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Old 10-25-2005, 05:17 PM   #5 (permalink)
73ChevelleSS
2.8 Liter Turbocharged V6
 
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Join Date: Mar 2005
Drives: 2008 Impala
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Re: What does GM mean by "Premium Gas Recommended" on the 2.4L I4?

Quote:
Originally Posted by gmsickofan
The HHR's new I4 says "recommends premium but accepts regular" or something to that extent.

Is it exactly the same as putting regular in a 2.2L? With NO possibility of damage to the engine or other problems down the road from excessive knocking and pinging?

Can I trust the computer to figure out what grade I've filled the tank with and run with it?

20 cents per gallon is pretty big, especially over time. If gas prices go up again I want the option of using regular, perhaps for months at a time, is this going to be a problem if I choose the 2.4L engine?

TIA!
First off the computer will not know what octane fuel you are running.Both of the 4 cyl's available in the HHR have the same compression ratio 10:1.The reason the 2.4 requires 91 or higher is because the PCM calibration is more agressive.Meaning it adds more timing,fuel curve is different etc.
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