Sponsored

85 Octane

nelson

Well-Known Member
Joined
Mar 13, 2016
Threads
23
Messages
133
Reaction score
20
Location
Colorado
Vehicle(s)
'16 Ford Fusion Energi
Hi fellas, about to do my first fill up and wondering if 85 Octane fuel will be fine for now. It's too cold here to do anything with half the HP this car has so I'm not worried about power reduction and more just engine knock and safety.

Reminder: I'm at altitude so the common fuels for Reg/Premium/SuperPremium here are 85, 87 and 91.
Sponsored

 

nastang87xx

Well-Known Member
Joined
Jun 5, 2015
Threads
89
Messages
6,546
Reaction score
4,189
Location
Wisconsin
Vehicle(s)
2016 GT350 Track Pack
What?! NO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!




tenor.gif



No, seriously. Octane isn't just about power production with accurate timing. There's cold start and detergent benefits involved too with higher octanes. Premium or nothing unless you're in a pinch.
 

Clink

Well-Known Member
Joined
May 22, 2014
Threads
42
Messages
4,163
Reaction score
1,294
Location
FL
Vehicle(s)
'14 Focus
Negative, what are you going to save over a few fill ups......$11?
 

Sponsored

OP
OP

nelson

Well-Known Member
Joined
Mar 13, 2016
Threads
23
Messages
133
Reaction score
20
Location
Colorado
Vehicle(s)
'16 Ford Fusion Energi
I still wouldn't do it, at a minimum 87 I believe is what the owners manual recommends.
Just playing devils advocate here.. everyones owners manual here at altitude says 87 but supposedly 85 is a safe equivalent due to air density, hence my question.
 

HeavyMetalMonk

Well-Known Member
Joined
Nov 18, 2017
Threads
15
Messages
395
Reaction score
94
Location
CA
Vehicle(s)
Oxford White 2018 GT Premium PP/MR
some cursory research seems to suggest that lower octane is ok at higher altitude like you said. I don't see anything definitive though.
I probably wouldn't risk it personally.
 

Nameless

Well-Known Member
Joined
Oct 19, 2013
Threads
2
Messages
520
Reaction score
290
Location
MĂ©xico
First Name
Tedd
Vehicle(s)
'13 GT
Just playing devils advocate here.. everyones owners manual here at altitude says 87 but supposedly 85 is a safe equivalent due to air density, hence my question.
It's true, at higher altitude an engine with 85 octane works kinda the same way it does with 87 at sea level (with less power though) because since the air density is less, there is a lower possibility to experience engine knock. However, HOWEVER i wouldn't fill the thank with ANYTHING less than 87 as the owner manual ask for.

Remember at higher altitude the engine with the 85 octane works "as safe" as it does with 87 at sea lever, HOWEVER 87 octane is the same gas at 15000ft below sea level, than it is at 15000ft above sea level.

TL;DR: Don't do it, fill your tank with AT LEAST 87 octane.
 

Sponsored

Nitronorth

Well-Known Member
Joined
Aug 2, 2016
Threads
2
Messages
46
Reaction score
18
Location
kamloops,bc
First Name
Rock
Vehicle(s)
2018 GT Auto
I rarely ever put anything in mine over regular fuel. (I live in the mtns) Occasionally i do 91, And i cant tell the diff on the street anyway, maybe at the track it show up with a few tenths quicker.. My mileage is the same with either. And yes I have burned 85 at elevation in all my stangs and turbo cars, nbd.
Have fun
 

NoVaGT

Banned
Banned
Banned
Joined
Sep 29, 2016
Threads
115
Messages
5,682
Reaction score
4,410
Location
Northern Virginia
Vehicle(s)
2019 PP1 GT Kona

youra6

Well-Known Member
Joined
Feb 8, 2018
Threads
6
Messages
161
Reaction score
30
Location
CO
Vehicle(s)
2005 Evo VIII RS, 2018 Mustang GT
Relax guys, he lives in Colorado. 85 octane at 5400ft above sea level is ~87 octane closer to sea level.

Its not an exact conversion but its pretty close.
 

15GTCA

Well-Known Member
Joined
Oct 26, 2015
Threads
4
Messages
432
Reaction score
225
Location
Carp
Vehicle(s)
Magnetic 2015 GT A6
And the owner's manual says.........................................................................................87
Sponsored

 
 




Top