K5 GT on regular fuel?

1st K5 said:

Kia recommends regular unleaded for the 2.5T wich I find bizarre. I for one will be using shell 91.Any GT owners use regular? I'm assuming the hp gets bumped up closer to 300 with premium fuel.

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I think Kia tuned the engine to run on regular due to the highrer cost of premium fuel. This cars price is still a level where it is within reach of allot of peoples budget. That being said, this same group of people (me included) do not want to pay the additional $0.60 - 0.70 per gallion for premium. If I could afford a Porsche 911, or something similar I would not care about the extra cost. I was actually looking at a Stinger GT with the 255 HP 4 banger about a year ago, it does require the premium fuel. Just my 2 cents.

I get your point. I would like to get the extra hp if possible by switching to premium.
Roughly 8$ more per week. And if ever it gets tuned, I'd add boostane to the mix.

Alot of newer turbo cars are being tuned to run on regular 87 fuels, this has been going on since 2015. It's pretty wild to be able to get 290hp/311tq on 87 out of a 2.5L 4 cylinder turbo. The hyundai n performance line requires premium fuel in the 2.0 that's in their cars. Hyundai,kia,genisis are all the same so it's weird to see for sure and I understand the want and need to run premium as most of us are used to that in turbo cars.

joel.heabeart said:

Alot of newer turbo cars are being tuned to run on regular 87 fuels, this has been going on since 2015. It's pretty wild to be able to get 290hp/311tq on 87 out of a 2.5L 4 cylinder turbo. The hyundai n performance line requires premium fuel in the 2.0 that's in their cars. Hyundai,kia,genisis are all the same so it's weird to see for sure and I understand the want and need to run premium as most of us are used to that in turbo cars.

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SXTH stock dyno of gt made 287 wheel hp, 324 tq

My 1 cent on 87 octane Vs 93 octane:

If you drive your car like a normal person, 87 octane is adequate.

If you drive your car with only 2 throttle positions - idle and WOT, then you should be using 93 octane.

If you're going to go to race your K5 on a dragstrip then you should use 93 octane.

Zillions of words have been spent on this topic, and some people - on either side - won't ever be convinced.

Bottom line:

• Octane rating is an index of knock prevention. Modern cars have knock sensors that take care of that by making small adjustments to spark timing. No big deal, negligible effect on performance.
• If Kia thought it was not wise to use 87 octane gas, the owner's manual would state: "Never ever in a million years use 87 octane, and if you accidentally put some in your car, have your engine rebuilt immediately."

I've always used 87 octane in all my turbo Kias with no ill effects, and it performs just fine. If blindfolded, I doubt you'd be able to feel the difference between the two fuels, if any. (But don't drive blindfolded).