Tyler HHR SS

Thanks Nebulous. Does anybody notice a big performance hit when running on 87?

Clevelandhhrss

My salesman gave me a "complementary" fill up with 87 when i bought the HHR 30 days ago. I didn't notice any difference. I didn't go WOT until almost 1500 miles on the motor. I run either 93 or 94, but I'll try 87 on my next trip to PA and see if I can average over 33mpg.

RussellM454

Headed from Dallas to Stutgart Ar this weekend with my 90lb dog a 200lb passenger and about 200 lb's of luggage/training equipment. I plan on driving the speed limit which will be 70 mph on I30. If I can pull down 30mpg I'll be happy anything above that is gravey. I'm running 89 octane on this trip, no need for anything higher unless your foot is in it and your concerned about detonation.

I'll post back with the results.

relicstone

I have a Interceptor guage and i have been monitoring knock retard. on 89 under execl i would see almost 7% retard. on 93 0 to 1.2% retard depending on which gear i was in. 5th gear always shown knock retard for a few sec.

Tyler HHR SS

Would increased knock retard translate to loss of power or fuel economy or both? Also for what it is worth it took me a few tanks full of 89 oct. to notice the drops in power and fuel economy.

MOTRV8D

you're lucky you're ONLY paying $3.75 a gal for premium.
My last fillup for my Z28 was $4.11 a gallon!

monster5601

Betcha you don't pay $200 a month to heat your home half the year.

I'll take $4.11 gas over my $3.85 a gallon for 12 months of nice weather and next to nothing heating bills.

I have three sons living in the peoples republic of California, they hate the gas prices and are jealous of my MPG (what is with the gas out there) so I tell them come on home. They rather stay.

monster5601

When timing retards, you loose the amount of power the engine can make on the same amount of fuel and air. You should never hear your engine knock, if you do, you either have really bad fuel or your engine needs service.

Fuel economy for the most part is unaffected by octane. Only under heavy acceleration, or towing, or very hot weather when the engine is under heavy load in stop and go traffic will you see a measurable difference.

Octane simply makes the fuel less volatile so that pre-detonation (knock) does not happen. The ideal combustion is to have the entire air and fuel charge detonate at the same time thus making the most power.

NickHHRSS

Your $200/mo doesn't even come close to making up for the cost of housing difference.

Clevelandhhrss

LOL, I though the topic was fuel, not the economy. Anyway, I'll pay whatever fuel costs to take another trip down highway 1... this time with MY SS. BTW, if you hate your heating bills and live in the midwest (4 seasons territories), look into geothermal retrofits. Take it from this Chem-e, the payback period is usually less than 6.5 years.