SI with 87 octane gas *Threads merged*

[mistuhyimstuh]

i drive an ex and i put shell vpower. the gas actually lasts longer and car feels smoother

[IotaMan]

put 87 and octane booster to bring it up to 91 octane...lol

[2007SilverCivicSI]

[clintdaniels]

i know that because the K20 has a higher compression ratio, it requires 91 or higher to minimize premature detonations of the fuel and air. The higher grade the gas is, the less the chance of premature detonations, which can result in costly internal damages in addition to performance loss

[clintdaniels]

i know that because the K20 has a higher compression ratio, it requires 91 or higher to minimize premature detonations of the fuel and air. The higher grade the gas is, the less the chance of premature detonations, which can result in costly internal damages in addition to performance loss

[Powered by Honda]

My mom owns a VQ35 Nissan engine that requires premium. For 4 years only put 87....but it runs fine and smooth. The cars have a ping sensor and the engine will retard the timing if you put 87 in so your fine as pie. mmmm gonna go get some.

[Itchytoe]

Originally Posted by IotaMan

put 87 and octane booster to bring it up to 91 octane...lol

You should read those labels. Each bottle only adds about 1 octane to the rating so you'd have to add four bottles of booster to a tank of regular unleaded to get to premium unleaded's octane rating. Even then you'd only have the same octane rating and not the added detergents and other addatives that you get with premium fuels. I think the four bottles of booster will make that tank more expensive than just getting premium.

[milestoneiii]

I see that gas has finally come back down in price. Also, the crisis in the southern region has been lifted. With premium falling below $2 who is worried about 87 anymore? I hope you all have a happy 91/93 octane time! I know I'm relieved!

No more fear of possibly using 87 for me. I skimmed by without having to dip in the low pool, lol.

[ponderosaTX]

I have my 07 Civic Sedan Owner's Manual in front of me. It says:

U.S. SI model only

Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. Use of a lower octane gasoline can cause occasional metallic knocking noises in the engine and result in decreased engine performance. Use of a gasoline with a pump octane number less than 87 can lead to engine damage.

--------

I have read several articles in magazines like Car & Driver where the staff measured the impact of using regular fuel in engines designed for premium. In every case (including a BMW M3), the performance loss (measured in peak horsepower) from using 87 octane gas was modest--on the order of 5-10%
and turbo-charged engines suffered from greater power losses than normally aspirated engines. The dynanometer curves comparing regular and premium gas for normally aspirated engines looked very similar.

I ran 87 octane in 1996 Integra GSR for many years without audible pinging or other incidents; I switched from premium to regular after gasoline prices went up and my Integra was out of warranty. I have regularly used 87 octane in 07 Civic SI sedan since the end of the break-in period and I cannot tell the difference between 87 octane and 93 octane either subjectively in observed performance (including pinging) or objectively in measured mileage. If were tracking my car, I would certainly use premium fuel but for everyday driving, 87 octane is fine.

Is pinging harmful? Some Acura TL owners report (on edmunds.com) that their cars audibly knock on premium gasoline but Acura (Honda) has refused to do anything beyond treating the car with BG 44K because pinging "is normal".

BTW, the testing standards for deposit control in "top tier" gasoline are the same for 87 octane as for 93 octane. See Top Tier Gasoline

On the wisdom of using 87 octane gas in a car designed for premium , "Click and Clack, the Tappet Brothers" appear to agree with me. See

Car Talk | Premium versus Regular

Do I think every car designed to run on premium fuel will run happily on reglar? No. In the early 90s, I drove a Porsche 944 Turbo S equipped with an Autothority Chip that significantly increased turbo boost. I was terrified when I was forced to use 89 octane gas for one fill-up.

[VanSin23]

I bought my 08 Si about 3 weeks ago and I did not even think abou the octane level I was puttin gin it. I came from Mazda 3 and used 87 octane all the time. I even used 87 in my 2001 jetta turbo. I never saw any advers affects in the VW at all. I did not see the premium gas only sticker on my SI until I filled up the first time with 87 and it was too late by then. I did not Vtec as much with the worry of damage and I got 31 mpg out of that tank. Since then I have only ran 93 octane and I am only gettign 28-29 mpg. I drive 75% hwy miles. My buddy had a 3.5 TL and has only used 87 since brand new with no probs. His service guy told him as long as he did not hear spark knock, to not worry about it. Since gas has gone back down, I am not worried about using 93. I don't keep cars long so if I had to run 87 and it hurts engine life, it would not be my prob anyway. LOL

[Doeboy211]

I cant believe theres 7 pages on this. Obviously from what the owners manual says and from what reputable members have said, use the better gas. If you dont want to, then your engine gets ****ed up. Doesnt seem like rocket science to me.

[EchoHawk7]

Originally Posted by Doeboy211

I cant believe theres 7 pages on this. Obviously from what the owners manual says and from what reputable members have said, use the better gas. If you dont want to, then your engine gets ****ed up. Doesnt seem like rocket science to me.

ahmen. now lets close this thread

[buurner]

It states 91 or higher for a reason.

[MILOT]

Hi
i've been told that I should put regular gas in winter instead of 91+ octane, because the ratio fuel/air isnt the same because of the air temp.
whats your opinion???
thanks
08 Civic SI

[av911]

Just put 91, there's nothing to think about here.

[xrs54]

^Yea that, not worth risking hurting the motor in the long run.

[Firestrife]

Who the hell told you that?
In the winter the air is more denser, so there technically is more air entering the engine than in the summer. So going by whoever told you's logic you should up the octane.

But stick with 93 because the fuel in the winter is also different depending on where you live, theses changes can have a major impact.

[sh33t_0f_p4p3r]

it was 37* outside just now, and im in florida

[JoeFromPA]

Ugh.....your car will sense the atmospheric conditions of air entering the engine and adjust accordingly. It will not adjust automatically to a lower octane fuel until it starts to sense knock (uncontrolled detonation in your cylinders).

Use 91+ octane and don't go below it unless you are forced.

Joe

[ryker]

Modern cars have intake air temp sensors (IAT). This is used to adjust A/F rations. 2nd many modern cars have a wide band .02 sensor that will also measure and control A/F rations.


The only benifit to cold weather is the cold air helps to cool down the combustion chamber so you might be able to use low octance fuel on cold days.