Northstar Engines and System Technical Discussion Discussion, Run mid-grade every other tank? in Cadillac Engine Technical Discussion; Hi all, i may be buying my grandmother's '96 SLS later this week, of course it has the northstar, ive ...
Hi all, i may be buying my grandmother's '96 SLS later this week, of course it has the northstar, ive always wanted a caddy with the northstar, ive had 3 with the 4.5, both PFI and TBI, and they are plenty powerful, i also have a 69 with the 472 but ive always admired the throaty power of the northstar, and even though a Seville wouldnt be my first choice im getting a great deal on a BEAUTIFUL, well taken care of car with 54,000 miles.
But my question refers to the gas that i have to run in it, i know premium is factory recomended, but ive also heard from a small cadillac dealer, and a couple caddy mechanics that its ok to run mid-grade every other tank, or fill it with premium every two tanks and run mid between. What are your thoughts? Ill die putting $1.40/gal gas in it all the time, but of course i will if i want the car to last and perform the way it should. Thanks for your opinions!
It will be just fine to run regular 87 octane gas in it all the time. These cars have a knock sensor that detects when detonation occurs due to lower octane ratings and it retards the timing appropriately to eliminate the detonation and the chance of damage. Lots of people on these forums run regular all the time and our resident Northstar engineer constantly says it's fine. If granny's had the car for a while, she probably babied it. Don't do that. Give that high performance engine what it needs, which is some good old fashioned Wide Open Throttle. Beat it up (legally and safely, of course) and blow the carbon out of the combusion chambers. Put it in 2nd and pull onto the freeway with your foot on the floor. Let the RPMs get up to 6000 and hold there for a few then let off and coast down to 30, then do it again a few more times. Get that crap out of there and your Northstar will love you for it.
You might notice a slight performance decrease with regular, but it's not going to hurt anything and you'll be better off with the $$$ in your pocket rather than the oil company's pocket.
Sorry, i did search the threads only after submitting this one, and had my answer ten times over. I should know better, i do know that this is a hot topic around these parts :banghead2 Oh an i did mean $2.40/gal, i live in MI so gas prices make me want to puke. silly me, i did try like hell to delete this thread shortly after i sent it. Thanks for the help though.
Anyhow, i think for my purposes ill run mid-grade/premium in the winter months and regular during the summer, unless i notice a change in performance. Thanks again. feel free to smack me, or delete this thread at your leisure.
Oh and by the way granny knows how to treat her N* i think an acurate quote is "Well the fastest ive had it is 95 or 100" i was assured by her roomate that she drives it like a hot rod, 75-80 is nothing to her on the freeway, and she wastes no time getting up there.
Run regular all the time unless you are planning on racing your buddy and want to make positively sure that you have maximum power available....then run the tank near empty and put the best premium you can find in it...winter or summer.