fill it with some gas, add 10% water to it, give it a shake and let it stand for a few minutes.
If the water on the bottom looks like it doubled in volume that's 10% methanol. No change in the 10% water level no methanol.
I've tested super at costco, shell, ultramar, etc., the premo is pure.
Last edited by Mark Henry; 04-22-2018 at 11:48 PM.