Funny thing is apparently the 2.4L engine also takes premium according to the manual, this true?

 

I think maybe the first couple model years did but more recent 2.4's do not require premium anymore.

 

Well in the 2008 manual it says that both the 2.4 and the 2.0 use premium fuel.

 

Oh... that's kind of confusing.


Try this link:
http://media.gm.com/us/powertrain/en...2008/08car.htm

If you click on the "SS" (Spec Sheet) link for each engine, there's a blurb about fuel type for each engine.

From what I can see, the 2.0 LNF Turbo says "Premium Fuel Recommended" and...

... the 2.4 says "Premium Fuel Recommended, not Required".

Close but subtle differences in wording.


Would be nice if they could make it a bit more clear.

 

Odd, here it is word for word page 5-5 under gasoline octain "If you vehicle has the 2.0L L4 engine (VIN Code X) or the 2.4L L4 engine (VIN Code P), use premium unleaded gasoline with a posted octane rating of 91 or higher".

It goes on to say that you can use 87 but performance will be reduced and you may notice a slight audible knocking noise.

So i guess it can take 87 but why risk it?

 

IMHO if you have a turbo or super charged vehicle you need premium fuel without exception. You never want to take the chance of a pre-ignition (pinging/knocking) with a turbo. Holes in pistons are a drag and a major repair. In the 2.2L and the 2.4L the computer and sensors will adjust for the fuel being used and I have rarely heard of pinging or spark knock on the late model vehicles with 87 octane. For better performance 91 octane and above is preferred for the HHR's.

 

[QUOTE=nerraD;251476]Oh... that's kind of confusing.


Try this link:
http://media.gm.com/us/powertrain/en...2008/08car.htm

If you click on the "SS" (Spec Sheet) link for each engine, there's a blurb about fuel type for each engine.

From what I can see, the 2.0 LNF Turbo says "Premium Fuel Recommended" and...

... the 2.4 says "Premium Fuel Recommended, not Required".

Close but subtle differences in wording.


Would be nice if they could make it a bit more clear.[/QUOTE]

looks pretty clear to me,,, use premium! if its not available, use mid grade untill you can get premium.

 

fueleconomy.gov shows the 2.4 as using premium and the 2.0 with regular

IIRC my Saab 93 Turbo required regular not premium. fueleconomy shows both

now the other kicker is my jeep (which I turned in today on empty) required mid grade fuel....but fuelconomy does not reflect that, only regualr and premium.

My Saab was the first turbo car I had ever seen not requiring premium. It ran fine and had plenty of power and consistently got 32mpg hwy.

It would be nice to see standards!

 

You don't really have to do all that. The electronic spark control is always on the job, knock sensors constantly monitoring for spark knock. At the first detection of spark knock, the ESC steps in and retards timing until the knock sensors no longer report knock.

The Ecotec is equipped with ESC (Electronic Spark Control), yes.

As mentioned by Chevymgr, no way would I run regular or even mid grade 89 in a turbo engine labeled for premium recommended. The pressures are so much greater in a forced induction engine that a slight ESC hiccup that might have no consequences in a normally aspirated motor can have damaging consequences in a turbo'd motor or a super charged motor.

 

You may never hear an audible knock from detonation when running 87 octane fuel, the system works pretty fast to calm detonation and avoid damage. If you never get your foot in it you could drive forever on lower octane fuels but for me........you never know when it might be necessary to really hammer it. BTW......I just returned from a 1750 trip on all sorts of roads, canyons, freeways......ran pretty hard from time to time, I averaged 27 mpg with three adults and a full load of luggage aboard. That's not bad.