Northstar Engines and System Technical Discussion Discussion, Premium vs. Regular in Cadillac Engine Technical Discussion; I was told by the dealer that my 05 DeVille runs just fine on regular unleaded, but I look up ...
I was told by the dealer that my 05 DeVille runs just fine on regular unleaded, but I look up the specs on the engine and the compression is 10:1 I thought the upper limit for 87 octane was 9.5:1 or else you risk problems from predetonation. Is this true, or has technology once again blew by me?
It will run on regular gas (slightly decreased performance) If you search this forum you'll find another thread which goes into how the engine deals with this. It is all based on knock sensors, variable ignition timing and the PCM. Northstar engine is "smart" enough to deal with this type of situation.
due to increased gas prices i alternate between super and regular, every other fill up or 2, I was running regular for a while after the 5th or 6th tank the car ran lousy, pinging and tapping, I went back to super and put half a gallon of lucas in, took it on the Highway and it was fine again.
I disagree with many replies in this thread, My 96 runs ok on 87, with a loss of power, but I get exactly 75-100 miles less per tank on that gas even 89 mid grade. With the 93 I can clear from 350 - 400 miles to a tank and a much smoother engine.
Tactical64, I agree with you. My car runs like crap on 87. Serious loss of mileage and performance. 20% loss of mileage.
And you know, back in 1999, Regular was around $1.40 here, and premium was $1.60, which was around 15% extra money for the premium. At today's prices, of $2.49 for regular, and $2.69 for premium, that's only about 8% extra price for the premium. Premium is a better deal than it's ever been....
I'm getting more than 10% extra mileage alone, so, it's worth it money wise alone, to say nothing of the huge performance gain.
And before I get flamed, I'm not just a premium freak. My Tahoe gets nothing but regular 87. I tried premium in that for a few tanks, there was utterly no difference in mileage or performance. None.
In the ETC, there is a big difference. I do not know why, I just know I put premium in it now.....