Octane level and performance

[RickfromChicago]

Hi everyone,

I know this has been discussed before, but there is something I just do not understand concerning the 2015/2016 Hyundai Genesis Sedan.

Hyundai publicizes the hp and torque numbers using both regular and premium gas for the V8 engine.

However, for the V6 3.8 engine, the hp and torque numbers are based on regular gas and no information is offered for the use of premium gas. I called Hyundai USA and they told me that this information was not available as they only publicize hp and torque information for the fuel they are recommending for each engine (regular for the V6).

I find this very strange. With the V8, the hp and torque jump up 13/11, respectively, so I would expect to have a jump up for the V6 as well using premium gas.

Would anyone know if tests have been done using premium gas to see what the hp and torque ratings would be for the V6 engine? Or has anyone been able to get this information from Hyundai directly?

Thanks.

 

[Mark_888]

Hi everyone,

I know this has been discussed before, but there is something I just do not understand concerning the 2015/2016 Hyundai Genesis Sedan.

Hyundai publicizes the hp and torque numbers using both regular and premium gas for the V8 engine.

However, for the V6 3.8 engine, the hp and torque numbers are based on regular gas and no information is offered for the use of premium gas. I called Hyundai USA and they told me that this information was not available as they only publicize hp and torque information for the fuel they are recommending for each engine (regular for the V6).

I find this very strange. With the V8, the hp and torque jump up 13/11, respectively, so I would expect to have a jump up for the V6 as well using premium gas.

Would anyone know if tests have been done using premium gas to see what the hp and torque ratings would be for the V6 engine? Or has anyone been able to get this information from Hyundai directly?

Thanks.

Hyundai did not say that you won't get more HP on the V6 with premium, they just don't publish any information on that.

Keep in mind that EPA mileage testing on the V8 is based on premium, and the V6 is based on regular. Given that, I would not expect them to publish information on the V6 using premium. Part of that is probably for marketing reasons, as the less expensive V6 is likely to appeal more to cost conscious buyers who don't want to pay for premium.

 

[RickfromChicago]

Hi Mark_888

I understand now. Thanks.

Do you think that the difference in hp/torque increase for the V6 would be about 3% higher, as it is for the V8?

Thanks.

 

[Uchiha madara]

more Octane means more power always

if you see in racing F1 they use Octane 100

 

[Mark_888]

Hi Mark_888

I understand now. Thanks.

Do you think that the difference in hp/torque increase for the V6 would be about 3% higher, as it is for the V8?

Thanks.

I am sure it is higher, but I have no idea how much.

I would experiment with various octane levels by testing various octane levels (you can mix regular and premium at the gas station when you fill up). Then I would carefully track MPG under the same driving conditions for each octane level. If you are getting better MPG, then I think it safe to assume that HP is also increasing. I am not sure if using 100% premium is the sweet spot, or whether a mid-grade would yield optimal results.

 

[jarred52]

If premium makes more HP, it did not correspond to increased fuel mileage for me. On three different road trips, I got the same as I had previously gotten on regular.

Prior to the "premium trips", I had made sure to run down the regular fuel and refill with premium twice before the trip to be certain that I had as much premium as possible without draining the tank. I had driven the same routes as before and got the same
29+ mpg. With premium about 20% higher than regular in my area, I will stick with top tier regular.

 

[need4spd]

I remember reading that Consumer Reports did a study just recently (again) and found that there was no difference in gas mileage putting premium in a car rated for regular unleaded, even the EPA came out with a statement about that.

Regarding HP increase, it all depends on how the software is written, if there are two maps or not like the V8 has (hence the 2 HP numbers), and if there are 2 or not in the V6. Typically a car designed to run on regular only has 1 map for fuel delivery and timing, where one rated on premium, will have 2, with the second a lower tier with retarded timing and such for when the car is not run on premium and the knock sensors activate.


Only way to truly check is on a dyno to see if HP changes on the V6.


But for the V6, the MPG will not increase on premium over regular.


In my own experience, with 2 other cars (both V8 where the Genesis is a V6 for me), I have found that they work best with premium. One has "premium recommended" (not required) and I have found it to knock some of the time when regular is used, but not on mid-grade or premium. The other car says regular, but it was a car maker rating switch at the last minute from premium as gas prices were skyrocketing at the time of intro) it runs better on premium (it has cylinder deactivation and it is the changeover from V8 to V4 that I can sense and hear, ie no rattling, the difference). Also the second car was a very small production run of less than 40K cars, so it isn't really well supported.

Personally I am a premium only type person, always going with the best, but in the case of the V6 Genesis, I have not detected any reason to use premium and I am sticking with regular.

Oh yeah - You will get a lot of personal opinions on this mater from what I have seen over the years.

 

[cj428cj]

more Octane means more power always

This is not true. A higher octane fuel just means that the gas can withstand higher pressures before detonating. If the gas ignites before the piston reaches a certain point in the compression stroke (near Top Dead Center) you may get pinging which is very hard on the engine. It has nothing to do with how much power the gas produces. Many modern cars can detect pinging and they will automatically adjust the engine timing (when the spark plug fires in relation to the piston's position) to eliminate the pinging. By retarding the timing a little bit in order to eliminate the pinging, you lose a little power. That is undoubtedly why Hyundai gives two different HP ratings for the two different octane fuels on the V8. The V6 can probably use either gas without the engine control systems adjusting the timing so there will be no impact on HP regardless of which fuel you use. Save your money and just go with regular in the V6.

 

[Mark_888]

I remember reading that Consumer Reports did a study just recently (again) and found that there was no difference in gas mileage putting premium in a car rated for regular unleaded, even the EPA came out with a statement about that.

Regarding HP increase, it all depends on how the software is written, if there are two maps or not like the V8 has (hence the 2 HP numbers), and if there are 2 or not in the V6. Typically a car designed to run on regular only has 1 map for fuel delivery and timing, where one rated on premium, will have 2, with the second a lower tier with retarded timing and such for when the car is not run on premium and the knock sensors activate.

Only way to truly check is on a dyno to see if HP changes on the V6.

But for the V6, the MPG will not increase on premium over regular.

In my own experience, with 2 other cars (both V8 where the Genesis is a V6 for me), I have found that they work best with premium. One has "premium recommended" (not required) and I have found it to knock some of the time when regular is used, but not on mid-grade or premium. The other car says regular, but it was a car maker rating switch at the last minute from premium as gas prices were skyrocketing at the time of intro) it runs better on premium (it has cylinder deactivation and it is the changeover from V8 to V4 that I can sense and hear, ie no rattling, the difference). Also the second car was a very small production run of less than 40K cars, so it isn't really well supported.

Personally I am a premium only type person, always going with the best, but in the case of the V6 Genesis, I have not detected any reason to use premium and I am sticking with regular.

Oh yeah - You will get a lot of personal opinions on this mater from what I have seen over the years.

There are several problems with this.

1. The Genesis V8 is specifically designed to run on regular or premium. Hyundai has in the past published numbers that claimed less HP with regular gas. I think it is safe to say that MPG is also better with premium since that is what was used during EPA mileage tests. Otherwise, one would have to assume Hyundai marketing people are idiots.

2. Hyundai Motor America has not made official claims about premium on the V6, but it is not unreasonable to think that the V6 could also have more HP and better MPG on with increased octane. Since they did EPA testing with regular gas, and the owners manual recommends regular gas, they can't really say much about premium without violating the law.

3. There is a big difference between regular and premium in terms of octane. Personally I use a mid-grade gas on my V6 (pre-GDI version), and I have measured about 1 MPG better mileage on highway driving during controlled testing. I found that using 100% premium does not improve MPG on my V6 over mid-grade gas. I believe HP is slightly better with mid-grade, but I have no way to measure that. Often times I put in about 2/3 tank of regular, and 1/3 premium instead of midgrade, partially because mid-grade is a rip-off price if you do the math on mixing the octane levels and comparing the prices.

4. Whether or not "most cars" that can run on regular can also benefit (HP or MPG) with higher octane is irrelevant. What matters is whether the Hyundai Genesis engines can do that. So unless Consumer Reports tested the Genesis, their conclusions are not valid.

5. As far as "maps" to make adjustments in the engine to take advantage of regular or premium, it is not black or white. The engine adjustments are variable, not binary. And yes, the V6 would have to have similar adjustments as the V8 to take advantage of higher octane levels. As I said above, I think the V6 can take advantage of some increase in octane over regular, although maybe not 100% premium. Plus the fact that that premium is not the same octane level at all gas stations.

 

[GCyr42]

more Octane means more power always

if you see in racing F1 they use Octane 100

Except when tested--see the following articles:
http://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

http://www.npr.org/2016/09/23/49519...illions-of-drivers-waste-money-on-premium-gas

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[danygenesis]

Just take a look at this recent AAA study
http://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

 

[Mark_888]

Just take a look at this recent AAA study
http://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

They didn't test Genesis engines. Are you saying that the Genesis V8 doesn't get better MPG with premium?

 

[Mark_888]

Except when tested--see the following articles:
http://newsroom.aaa.com/2016/09/u-s-drivers-waste-2-1-billion-annually-premium-gasoline/

http://www.npr.org/2016/09/23/49519...illions-of-drivers-waste-money-on-premium-gas

They didn't test Genesis engines. Are you saying that the Genesis V8 doesn't get better MPG with premium?

 

[srobak]

I accidentally ran a tank of premium in my awd v6 a couple tanks ago. While I cannot necessary speak to performance - I will say the engine ran noticeably quieter and smoother. My mileage went down - but my driving is very dynamic week to week, so I am not putting any stock in that.

 

[cletus]

They didn't test Genesis engines. Are you saying that the Genesis V8 doesn't get better MPG with premium?

Even if it does, the price premium would not be worth the increased MPG.

If the difference between grades was only 10 cents like it used to be and gas was 1.99,2.09,2.19 for 87/91/93 then why not go ahead? However, right now I can buy regular for $1.77 vs $2.37 which is a whopping 34% higher. Not going to be worth it.

 

[Mark_888]

Even if it does, the price premium would not be worth the increased MPG.

If the difference between grades was only 10 cents like it used to be and gas was 1.99,2.09,2.19 for 87/91/93 then why not go ahead? However, right now I can buy regular for $1.77 vs $2.37 which is a whopping 34% higher. Not going to be worth it.

Right, each person has to decide for themselves whether better MPG and increased HP are worth the higher price of premium.

I see a lot of people on this forum replacing the air intake, changing the exhaust system, and doing other similar things trying to squeeze more HP, which are probably even less cost effective than using premium on the V8.

 

[Mark_888]

I accidentally ran a tank of premium in my awd v6 a couple tanks ago. While I cannot necessary speak to performance - I will say the engine ran noticeably quieter and smoother. My mileage went down - but my driving is very dynamic week to week, so I am not putting any stock in that.

Try mid-grade, or mix your own (1/2 tank regular, and 1/2 tank of premium).

My V6 also runs smoother and quieter with mid-grade (and with better MPG). I found that going beyond mid-grade did not help any further.

 

[srobak]

So noted... I will give that a whirl. Thanks Mark

 

[cletus]

Try mid-grade, or mix your own (1/2 tank regular, and 1/2 tank of premium).

My V6 also runs smoother and quieter with mid-grade (and with better MPG). I found that going beyond mid-grade did not help any further.

Good suggestion. Midgrade is itself 50% regular/50% premium blended. Thus for 10 gallons each ($1.77 regular and $2.37 premium) your average cost for the 20 gallons is $2.07 BUT the gas station near me sells it for $2.27. Solid savings.

 

[danygenesis]

They didn't test Genesis engines. Are you saying that the Genesis V8 doesn't get better MPG with premium?

Where did you see in my post such a thing? Are you blind or having some kind of visual illusions? I just posted a link of a very recent and interesting article about Premium Gas Consumption in USA.