What grade of gas? All gas questions answered! **Merged all gas threads**

[pks17]

The non SI civics ping for about .5 of a second at certain times when the load is high or if your in the wrong gear.
Using High octane fuel solves this, and im almost 100% sure it will have higher hp ratings then if using regular.
The R18 is rated at 10.5:1 compression.

BUT i use regular because its recommended by honda and gas is so expensive now.

[ryker]

Originally Posted by pks17

' and im almost 100% sure it will have higher hp ratings then if using regular.
The R18 is rated at 10.5:1 compression.
.

Nope. No extra HP from high octane fuel. However IF its really hot and your running the car hard on cheap gas the engine might ping and the ECU correct the timing to adjust for the ping thus a loss of HP. Higher octane fuel would prevent the loss but not increase the HP.

I only purchase high octane if its really hot or I am carrying a full load in my car. r18 owner. If I owned the Si I'd only run cheap gas during the colder winter months. Any warm weather would be high octane.

[cjackson2435]

Originally Posted by ryker

Nope. No extra HP from high octane fuel. However IF its really hot and your running the car hard on cheap gas the engine might ping and the ECU correct the timing to adjust for the ping thus a loss of HP. Higher octane fuel would prevent the loss but not increase the HP.

I only purchase high octane if its really hot or I am carrying a full load in my car. r18 owner. If I owned the Si I'd only run cheap gas during the colder winter months. Any warm weather would be high octane.

ok no offense but thats not true at all, you have to run premium in Si's at all times because of the way it is tuned

[DarrenG]

Ok so I attempted to to skim through this thread but between all the flaming and all the BS posts I don't have the patience to read anymore.

So I'm probably repeating a question thats been covered numerous times, but I have an 07 Si with a touch over 34k miles (yea I love to drive) Yokohama Avid W4s tires at ~36psi, Injen CAI. 70/30 City/Hwy and Im usually shifting in the 4-5k range. I don't mind getting on the car at any time and since I bought it (1/26/07) it has been taking Sunoco Premium fuel from the same station with the exception of a handful of times (but still always Sunoco). I average roughly 250-270miles to the tank. Are these normal-ish numbers? Ive really only noticed a drop in about 1 mpg with the intake and of course my mileage dips a little once the maintenance-minder hits about 30% Oil.

[Agnt004]

Originally Posted by pks17

The non SI civics ping for about .5 of a second at certain times when the load is high or if your in the wrong gear.
Using High octane fuel solves this, and im almost 100% sure it will have higher hp ratings then if using regular.
The R18 is rated at 10.5:1 compression.

BUT i use regular because its recommended by honda and gas is so expensive now.

The 10.5:1 compression ratio is not the full story. It is not all gas and air mixture being compressed. Some of the exhaust gases are routed back into the intake manifold, so even though the compression is high, it is only partially filled with fresh air and fuel, and thus the temps are kept low enough to prevent pinging.

Exhaust gas recirculation - Wikipedia, the free encyclopedia

For those of you that are wondering, it is the little black cylinder looking thing in the bottom right of the picture, below the spark plug: http://upload.wikimedia.org/wikipedi...18A_Engine.JPG

[cjackson2435]

Originally Posted by DarrenG

Ok so I attempted to to skim through this thread but between all the flaming and all the BS posts I don't have the patience to read anymore.

So I'm probably repeating a question thats been covered numerous times, but I have an 07 Si with a touch over 34k miles (yea I love to drive) Yokohama Avid W4s tires at ~36psi, Injen CAI. 70/30 City/Hwy and Im usually shifting in the 4-5k range. I don't mind getting on the car at any time and since I bought it (1/26/07) it has been taking Sunoco Premium fuel from the same station with the exception of a handful of times (but still always Sunoco). I average roughly 250-270miles to the tank. Are these normal-ish numbers? Ive really only noticed a drop in about 1 mpg with the intake and of course my mileage dips a little once the maintenance-minder hits about 30% Oil.

those numbers are a bit low, i go to great stops getting premium and i can go about 320 miles to a tank but i think you should atleast be able to do 290 with shifting that high

[ryker]

Originally Posted by cjackson2435

ok no offense but thats not true at all, you have to run premium in Si's at all times because of the way it is tuned

You need high octane fuel because of cylinder head temps are high due to the high compression design.

In colder weather below 50 the cylinder head temps should be low enough to combat pinging.

[fryrice]

currently traded my 95 dx civic sedan for a 08 si sedan and i luv the car it's like a HUGE step up from the old dx model.

Now Im sure this has probably been answered but i dont feel like going through 44 pages of this, I know that the si require 91 octane, could i feel up one time 91 and one time 89? cuz here in MA it goes 87, 89, 91. So would can i mix the mid grade and the higher grade 89 and 91?

Thx guys i love my si

[Whocares05050]

Originally Posted by fryrice

currently traded my 95 dx civic sedan for a 08 si sedan and i luv the car it's like a HUGE step up from the old dx model.

Now Im sure this has probably been answered but i dont feel like going through 44 pages of this, I know that the si require 91 octane, could i feel up one time 91 and one time 89? cuz here in MA it goes 87, 89, 91. So would can i mix the mid grade and the higher grade 89 and 91?

Thx guys i love my si

Why? to save 1.00 dollar? seriously? Dont do it...

[Agnt004]

Originally Posted by fryrice

currently traded my 95 dx civic sedan for a 08 si sedan and i luv the car it's like a HUGE step up from the old dx model.

Now Im sure this has probably been answered but i dont feel like going through 44 pages of this, I know that the si require 91 octane, could i feel up one time 91 and one time 89? cuz here in MA it goes 87, 89, 91. So would can i mix the mid grade and the higher grade 89 and 91?

Thx guys i love my si

Originally Posted by Whocares05050

Why? to save 1.00 dollar? seriously? Dont do it...

Premium is REQUIRED and only costs a little bit more per gallon. If you can't find the extra buck or two to fill up your car, then drive slower and hypermile for half the tank to make up the difference. Read the thread, good info in here....

[Rufio]

I just hit 32mpg! im so excited. but anyway STUPID question... i haven't figured out if i have one bar left on my gas light does that turn off how far can i push it?

[Agnt004]

Originally Posted by Rufio

I just hit 32mpg! im so excited. but anyway STUPID question... i haven't figured out if i have one bar left on my gas light does that turn off how far can i push it?

You have about 1.3 gallons left in the SI when the last bar goes out.

[bsbabcock]

Ok.. Good merged thread and I'm learning..
Problem: I'd love to put 93 (the std premium around here) in my roll (08 Si Sedan).. NONE and I mean NO PREMIUM available here. Rumors of one station but it's in the next town. That's how bad it is today. Tomorrow may be different. Cops and fights are happening at the tanks.. Time to go out into the desert and build a thunderdome and process pig poop and put master blaster in charge to keep the peace. hehehe :)

But anyway...
Currently I'm on about 1/2 tank of 89 mid-grade that was available last week at the pump. This week.. Nuthin' but 87. Beginning to get concerned. Found this thread searching for "knock sensor" if that tells you.

I'm babying it.. eeeeeasy on the throttle, hyper-ing in neutral as much as possible (as I always try to do and hopefully this is not harmful to other.. transmission etc).. Shifts no higher than 4500-5kish. NO heavy accelaration. I may end up wishing it was an EX after all. :)

[agr5]

Originally Posted by DarrenG

Ok so I attempted to to skim through this thread but between all the flaming and all the BS posts I don't have the patience to read anymore.

So I'm probably repeating a question thats been covered numerous times, but I have an 07 Si with a touch over 34k miles (yea I love to drive) Yokohama Avid W4s tires at ~36psi, Injen CAI. 70/30 City/Hwy and Im usually shifting in the 4-5k range. I don't mind getting on the car at any time and since I bought it (1/26/07) it has been taking Sunoco Premium fuel from the same station with the exception of a handful of times (but still always Sunoco). I average roughly 250-270miles to the tank. Are these normal-ish numbers? Ive really only noticed a drop in about 1 mpg with the intake and of course my mileage dips a little once the maintenance-minder hits about 30% Oil.

I get 340-370 in my 08 FA5, which is about 30-31 miles/gal

[Agnt004]

Originally Posted by bsbabcock

Ok.. Good merged thread and I'm learning..
Problem: I'd love to put 93 (the std premium around here) in my roll (08 Si Sedan).. NONE and I mean NO PREMIUM available here. Rumors of one station but it's in the next town. That's how bad it is today. Tomorrow may be different. Cops and fights are happening at the tanks.. Time to go out into the desert and build a thunderdome and process pig poop and put master blaster in charge to keep the peace. hehehe :)

But anyway...
Currently I'm on about 1/2 tank of 89 mid-grade that was available last week at the pump. This week.. Nuthin' but 87. Beginning to get concerned. Found this thread searching for "knock sensor" if that tells you.

I'm babying it.. eeeeeasy on the throttle, hyper-ing in neutral as much as possible (as I always try to do and hopefully this is not harmful to other.. transmission etc).. Shifts no higher than 4500-5kish. NO heavy accelaration. I may end up wishing it was an EX after all. :)

Maybe look into adding some octane booster to your tank? Should work temporarily, and I don't think it could hurt.

[bsbabcock]

In this thread I asked the questions about which or what booster is safe or recommended or if it's cool to use any at all in an 08 Si. Pls reply there for feedback from you pro's or those that knows. :)

[nachobel]

Originally Posted by DarrenG

Ok so I attempted to to skim through this thread but between all the flaming and all the BS posts I don't have the patience to read anymore.

So I'm probably repeating a question thats been covered numerous times, but I have an 07 Si with a touch over 34k miles (yea I love to drive) Yokohama Avid W4s tires at ~36psi, Injen CAI. 70/30 City/Hwy and Im usually shifting in the 4-5k range. I don't mind getting on the car at any time and since I bought it (1/26/07) it has been taking Sunoco Premium fuel from the same station with the exception of a handful of times (but still always Sunoco). I average roughly 250-270miles to the tank. Are these normal-ish numbers? Ive really only noticed a drop in about 1 mpg with the intake and of course my mileage dips a little once the maintenance-minder hits about 30% Oil.

I get about the same. Seems lower than what I've heard from most people, but I drive my car.

[Cooter007]

I'm with you... My area is totally out of 89 and 92. 87 only.

[fryrice]

so i guess its okay to pump 89 or 87 on the si???

[bsbabcock]

87 in an Si ... Three rules:

octane booster.. use it.
gas pedal.. stay out of it.
prayer.. say it.

.. about sums up what I've determined from reading all these pages and opinions.