farmer52

My 2011 HHR w/2.4L engine has RPO code NU5 - California Bin 4. It was sold new in Rhode Island. The Federal emission system code is NT7. Do all 2011s have the NU5 code? Will the Federal NT7 code provide better performance and fuel mileage? If so, how do I go about changing to the NT7 (new ECU)? Thanks!

Greybeard999

They are probably all up to California spec. Just because someone may bring one into the state for sale or relocate to there. I doubt there even is a "NT7 only" spec car made, so there wouldn't be a way to change.


Why not go with a Trifecta tune for better performance/MPG?

843de

Some states have adopted California emissions standards like New York State for example, its for air quality reasons and it also makes the politicians look good.

As it is there is no difference in horsepower and torque specs between vehicles with California emissions packages and those with Federal systems. Changing the ECM would not gain you anything other than a dent in your credit card from buying it. Plus there are warranty issues to consider.

As an aside, my 2011 2LT which was ordered here in Carolina, for use in Carolina, is equipped with the California emissions package.

From what I've been able to gather the main differences between the emission packages is a change in calibration allowing the California spec vehicle to enter its "closed loop" mode sooner for better cold engine emissions.