B Gordon

As the title suggests, I have a stock 2000 Z28 LS1 engine and ECU that is swapped into my Miata.
My question is this;


What octane fuels are safe to run in the car while keeping the engine happy and also to keep from getting detonation problems?
What does the factory 2000 Z28 owner's manual say with respect to recommended octane?


Is 87 octane safe?


My "other" car is a 2015 Mustang GT with the 5.0 Coyote engine.
The factory manual for it says that octane ratings of 87 and above are fine but maximum HP will be achieved with 91 octane.
According to actual chassis dyno testing done by folks over on the Mustang forum, the car only gains about 8 HP by running 91 over 87.


My intention is to run 91 octane as a normal routine but I want to know what is safe in a pinch.

HCI2000SS

iTrader: (2)

I ran 87 a couple times on my stock 98 LS1 Camaro but never ran it hard. It did fine but I'd never do it if I was pushing it hard

Nick V.

iTrader: (1)

you can run 87 just fine. all sportscars reccommend premium or something other than 87.

but you can run it just fine. especially stock

tsteel1

I ran 87 for mine for the first year I owned it and then read manual and it said to run 91 so I started to run 93 in it ,and my mileage jumped to 27mpg from 23 this was good for me since driving on interstate 500 miles a week. did not noticed any spark knock or anything like that but mileage consistently improved .

Crf450r420

iTrader: (1)

The lighter load of that car will help out some with running a lower octane.

Need4Camaro

iTrader: (1)

87 wont hurt it in a pinch, just dont drive it hard or spirited and it will be fine.

B Gordon

Will the low octane cause problems or is the compression low enough to work with 87 and the problem being the ECU tune?

RevGTO

iTrader: (12)

There is a low octane spark table in the operating system that kicks in when the PCM detects detonation. So technically you're going to be safe, just with a significant power loss.

However, with the growing price gap between 87 and premium, perhaps some may consider running the low octane table as the default for general daily driving to save $$$.

Docrocket1967

iTrader: (1)

When hurricane Irma hit us a couple months ago the gas stations in my area in Florida had absolutely no gas at all and I was running close to Empty. I found one station that had 87 octane and I ran it which kinda sucked cause I always made sure I ran 93 but it is what it is. I ran 87 in my 99 Camaro a couple times back in the day when I was low on funds and never had a problem. You should be fine but fuel mileage will drop, at least it did for me anyways.

Nathan C

The owners manual says use premium, so that's what I use in my ls1 cars.

cookseyb

If you can't afford premium fuel the manual recommends, get a Smart Car...

01ssreda4

iTrader: (96)

Let me slightly correct you. They both are very conservative. Any high quality 87 octane will be fine.

RevGTO

iTrader: (12)

Yep, especially on the 01-02 operating systems. The 99-00 had a more aggressive advance curve. I'll get some KR at WOT on 91 in my 2000 car.

JC316

iTrader: (1)

Hate to break it to you, but the smart requires premium fuel as well.

cookseyb

LOL I was just being a smart ***, I can't understand People buying a performance car and trying to cheap out on fuel! The mileage and lack of performance will more than offset the cost difference.. It's kinda like kissing your sister..... What engine is in the smart car anyway?

MonmouthCtyLS7

iTrader: (6)

My first question would be why would you even consider it, if you can find regular in a pinch more then likely they'll also have some type of premium. Though like mentioned im sure you'd be fine.