Using 89 octance fuel in base engine...
Thread Starter
Heel & Toe
Joined: Dec 2012
Posts: 18
Likes: 0
From: Seneca SC
Using 89 octance fuel in base engine...
I know this has to be a well-discussed topic, but I didn't see it so... What are the trade-offs, potential hazards for using 89 octane [mid-grade] instead of premium in the base, 430 hp (for 2013) engine? Since I'm not concerned about getting the full 430 hp out of it, can I run 89 fuel in it w/o issues? The manual says I can but I'd rather hear answers from the real-life owners out there. Thanks.
Drifting
Joined: Jan 2012
Posts: 1,548
Likes: 15
From: Paris TN
The compression ratio is the problem with running lower octane fuel. The computer will adjust timing to some degree to allow lesser octane fuel, but...but not that much. I know on my C5 that running lower octane fuel made for huge timing "ping" and scared the heck out of me. I was in Europe and could not find a station with higher octane and was nearly out of fuel.
The difference in cost of a tank of 93 compared to 89 couldn't be much more than $4.00. Why would you risk serious engine damage for that little bit of money? Just my opinion.
The difference in cost of a tank of 93 compared to 89 couldn't be much more than $4.00. Why would you risk serious engine damage for that little bit of money? Just my opinion.
Race Director
Joined: Oct 1999
Posts: 13,298
Likes: 14
From: Somers NY
Why the hell would someone/anyone put in 89 just to save ..(like you said) about $4.00 on a tank of gas...He would be better off getting a Cobalt 4 cyl. they are designed to run on 89 !!!
Team Owner
Joined: Sep 2000
Posts: 25,015
Likes: 2,709
From: Far NW 'burbs of Chicago
St. Jude Donor '13
With 89 instead of 91/93:
You lose a bit of power.
You lose a bit of MPG, which partly negates the cost savings.
You are betting your engine that the knock retard system will work properly when you get on the throttle. Failures are pretty rare, but that's a bet I prefer not to make.
If 89, or even 87; is the only gas available, then I use it and don't worry much. But if I have a choice, I go for 91/93.
You lose a bit of power.
You lose a bit of MPG, which partly negates the cost savings.
You are betting your engine that the knock retard system will work properly when you get on the throttle. Failures are pretty rare, but that's a bet I prefer not to make.
If 89, or even 87; is the only gas available, then I use it and don't worry much. But if I have a choice, I go for 91/93.
Thread Starter
Heel & Toe
Joined: Dec 2012
Posts: 18
Likes: 0
From: Seneca SC
Octane...
At issue is what's available at times. Sometimes, the highest grade at a station is 91 or even 89. I don't want to hurt my lil red machine but I suspect, from time to time, it'll have to get by with 2% instead of whole milk...
My wife's Miata absolutely complains with anything less than 93; hopefully my car is more forgiving.
Yesterday I took my machine out for a curvy drive Seneca, SC to Highlands, NC to Cashiers, NC and then home - wonderful day and great tryout for my paddle shift auto - works fantastically! It's probably faster to respond to gear changes than I'd be shifting the manual w/o some serious practice. {I've been using manuals for 54 years so I'm good with them but each manual has it's own personality.} If you're contemplating the paddle shift auto, test drive one and check it out - you may become a convert.
My wife's Miata absolutely complains with anything less than 93; hopefully my car is more forgiving.
Yesterday I took my machine out for a curvy drive Seneca, SC to Highlands, NC to Cashiers, NC and then home - wonderful day and great tryout for my paddle shift auto - works fantastically! It's probably faster to respond to gear changes than I'd be shifting the manual w/o some serious practice. {I've been using manuals for 54 years so I'm good with them but each manual has it's own personality.} If you're contemplating the paddle shift auto, test drive one and check it out - you may become a convert.
Last edited by South40; Jan 22, 2013 at 08:24 AM. Reason: typo
