higher octane gas?

Alfer

Registered Member
180
27
28
USA
Genesis Model Type
2G Genesis Sedan (2015-2016)
My 5.0 seems to run smoother with premium. Maybe it's just me.
It's just you. Mind over matter.

You buy "Premium" thinking it will do something different to your car and your brain tricked you into thinking it worked.

It didn't. Just wasted a few extra dollars is all that occurred.
 

surprisinguy

Registered Member
147
24
18
NC
Genesis Model Type
2G Genesis Sedan (2015-2016)
the engine began vibrating violently
Sounds like a little water in the gas...
I usually always use a Top Tier (detergent) 87 Gasoline unless I'm super low. On a previous car it had a 89 octane recommendation which I adhered to except for the last 5 years I had it when I moved to 87 because of cost. Ran fine then too....
 

cubanben

Hasn't posted much yet...
16
1
3
New Jersey
Actually a lot more than your 2 cents. Quite an upcharge for the 93 octane. I've been tempted a couple of times but never bothered. I have over 50,000 miles on two different 3.8 engines with not a problem. That is about 2000 gallons over 3 years. The difference is considerable and can be put to better use IMO, but, your money, your choice.
Yes, it's more than two cents, but when I'm spending less than $50 a month on fuel it's worth it to me.
 

jarred52

Registered Member
233
1
18
Agreed! I use only Top Tier 87 in my ‘12 3.8 and it’s great!

Just a minor point. The GDI engine is hardly a “naturally aspirated” engine. It’s a direct fuel injected engine, a big step up from the olden days of carburetors and even the early fuel injected engines.
______________________________
 

robthoke

Been here awhile...
239
4
18
Valdosta, Ga
Genesis Model Type
2G Genesis Sedan (2015-2016)
I originally had an 09 4.6 Genesis that recommended premium fuel and that is what I used. Believe both the current 5.0 and the twin turbo 3.3 recommend premium as well. Fortunately I've never had an issue with 87 octane in my current 3.8.
 
11
2
3
Genesis Model Type
2G Genesis Sedan (2015-2016)
I have a 2015 AWD 3.8 and recently traded a 2013 3.8 RWD. I have used 87 octane for both vehicles with no problems. I tried 93 octane in my 2013 3.8 and noticed no real horsepower upgrades. I did notice a lighter wallet though ;).
 

EdP

Supporting Member
SUPPORTING MEMBER
SUSTAINING MEMBER
2,717
480
83
CT
Genesis Model Type
Genesis G80
I have a 2015 AWD 3.8 and recently traded a 2013 3.8 RWD. I have used 87 octane for both vehicles with no problems. I tried 93 octane in my 2013 3.8 and noticed no real horsepower upgrades. I did notice a lighter wallet though ;).
Automotive engineers put a lot of effort into making cars lighter for better performance. Buying the 93 octane and a lighter wallet does change the weight to horsepower ratio so you should have had faster acceleration, though very slight. Good job!
______________________________
 

Paulsr

Registered Member
169
13
18
Genesis Model Type
Genesis G90
Automotive engineers put a lot of effort into making cars lighter for better performance. Buying the 93 octane and a lighter wallet does change the weight to horsepower ratio so you should have had faster acceleration, though very slight. Good job!
Yes, and a lighter wallet will improve gas mileage.
 
11
2
3
Genesis Model Type
2G Genesis Sedan (2015-2016)
Automotive engineers put a lot of effort into making cars lighter for better performance. Buying the 93 octane and a lighter wallet does change the weight to horsepower ratio so you should have had faster acceleration, though very slight. Good job!
Now thats funny.
 

need4spd

Registered Member
51
2
8
Hey, I did not see mentioned that the 5.0 recommends (not required) 91 octane, and does have a different HP number when run on 87 than 91.

This was documented early on, that Hyundai has two HP levels for the 5.0, and Hyundai even published those numbers somewhere back in 15 and 16.

They may have re-tuned afterwards, as Genesis, but if I remember correctly it as about 15-20 hp difference.

However, Hyundai only released one HP number for the 3.8 which was on 87 octane and they said that was the only one needed.

There were posts about this back in 15 and 16, probably in the archive now.

So those with 5.0's the 91 and higher will make more HP and the car will not have to retard timing, but 87 is also fine for the car, with the loss of a few HP.

3.8's no need to go higher.
______________________________
 

need4spd

Registered Member
51
2
8
I checked my electronic copy of the 2016 manual and it is confirmed in it (though no HP numbers):

3.8 engine
Your new vehicle is designed to use
only unleaded fuel having an octane
number ((R+M)/2) of 87 (Research
Octane Number 91) or higher. (Do not
use methanol blended fuels.)

5.0 engine
Your new vehicle is designed to use
only unleaded fuel having an octane
number ((R+M)/2) of 87 (Research
Octane Number 91) or higher. For
improved vehicle performance, premium
unleaded fuel with an octane
number ((R+M)/2) of 91 (Research
Octane Number 96) or higher is recommended.

(Do not use methanol
blended fuels.)
 

Philip2

Hasn't posted much yet...
11
3
3
Genesis Model Type
No Genesis Yet!
In my 2015 3.8 the first tank full was 87 octane regular (Shell). The following day, the engine began vibrating violently, the car was jerking back and forth, every light imaginable lite up on the dash. I had to pull over and shut down the car. I restarted and everything ran fine. The only remaining issue was the check engine light remained on. Oh great I thought. I just bought this car and three days in I have a problem. Two days later the check engine light turned off. On my next refill, I went with 93 octane (BP preferably & Shell) and I've never looked back.

I've never noticed performance difference in the octanes, but I've normally used 93 octane on my vehicles in the past. Lucky (unlucky actually) for me I barely drive since I use public transportation during the week; so I only fill-up once every 4 to 6 weeks (I have less that 10K miles). Higher octane fuels burn cleaner and therefore leave fewer deposits giving better, overall performance.

Anyway, that's my 2 cents. Enjoy your rides.
Interesting- I was told that Shell is the worst of the brand name gases ( and BP is the best) Any opinions on this?
 

EdP

Supporting Member
SUPPORTING MEMBER
SUSTAINING MEMBER
2,717
480
83
CT
Genesis Model Type
Genesis G80
Interesting- I was told that Shell is the worst of the brand name gases ( and BP is the best) Any opinions on this?
They both use the Top Tier additive package so I doubt there is much difference. It all comes out of the same pipeline from the refinery. I've never felt a difference between brands in any car.
 

cubanben

Hasn't posted much yet...
16
1
3
New Jersey
Interesting- I was told that Shell is the worst of the brand name gases ( and BP is the best) Any opinions on this?
Shell and BP are both top rated fuels and as EdP said, they use top tier additives. I'd heard from a friend who owned and operated and Exxon gas station that their fuels were the worst. He wouldn't put Exxon fuel into his own cars, so what does that tell you.
 
Your email address will not be publicly visible. We will only use it to contact you to confirm your post.
Top