Fuel Grade

[Genesis5.0]

What fuel are you all using in your 2015 Genesis V6 and V8?

I have a 2015 V8 and using regular gas 89 octane.

Also is anyone using fuel additives such as Seafoam?

 

[ferrethouse]

I switch back and forth between 89 and 91.

 

[anonymous1]

Use 91+ consistantly in the 5.0 considering that hyundai increased the compression ratio and torque force and it will better protect from carbon on valves and those quad exhausts, but i think hyundai changed mapping and timing to prevent carbon on the new tau v8s.

 

[Midnightsun]

This is my third Genesis sedan. All V8's, all have only had regular unleaded. If you say you can feel 7 or 8 ponies extra with premium out of 400+ you are imagining things and should lay off the weed a little.

Heck, some here claim they barely notice the 120hp diff between the V6 and V8.

 

[EXBMWGUY]

Seafoam is safer used on older cars that do not have high pressure fuel pumps and direct injection. BMW has threatened to void warranties where they can prove additives (especially Seafoam) have been used. The Chevron fuel system additives branded Techron are considered ok by Hyundai because it's the same product as the Hyundai branded additive.

 

[lobsenza]

I run regular 87 octane in my 5.0. I don't think I would notice the power difference.

 

[ferrethouse]

Use 91+ consistantly in the 5.0 considering that hyundai increased the compression ratio and torque force and it will better protect from carbon on valves and those quad exhausts, but i think hyundai changed mapping and timing to prevent carbon on the new tau v8s.

I see lots of carbon on my exhausts so I imagine it is further up the system too.

 

[Tpr5.0]

Always 93.

 

[simplyaddo]

95

 

[Alwaysforward]

I have been running Super Unleaded since the purchase of my 5.0 Ultimate. I commute 40 miles per day to & from work with all driving on US1 (city driving) and am getting consistently 19.8 MPG (calculated) with the car set on ECO mode. After the first oil change I plan on switching to Regular Unleaded for one tankful to see if my MPG drops any. I keep a log (yes I am an engineer and anal) of my fuel mileage (both cars computers readings and calculated) and should see a trend downward when going to Regular Unleaded. I will report back my findings. I only have 1500 miles on the car so far so it will be a couple months.

______________________________

Help support this site so it can continue supporting you!

 

[allisondbl]

Wow this topic garnered responses! I have a 2015 3.8 Ultimate AWD and have never used anything but 87 and the manual calls for 87 (can't seem to find where now though ;( .) Being able to use 87 was one of the reasons - among many others to be clear - I opted for our baby over the alternative Mercedes and, per the below article *feeling smug* right now fer sure!

http://www.bloomberg.com/news/2014-...oom-s-quirks-at-the-pump.html?alcmpid=mostpop

 

[Midnightsun]

I have been running Super Unleaded since the purchase of my 5.0 Ultimate. I commute 40 miles per day to & from work with all driving on US1 (city driving) and am getting consistently 19.8 MPG (calculated) with the car set on ECO mode. After the first oil change I plan on switching to Regular Unleaded for one tankful to see if my MPG drops any. I keep a log (yes I am an engineer and anal) of my fuel mileage (both cars computers readings and calculated) and should see a trend downward when going to Regular Unleaded. I will report back my findings. I only have 1500 miles on the car so far so it will be a couple months.

I am waiting impatiently for your anal test results and I am not talking about your colonoscopy results. I suggest you go for at least 3 tanks of regular to really get the big true picture. I am pretty sure the difference will be negligible and you will run Regular after doing this. There is no way the increased fuel economy (if any, I predict unmeasurable) will outweigh the higher costs of Premium. Wanna start taking bets?

 

[Mark_888]

I am waiting impatiently for your anal test results and I am not talking about your colonoscopy results. I suggest you go for at least 3 tanks of regular to really get the big true picture. I am pretty sure the difference will be negligible and you will run Regular after doing this. There is no way the increased fuel economy (if any, I predict unmeasurable) will outweigh the higher costs of Premium. Wanna start taking bets?

I agree that the better fuel economy probably does not out-weigh the extra cost of premium. But I assume there is some measurable difference since Hyundai conducted their EPA fuel economy tests with premium. If they did not get better fuel economy with premium then they are really stupid to have tested with it (and I don't think they are stupid).

 

[Genesis5.0]

any other thoughts / comments on using fuel additives such as Seafoam? I'm debating using some type of additive if I don't run premium gas.

 

[Mark_888]

any other thoughts / comments on using fuel additives such as Seafoam? I'm debating using some type of additive if I don't run premium gas.

1. Seafoam is designed for engines with major problems, typical of very high mileage or abused engines. This includes leaky seals, excess oil consumption, etc. The additive manufacturer says it is also for new engines, but that is only so they can increase sales.
2. If something does go wrong with your engine and you file a warranty claim, if Hyundai finds out that you used Seafoam, your warranty will be instantly voided (with extreme prejudice).
3. Personally, I find it mind-boggling that someone would use a additive in their crankcase that the additive manufacturer also says is suitable for the gas tank.

If you want to use an additive, try Chevron Fuel Injection Cleaner with Techron. Costco has very good prices for this item, or you can get it any discount or auto parts store.

 

[Midnightsun]

I agree that the better fuel economy probably does not out-weigh the extra cost of premium. But I assume there is some measurable difference since Hyundai conducted their EPA fuel economy tests with premium. If they did not get better fuel economy with premium then they are really stupid to have tested with it (and I don't think they are stupid).

Let's wait for the tests before we assume anything. The V6 is also is a dual fuel capable/recommended engine and the rated HP of 311 is with Premium as can be seen here. https://www.hyundaigenesis.com/features/specs

Why are all the milage figures done with Regular on this model and not Premium like the V8? Compression ratios of both are very similar @ 11.5 vs 11.8

 

[Mark_888]

Let's wait for the tests before we assume anything. The V6 is also is a dual fuel capable/recommended engine and the rated HP of 311 is with Premium as can be seen here. https://www.hyundaigenesis.com/features/specs

Why are all the milage figures done with Regular on this model and not Premium like the V8? Compression ratios of both are very similar @ 11.5 vs 11.8

Any manufacturer wants to advertise the best fuel economy they possibly can. We know from past "experience" how obsessed Hyundai is about this, not to mention that there are CAFE requirements from the US Federal government that will get more stringent over the upcoming years.

At the same time, manufacturers want to advertise the lowest cost of ownership for their vehicles, since that is a factor in the purchasing decision for many buyers. It is more likely to be a concern for a V6 buyer than a V8 buyer.

 

[Aquineas]

No additive here, but I did pay $2.92 a gallon for 93 octane premium at Sam's Club on Saturday.

 

[pusaterkm]

This has been discussed on this forum many times and my response has always been the same. I bought a V8 because I wanted V8 power. I paid for 420HP and I want all 420HP, so premium (and non ethenol if I can get it) is the only fuel that my Genny gets. If I was worried about saving a dollar at the pump I wouldn't have bought the V8 in the first place I would have gotten a Civic. Not using premium in this car to save a few bucks is like ordering four Big Macs but drinking a diet coke. I do recommend a fuel additive that can counter the effects of E10/E15 gas like Sta-Bil. Not a big deal for my Genny, but for my 1972 442 it is a must.

 

[Mark_888]

I do recommend a fuel additive that can counter the effects of E10/E15 gas like Sta-Bil. Not a big deal for my Genny, but for my 1972 442 it is a must.

Does using premium fuel somewhat offset the effect of E10 on a Genesis?