Premium vs Regular Gas

[Hammer578]

Hello

I am a new Hyundai owner. I have the 5.0 R Spec and was wondering what the recommendation was for gasoline. Thanks for the help.

 

[nextcar]

i would try both.
if you can't tell the difference, stick with regular.

 

[EXBMWGUY]

I've used 87 - 93 - everything works quite well, with about 7-9 hp loss with 87. I'd for sure use top tier. Welcome to the club!

 

[Jbo]

Tried both in 4K tour for 16 days, seat of pants tells me slight performance increase wand mileage increase with premium. I averaged 26.1 mpg overall with several hours of 80-85 mph and a lot of 72-78 mph. Sweat spot for my R-Spec with now 13k on clock, is 78mph or about 1850 rpm@ 27 mpg.

 

[OneFunGenesis]

Have the 4.6 but they are the same engine. I used regular and got 20mpg. Switched to premium and got 22.7mpg on my last fill up. For more MPG and more HP, I'll spend $3 more a tank ha

 

[Hammer578]

Thanks Guys! Premium it is.

 

[Stoofpilot]

I have the 4.6 and use only regular. On trips we get 27 and around 18 around town.

 

[jnc2000]

Top tier premium...

 

[Hammer578]

Yeah I assumed that with the 4.6 and 5.0 it would be the best option. Thanks.

 

[Crusty Old Shellback]

10K miles on the clock. Been running regular the whole time. Hit 27 MPG on long trips. More than enough power to get me into trouble. I don't really see a reason to run premium at this time. Maybe if I was racing or something. But this is supposed to be the family car.

However I will say this, I run premium in my Harley. But that is because I built and tuned the engine to run on premium. It dosen't like regular. I also ran premium in my hotrod truck for the same reasons, it just wouldn't run on regular. Maybe the blower sitting on top had something to do with that.

______________________________

Help support this site so it can continue supporting you!

 

[jnc2000]

One finally thought... have you guys seen the timing retard on these motors with regular? Just causes the car to dump more fuel when its not needed. I'm tweaking some things in the coming weeks to see just how much timing can be advanced with the stock mapping in place.

AFR tuning is a must. Tuning period is a must for the gains I'm looking for...

But, getting back to the point hook up a wideband and scanguage and you'll see just how she performs under each scenario. Will it run on 87? Sure! Does the OEM ECU parameters adjust for this? Sure! Is it the best option? That's up to you to decided.... I don't like timing retard, and I most certainly like unburnt fuel. Lean, or as close to stoich (14.7) with WOT sitting at 12.5 would be ideal.

 

[Hammer578]

Jnc2000, you are way above my car knowledge on this one. The good thing is my company pays for my gas so I will just run the high grade. The main reason I was asking is my wife's Sequioa actually does better on regular thank goodness.

 

[brfatal]

One finally thought... have you guys seen the timing retard on these motors with regular? Just causes the car to dump more fuel when its not needed. I'm tweaking some things in the coming weeks to see just how much timing can be advanced with the stock mapping in place.

AFR tuning is a must. Tuning period is a must for the gains I'm looking for...

But, getting back to the point hook up a wideband and scanguage and you'll see just how she performs under each scenario. Will it run on 87? Sure! Does the OEM ECU parameters adjust for this? Sure! Is it the best option? That's up to you to decided.... I don't like timing retard, and I most certainly like unburnt fuel. Lean, or as close to stoich (14.7) with WOT sitting at 12.5 would be ideal.

My biggest concern would be that that if you're pulling timing it's because your knock sensors have detected enough detonation to do so. Detonation is never a good thing. All cars, even "premium only" are designed with ECUs capable of pulling timing to help TEMPORARILY accommodate lower octane fuels or gas that just isn't very good. The issue is that the ECU will attempt to advance timing again until it starts knocking from continued use of lower octane fuel. This is a cycle that will just repeat itself over and over and it can't be good in the long run for the car. Any car designed/tuned with premium in mind really should be kept using premium all the time.

 

[Canuck Genesis V8]

I would think the premium (94 octane in my area) should give a few more hp. Our '09 Genesis was rated at 368hp/323lb-ft with 87 octane and 375hp/333hp with 91 octane. The '12 Genesis R-Spec did not have such ratings, just the 429hp/376lb-ft rating. However, I would suspect that our R-Spec's would get another 3-5hp with 94 octane. Does anybody have any hard facts that would either support or disprove this point?

 

[EXBMWGUY]

I have seen Hyundai information that shows the 5.0 at 429 with 91 and 420 with 87. Unfortunately I can't place it right now. Mark_888 perhaps can. I love 93 (limited availability here), but doubt there is an equal increase between 91 and 93-94 as between 87 and 91. Anybody who has been seriously into the 5.0 ECU should be able to answer that question with more authority than I can.

 

[jnc2000]

I'm working on the tables... give me some time guys and I should have more data as to how much the OEM ECU parameters allow for adjustment

 

[EXBMWGUY]

I'm working on the tables... give me some time guys and I should have more data as to how much the OEM ECU parameters allow for adjustment

 

[rockymax]

With the 4.6 - 5.0, the owners manual recommends 91+ for better engine performance (is not defined), I do not understand why you would want to use 87 particularly if you have the R-spec.. It cannot be to save a few dollars a tank or you would not have bought the R-spec. The other engines perhaps but not the R-spec.

 

[InTheLou]

You are not going to notice a 10 hp difference in a 300-400 hp behind the wheel.
The fake chip ads won't even claim a change that low (we know those are a scam).
10 horsepower, which is only a 2-3% gain in total horsepower, can be easily translated by weather temp, humidity, or even a 100 foot change in altitude, not higher octane between regular and premium pump fuel.

Maybe a 10% change where you will notice 30-40 hp, and you are not going to get that on premium gas, but not 3-5 hp, you will even get that much variance on different dyno runs with the same gas. Plus premium gas has to meet minimum standards posted on the gas station sticker, many or different, some are better, some or worse. The R Spec says you can use regular or premium, rather than BMW, AUDI, and many other high tuned cars where premium is required. Not on the R Spec, but if it makes you feel better, use it, but I doubt if you are getting any performance or treating your engine any better. In the Midwest, premium is about 30-40 cents more a gallon, with a near 20 gallon tank that's $6.00 or $8.00/tank, or another 40-60 miles distance.

 

[QuantumRift]

If an engine is designed to primarily operate on premium fuel (91+ octane), then you will see a degradation in performance and economy. 87 and 89 octane fuels burn faster (and can cause pinging or knocking). The engine has knock sensors and can adjust the timing and injectors to compensate for the lower octane fuel. This in turn, causes lower HP output and a decrease in economy. On the other hand, a car designed to operate on 87 octane will not see ANY improvement or performance improvement by using 89 or 91 or 93 octane fuel.

Having said, that, there is NO advantage to fiddlefarting around with the 'stock' timing as the CPU does that anyways on the FLY as needed. This isn't your dad's muscle car.