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Discussion Starter · #1 ·
In the three years of driving my 5-speed Insight, I have never used Premium gas as it seems the car manual says 89 octane is just fine. If better acceleration is the main benefit of Premium gas, then it probably matters little on a hybrid. A "premium battery pack" might make more of a difference. :D Since the CVT Insight is keeping fairly constant rpms, premium gas would seem irrevalant.

My question is did anyone notice any difference when using Premium gas?

On a related topic, I have heard that sulphur content is not only an enviromental concern, but it can shorten the CO2 sensor's life. I'd love to know which gas brands are low-sulfur.

Right now I'm in the "if it ain't broke - don't fix it" but I could be pumping high-sulphur gas oblivious to the problems down the road...
 

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The owners manual says 87 is fine in the US, but everything else says 91 or higher. In the service manual it says something like 91 octane or higher is recommended for best preformance and mileage. If you go in the the owners manuals from other countries they all say to use whatever their equivelent of premium gas is.

I ran one tank of 87 through mine then the rest were 91. There is a slight noticable difference. More over while in lean burn the effects might be more felt. All things considered you've got 10.8:1 compression which is up there high octane won't hurt a bit. The Hot Rod toy we have in our garage has about the same compression and it barely likes 91 octane, it ran much better on the 100 octane racing fuel we recently fed it. Then again thats old technology, your results may varry. I'm sticking to what the service manual says.
 

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Discussion groups on Yahoo have beat this to death over the years. I did my own tests, alternating tanks from regular to premium and back. I saw no difference between regular and premium. I saw much bigger differences from minor day-to-day differences in the commute.

Double-check what it says in the service manual, from what I remember of those discussions the 91 was the higher of the two "octanes" (Research Octane Number or Motor Octane Number). The average of the two (R+M)/2 is what is posted at the pump.
 

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Premium vs Regular

Recently I ran two tanks of regular thru my 2000 five speed. Then I went back to Shell premium. The car seems peppier and the mpg slightly better with premium gas. The majority of my driving is expressways and parkways and I'm back up to 62mpg.

Jef Gamblee
 

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Discussion Starter · #5 ·
My CRX service manual suggested occasional fill-ups with Premium to prevent fuel injectors from clogging. They might have clogged once in the 12 years and 250,000 miles I had it.
 
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Hi DF:

___Reading through a recent “Acura Style” magazine, there was a Q&A where someone asked if Premium was mandatory in the Premium recommended Acura’s. The answer from one of the Honda engine designers was that you can use Regular with a small decrease in performance. The Honda Pilot uses basically the exact same motor as the 01 Acura MDX (3.5 L - 240 HP/242 Ft.-Lb.’s of torque at a 10:1 compression ratio) and Regular Unleaded is recommended unless towing. For the MDX, Premium is recommended alone. That being said, I have been using Regular Unleaded in our 03 MDX (3.5 L – 260 HP/250 Ft.-Lb.’s of Torque at the same 10:1 Compression ratio) since day 1 and have far exceeded anyone’s mileage over in the SUV forum but I never ever run the X’s engine up to even half of redline.

___Even if you were run the Insight to WOT w/ 87 Octane, the KS should pull back timing before you could actually here any Ping or cause damage. The negative to all of this is that the Insight’s 10.8 and 10.3:1 compression ratio is at a point I have never heard of any automobile that can use Regular unleaded across all ranges. If you do in fact hear ping, I would have it checked out. There has to be a KS in there somewhere.

___If I ever do pick one up, it will be 87 all the way given the extra $0.20 in my locale for 91 Octane. That is equivalent of losing ~ 13% of my expected hwy mileage via fuel costs alone.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:2lftf860][email protected]earthlink.net[/email:2lftf860]
 

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I would think running 91octane gas would be a smart thing to do, if the owner's manual recommends it. But, if it recommends 87, then just go with what the manual says.

On an Insight, which gets extremely good gas mileage, I think the $ difference by filling up the car with 87 vs. 91 octane would be very minimal.

I am sure that the knock-sensor would retard the timing accordingly if 87 octane is used under heavy load... so the onlly thing you would have to worry would be performance issues. But, I guess this topic has been covered in the Yahoo group.
 

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Delta Flyer said:
My CRX service manual suggested occasional fill-ups with Premium to prevent fuel injectors from clogging. They might have clogged once in the 12 years and 250,000 miles I had it.

They suggested premium to unclog injectors because back then only premium gas had the detergents to do it. Now regular gas has detergents.

Don't get caught up in this premium gas kick. The Insight was designed for regular gas. I've also done my own tests and tried to keep my same driving style during it. I saw no difference in mpg.
 

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Discussion Starter · #9 ·
I knew someone that used the old octane boost trick of putting mothballs in the tank. He burned up the engine. :(
 

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The trick with moth balls is 1 ball per 3 gallons of gas and only 100% naphthaline. I used it for years in high compression cars and never had a problem.
Louis
 

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People.. .. the lower grade gases contain mmt which ruins your spark plugs and cat converter.... I only put 94 octance from Sunoco where I live because its the only gas without mmt... I don't know that the rules are in all the US states but in most states mmt isn't allowed but I'd check on this.

the Honda manual is pretty clear on not using gas with mmt... disgusting nasty additive...
 

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.....No cause for alarm. Mr. Meow should make it clear he lives in Canada. MMT is an additive used to enhance octane levels. It is currently NOT sold at gas stations in the U.S.A. Anyway, octane is not the issue. Even with the relatively high compression engine, the Insight is designed to run fine with gas of 86 octane. Most regular unleaded in the U.S. is 87 octane. I use a good name brand like Chevron or Shell, because in my area (WA) they do not contain ethanol (grain alcohol). This is the same brand I use in my airplane. However, the Insight runs fine on up to 10 % ethanol, according to the section on oxygenates on page 250 of my 2003 owners manual. Billy.......
 

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Mr. Billy should be aware that not all states in the US follow the mmt rule each state has its own rules.. and should be checked... most US gas is not affected. However not all states.... The second thing to keep in mind a higher octane gas means cleaner burning better gas mileage..
 

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In the three years of driving my 5-speed Insight, I have never used Premium gas as it seems the car manual says 89 octane is just fine. If better acceleration is the main benefit of Premium gas, then it probably matters little on a hybrid. A "premium battery pack" might make more of a difference. :D Since the CVT Insight is keeping fairly constant rpms, premium gas would seem irrevalant.

My question is did anyone notice any difference when using Premium gas?

On a related topic, I have heard that sulphur content is not only an enviromental concern, but it can shorten the CO2 sensor's life. I'd love to know which gas brands are low-sulfur.

Right now I'm in the "if it ain't broke - don't fix it" but I could be pumping high-sulphur gas oblivious to the problems down the road...
It has 10:1 compression so being a technician myself high compression motors like all 10to1 compression should use 91 octane gives you more power and its better for the engine
 

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So why didn't Honda specify it? You don't need Premium unless it is pinging. I tried a tank of it and it ran worse. Premium burns slower.

You just can't apply "normal car" rules to an Insight. It's a different animal.

And you replied to an EIGHTEEN year old thread! That may be a record.

Sam
 

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Please include your Location in your Profile. Thank You.
 

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So why didn't Honda specify it? You don't need Premium unless it is pinging. I tried a tank of it and it ran worse. Premium burns slower.

You just can't apply "normal car" rules to an Insight. It's a different animal.

And you replied to an EIGHTEEN year old thread! That may be a record.

Sam

lolz wow 18 year year old thread bump indeed haha
 

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I've done premium vs. regular 'tests' a few times. I went premium for several tanks recently, and went back to regular again recently. My overall conclusions: One would be very hard pressed to tell the difference. I'd say there is a noticeable difference at the very ragged edge. I use my car at very very low RPM a lot, like near 1000, maxing-out electric usage. And, it seems premium smooths-out the performance in such situations. I can go just a little lower on engine speed, push things harder, running premium, without having the engine bog, rattle, vibrate, etc...

The thing is, though, using the car this way requires 'special' skill, because you have to exercise the throttle a lot more than you normally would, to invoke electric. It's not something most people would...know how to do, would even think of doing. On top of this, you have to have a highly functional IMA to make this work.

Point is, most driving circumstances would never require the 'extra smoothness' that premium seemingly can enable.

In the past I watched 'KNK' and 'SPK' (or something like that) parameters on the OBDIIC&C. Premium gas made a difference in the 'SPK' - spark advance, the ignition timing - values. I don't recall what the difference was though. Something like the frequency of retarded values dropped, if not the actual amount of retardation...

There's a few things like this that make it difficult to judge the difference in performance between premium and regular, in the Insight. You have systems, like the IMA and ignition timing/knock sensor, that will adjust. For example, not sure this is so, but in theory you'd have the IMA kicking in more with a lower grade gas, to make up for potential deficiencies in power running 'weaker' gas. Or, you'll have the knock sensor (again in theory) detecting knock sooner with regular vs. premium - so ignition timing is retarded more. Power should decrease, but you shouldn't hear knock. The power decrease would likely be so small you'd never notice anyway.

So, my report here, about the 'performance at the ragged edge', is about the best you can do, I think, barring actual, serious testing, collecting of data and such... It's easier to demarcate that junction, that threshold at which your engine starts to rumble and rattle and bog running one gas vs. another, than to just drive normally and ask, 'Is there a difference?' and conclude, 'I don't feel it'. It's a bit like reports about whether indexed plugs are worth it or not. Or maybe over-pressurized tires. Stuff can matter, but it matters at the margins...

Oh, also, the owner's manual describes regular 87 octane gas as being the minimum. It doesn't recommend 87. It simply says 87 or higher.

Overall, I see very little reason to run premium. Most of the time regular would be fine. It's fun to test the difference, especially if the price of gas is low. Or maybe you'll be doing some mountain driving, or driving in a hot climate - premium might be a better choice. Or maybe you want to max-out total performance, get every last bit of oomph out of the car, push it hard - premium might be better. ETC. But all other times regular seems perfectly up to the job...
 

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The main reason I go up in octane is because here in Iowa, higher octane is usually ethanol free.
 

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Oh, also, the owner's manual describes regular 87 octane gas as being the minimum. It doesn't recommend 87. It simply says 87 or higher.

Overall, I see very little reason to run premium. Most of the time regular would be fine. It's fun to test the difference, especially if the price of gas is low. Or maybe you'll be doing some mountain driving, or driving in a hot climate - premium might be a better choice.
Mountains = lower air pressure = less need for knock reduction. "Premium" should never be called that. It isn't any better, just has a different knock rating and burns less efficiently in lower compression engines.

Higher octane than necessary to prevent knock (we have no problems with that on these cars that I've ever heard of) = wasted fuel, wasted money, less power, less mpg, and more carbon buildup.
 
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