: Premium or regular



shimy86
04-20-11, 06:28 PM
07 EXT, what do you guys use? I always use regular, getting 15-16 with city/highway mix. Whats the story on this diablo predator system????

jordan00escalade
04-20-11, 06:37 PM
PREMIUM.. I have an 06 Escalade (base), never anything less. Compression ratios and things like that, I keep it PREMIUM. How does your vehicle run, and does it knock? One more thing, how long have you been using regular?

Nixin
04-20-11, 09:45 PM
A good friend of mine, a mechanic extraordinaire, said to me once, "it's better to pay a little more at the pump now (for premium fuel) than pay a lot more down the road to a mechanic." The rest is up to you.

fivepix
04-20-11, 10:22 PM
I use premium 91 Octane or higher tons of posts on the forum on this topic, you're definitely not the only one who uses regular fuel.

sims1dh
04-20-11, 11:08 PM
I use regular, unless a engine calls for high octane only its a waist of money to use anything else in my experience.

Fast Eddie
04-20-11, 11:08 PM
Mix some water with some extra fry oil, all will be good. Seriously, is anyone else ridiculously sick of seeing these threads pop up every few weeks? Fill it with anything your heart desires, if the oil pan falls on the floor of the expressway, pay for a new one. What does the manual call for? Do you ask if it is necessary to use the right motor oil? After all, wont 20/50 do the same thing as 5/30? You put it in once and all seemed ok, so I guess you can always use it right????????

andre_outlaw
04-20-11, 11:16 PM
I really don't care, they are asking a question.. don't read them if it bothers you.

doctordog
04-21-11, 12:20 AM
I run regular with no problems i am a airlilne mechanic when running regular your are not getting the max. Performance out of the engine the manaul states page 395 87 or higher if your engine is not knockig save your money

07Lambert
04-21-11, 01:58 AM
I've used premium since day one. 4 years later, the car knocks like a diesel (occasionally) and the dealer says it's normal. Use whatever you want.

If your concerned about fuel economy and the money in your pocket, then you bought the wrong truck.

But since you have the truck already, buy the predator and take it to one of their programing/tuning dealers and get the E85 programing. E85 is supposed to be cheaper.

jordan00escalade
04-21-11, 02:46 AM
Manual for my 06 (base) 6.0L Vortec Max say use premium. If it says you can use 87 octane then why even ask.. My DTS states i can use 87 octane, so I use 87 octane. Occasionally I'll fill up with 91 and open it up. If your manual says use premium and you use regular, you're just asking for trouble.

skierjp
04-21-11, 06:12 AM
All my motor head friends say you can run 87. GM recommends 91 to get the proper HP rating (409). By running 87 you're probably losing 10 HP, big deal. Todays motors are managed by computers to offset knock. Pump whatever you like and let the computer adjust. I've run both 93 and 87 and can't tell the difference.
My Nautique ski boat has the same motor and the recommended fuel octane is 87. Go figure. This boats normal RPM range at 34MPH ( speed I ski ) is 3800 RPM. At 36 it runs 4100. we due this all day long in tournaments.

TexFinn
04-21-11, 10:56 AM
Regular.

shimy86
04-21-11, 10:59 AM
Mix some water with some extra fry oil, all will be good. Seriously, is anyone else ridiculously sick of seeing these threads pop up every few weeks? Fill it with anything your heart desires, if the oil pan falls on the floor of the expressway, pay for a new one. What does the manual call for? Do you ask if it is necessary to use the right motor oil? After all, wont 20/50 do the same thing as 5/30? You put it in once and all seemed ok, so I guess you can always use it right????????

Have you ever picked up a wrench, do you have any clue mechanically. As a later poster states, the ECM see's what the detonation sensors are picking up and adjusts the timing acordingly. My question was not if 87 would harm anything....IT WONT...my question was is it was hurting my MPG

From the replies it appears the MPG is unaffected and as expected, with any timing adjustments for the lower octane I'm losing a few HP....I can live with 399.

Thanks to the rest of the replies

lousy_investor
04-21-11, 11:18 AM
FWIW, the sales manager at the Cadillac dealership told me after I had already bought the truck that 87 was okay, and that he never used anything else in any of the cars he had ever owned. Told me 91 was reserved for special engines. That said he probably changed cars every year so he wouldn't worry about long term effects as much.

From my personal experience, I found using 91 gave me better mileage. Is it enough to offset the premium I have to pay for 91? Not quite there, but it helps. I also sometimes find the engine running smoother with 91...

I am currently on my 2nd tank of 87. I tend to find myself switching to 87 when I see threads like this on the forum :)

ELUSIVE
04-21-11, 12:55 PM
My Nautique ski boat has the same motor and the recommended fuel octane is 87. Go figure. This boats normal RPM range at 34MPH ( speed I ski ) is 3800 RPM. At 36 it runs 4100. we due this all day long in tournaments.

If you had a Mastercraft, I'd be much more likely to listen to your advice. :D

surfer
04-21-11, 05:22 PM
I have been trying to determine the increased MPG using 91 octane as well, it seems to be a slippery slope. I can tell you that with premium being $4.29 a gallon here vs $4.09 for regular, that 5% cost differential is far less than the days of 1 or 2 dollar gas. On my EXT, if I can get just .7 MPG more, premium pays for itself; and then you have all the additional real or perceived benefits this thread discusses.

At these gas prices - which I believe are here to stay, with 5 dollar gas in the near future; a fresh look at all methods of increasing gas mileage is in order.

gragravar
04-21-11, 06:48 PM
I have tried both premium and regular unleaded and I notice no difference in MPG or in power. I am sticking with the lower grade stuff.

lousy_investor
04-21-11, 07:16 PM
10%+ difference between regular and premium where we are - Toronto, Canada

At times I thought I could get at least 5% better mileage based on the computer, and other times I don't. I am wondering if it has anything to do with the cold weather in the winter time, that when the engine is running very cold, the impact of the gasoline on mileage is lessen. When it becomes warmer (and stays warmer), I will try my very unscientific test again.

WaterKing
04-21-11, 07:50 PM
For the Original poster with 2007 EXT, do NOT use E85 even if tuned for it...2007 model years were not certified for E85. To run properly on E85 the injectors, pump and/or ECM must be modified to inject more fuel which 2007's are not set up for. Also it voids the warranty if your engine fails and it is found to be running on non approved fuel..pages 399-401 of 2007 EXT owner's manual. E85 capable vehicles when using E85 get 1-3 LESS MPG than when running on regular and premium gas. Gm recommends premium from a "Top Tier" source.

skierjp
04-22-11, 06:10 AM
MasterCrafts rate right up ther with Lincoln Navigators :) LOL, All jokes aside, I've had had 12 MC/s and 13 CC's, both are great boats.

ELUSIVE
04-22-11, 09:23 AM
MasterCrafts rate right up ther with Lincoln Navigators :) LOL, All jokes aside, I've had had 12 MC/s and 13 CC's, both are great boats.

I completely agree.
Just playing. :D

Bigjason
04-25-11, 04:10 PM
Premium for me and nothing but. Its a few cents more; if its a problem for some maybe a Escalade is not for you.

xxe92xx
04-25-11, 11:32 PM
Shell 93