Best octane number for Niro PHEV gas? - Kia Niro Forum
 2Likes
  • 2 Post By cockedandglocked
 
LinkBack Thread Tools
post #1 of 10 (permalink) Old 12-31-2018, 01:48 PM Thread Starter
Junior Member
 
Join Date: Dec 2018
Posts: 14
Best octane number for Niro PHEV gas?

I've read conflicting advice about the best gasoline octane rating to use in the Niro PHEV. The traditional view says, use the highest octane rating available or that you can afford, since it will provide more usable energy (performance and mileage) per gallon for the ICE. The other view is that the Atkinson cycle engine in the Niro does NOT, in fact, run better on high-octane gas, and you will actually get improved results with 87 octane. According to this latter view, the Atkinson cycle design is not best suited to the slower flame ignition and burn rate of high-octane gas, and it can even result in engine misfires and error messages. I'd like to understand which view is correct, and the engineering reasoning behind it.

At 1,100 miles, I've just filled my car for the first time, with 87 octane. I'd like to figure out if this is the best approach by the time a second tank is needed!
Fiddlesticks is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 12-31-2018, 02:14 PM
Senior Member
 
Join Date: Sep 2018
Location: California
Posts: 249
Garage
Using a higher octane is only necessary in cars where knocking or detonations are a problem if the octane rating is too low.


Contrary to what most people think, higher octane does NOT mean the fuel is more powerful, or burns more easily, etc. It actually means the opposite. Higher octane fuel takes a higher temperature/pressure to ignite it, preventing premature fuel ignition in the cylinder (knocking / detonating). This is critical in a lot of high performance cars that have higher compression ratios, especially forced induction cars. On economy 4-cylinder cars? Nope. You're flushing money down the toilet buying higher-octane fuel because your engine does not have any use for it whatsoever. These engines are not even remotely close to knocking with 87 octane fuel.


And despite the naming of fuel types (regular, mid-grade, premium), don't be fooled - they are all exactly the same quality fuel. The only difference is that the higher octane varieties are necessary for certain cars - but not ours.


This is actually the first car I've owned in 10 years that didn't require 91 octane gas, and I'm LOVING getting to push the"87" button at the fuel pump lately. I'd never waste my money on anything higher than 87 for my Niro.
charlesH and Nouseformonkeys like this.

2018 PHEV
cockedandglocked is online now  
post #3 of 10 (permalink) Old 12-31-2018, 03:02 PM Thread Starter
Junior Member
 
Join Date: Dec 2018
Posts: 14
Thanks for the info! I think one reason people have told me I "should" use premium gas in my Niro is because the engine is pretty high-compression at 13:1. And for a standard Otto cycle engine that might be the case. However, it seems that for an Atkinson cycle engine, octane rating vs. compression really isn't the deciding factor on what the correct gas should be. I'm going with the standard 87 octane at the local pumps (western Washington) unless anyone else has a good reason that I really shouldn't. And I also love hitting the "87" button and not wasting my money.
Fiddlesticks is offline  
post #4 of 10 (permalink) Old 12-31-2018, 03:23 PM
Super Moderator
 
Join Date: Sep 2018
Posts: 395
I would say that sticking with 87 Octane is the better choice, but choose a better quality of gas from decent branded gas station, not whatever is out there at the best price. There are some stations that source their gas from whatever surplier proviced them the best price so gas one week might be fine, and the next week can run horrible depending on where they sourced from at the condition of the gas.

2018 Niro EX - Ocean Blue
GTA - Canada.
Roadkill401 is online now  
post #5 of 10 (permalink) Old 12-31-2018, 03:46 PM
Senior Member
 
Join Date: Sep 2018
Location: California
Posts: 249
Garage
Agreed, I use Chevron w/ techron because I don't trust "bargain" gas. Certainly some brands are higher quality than others. But different tiers of gas from any one brand aren't. Chevron has always done me well so it's what I choose to use in all my cars.

2018 PHEV
cockedandglocked is online now  
post #6 of 10 (permalink) Old 12-31-2018, 04:19 PM
Senior Member
 
KK6PD's Avatar
 
Join Date: Dec 2017
Location: Foothills of Los Angeles
Posts: 173
Garage
87....nuff said!

73's de Pat KK6PD


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KK6PD is offline  
post #7 of 10 (permalink) Old 12-31-2018, 11:17 PM
Member
 
Join Date: Sep 2018
Location: Colorado
Posts: 32
I use 85 and it's perfect* for the engine.


*I live at 6000 feet.

2018 Niro LX PHEV
2019 Pacifica PHEV
dots is offline  
post #8 of 10 (permalink) Old 12-31-2018, 11:22 PM
Senior Member
 
Join Date: Mar 2017
Location: SW Ohio
Posts: 1,810
Any modern car will run fine on regular. Possibly lower HP, but they all have knock detectors and will retard ignition timing if needed.

I always buy the cheapest gas and have yet to have any sort of issue with engines (last car was 175,000 when I sold it). Anecdotal to be sure, but those same trucks refilling Chevron stations and other top tier stations appear to sell to others as well. There is also a technical issue that suggests the Chevron "detergent" additives may not help Niros as much as other engine designs. No "cleaning" of intake valves as we have direct injection, not port injection. Difficult for me to understand what the benefit of paying another 20 cents or so per gallon might be for us. Any additive that might scrub injectors (which seem like perhaps the weakest link) would likely be too abrasive to promote engine (or injector) longevity.

2018 Kia LX HEV Metal Stream with Advanced Tech
yticolev is online now  
post #9 of 10 (permalink) Old 01-01-2019, 01:52 AM
Senior Member
 
Join Date: Oct 2018
Location: Murrieta, CA
Posts: 330
Quote:
Originally Posted by yticolev View Post
There is also a technical issue that suggests the Chevron "detergent" additives may not help Niros as much as other engine designs. No "cleaning" of intake valves as we have direct injection, not port injection. Difficult for me to understand what the benefit of paying another 20 cents or so per gallon might be for us. Any additive that might scrub injectors (which seem like perhaps the weakest link) would likely be too abrasive to promote engine (or injector) longevity.

I agree with what others have suggested in this thread: regular 87 octane is recommended by the owner's manual and you are likely to be wasting money if you purchase higher octane. But I'm curious about the "technical issue" that you mention. Can you elaborate further or did your previous post explain it as fully as you understand that issue?



I'm not religious about buying Chevron, but I do pay the extra 20 cents per gallon for Chevron when I can, for the following reasons:
  • My Niro is still very new and I want to baby it for a while, and feeding it Chevron (or similar) is part of my idea about how to take premium care of it.
  • The owner's manual does recommend using gas from a brand that is listed on toptiergas.com (Chevron is one of several brands listed there).
  • When my 2008 Honda CRV would start to occasionally misfire, I'd put a tank of Chevron through it and the problem would go away for several months. Correlation doesn't prove "cause and effect" and maybe my experience was just a coincidence, but it certainly created the impression that the Chevron conveyed a benefit that I wasn't getting from the generic brand gas that I used at other times.
  • My brother is a service manager at a GM dealership and he has regaled me on several occasions that he loses some significant fraction of his potential customer engagements (I'm guessing about 15% but I've never tried to pin him down on this) by telling his customers who have certain kinds of complaints to burn through a tank of Chevron and then make their service appointment with him if they are still having problems. Some fraction of them do that and either don't call back to make an appointment, or call back to thank him for the advice. If I recall correctly, his advice is coming from GM guidance to their service managers.


There are probably less expensive alternatives on the toptiergas.com site than Chevron, and perhaps I will use one of those alternatives in the future. But I do think that, especially while the car is relatively new and various folks are still running into occasional strange issues, it's best to use a brand that the manufacturer recommends, if only to ensure that you can easily rule out that particular concern if anything should come up that requires an unexpected service call at the dealer.

2018 Niro PHEV Gravity Blue
deltasmith is offline  
post #10 of 10 (permalink) Old 01-01-2019, 11:34 AM
Senior Member
 
Join Date: Mar 2017
Location: SW Ohio
Posts: 1,810
"Issue" is probably the wrong word. Technical design feature of the Kappa engine is direct injection of fuel into the cylinder similar to a diesel engine. This means no flow of fuel over the intake valves and thus no cleaning benefit to the intake valves. As I read the propaganda online from Chevron, this would be the major benefit of Techron. Thus even less benefit to us versus normal port injected cars.

Techron (and other additives) can reduce deposits on valves in a few thousand miles, so your brother is generally right. However it is not possible for additives to clean the intake valves on the Niro. I'm not sure what that means for valve issues in the Niro, but most of those valve deposits come from gasoline that is no longer flowing directly over and through the intake valves.

Car manuals tend to use boilerplate relevant to the majority of a manufacturer's cars, and like the internet, they often propagate and continue old discredited "wisdom". For example, in some markets, they have ludicrously short oil change intervals. In the case of Britain, there does seem to be a quality difference between "supermarket" gas and branded gas (possibly just water contamination). Thus, a blanket recommendation for more expensive gas that seems to be in their manual for all countries. Doesn't cost them anything to add a few words of warning that may actually be worthwhile in some areas.

Again, completely anecdotal, but I've never had an engine problem that could be traced to deposits. I invariably buy the cheapest possible gas, but in this country, that often means I'm buying from branded stations as they have to be competitive. A Marathon dealer in my home town went independent about 6 months ago, but he tells me the exact same company still fills his tanks with the exact same gas. My PT Cruiser warped a head from overheating at about 100,000 miles (a common issue to that engine I read) and I had a look at it at the dealer when it was apart. Spotless valves and cylinders!

2018 Kia LX HEV Metal Stream with Advanced Tech
yticolev is online now  
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Question for PHEV users only... lafe005 Kia Niro General Discussion 4 12-17-2018 10:35 PM
Niro PHEV resale values picstart Kia Niro General Discussion 3 11-08-2018 05:06 PM
New member, 2500 miles on 2018 PHEV aak New Member Introductions 5 08-29-2018 03:28 PM
2018 Kia Niro PHEV EX hawke New Member Introductions 22 08-02-2018 04:21 PM
PHEV vs Hybrid kevperro Kia Niro General Discussion 16 07-04-2018 10:14 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome