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Discussion Starter #1 (Edited)
Hello friends.. A couple of question.
What type of fuel would you recommended for my 2005 insight. Premium or just the regular stuff?....also would "Shell' fuel be any better?

And what would the best spark plugs to use ..
Denso,pulsar or Bosh.... Thanks guys or gals.
 

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Hello friends.. A couple of question.
What type of fuel would you recommended for my 2005 insight. Premium or just the regular stuff?....also would "Shell' fuel be any better?

And what would the best spark plugs to use ..
Denso,pulsar or Bosh.... Thanks guys or gals.
My family prefers 87 Octane Chevron or Texaco (has Techron and is also good quality fuel) if we can't get Ethanol Free gas, which is 90 Octane. Don't think premium will help much. For plugs, I would only buy the indexed plugs (usually "B") that Honda sells.

My 0.02 worth,
Tim
 

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Spark plugs: We have no choice but the indexed plugs (unless you are willing to let MPG drop).

Top Tier Gas is what many manufacturers recommend. The car makers got tired of fixing engines for free (under warranty) due to rotten US gasoline, so they developed their own standard.

LINK: Top Tier Gasoline
 

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Don't think premium will help much.
Correction: higher-octane gasoline won't help in the slightest in engines that don't obtain high enough pressure to utilize it to the fullest (like ours).

A much better use of the money you would spend on the high octane gasoline would be fully-synthetic 0W-20 oil.
 

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0W-30 synthetic will provide even better protection (thicker oil forms a boundary layer to stop metal-on-metal contact). 5W-30 Mobil Extended Performance provides longer 15,000 mile drains. I use the M1 EP.

91 octane gave me +1 mpg because it gave more power climbing hills in 5th gear (instead of switching to 4th ehich eats more gas). And yes the 11:1 engine would be considered high compression. Most cars are only 9 or 10, in order to avoid knocking on low octane gas.

Of course 87 is still cheaper to run.
:)
 

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as far as octane-its a argument that NEVER gets a consensus. My advice is hook up a obd and watch the numbers-it will give all the proof needed. And cost is negligable anyway 2.00-3.00 more a tank (people act like its $10 or more at times).
Id go with the indexed plugs for the best possible mpg gains
 

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as far as octane-its a argument that NEVER gets a consensus. My advice is hook up a obd and watch the numbers-it will give all the proof needed. And cost is negligable anyway 2.00-3.00 more a tank (people act like its $10 or more at times).
Id go with the indexed plugs for the best possible mpg gains
Watch which numbers, and what should I watch for? I'd love to have something that would tell me definitively (other than the very respected G1 owners on this forum, who all know the right answer, but they seem to be different right answers).

I've been back and forth about the octane mess several times. It's all mixed up for me, with being a relatively new owner and having so many mods interacting.

The previous owner used premium, and filled the tank when I bought it. I used regular for the next couple of tanks and got 65 mpg. Then I found a station with premium no-ethanol and got 75 mpg. Thinking that the no-ethanol was great, I found another station that sold E0 regular -- back down to 65 mpg. Stuck with the E0 premium after that but with no definitive results.

In Texas, there is no E0 to speak of, so I have mostly been using premium E10ish. Speed limits are higher here, and I tend to drive hilly routes, but my FE has been in the low to mid 60's. Decided to try regular again, and the first tank was 61 mpg (filled again with regular). Decided that was no good, so back to premium on the next tank, except the SECOND tank with regular (after filling up with premium) got 69 mpg.

Anyway, I guess my observations are this:

1) driving habits and environment make a lot more difference than type of fuel

2) one tank is not enough time to make a judgement

3) I have no idea if using premium makes a difference, but I'm cheap so I'm going back to try regular again.

Spark plugs? Why not use the Honda indexed plugs. They are more expensive and I am cheap, but the difference in price is about 3¢ per 1000 miles. Falls in the "not worth the risk" category for me.
 

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Higher than 87 octane will not improve performance unless the car is detonating. Unless your engine has been turbocharged, its unlikely that you would detonate unless you are using blockoff plates and under trays that increase heat in the engine bay as well as intake air temps. Ethanol free fuel should provide the best mpg. Staying in leanburn as much as possible is the number one factor IMO. Having lightweight tires such as the RE90/92 is also an important factor. 0w20 should provide better mpg than 0w30.
 

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performance is improved by the addition of timing. for example. 87may only allow 28* of advance. but 92 may allow 32 (more timing=mpg) While i just tossed some random numbers out there, the proof is watching the ecm data like timing, calculated load etc. IMO, after 14yrs and 300+K later, taking the same route hundreds of times, 92oct ALWAYS netted better mpg then regular-and both are e10 gas, and only is about $3 more a tank.

If i may, lets focus on that $3 extra for a min. Lets say i spend that $3 on a extra gal of 87. Thats 50 miles more i can go (conservatively). Now take premium, I know for a fact it will add at the min 50 more miles a tank min-so cost right there is even. any extra miles are "profit" so to speak.
 

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performance is improved by the addition of timing. for example. 87may only allow 28* of advance. but 92 may allow 32 (more timing=mpg) While i just tossed some random numbers out there, the proof is watching the ecm data like timing, calculated load etc. IMO, after 14yrs and 300+K later, taking the same route hundreds of times, 92oct ALWAYS netted better mpg then regular-and both are e10 gas, and only is about $3 more a tank.

If i may, lets focus on that $3 extra for a min. Lets say i spend that $3 on a extra gal of 87. Thats 50 miles more i can go (conservatively). Now take premium, I know for a fact it will add at the min 50 more miles a tank min-so cost right there is even. any extra miles are "profit" so to speak.
So in your experience, the % MPG gained by using premium is about a wash with the 10% more that the premium fuel costs? You see 10%+ better fuel economy from premium? I can't ever tell, but my ever-changing driving style and route and mods all make it so difficult to get a handle on it.
 

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Speaking of sparkplugs.
I ordered an indexed (B) set from Majestic last week. Shipped to Ca. total is $59.40.

I can also pick up at set from the dealer locally in El Cajon for $90.20.Called three other local dealers and they were also $85-$90 total.

Buy them now if you plan on keeping the Insight over 100K miles of use.

HTH
Willie
 

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Regular gasoline is fine. The brand really doesn't matter.

For plugs, get them from Honda. Yes they're expensive, but they last 250,000 miles so you'll only need to replace them once. And yes, I know that Honda recommends replacing them at around half that mileage, but it really isn't necessary. A total waste of time and money, from my personal experience.
 

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After reading others' responses, I still stick with my thoughts:
Spark plugs: We have no choice but the indexed plugs (unless you are willing to let MPG drop). Top Tier Gas is what many manufacturers recommend. The car makers got tired of fixing engines for free (under warranty) due to rotten US gasoline, so they developed their own standard. LINK: Top Tier Gasoline
 

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Regular Versus Premium Gasoline

Since the energy content is the same, maybe folks who are getting better MPG is a result of the timing not having to be retarded as it might be if they were running regular during the same routes in the past..

That's of course I assume the insight can adjust timing triggered by the knock sensors. I am too new to the car to know this, but suspect it can.
 

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On premium vs. regular and timing, the Insight does have an active - very active - knock sensor, and I generally see about 5 degrees more advance with premium vs. regular (for instance, under such and such conditions, I might see 10 degrees of retardation with regular vs. only 5 degrees with premium). Whether it makes a difference in fuel economy - I can never tell. It seems like it has to to some degree...

What's kind of interesting is just how active the knock sensor is. Supposedly it is an acoustical device that detects the actual knocking sound, or more precisely, the very beginnings of what we'd call a 'knock' or 'ping'. It retards timing so the full knock doesn't happen. Well, even if you're idling and turn on the AC, more so with regular vs. premium, the knock sensor reading (on OBDIIC&C) will show retardation... Very sensitive and active...
 

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Once again: 11:1 is high compression. So too is the new 13:1 Mazda engine, but they used timing retardation & other tricks to "allow" it to run on 87 octane. Nevertheless if you put supreme gasoline in the car, it will give slightly more horsepower/efficiency. That was Mazda's goal.

BTW the Volt is only 10:1 compression, and yet it uses high octane gasoline. If 10:1 uses high octane, and benefits from it, why wouldn't a higher compression insight engine?

In my insight:

I've seen higher MPG with 91 octane, but it was only +1 MPG. I could also feel more power when climbing slopes in 5th gear. So is it worth 20 cents/gallon extra to get +1 mpg? Not by my calculations in insight #2. (I would have to get +3 mpg in order to justify the 91 expense.) I should also add I ran nothing but supreme in my first insight... I was trying to beat Wayne Gerdes' lifetime MPG. ;)

$4.10/55 mpg == 7.4 cents/mile
$3.90/54 mpg == 7.2 cents/mile
 

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Evidently that engine is GDI. Gasoline direct injection that cools the pistons and charge air while finely atomizing the fuel at diesel-like fuel pressures 10-15x a non GDI fuel pressure.
 

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Compression ratio is related to octane requirements in the same way that MHz is related to processing power and megapixels to picture quality.

Combustion chamber design plays just as much of a role as static compression ratio, if not more. You could make a 9:1 compression engine knock on 87 octane if you wanted to.
 

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Evidently that engine is GDI. Gasoline direct injection that cools the pistons.
You have it backwards. GDI engines run hotter, produce more NOx, and as recently discovered: Make 10x more particulate matter (soot) than a modern SCR-equipped diesel, due to the GDI's higher temperatures.

Anyway I'm convinced by the other owners data which shows 87 increases the insight's knocking (and the computer compensates with delayed timing). That means the insight engine runs less efficiently.
 

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You have it backwards. GDI engines run hotter, produce more NOx, and as recently discovered: Make 10x more particulate matter (soot) than a modern SCR-equipped diesel, due to the GDI's higher temperatures.

Anyway I'm convinced by the other owners data which shows 87 increases the insight's knocking (and the computer compensates with delayed timing). That means the insight engine runs less efficiently.
Here is some data relevant to GDI engines.

I'm afraid you are incorrect.

WIKIPEDIA said:
In internal combustion engines, Gasoline Direct Injection (GDI), also known as Petrol Direct Injection or Direct Petrol Injection or Spark Ignited Direct Injection (SIDI) or Fuel Stratified Injection (FSI), is a variant of fuel injection employed in modern two-stroke and four-stroke gasoline engines. The gasoline is highly pressurized, and injected via a common rail fuel line directly into the combustion chamber of each cylinder, as opposed to conventional multi-point fuel injection that happens in the intake tract, or cylinder port.

In some applications, gasoline direct injection enables a stratified fuel charge (ultra lean burn) combustion for improved fuel efficiency, and reduced emission levels at low load..Decreased combustion temperature allows for lowest emissions and heat losses and increases air quantity by reducing dilation, which delivers additional power.

This technique enables the use of ultra-lean mixtures that would be impossible with carburetors or conventional fuel injection.

By virtue of better dispersion and homogeneity of the directly injected fuel, the cylinder and piston are cooled, thereby permitting higher compression ratios and more aggressive ignition timing, with resultant enhanced power output. More precise management of the fuel injection event also enables better control of emissions. Finally, the homogeneity of the fuel mixture allows for leaner air/fuel ratios, which together with more precise ignition timing can improve fuel efficiency. Along with this, the engine can operate with stratified (lean burn) mixtures, and hence avoid throttling losses at low and part engine load. Some direct-injection systems incorporate piezoelectronic fuel injectors. With their extremely fast response time, multiple injection events can occur during each cycle of each cylinder of the engine.
 
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